Kenneth I Forster

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• Forster, K. I. (2012). A parallel activation model with a sequential twist. In Visual Word Recognition.

Journals/Publications

• Adelman, J. S., Johnson, R. L., McCormick, S. F., McKague, M., Kinoshita, S., Bowers, J. S., Perry, J. R., Lupker, S. J., Forster, K. I., Cortese, M. J., Scaltritti, M., Aschenbrenner, A. J., Coane, J. H., White, L., Yap, M. J., Davis, C., Kim, J., & Davis, C. J. (2014). A behavioral database for masked form priming. Behavior Research Methods, 1-16.
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  Abstract: Reading involves a process of matching an orthographic input with stored representations in lexical memory. The masked priming paradigm has become a standard tool for investigating this process. Use of existing results from this paradigm can be limited by the precision of the data and the need for cross-experiment comparisons that lack normal experimental controls. Here, we present a single, large, high-precision, multicondition experiment to address these problems. Over 1,000 participants from 14 sites responded to 840 trials involving 28 different types of orthographically related primes (e.g., castfe-CASTLE) in a lexical decision task, as well as completing measures of spelling and vocabulary. The data were indeed highly sensitive to differences between conditions: After correction for multiple comparisons, prime type condition differences of 2.90 ms and above reached significance at the 5% level. This article presents the method of data collection and preliminary findings from these data, which included replications of the most widely agreed-upon differences between prime types, further evidence for systematic individual differences in susceptibility to priming, and new evidence regarding lexical properties associated with a target word's susceptibility to priming. These analyses will form a basis for the use of these data in quantitative model fitting and evaluation and for future exploration of these data that will inform and motivate new experiments. © 2014 Psychonomic Society, Inc.
• Forster, K. I. (2013). How many words can we read at once? More intervenor effects in masked priming. Journal of Memory and Language, 69(4), 563-573.
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  Abstract: It is argued that the existence of masked translation priming from L1 to L2 with a 50. ms prime implies that processing of the prime must continue well after it has been replaced by the target, since it is estimated that the meaning of a word is not established until at least 120. ms after stimulus onset. This fact implies that the lexical processor must be equipped to handle two words simultaneously. However when a masked word intervenes between the prime and the target, three words must be processed simultaneously. Under these conditions, form priming is eliminated altogether, and identity priming is reduced, suggesting that the capacity of the lexical processor does not extend to three words. Four experiments are reported showing that this disruption of priming only occurs when the intervenor triggers lexical processing. It is argued that the differential effect of the intervenor on identity and form priming can be explained on the assumption that priming takes place at the level of form, and at the level of meaning. As support for this interpretation, it is shown that an identity prime is capable of generating a congruence effect in a semantic categorization experiment despite the presence of a masked intervenor. © 2013 Elsevier Inc.
• Forster, K., & Forster, K. I. (0). Category size effects revisited: frequency and masked priming effects in semantic categorization. Brain and language, 90(1-3).
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  Previous work indicates that semantic categorization decisions for nonexemplars (e.g., deciding that TURBAN is not an animal name) are faster for high-frequency words than low-frequency words. However, there is evidence that this result might depend on category size. When narrow categories are used (e.g., Months, Numbers), there is no frequency effect for nonexemplars. This result is confirmed, and is explained in terms of a category search model, which allows a "No" decision to be generated without access to the lexical entry for the target word. This explains the absence of a frequency effect, but not the presence of a strong masked repetition priming effect, which is assumed to have a lexical source. It is shown that this effect may not be lexical, since nonwords also show similar priming. Both of these priming effects disappear when a larger category is used. This pattern of results is explained on the assumption that category search is only possible with small categories, and that tentative category decisions are generated for the unconsciously perceived prime, which leads to a marked response congruence effect.
• Qiao, X., & Forster, K. I. (2013). Novel word lexicalization and the prime lexicality effect. Journal of Experimental Psychology: Learning Memory and Cognition, 39(4), 1064-1074.
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  PMID: 23088548;Abstract: This study investigates how newly learned words are integrated into the first-language lexicon using masked priming. Two lexical decision experiments are reported, with the aim of establishing whether newly learned words behave like real words in a masked form priming experiment. If they do, they should show a prime lexicality effect (PLE), in which less priming is obtained due to form similarity when the prime is a word. In the first experiment, subjects were taught the meanings of novel words that were neighbors of real words, but no PLE was observed; that is, equally strong form priming was obtained for both trained and untrained novel primes. In the second experiment, 4 training sessions were spread over 4 weeks, and under these conditions, a clear PLE was obtained in the final session. It is concluded that lexicalization requires multiple training sessions. Possible explanations of the PLE are discussed. © 2013 American Psychological Association.
• Witzel, J. D., Cornelius, S., Witzel, N., Forster, K. I., & Forster, J. C. (2013). Testing the viability of webDMDX for masked priming experiments. The Mental Lexicon, 8, 421-449.
• Qiao, X., Shen, L., & Forster, K. (2012). Relative clause processing in Mandarin: Evidence from the maze task. Language and Cognitive Processes, 27(4), 611-630.
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  Abstract: Contradictory results have been found in Chinese as to whether subject relative clauses are easier to process than object relative clauses. One major disagreement concerns the region where the difficulty arises. In this study. "maze" task was used to localise processing difficulty by requiring participants to mak. choice between two alternatives at every single position of the sentence. The results confirmed that object relatives are indeed easier than corresponding subject relatives in the relative clause region, although this difference is reversed in the subsequent relative marker region. No difference was found in the head noun position. It is argued that these results ar. function of the fact that the task forces participants to adop. strict incremental processing mode, whereas self-paced reading allows more freedom. Implications for experimental techniques for studying sentence processing are discussed. © 2012 Copyright Psychology Press Ltd.
• Witzel, J., & Forster, K. (2012). Lexical co-occurrence statistics and ambiguity resolution. Language and Cognitive Processes, 29, 158-185.
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  Abstract: This study investigates the possible influence of lexical co-occurrence on lexical ambiguity resolution in sentence contexts. Lexical co-occurrence refers to similarity between the co-occurrence vectors of words, such that if two words have similar profiles of occurrence with other words, they are said to have a strong co-occurrence relationship. The present study examines whether lexical ambiguity resolution can be biased by the prior presentation of a word that shares a strong co-occurrence relationship with an ambiguous word under one of its meanings, despite the absence of plausibility support. Two "maze" word-by-word reading experiments examined highly implausible/anomalous sentences with balanced homographs. In sentences in which the ambiguous word (e.g., bat) was preceded by a biasing word with which it shares a strong co-occurrence relationship (e.g., umpire), (1) response times (RTs) to the ambiguous word were facilitated, and (2) garden-path effects were found when subsequent (disambiguating) information was incongruent with the biased meaning (e.g., The umpire tried to swallow the bat but its wings got stuck in his throat). Additional experiments showed that these biasing effects resist explanation in terms of a passive process of spreading activation. Furthermore, an eye-tracking experiment revealed a pattern of results comparable to that of the maze task experiments, indicating that these effects are not artefacts of the maze procedure. These results are taken to support a heuristic for lexical ambiguity resolution that is driven by relatively low-level intralexical connections based on lexical co-occurrence. © 2012 Copyright Taylor and Francis Group, LLC.
• Witzel, N. O., & Forster, K. I. (2012). How L2 words are stored: The episodic L2 hypothesis. Journal of Experimental Psychology: Learning Memory and Cognition, 38(6), 1608-1621.
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  PMID: 22545605;Abstract: This article reports findings from 3 experiments examining whether 2nd language (L2) words are represented in episodic memory, as originally proposed by Jiang and Forster (2001). Experiment 1 was a direct replication of Jiang and Forster, testing highly proficient Chinese-English bilinguals. Masked translation priming was obtained in an episodic recognition task from L2 to the 1st language (L1) for studied "old" L1 targets but not for unstudied "new" targets. This experiment also confirmed the translation asymmetry generally found in lexical decision tasks, namely, priming in the L1-L2 direction but not in the L2-L1 direction. Experiment 2 showed that recently learned words in an unfamiliar language (therefore, words that are obviously represented episodically) could also prime their L1 translations in an episodic recognition task but not in a lexical decision task. Finally, in Experiment 3, masked repetition priming was used with an episodic recognition memory task. For native speakers of English, repetition (L1-L1) priming is obtained only for old words, because there is no episodic representation for new words. However, Chinese-English bilinguals tested with the same items showed repetition (L2-L2) priming for both old and new words, indicating that the new L2 words were represented episodically as well. Overall, the results from these 3 experiments support the hypothesis that L2 words are represented in episodic memory. Finally, the mechanisms behind why L2-L1 translation priming can be obtained in episodic recognition and not in lexical decision are discussed. © 2012 American Psychological Association.
