Strategic control of processing in word recognition

Is pupillary response a reliable index of word recognition? Evidence from a delayed lexical decision task

Previous word recognition studies have shown that the pupillary response is sensitive to a word's frequency. However, such a pupillary effect may be due to the process of executing a response, instead of being an index of word processing. With the aim of exploring this possibility, we recorded the pupillary responses in two experiments involving a lexical decision task (LDT). In the first experiment, participants completed a standard LDT, whereas in the second they performed a delayed LDT. The delay in the response allowed us to compare pupil dilations with and without the response execution component. The results showed that pupillary response was modulated by word frequency in both the standard and the delayed LDT. This finding supports the reliability of using pupillometry for word recognition research. Importantly, our results also suggest that tasks that do not require a response during pupil recording lead to clearer and stronger effects.

Nonword Repetition in Lexical Decision: Support for two Opposing Processes

We tested and confirmed the hypothesis that the prior presentation of nonwords in lexical decision is the net result of two opposing processes: (1) a relatively fast inhibitory process based on global familiarity; and (2) a relatively slow facilitatory process based on the retrieval of specific episodic information. In three studies, we manipulated speed-stress to influence the balance between the two processes. Experiment 1 showed item-specific improvement for repeated nonwords in a standard “respond-when-ready” lexical decision task. Experiment 2 used a 400-ms deadline procedure and showed performance for nonwords to be unaffected by up to four prior presentations. In Experiment 3 we used a signal-to-respond procedure with variable time intervals and found negative repetition priming for repeated nonwords. These results can be accounted for by dual-process models of lexical decision (e.g., Balota & Chumbley, 1984; Balota & Spieler, 1999).

Beyond the Two-Strategy Model of Skilled Spelling: Effects of Consistency, Grain Size, and Orthographic Redundancy

Most models of spelling assume that people rely on two procedures when engaging in spelling: a lexical look-up procedure that retrieves spellings in their entirety, and a nonlexical procedure that constructs spellings with a set of phoneme-grapheme rules. In the present research, we investigated whether larger sized subsyllabic relationships also play a role in spelling, and how they compare to small-sized phoneme-grapheme relationships. In addition, we investigated whether purely orthographic units can explain some of the variance typically attributed to the mapping between sound and spelling. To do this, we ran five spelling experiments, two using real words and three using nonwords. Results from the experiments showed that there were independent contributions of both phoneme-grapheme