• Witzel, N., Witzel, J., & Forster, K. (2012). Comparisons of Online Reading Paradigms: Eye Tracking, Moving-Window, and Maze. Journal of Psycholinguistic Research, 41(2), 105-128.
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  PMID: 22002037;Abstract: This study compares four methodologies used to examine online sentence processing during reading. Specifically, self-paced, non-cumulative, moving-window reading (Just et al. in J Exp Psychol Gen 111:228-238, 1982), eye tracking (see e. g., Rayner in Q J Exp Psychol 62:1457-1506, 2009), and two versions of the maze task (Forster et al. in Behav Res Methods 41:163-171, 2009)-the lexicality maze and the grammaticality maze-were used to investigate the processing of sentences containing temporary structural ambiguities. Of particular interest were (i) whether each task was capable of revealing processing differences on these sentences and (ii) whether these effects were indicated precisely at the predicted word/region. Although there was considerable overlap in the general pattern of results from the four tasks, there were also clear differences among them in terms of the strength and timing of the observed effects. In particular, excepting sentences that tap into clause-closure commitments, both maze task versions provided robust, "localized" indications of incremental sentence processing difficulty relative to self-paced reading and eye tracking. © 2011 Springer Science+Business Media, LLC.
• Forster, K., Witzel, N., Qiao, X., & Forster, K. I. (2011). Transposed letter priming with horizontal and vertical text in Japanese and English readers. Journal of experimental psychology. Human perception and performance, 37(3).
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  It is well established that in masked priming, a target word (e.g., JUDGE) is primed more effectively by a transposed letter (TL) prime (e.g., jugde) than by an orthographic control prime (e.g., junpe). This is inconsistent with the slot coding schemes used in many models of visual word recognition. Several alternative coding schemes have been proposed in which special bigram detectors for frequently occurring nonadjacent letter combinations are developed as a product of perceptual learning. In order to examine this perceptual learning hypothesis, we asked whether bigram detectors are defined in terms of visuospatial coordinates. Japanese-English bilinguals who were equally familiar with horizontal and vertical text in Japanese demonstrated strong TL priming in both orientations when reading Japanese words, but, when reading English words, the evidence for vertical TL priming was not as strong. However, native English speakers showed a clear TL priming effect with vertically presented English words despite minimal exposure to vertical text, which is not consistent with a perceptual learning account. It is proposed instead that the initial letter array is transformed into an abstract ordinal code (first to last) regardless of orientation and that the speed with which this transformation is carried out depends on the familiarity of the script.
• Kinoshita, S., Mozer, M. C., & Forster, K. I. (2011). Dynamic adaptation to history of trial difficulty explains the effect of congruency proportion on masked priming. Journal of Experimental Psychology: General, 140(4), 622-636.
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  PMID: 21707205;Abstract: In reaction time research, there has been an increasing appreciation that response-initiation processes are sensitive to recent experience and, in particular, the difficulty of previous trials. From this perspective, the authors propose an explanation for a perplexing property of masked priming: Although primes are not consciously identified, facilitation of target processing by a related prime is magnified in a block containing a high proportion of related primes and a low proportion of unrelated primes relative to a block containing the opposite mix (Bodner & Masson, 2001). In the present study, this phenomenon is explored with a parity (even/odd) decision task in which a prime (e.g., 2) precedes a target that can be either congruent (e.g., 4) or incongruent (e.g., 3). It is shown that the effect of congruence proportion with masked primes cannot be explained in terms of the blockwise prime-target contingency. Specifically, with masked primes, there is no congruency disadvantage in a block containing a high proportion of incongruent primes, but there is a congruency advantage when the block contains an equal proportion of congruent and incongruent primes. In qualitative contrast, visible primes are sensitive to the blockwise prime-target contingency. The authors explain the relatedness proportion effect found with masked primes in terms of a model according to which response-initiation processes adapt to the statistical structure of the environment, specifically the difficulty of recent trials. This account is supported with an analysis at the level of individual trials using the linear mixed effects model. © 2011 American Psychological Association.
• Witzel, N., Qiao, X., & Forster, K. (2011). Transposed letter priming with horizontal and vertical text in Japanese and English readers. Journal of Experimental Psychology: Human Perception and Performance, 37(3), 914-920.
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  PMID: 21639675;Abstract: It is well established that in masked priming, a target word (e.g., JUDGE) is primed more effectively by a transposed letter (TL) prime (e.g., jugde) than by an orthographic control prime (e.g., junpe). This is inconsistent with the slot coding schemes used in many models of visual word recognition. Several alternative coding schemes have been proposed in which special bigram detectors for frequently occurring nonadjacent letter combinations are developed as a product of perceptual learning. In order to examine this perceptual learning hypothesis, we asked whether bigram detectors are defined in terms of visuospatial coordinates. Japanese-English bilinguals who were equally familiar with horizontal and vertical text in Japanese demonstrated strong TL priming in both orientations when reading Japanese words, but, when reading English words, the evidence for vertical TL priming was not as strong. However, native English speakers showed a clear TL priming effect with vertically presented English words despite minimal exposure to vertical text, which is not consistent with a perceptual learning account. It is proposed instead that the initial letter array is transformed into an abstract ordinal code (first to last) regardless of orientation and that the speed with which this transformation is carried out depends on the familiarity of the script. © 2011 American Psychological Association.
• Forster, K. (2010). Using a maze task to track lexical and sentence processing. Mental Lexicon, 5(3), 347-357.
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  Abstract: A word maze consists of a sequence of frames, each containing two alternatives. Subjects are required to select one of those alternatives according to some criterion defined by the experimenter. Tis simple technique can be used to investigate a wide range of issues. For example, if one alternative is a word and the other is a nonword, the subject may be required to press a key to indicate where the word is. Tis provides an interesting variant of the lexical decision task, since the dificulty of the lexical discrimination can be manipulated on a trial-by-trial basis by varying the properties of the nonword alternative. On the other hand, a version of a self-paced reading task is created if each successive frame contains a word that can continue a sentence, and the subject is required to identify which word that is. Once again, by manipulating the properties of the incorrect alternative one may be able to control the mode of processing adopted by the subject. Although this is a highly artificial form of reading, it does allow one to study the sentence processing under more tightly controlled conditions. © John Benjamins Publishing Company.
• Wang, X., & Forster, K. I. (2010). Masked translation priming with semantic categorization: Testing the Sense Model. Bilingualism, 13(3), 327-340.
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  Abstract: Four experiments are reported which were designed to test hypotheses concerning the asymmetry of masked translation priming. Experiment 1 confirmed the presence of L2-L1 priming with a semantic categorization task and demonstrated that this effect was restricted to exemplars. Experiment 2 showed that the translation priming effect was not due to response congruence. Experiment 3 replicated this finding, and demonstrated that the 150 ms backward mask that had been used in earlier translation priming experiments was not essential. Finally, it was demonstrated in Experiment 4 that L2-L1 priming was not obtained for an ad hoc category, indicating that priming was not obtained merely because the task required semantic interpretation. These results provide further support for the Sense Model proposed by Finkbeiner et al. (2004). © Cambridge University Press 2010.
• Forster, K. I. (2009). The intervenor effect in masked priming: How does masked priming survive across an intervening word?. Journal of Memory and Language, 60(1), 36-49.
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  Abstract: Four masked priming experiments are reported investigating the effect of inserting an unrelated word between the masked prime and the target. When the intervening word is visible, identity priming is reduced to the level of one-letter-different form priming, but form priming is largely unaffected. However, when the intervening word is itself masked, form priming is eliminated altogether, while identity priming remains at the level observed with a visible intervenor. Normal priming effects are obtained when the order of the masked prime and the intervenor is reversed. It is suggested that identity priming consists of two effects, one that depends on the prime being adjacent to the target (a semantic effect), and one that is independent of adjacency (a form effect). © 2008.
• Forster, K. I., Guerrera, C., & Elliot, L. (2009). The maze task: Measuring forced incremental sentence processing time. Behavior Research Methods, 41(1), 163-171.
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  PMID: 19182136;Abstract: The maze task is an online measure of sentence processing time that provides an alternative to the standard moving window version of self-paced reading. Rather than each word of the sentence being presented in succession, two words are presented at the same time, and the participant must choose which word is a grammatical continuation of the sentence. This procedure forces the reader into an incremental mode of processing in which each word must be fully integrated with the preceding context before the next word can be considered. Previous research with this technique has not considered whether it is sufficiently sensitive to syntactic complexity effects or to garden path effects. Four experiments are reported demonstrating that reliable differences in processing time for subject relatives and object relatives can be obtained, and that this technique generates garden path effects that correspond closely with the data from eyetracking experiments, but without the spillover effects that are sometimes obtained with eyetracking. It is also shown that the task is sensitive to word frequency effects, producing estimates well in excess of those found with eyetracking. © 2009 The Psychonomic Society, Inc.
• Qiao, X., Forster, K., & Witzel, N. (2009). Is banara really a word?. Cognition, 113(2), 254-257.
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  PMID: 19717145;Abstract: Bowers, Davis, and Hanley (Bowers, J. S., Davis, C. J., & Hanley, D. A. (2005). Interfering neighbours: The impact of novel word learning on the identification of visually similar words. Cognition, 97(3), B45-B54) reported that if participants were trained to type nonwords such as banara, subsequent semantic categorization responses to similar words such as banana were delayed. This was taken as direct experimental support for a process of lexical competition during word recognition. This interpretation assumes that banara has been lexicalized, which predicts that masked form priming for items such as banara-banana should be reduced or eliminated. An experiment is reported showing that the trained novel words produced the same amount of priming as untrained nonwords on both the first and the second day of training, suggesting that the interference observed by Bowers et al was not due to word-on-word competition. © 2009 Elsevier B.V. All rights reserved.
• Davis, C., Kim, J., & Forster, K. I. (2008). Being forward not backward: Lexical limits to masked priming. Cognition, 107(2), 673-684.
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  PMID: 17765887;Abstract: This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information. © 2007 Elsevier B.V. All rights reserved.
• Finkbeiner, M., & Forster, K. I. (2008). Attention, intention and domain-specific processing. Trends in Cognitive Sciences, 12(2), 59-64.
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  PMID: 18178512;Abstract: Many researchers use subliminal priming to investigate domain-specific processing mechanisms, which have classically been defined in terms of their autonomy from other cognitive systems. Surprisingly, recent research has demonstrated that nonconsciously elicited cognitive processes are not independent of attention. By extension, these findings have been used to call into question the autonomy of domain-specific processing mechanisms. By contrast, we argue that the demonstrated modulation of nonconscious cognitive processes by attention occurs at a predomain-specific stage of processing. Thus, although we agree that attention might be a prerequisite of nonconscious processes, we suggest that there is no reason to think that higher-level cognitive systems directly modulate domain-specific processes. © 2007 Elsevier Ltd. All rights reserved.
• Forster, K. I. (2008). What is F2 Good For?. Journal of Memory and Language, 59(4), 389-.
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  Abstract: It is commonly assumed that a significant item analysis (F2) provides an assurance that the treatment effect is generalizable to the population of items from which the items were drawn, which in turn implies that the effect is reasonably general across items. The latter implication is shown to be false, and it is argued that a new test of generality rather than generalizability is required. Comments from a number of prominent researchers in the field are provided on a separate website. © 2008 Elsevier Inc. All rights reserved.
• Forster, K., & Masson, M. (2008). Introduction: Emerging data analysis. Journal of Memory and Language, 59(4), 387-388.
• Guerrera, C., & Forster, K. (2008). Masked form priming with extreme transposition. Language and Cognitive Processes, 23(1), 117-142.
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  Abstract: Using eight-letter words, masked form-priming is examined with more extreme versions of transposed primes than are normally considered. Strong priming effects are observed when as few as two out of eight letters are correctly positioned within the prime, indicating that the word recognition system is surprisingly flexible with regard to letter position. Three prominent models of letter position coding are considered in light of the observed data. The comparison between models focuses on the assumptions and mechanisms within each. Strengths and weaknesses are identified for all approaches. Some evidence is found in support of differential weighting of letter positions, although the more specific question of whether it is exterior or initial letters that are most crucial to word recognition remains unresolved.
• Kinoshita, S., Forster, K. I., & Mozer, M. C. (2008). Unconscious cognition isn't that smart: Modulation of masked repetition priming effect in the word naming task. Cognition, 107(2), 623-649.
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  PMID: 18206138;Abstract: Masked repetition primes produce greater facilitation in naming in a block containing a high, rather than low proportion of repetition trials. [Bodner, G. E., & Masson, M. E. J. (2004). Beyond binary judgments: Prime-validity modulates masked repetition priming in the naming task. Memory & Cognition, 32, 1-11] suggested this phenomenon reflects a strategic shift in the use of masked prime as a function of its validity. We propose an alternative explanation based on the Adaptation to the statistics of the environment (ASE) framework, which suggests the proportion effect reflects adaptation of response-initiation processes to recent trial difficulty. Consistent with ASE's prediction, (1) stimuli that produce the proportion effect also produced an "asymmetric blocking effect", showing a smaller fall in response latencies of hard items than the rise of easy items when the two item types were intermixed relative to pure blocks comprised of only one item type, and (2) manipulation of prime validity was neither necessary nor sufficient to modulate the size of masked-priming effect. © 2007 Elsevier B.V. All rights reserved.
• Murray, W. S., & Forster, K. I. (2008). Postscript: The Rank Hypothesis and Lexical Decision. Psychological Review, 115(1), 251-252.
• Murray, W. S., & Forster, K. I. (2008). The Rank Hypothesis and Lexical Decision: A Reply to Adelman and Brown (2008). Psychological Review, 115(1), 240-251.
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  PMID: 18211198;Abstract: J. S. Adelman and G. D. A. Brown (2008) provided an extensive analysis of the form of word frequency and contextual diversity effects on lexical decision time. In this reply, the current authors suggest that their analysis provides a valuable tool for the evaluation of models of lexical access and that the results they report are broadly supportive of the rank hypothesis suggested by W. S. Murray and K. I. Forster (2004)-more supportive, in fact, than the originally reported data. However, Adelman and Brown's conclusion that the results of these analyses can be taken as evidence against rank (and thereby serial models of lexical access) and for instance models is rejected. It is shown that at least one instance model makes the wrong predictions and that Adelman and Brown's conclusions rest on the assumption that lexical decision time presents a pure measure of the time involved in lexical access. Results from eye tracking are reported, which also support a rank account, as do results from analyses that show that a log frequency account is clearly inadequate. Finally, it is demonstrated that, unlike other models, the rank account continues to make accurate predictions regarding the form of both reaction time and error rate effects. © 2008 American Psychological Association.
• Castles, A., Davis, C., Cavalot, P., & Forster, K. (2007). Tracking the acquisition of orthographic skills in developing readers: Masked priming effects. Journal of Experimental Child Psychology, 97(3), 165-182.
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  PMID: 17408686;Abstract: A masked priming procedure was used to explore developmental changes in the tuning of lexical word recognition processes. Lexical tuning was assessed by examining the degree of masked form priming and used two different types of prime-target lexical similarity: one letter different (e.g., rlay → PLAY) and transposed letters (e.g., lpay → PLAY). The performance of skilled adult readers was compared with that of developing readers in Grade 3. The same children were then tested again two years later, when they were in Grade 5. The skilled adult readers showed no form priming, indicating that their recognition mechanisms for these items had become finely tuned. In contrast, the Grade 3 readers showed substantial form priming effects for both measures of lexical similarity. When retested in Grade 5, the developing readers no longer showed significant one letter different priming, but transposed letter priming remained. In general, these results provide evidence for a transition from more broadly tuned to more finely tuned lexical recognition mechanisms and are interpreted in the context of models of word recognition. © 2007 Elsevier Inc. All rights reserved.
• Frost, R., Kugler, T., Deutsch, A., & Forster, K. I. (2005). Orthographic structure versus morphological structure: Principles of lexical organization in a given language. Journal of Experimental Psychology: Learning Memory and Cognition, 31(6), 1293-1326.
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  PMID: 16393048;Abstract: Most models of visual word recognition in alphabetic orthographies assume that words are lexically organized according to orthographic similarity. Support for this is provided by form-priming experiments that demonstrate robust facilitation when primes and targets share similar sequences of letters. The authors examined form-orthographic priming effects in Hebrew, Arabic, and English. Hebrew and Arabic have an alphabetic writing system but a Semitic morphological structure. Hebrew morphemic units are composed of noncontiguous phonemic (and letter) sequences in a given word. Results demonstrate that form-priming effects in Hebrew or Arabic are unreliable, whereas morphological priming effects with minimal letter overlap are robust. Hebrew bilingual subjects, by contrast, showed robust form-priming effects with English material, suggesting that Semitic words are lexically organized by morphological rather than orthographic principles. The authors conclude that morphology can constrain lexical organization even in alphabetic orthographies and that visual processing of words is first determined by morphological characteristics. Copyright 2005 by the American Psychological Association.
• Finkbeiner, M., Forster, K., Nicol, J., & Nakamura, K. (2004). The role of polysemy in masked semantic and translation priming. Journal of Memory and Language, 51(1), 1-22.
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  Abstract: A well-known asymmetry exists in the bilingual masked priming literature in which lexical decision is used: namely, masked primes in the dominant language (L1) facilitate decision times on targets in the less dominant language (L2), but not vice versa. In semantic categorization, on the other hand, priming is symmetrical. In Experiments 1-3 we confirm this task difference, finding robust masked L2-L1 translation priming in semantic categorization but not lexical decision. In formulating an account for these findings, we begin with the assumption of a representational asymmetry between L1 and L2 lexical semantic representations, such that L1 representations are richly populated and L2 representations are not. According to this representational account, L2-L1 priming does not occur in lexical decision because an insufficient proportion of the L1 lexical semantic representation is activated by the L2 prime. In semantic categorization, we argue that the semantic information recruited to generate a decision is restricted by the task category, and that this restriction enhances the effectiveness of the L2 prime. In Experiments 4-6, these assumptions were tested in a within-language setting by pairing many-sense words (e.g., "head") with few-sense words (e.g., "skull"). In lexical decision, robust priming was obtained in the many-to-few direction (analogous to L1-L2), but, no priming was obtained in the few-to-many direction (analogous to L2-L1) using the same word pairs. Priming in semantic categorization, on the other hand, was obtained in both directions. We propose the Sense Model as a possible account of these findings. © 2004 Elsevier Inc. All rights reserved.
• Forster, K. I. (2004). Category size effects revisited: Frequency and masked priming effects in semantic categorization. Brain and Language, 90(1-3), 276-286.
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  PMID: 15172545;Abstract: Previous work indicates that semantic categorization decisions for nonexemplars (e.g., deciding that TURBAN is not an animal name) are faster for high-frequency words than low-frequency words. However, there is evidence that this result might depend on category size. When narrow categories are used (e.g., Months, Numbers), there is no frequency effect for nonexemplars. This result is confirmed, and is explained in terms of a category search model, which allows a "No" decision to be generated without access to the lexical entry for the target word. This explains the absence of a frequency effect, but not the presence of a strong masked repetition priming effect, which is assumed to have a lexical source. It is shown that this effect may not be lexical, since nonwords also show similar priming. Both of these priming effects disappear when a larger category is used. This pattern of results is explained on the assumption that category search is only possible with small categories, and that tentative category decisions are generated for the unconsciously perceived prime, which leads to a marked response congruence effect. All rights reserved.
• Lachter, J., Forster, K. I., & Ruthruff, E. (2004). Forty-five years after broadbent (1958): Still no identification without attention. Psychological Review, 111(4), 880-913.
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  PMID: 15482066;Abstract: According to D. E. Broadbent's (1958) selective filter theory, people do not process unattended stimuli beyond the analysis of basic physical properties. This theory was later rejected on the basis of numerous findings that people identify irrelevant (and supposedly unattended) stimuli. A careful review of this evidence, however, reveals strong reasons to doubt that these irrelevant stimuli were in fact unattended. This review exposed a clear need for new experiments with tight control over the locus of attention. The authors present 5 such experiments using a priming paradigm. When steps were taken to ensure that irrelevant stimuli were not attended, these stimuli produced no priming effects. Hence, the authors found no evidence that unattended stimuli can be identified. The results support a modern version of Broadbent's selective theory, updated to reflect recent research advances.
• Murray, W. S., & Forster, K. I. (2004). Serial mechanisms in lexical access: The rank hypothesis. Psychological Review, 111(3), 721-756.
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  PMID: 15250781;Abstract: There is general agreement that the effect of frequency on lexical access time is roughly logarithmic, although little attention has been given to the reason for this. The authors argue that models of lexical access that incorporate a frequency-ordered serial comparison or verification procedure provide an account of this effect and predict that the underlying function directly relates access time to the rank order of words in a frequency-ordered set. For both group data and individual data, it is shown that rank provides a better fit to the data than does a function based on log frequency. Extensions to a search model are proposed that account for error rates and latencies and the effect of age of acquisition, which is interpreted as an effect of cumulative frequency.
• Forster, K. I., & Forster, J. C. (2003). DMDX: A Windows display program with millisecond accuracy. Behavior Research Methods, Instruments, and Computers, 35(1), 116-124.
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  PMID: 12723786;Abstract: DMDX is a Windows-based program designed primarily for language-processing experiments. It uses the features of Pentium class CPUs and the library routines provided in DirectX to provide accurate timing and synchronization of visual and audio output. A brief overview of the design of the program is provided, together with the results of tests of the accuracy of timing. The Web site for downloading the software is given, but the source code is not available.
• Forster, K., Forster, K. I., & Forster, J. C. (2003). DMDX: a windows display program with millisecond accuracy. Behavior research methods, instruments, & computers : a journal of the Psychonomic Society, Inc, 35(1).
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  DMDX is a Windows-based program designed primarily for language-processing experiments. It uses the features of Pentium class CPUs and the library routines provided in DirectX to provide accurate timing and synchronization of visual and audio output. A brief overview of the design of the program is provided, together with the results of tests of the accuracy of timing. The Web site for downloading the software is given, but the source code is not available.
• Forster, K. I., & Hector, J. (2002). Cascaded versus noncascaded models of lexical and semantic processing: The turple effect. Memory and Cognition, 30(7), 1106-1117.
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  PMID: 12507375;Abstract: The density of the orthographic neighborhood surrounding an item has been shown to have an inhibitory effect for nonwords in a lexical decision experiment. Four experiments are reported investigating whether a similar pattern holds for a semantic categorization task (animal vs. non-animal). In the first experiment, no effects of neighborhood density were found for nonexemplars, whether they were words or nonwords. The absence of any inhibitory effect for nonwords implies that close orthographic neighbors are ignored. However, the second experiment showed that if the nonword has a neighbor that is an animal name (e.g., turple), an interference effect is observed, implying that neighbors do exert an effect if they have the right semantic properties. The same items showed no additional interference in lexical decision. These results suggest the involvement of semantic properties very early in the processing cycle. A cascaded processing system monitoring activation in semantic features can explain these results, but cannot explain the frequency effect observed for nonexemplar words or the fact that variation in density is irrelevant when one of the neighbors is an exemplar. It is argued that existing models of semantic categorization must be extended to accommodate these results.
• Jiang, N., & Forster, K. I. (2001). Cross-Language Priming Asymmetries in Lexical Decision and Episodic Recognition. Journal of Memory and Language, 44(1), 32-51.
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  Abstract: Masked translation priming between languages with different scripts exhibits a marked asymmetry in lexical decision, with much stronger priming from L1 to L2 than from L2 to L1. This finding was confirmed in a lexical decision task with Chinese-English bilinguals who were late learners of English. Following a suggestion made by Bradley (1991), the experiment was repeated using a speeded episodic recognition task. Participants studied Chinese words, and then were tested in an old/new classification task in which Chinese target words were primed by masked English translation equivalents. Significant priming was obtained for old items, not for new items. However, no priming was obtained when lexical decision was used. Unexpectedly, the episodic task showed a reverse asymmetry, since L1-L2 priming was not obtained with this task, although strong effects were obtained for lexical decision. A possible explanation for this pattern of results is that knowledge of L2 lexical items is represented episodically for late learners. © 2001 Academic Press.
• Forster, K. I. (2000). The potential for experimenter bias effects in word recognition experiments. Memory and Cognition, 28(7), 1109-1115.
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  PMID: 11185767;Abstract: Word recognition experiments that involve comparisons between two different matched sets of words allow for possible experimenter bias if there are many equally well-matched pairs to choose from. The possible extent of this bias depends on the experimenter's intuitive knowledge of the likely difficulty of individual items. This is assessed by asking a number of experimenters to decide which of two frequency-matched words would produce the fastest reaction time in a lexical decision experiment, and then comparing their predictions with actual data. All experimenters demonstrated substantial above-chance accuracy, which was unrelated to the amount of experience they had in the field. It was concluded that the experimenters could potentially produce spurious effect sizes ranging from 16 to 38 msec.
• Forster, K. I., & Azuma, T. (2000). Masked priming for prefixed words with bound stems: Does submit prime permit?. Language and Cognitive Processes, 15(4-5), 539-561.
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  Abstract: Masked priming effects for prefixed words sharing a bound stem (e.g., submit-PERMIT) are compared with priming effects for semantically transparent prefixed words (e.g., fold-UNFOLD). In three experiments, priming effects were obtained for both types with no significant difference between them. These results suggest that semantic transparency is not critical for priming in this paradigm. However, in Experiment 2, priming in the bound stem condition did not differ significantly from an orthographic control condition (e.g., shallow-FOLLOW). In Experiment 3, form priming effects were suppressed by the use of close distractors and a longer prime duration. The morphological effects remained unaltered, indicating that they were not a product of orthographic overlap. The magnitude of bound stem priming was also found to be related to productivity of the stem.
• Frost, R., Deutsch, A., & Forster, K. I. (2000). Decomposing Morphologically Complex Words in a Nonlinear Morphology. Journal of Experimental Psychology: Learning Memory and Cognition, 26(3), 751-765.
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  PMID: 10855429;Abstract: Most Hebrew words are composed of 2 intertwined morphemes: a triconsonantal root and a phonological word pattern. Previous research with conjugated verb forms has shown consistent priming from the verbal patterns, suggesting that verbal forms are automatically parsed by native speakers into their morphemic constituents. The authors investigated the decomposition process, focusing on the structural properties of verbal forms that are perceived and extracted during word recognition. The manipulations consisted of using verbal forms derived from "weak" roots that have one consonant missing in some of the forms. The results demonstrated that if 1 consonant is missing, the parsing system collapses, and there is no evidence for morphological priming. In contrast, when a random consonant is inserted into the weak form, the verbal-pattern priming re-emerges. This outcome suggests that the constraint imposed on the decomposition process is primarily structural and abstract. Moreover, the all-or-none pattern of results is characteristic of rule-based behavior and not of simple correlational systems.
• Forster, K. I. (1999). The microgenesis of priming effects in lexical access. Brain and Language, 68(1-2), 5-15.
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  PMID: 10433733;Abstract: The implications of priming experiments for a structural theory of the mental lexicon depend critically on the development of an adequate theory of the mechanics of priming. Masked priming techniques may simplify this task, since consciously perceived relationships play no role in masked priming. the implications of adopting an activation-based approach to morphological priming is discussed, and an alternative model is described.
• Shen, D., & Forster, K. I. (1999). Masked phonological priming in reading Chinese words depends on the task. Language and Cognitive Processes, 14(5-6), 429-459.
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  Abstract: In two masked priming experiments with Chinese characters, orthographic priming effects were observed in lexical decision and naming tasks despite the fact that the primes were phonologically unrelated to the target characters. In contrast, phonological priming was found only in naming, a task that explicitly required a vocal response. No additional priming effects were obtained for masked primes that were simultaneously visually similar and phonologically identical to the targets. The data suggest that the recovery of lexical information for Chinese characters does not depend on the prior activation of phonological information. © 1999 Psychology Press Ltd.
• Deutsch, A., Frost, R., & Forster, K. I. (1998). Verbs and nouns are organized and accessed differently in the mental lexicon: Evidence from Hebrew. Journal of Experimental Psychology: Learning Memory and Cognition, 24(5), 1238-1255.
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  PMID: 9747532;Abstract: A masked priming paradigm was used to examine the role of the root and verbal-pattern morphemes in lexical access within the verbal system of Hebrew. Previous research within the nominal system had showed facilitatory effects from masked primes that shared the same root as the target word, but not when the primes shared the word pattern (R. Frost, K. I. Forster, & A. Deutsch, 1997). In contrast to these findings, facilitatory effects were obtained for both roots and word patterns in the verbal system. In addition, verbal pattern facilitation was obtained even when the primes were pseudoverbs consisting of illegal combinations of roots and verbal patterns. Significant priming was also found when the primes and the targets contained the same root. The results are discussed with reference to the factors that may determine the lexical status of morphological units in lexical organization. A model of morphological processing of Hebrew words is proposed.
• Forster, K. I. (1998). The Pros and Cons of Masked Priming. Journal of Psycholinguistic Research, 27(2), 203-233.
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  PMID: 9561785;Abstract: Masked priming paradigms offer the promise of tapping automatic, strategy-free lexical processing, as evidenced by the lack of expectancy disconfirmation effects, and proportionality effects in semantic priming experiments. But several recent findings suggest the effects may be prelexical. These findings concern nonword priming effects in lexical decision and naming, the effects of mixed-case presentation on nonword priming, and the dependence of priming on the nature of the distractors in lexical decision, suggesting possible strategy effects. The theory underlying each of these effects is discussed, and alternative explanations are developed that do not preclude a lexical basis for masked priming effects.
• Forster, K. I., & Veres, C. (1998). The prime lexicality effect: Form-priming as a function of prime awareness, lexical status, and discrimination difficulty. Journal of Experimental Psychology: Learning Memory and Cognition, 24(2), 498-514.
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  PMID: 9530846;Abstract: G. W. Humphreys, D. Besner, and P. T. Quinlan (1988) found that form-primes (e.g., contrast-CONTRACT) were effective only with masked primes. C. Veres (1986) obtained the same effect for word primes but found that nonword primes (e.g., contract) were effective regardless of masking. In a lexical-decision task, the present study failed to find any priming with word primes but only when the nonword distractors were very close to a particular word (e.g., UNIVORSE). With more distant nonword distractors (e.g., ANIVORSE), priming with word primes was restored in the masked condition. In terms of an entry-opening model of priming, this effect was interpreted as a blocking of priming by a postaccess checking operation. Alternatively, in an interactive activation model, this effect could be modeled either by decreasing the strength of lexical competition or by changing the decision criterion from local to global activation.
• Frost, R., Forster, K. I., & Deutsch, A. (1997). What can we learn from the morphology of Hebrew? A masked-priming investigation of morphological representation. Journal of Experimental Psychology: Learning Memory and Cognition, 23(4), 829-856.
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  PMID: 9265076;Abstract: All Hebrew words are composed of 2 interwoven morphemes: a triconsonantal root and a phonological word pattern. The lexical representations of these morphemic units were examined using masked priming. When primes and targets shared an identical word pattern, neither lexical decision nor naming of targets was facilitated. In contrast, root primes facilitated both lexical decisions and naming of target words that were derived from these roots. This priming effect proved to be independent of meaning similarity because no priming effects were found when primes and targets were semantically but not morphologically related. These results suggest that Hebrew roots are lexical units whereas word patterns are not. A working model of lexical organization in Hebrew is offered on the basis of these results.
• Gollan, T. H., Forster, K. I., & Frost, R. (1997). Translation priming with different scripts: Masked priming with cognates and noncognates in Hebrew-English bilinguals. Journal of Experimental Psychology: Learning Memory and Cognition, 23(5), 1122-1139.
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  PMID: 9293625;Abstract: Hebrew-English cognates (translations similar in meaning and form) and noncognates (translations similar in meaning only) were examined in masked translation priming. Enhanced priming for cognates was found with L1 (dominant language) primes, but unlike previous results, it was not found with L2 (nondominant language) primes. Priming was also obtained for noncognates, whereas previous studies showed unstable effects for such stimuli. The authors interpret the results in a dual-lexicon model by suggesting that (a) both orthographic and phonological overlap are needed to establish shared lexical entries for cognates (and hence also symmetric cognate priming), and (b) script differences facilitate rapid access by providing a cue to the lexical processor that directs access to the proper lexicon, thus producing stable noncognate priming. The asymmetrical cognate effect obtained with different scripts may be attributed to an overreliance on phonology in L2 reading.
• Nicol, J. L., Forster, K. I., & Veres, C. (1997). Subject-verb agreement processes in comprehension. Journal of Memory and Language, 36(4), 569-587.
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  Abstract: Studies of elicited sentence production show that the occasional subject-verb agreement errors that speakers make are more likely to occur when a singular head noun is followed by a plural, as in The producer of the adventure movies have arrived, than when a plural head is followed by a singular (e.g., Bock & Miller, 1991). The significance of this asymmetric pattern of errors depends on whether interference from plurals arises only during the production of sentences, or whether it also occurs in sentence comprehension tasks. Five reading experiments revealed the following: (1) patterns of reading times mirror the production error asymmetry; (2) a phrase which is conceptually plural but grammatically singular (e.g., The label on the bottles) produces no more reading difficulty than one which is conceptually and grammatically singular, a result which mimics Bock and Miller's 1991 production results; (3) interference from an intervening plural depends on a close syntactic link to the head noun phrase (e.g., The owner of the house who charmed the realtors). These results suggest that although the computation of agreement may be accomplished differently in the two systems, interference may arise whenever a structure containing a singular head and intervening plural is computed, whether during production or comprehension. © 1997 Academic Press.
• Forster, K. I., & Shen, D. (1996). No enemies in the neighborhood: Absence of inhibitory neighborhood effects in lexical decision and semantic categorization. Journal of Experimental Psychology: Learning Memory and Cognition, 22(3), 696-713.
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  PMID: 8656152;Abstract: The effect of neighborhood density on visual word recognition was found to be facilitatory for words but inhibitory for nonwords in 3 lexical-decision experiments. However, the facilitation virtually disappeared when the task was changed to semantic categorization (animal vs. nonanimal), despite the presence of a strong frequency effect. None of these experiments showed a consistent inhibitory effect of a higher frequency neighbor. The absence of inhibitory effects suggests that competition does not play a key role in visual word recognition. The data also suggest that the neighborhood density effect is not an access effect but is a task-dependent effect instead.
• Forster, K. I. (1994). Computational Modeling and Elementary Process Analysis in Visual Word Recognition. Journal of Experimental Psychology: Human Perception and Performance, 20(6), 1292-1310.
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  PMID: 7844513;Abstract: An attempt is made to isolate the assumptions that make a connectionist approach to visual word recognition distinctive. These include the commitment to distributed representations, the claim that there is no distinction between lexical and nonlexical systems in the naming task, and the claim that it is possible to map from orthography to meaning without using localized representations. It is argued that merely demonstrating that a network model can perform these tasks is not sufficient and that a detailed theory of how the network performs its tasks must accompany the simulation, because a simulation is not equivalent to an explanation. It is argued that further progress requires detailed modeling and experimental study of the elementary processes assumed to be involved in networks and that it is premature to dismiss alternative models of lexical access such as serial search models.
• Forster, K. I., & Taft, M. (1994). Bodies, Antibodies, and Neighborhood-Density Effects in Masked Form Priming. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20(4), 844-863.
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  PMID: 8064249;Abstract: Facilitatory priming effects due to similarity of orthographic form are obtained for high-N target words provided that they have low-frequency bodies and the body is shared between the prime and target (e.g., perd-HERD). Conversely, it is shown that low-N target words show priming regardless of the frequency of the body, provided that the prime and target do not share the same body (e.g., drice-DRIVE). If the body is shared, then priming occurs only for targets with low-frequency bodies. These results suggest that neighborhood density should be defined in terms of both individual letter units and subsyllabic units and that both types of density jointly determine priming.
• Forster, K. (1992). Chapter 21 Memory-addressing Mechanisms and Lexical Access. Advances in Psychology, 94(C), 413-434.
• Forster, K. I., & Davis, C. (1991). The density constraint on form-priming in the naming task: interference effects from a masked prime. Journal of Memory and Language, 30(1), 1-25.
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  Abstract: Form-priming effects occur when the prime has similar but nonidentical orthographic form to the target (e.g., mature-NATURE). In visual word recognition tasks, strong facilitatory effects of form similarity are readily obtained when the prime is heavily masked and cannot be reported. In the lexical decision task, this effect is subject to a special density constraint, namely, that form-priming only occurs for words that have few orthographic neighbors and hence are located in low-density regions of the lexicon. However, it has been reported that no such constraint applies to the naming task, which shows strong priming for short words regardless of the neighborhood density. It is shown that performance in the naming task is subject to a special Stroop-like interference effect when the prime and target begin with different onsets. When this interference effect is held constant by matching onsets across conditions, the naming task exhibits the same properties as the lexical decision task. Further analysis shows that this onset effect is not obtained for all words. Words from low-density regions show no such effect, nor do low-frequency words or irregular words. These effects are interpreted in terms of response competition arising from a nonlexically mediated naming response to the prime. When a modified naming task is used (name-if-a-word), which requires the inhibition of all naming responses until lexical processing is completed, no onset effect is obtained. © 1991.
• Neville, H., Nicol, J. L., Barss, A., Forster, K. I., & Garrett, M. F. (1991). Syntactically based sentence processing classes: Evidence from event-related brain potentials. Journal of Cognitive Neuroscience, 3(2), X4-165.
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  Abstract: Theoretical considerations and diverse empirical data from clinical, psycholinguistic, and developmental studies suggest that language comprehension processes are decomposable into separate subsystems, including distinct systems for semantic and grammatical processing. Here we report that event-related potentials (ERPs) to syntactically well-formed but semantically anomalous sentences produced a pattern of brain activity that is distinct in timing and distribution from the patterns elicited by syntactically deviant sentences, and further, that different types of syntactic deviance produced distinct ERP patterns. Forty right-handed young adults read sentences presented at 2 words/sec while ERPs were recorded from over several positions between and within the hemispheres. Half of the sentences were semantically and grammatically acceptable and were controls for the remainder, which contained sentence medial words that violated (1) semantic expectations, (2) phrase structure rules, or (3) WH-movement constraints on Specificity and (4) Subjacency. As in prior research, the semantic anomalies produced a negative potential, N400, that was bilaterally distributed and was largest over posterior regions. The phrase structure violations enhanced the N125 response over anterior regions of the left hemisphere, and elicited a negative response (300-500 msec) over temporal and parietal regions of the left hemisphere. Violations of Specificity constraints produced a slow negative potential, evident by 125 msec, that was also largest over anterior regions of the left hemisphere. Violations of Subjacency constraints elicited a broadly and symmetrically distributed positivity that onset around 200 msec. The distinct timing and distribution of these effects provide biological support for theories that distinguish between these types of grammatical rules and constraints and more generally for the proposal that semantic and grammatical processes are distinct subsystems within the language faculty.
• Bradley, D. C., & Forster, K. I. (1987). A reader's view of listening. Cognition, 25(1-2), 103-134.
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  PMID: 3581723;Abstract: There is a view that the fundamental processes involved in word recognition might somehow be different for speech and print. We argue that this view is unjustified, and that the models of lexical access developed for the written form are also appropriate for speech, provided that we allow for obvious differences due to the physical characteristics of speech signals. Particular emphasis is given to the role of word frequency in the recognition process, since this places restrictions on the types of models that can be considered (e.g., the cohort model). We reject the view that there are no frequency effects in spoken word recognition, and we also reject the view that frequency effects in printed word recognition can be relegated to the minor status of a post-access decision effect. © 1987.
• Forster, K. I., & Stevenson, B. J. (1987). Sentence matching and well-formedness. Cognition, 26(2), 171-186.
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  PMID: 3652649;
• Freedman, S. E., & Forster, K. I. (1985). The psychological status of overgenerated sentences. Cognition, 19(2), 101-131.
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  PMID: 4017513;Abstract: A sentence matching task is used to assess the processing effects of the ungrammaticality produced by violations of constraints on movement rules. Surprisingly, no effects of ungrammaticality were observed either for violations of the Specified Subject Constraint or the Subjacency constraint. These 'overgenerated' sentences could apparently be processed with the same fluency as fully grammatical controls, despite the fact that other types of ungrammaticality produced marked increases in matching times. It is proposed that the matching task utilizes a level of mental representation at which overgenerated sentences are indistinguishable from fully grammatical sentences. This implies a close correspondence between formal derivational mechanisms and features of the operation of the language processor. © 1985.
• Forster, K. I., & Davis, C. (1984). Repetition priming and frequency attenuation in lexical access. Journal of Experimental Psychology: Learning, Memory, and Cognition, 10(4), 680-698.
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  Abstract: Six experiments investigated repetition priming and frequency attenuation in lexical access with 164 college students. Repetition priming effects in lexical decision tasks are stronger for low-frequency words than for high-frequency words. This frequency attenuation effect creates problems for frequency-ordered search models that assume a relatively stable frequency effect. It was posited that frequency attenuation is a product of the involvement of the episodic memory system in the lexical decision process. This hypothesis was supported by the demonstration of constant repetition effects for high- and low-frequency words when the priming stimulus was masked; the masking was assumed to minimize the influence of any possible episodic trace of the prime. It was further shown that long-term repetition effects were much less reliable when the S was not required to make a lexical decision response to the prime. When a response was required, the expected frequency attenuation effect was restored. It is concluded that normal repetition effects consist of 2 components: a very brief lexical effect that is independent of frequency and a long-term episodic effect that is sensitive to frequency. (32 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1984 American Psychological Association.
• Forster, K. I. (1981). Frequency blocking and lexical access: One mental lexicon or two?. Journal of Verbal Learning and Verbal Behavior, 20(2), 190-203.
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  Abstract: Three experiments are reported in which a naming task is used to investigate the effects of frequency blocking on lexical access time. The first two experiments examined the long-term effects of a training list of either high-frequency or low-frequency words on a subsequent test list. No consistent effects were observed. The third experiment tested for short-term effects of frequency blocking by comparing performance on the same set of words in pure-frequency and mixed-frequency lists. No advantage was found for pure lists, nor was there any modification of the graded frequency effect found in mixed lists. These results are compatible with a frequency-ordered search model of lexical access in which all words are listed in a single lexicon regardless of frequency, and in which the search always begins at the highest-frequency entry. © 1981 Academic Press, Inc.
• O'Connor, R., & Forster, K. I. (1981). Criterion bias and search sequence bias in word recognition. Memory & Cognition, 9(1), 78-92.
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  PMID: 7231172;Abstract: Six experiments that were designed to test the adequacy of criterion bias explanations of the word frequency effect and the semantic priming effect are reported. It was found that criterion bias models correctly predicted higher error rates in a lexical decision task for nonwords that were misspelled versions of high-frequency words (e.g., MOHTER), rather than low-frequency words (e.g., BOHTER). Also correct was the prediction of increased error rates for misspelled words preceded by a semantically related word (e.g., NURSE-DOTCOR). However, in a misspelling decision task (in which the subject must decide whether the stimulus is a word, a misspelled word, or a nonword), it can be argued that criterion bias should be inoperative, since correct responses must be delayed until all orthographic information has been checked; this should eliminate both frequency and semantic priming effects. This was found not to be the case; clear frequency and priming effects were obtained for both words and misspelled words. © 1981 Psychonomic Society, Inc.
• Forster, K. I. (1980). Absence of lexical and orthographic effects in a same-different task. Memory & Cognition, 8(3), 210-215.
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  PMID: 7392947;Abstract: Two experiments are reported that investigate whether the lexical and orthographic effects typically found in a simultaneous matching task are due to the facilitating effect of linguistic context on letter identification. The first experiment used a delayed matching task (2-sec SOA), with serial incremental display of the letters of the second stimulus (e.g., B, BR, BRA, BRAI, BRAIN). Lexical and orthographic effects were clearly demonstrated when the letters of the second stimulus were displayed rapidly (40 msec/letter), but these effects were absent at a slower speed (400 msec/letter). The same results were obtained in a second experiment, in which the letters of both stimuli were synchronously presented at either the fast rate or the slow rate. These results were interpreted in terms of a multilevel race model that assumes no interaction between levels of processing and attributes the effects to differing degrees of decision-processing lag. © 1980 Psychonomic Society, Inc.
• Day, R. H., Dickinson, R. G., & Forster, K. I. (1976). Induced subject-relative movement: Persistence of apparent movement of a stationary point after removal of inducing stimulus. Perception & Psychophysics, 19(6), 510-517.
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  Abstract: It was observed by chance that perceived movement of a stationary spot of light in a dark featureless field persists after its induced movement by a moving frame. When the frame was suddenly occluded, apparent movement of the spot persisted in the same direction as prior induced movement. The effect which is compelling and readily reported and referred to as induced subject-relative movement (ISRM) was confirmed and further investigated in four experiments. In the first, the informal observations of ISRM were confirmed using manual tracking to index perceived movement, and in the second, it was shown to occur only very slightly and briefly when the frame merely stopped. In the third experiment, ISRM was shown to occur following two different paths of induced movement, and in the fourth, not to occur following real movement of the spot, which was almost indistinguishable from its induced movement. It is suggested that the effect arises from the absence of a signal for cessation of perceived movement when the frame disappears. © 1976 Psychonomic Society, Inc.
• Forster, K. I., & Bednall, E. S. (1976). Terminating and exhaustive search in lexical access. Memory & Cognition, 4(1), 53-61.
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  PMID: 21286959;Abstract: Two experiments which test predictions derived from the assumption that lexical access involves a search process are reported. In the first experiment, test items must be classified as ambiguous or unambiguous, and in the second experiment, they are classified according to their syntactic properties. In both experiments, it is shown that when the target of the search is a nonexistent entry, an exhaustive search is involved, even though the test items are words. Further, in these conditions, frequency of occurrence is no longer related to decision time, as it is in lexical decision experiments. It is concluded that the search model adequately explains the procedure whereby the most common meaning of a homograph is accessed, but that the less common meaning is accessed in some completely different manner. © 1976 Psychonomic Society, Inc.
• Forster, K. I., & Dickinson, R. G. (1976). More on the language-as-fixed-effect fallacy: Monte Carlo estimates of error rates for F₁,F₂,F′, and min F′. Journal of Verbal Learning and Verbal Behavior, 15(2), 135-142.
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  Abstract: The properties of four different tests of the treatment effect in experiments using linguistic materials are examined using Monte Carlo procedures for estimating Type I error rates. It is shown that: (a) in extreme cases, the Type I error rates for F1 and F2 can exceed the desired rate by a factor of at least 10; (b) minF′ tends to be a very close estimate of F′; (c) both minF′ and F′ are very conservative tests when between item variance or subject-by-treatment variance is low; (d) requiring both F1 and F2 to be significant before H0 is rejected does not prevent the nominal Type I error rate from being exceeded; (e) most of these problems can be minimized by using multistage decision rules which select the most appropriate test on the basis of preliminary tests of item variance and subject-by-treatment variance. © 1976 Academic Press, Inc.
• Taft, M., & Forster, K. I. (1976). Lexical storage and retrieval of polymorphemic and polysyllabic words. Journal of Verbal Learning and Verbal Behavior, 15(6), 607-620.
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  Abstract: Five experiments are deseribed which examine how polysyllabic words (e.g., DAY-DREAM, ATHLETE) are stored and retrieved from lexical memory. The first four experiments look at interference effects caused by the accessing of inappropriate lexical entries. It is found that compound nonwords whose first constituent is a word (e.g., DUSTWORTH, FOOTMILGE) take longer to classify as nonwords than compound nonwords whose first constituent is not a word (e.g., TROWBREAK, MOWDFLISK). Moreover, the presence of a word in the second constituent position appears to be irrelevant. These effects hold even when the boundary between constituents is unclear on an orthographic basis (e.g., TRUCERIN). It is also argued that first syllables, as opposed to last syllables, have independent status in the lexicon since nonword first syllables (e.g., ATH) show interference effects, while last syllables (e.g., CULE) do not. The fifth experiment reveals that the frequency of the first constituent of a compound word influences classification times. The results point to the conclusion that polysyllabic words, regardless of whether they are polymorphemic or monomorphemic, are accessed via their first syllable. © 1976 Academic Press, Inc.
• Chambers, S. M., & Forster, K. I. (1975). Evidence for lexical access in a simultaneous matching task. Memory & Cognition, 3(5), 549-559.
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  PMID: 24203880;Abstract: Reaction times in a simultaneous visual matching task were obtained for four types of letter strings: high-frequency words, low-frequency words, orthographically legal nonwords, e.g., CRAWN, and random letter strings. Two findings supported the notion that the matching of word items involves lexical access. First, words were processed faster than legal nonwords, indicating that the analysis of words uses an additional source of information apart from the constraints imposed by orthographic rules. Second, high-frequency words were processed faster than low-frequency words, indicating lexical search. It is proposed that three levels of identification and comparison operate simultaneously in the matching task: at a word level, a letter cluster level, and a letter level. The results of a second experiment give some support to the idea that these levels operate for "different" items as well as "same" items. Whether familiarity effects will be observed for "different" items will depend on the amount of identification and comparison of the two letter strings which is necessary before a difference is detected. © 1975 Psychonomic Society, Inc.
• Taft, M., & Forster, K. I. (1975). Lexical storage and retrieval of prefixed words. Journal of Verbal Learning and Verbal Behavior, 14(6), 638-647.
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  Abstract: Three experiments are described which support the hypothesis that in a lexical decision task, prefixed words are analyzed into their constituent morphemes before lexical access occurs. The results show that nonwords that are stems of prefixed words (e.g., juvenate) take longer to classify than nonwords which are not stems (e.g., pertoire), suggesting that the nonword stem is directly represented in the lexicon. Further, words which can occur both as a free and as a bound morpheme (e.g., vent) take longer to classify when the bound form is more frequent than the free form. Finally, prefixed nonwords took longer to classify when they contained a real stem (e.g., dejuvenate), compared with control items which did not (e.g., depertoire). A general model of word recognition is presented which incorporates the process of morphological decomposition. © 1975 Academic Press, Inc. All rights reserved.
• Forster, K. I., & Chambers, S. M. (1973). Lexical access and naming time. J.VERB.LEARN.VERB.BEHAV., 12(6), 627-635.
• Forster, K. I., & Chambers, S. M. (1973). Lexical access and naming time. Journal of Verbal Learning and Verbal Behavior, 12(6), 627-635.
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  Abstract: Naming times and word-nonword classification times (lexical decision times) for samples of words, nonwords, and unfamiliar words were compared. It was found that naming times for words were shorter than for nonwords, and that naming times for high frequency words were shorter than for low frequency words, indicating that word naming occurred as a result of a lexical search procedure, rather than occurring prior to lexical search. It was also found that there was a positive correlation between naming times and lexical decision times for words, but not for nonwords. The results are discussed in terms of their implications for the phonemic recoding hypothesis of Rubenstein, Lewis, and Rubenstein (1971). © 1973 Academic Press, Inc. All rights reserved.
• Forster, K. I., & Olbrei, I. (1972). Semantic heuristics and syntactic analysis. Cognition, 2(3), 319-347.
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  Abstract: This paper investigates the hypothesis that the component of sentence processing time directly attributable to syntactic processing depends critically on certain semantic properties of the sentence. Using two different procedures, it is found in a series of experiments that there is little evidence to support this view. Specifically, it is shown that syntactic processing time tends to be constant for sentences of varying semantic plausibility but constant syntactic structure, and further, that reversibility fails to affect sentence processing in a systematic way. These facts are interpreted as indicating that the recovery of the underlying structure of a sentence is controlled by purely syntactic properties of the input. © 1974.
• Holmes, V. M., & Forster, K. I. (1972). Click location and syntactic structure. Perception & Psychophysics, 12(1), 9-15.
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  Abstract: Four experiments are reported in which Ss had to judge the location of clicks superimposed on recorded sentences. The first experiment showed that the accuracy of locating the clicks was a function of the position of the click in the constituent structure, the greatest accuracy being for clicks at major clause boundaries. The second experiment showed that this effect was independent of migration, i.e., the tendency for judgments to be displaced towards the major clause break. In the third experiment, it was shown that the requirement that S reproduce the sentence did not influence the response distribution. Finally, in the fourth experiment, a small but significant trend for location accuracy to decrease with decreasing separation of the click from the major break was found. However, this trend was much smaller than the differences in accuracy for various positions in the constituent structure. It was concluded that click location accuracy can be used as an index of perceptual processing load during recognition of individual sentences. © 1972 Psychonomic Society, Inc.
• Holmes, V. M., & Forster, K. I. (1972). Perceptual complexity and underlying sentence structure. Journal of Verbal Learning and Verbal Behavior, 11(2), 148-156.
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  Abstract: The perceptual complexity of sentences was assessed using a rapid visual presentation procedure. One-clause sentences with complement verbs were shown to be significantly harder to process than one-clause sentences with simple verbs. This result indicates the importance of the matrix verb in determining how S perceives sentence structure. It was also shown that, although there were differences within two-clause complement constructions, they were no harder to process than both kinds of one-clause sentence. This suggests that the presence of more than one underlying structure sentence does not always increase perceptual complexity. © 1972 Academic Press, Inc. All Rights Reserved.
• Forster, K. I., & Ryder, L. A. (1971). Perceiving the structure and meaning of sentences. Journal of Verbal Learning and Verbal Behavior, 10(3), 285-296.
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  Abstract: The effects of syntactic complexity on visual perception of very rapidly presented word sequences were examined under three different semantic conditions. It was found that more words were reported from one-clause sentences than from two-clause sentences, and that this effect was present for semantically anomalous and semantically bizarre sentences, as well as for normal sentences. It was also found that the relative difficulty of different sentence types was approximately constant under all three semantic conditions. Semantically bizarre sentences were markedly more difficult than normal sentences, as were anomalous sentences. It was concluded that the effect of syntactic structure on perception was essentially independent of the effects of semantics. © 1971 Academic Press, Inc. All rights reserved.
• Forster, K. I. (1970). Visual perception of rapidly presented word sequences of varying complexity. Perception & Psychophysics, 8(4), 215-221.
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  Abstract: Four experiments are described that determine whether or not syntactic complexity affects the visual perception of rapidly presented word sequences. The results indicate that sentences containing only one sentence in the underlying structure are more accurately reported than sentences containing two underlying sentences. It is shown that this result is not due solely to distortion of the input, but is likely to reflect the rate at which structural representations of the input can be developed. © 1970 Psychonomic Society, Inc.
• Holmes, V. M., & Forster, K. I. (1970). Detection of extraneous signals during sentence recognition. Perception & Psychophysics, 7(5), 297-301.
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  Abstract: In two separate experiments, 40 Ss were presented with recorded sentences during each of which a click occurred. Ss had to depress a key as soon as they heard the click. RTs were f aster when the click was located at the major syntactic break of the sentence compared with RTs to clicks not at a break. This confirmed the hypothesis that processing load is a function of the surface structure of sentences, although the role of minor breaks was not clear. A second finding was that RTs were slower when the click was in the first rather than in the second half of the sentence. This can also be explained in terms of differential processing loads. © 1970 Psychonomic Society, Inc.
• Forster, K. I. (1968). Sentence completion in left- and right-branching languages. Journal of Verbal Learning and Verbal Behavior, 7(2), 296-299.
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  Abstract: Sentence-completion performance of German and Japanese Ss was compared with the performance of English and Turkish Ss under two conditions: (a) where the end of the sentence was specified in advance, and (b) where the beginning of the sentence was specified in advance. It was shown that the relative difficulty of these tasks varied as a function of the typical branching characteristics of the surface structures of sentences in these languages. It was also shown that this variation occurred only in items where the specified material did not form a major constituent of the sentence to be constructed. © 1968 Academic Press Inc.
• Forster, K. I. (1968). The effect of removal of length constraint on sentence completion times. Journal of Verbal Learning and Verbal Behavior, 7(1), 253-254.
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  Abstract: Previous results have shown that Ss find it more difficult to complete a sentence when the end, rather than the beginning of the sentence has been specified in advance. The results of the present experiment demonstrate that this effect is maintained when no constraint is placed on the length of the completion. © 1969 Academic Press Inc. All rights reserved.
• Forster, K. I., & Clyne, M. G. (1968). Sentence construction in German-English bilinguals.. Language and speech, 11(2), 113-119.
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  PMID: 4876589;
• Forster, K. I. (1967). Sentence completion latencies as a function of constituent structure. Journal of Verbal Learning and Verbal Behavior, 6(6), 878-883.
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  Abstract: Previous experiments have shown that if a sentence is fragmented by removing either the first or the second half of the sentence, Ss experience more difficulty in reconstructing sentences when the first half is missing than when the second half is missing. In the present experiment, an attempt was made to analyze the relationship between the number of constituents damaged by the fragmenting of the sentence and the time required to complete the sentence. It was shown that the number of damaged constituents predicted difficulty if the first half of the sentence had been deleted, but not if the second half had been deleted. This result was interpreted as being consistent with the view that the sentence producing device is equivalent to the left-to-right sentence generator described by Yngve (1960). © 1967.
• Forster, K. I. (1966). Left-to-right processes in the construction of sentences. Journal of Verbal Learning and Verbal Behavior, 5(3), 285-291.
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  Abstract: The purpose of this study was to test certain predictions derived from an extension of Yngve's left-to-right model of sentence construction. On the basis of assumed development of predictive integrations between successive rule-applications, it was predicted that for a right-branching language such as English, it should be more difficult to provide the beginning of an already completed sentence, than to provide the end of an already started sentence. But for a left-branching language such as Turkish, this tendency should be considerably reduced. The obtained results supported these predictions. It was also found for English that this result could not have been solely due to differential decoding times. © 1966.
• Forster, K. I. (1966). The effect of syntactic structure on nonordered recall. Journal of Verbal Learning and Verbal Behavior, 5(3), 292-297.
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  Abstract: The present study was designed to test the hypothesis that the facilitative effect of syntactic structure on the recall of nonsense sentences is due solely to the fact that S is relieved of the necessity of storing information concerning item order. It was predicted that if Ss were not required to recall the items in order, then the facilitative effect should disappear. Four types of lists were used, representing combinations of two variables: (a) whether the list was structured, and (b) whether bound morphemes were present. Under conditions of nonordered recall, a facilitation effect was still apparent, and thus the hypothesis was rejected. © 1966.

Presentations

• Forster, K. I. (2012, June). How many words can we read at once?. Macquarie University Center for Cognitive Science.
• Forster, K. I. (2012, November). How many words can we read at once?. 50th Annual Meeting of the Psychonomics Society. Minneapolis, MN.
• Forster, K. I. (2012, October). Thirty years of masked priming. 8th International Conference on the Mental Lexicon.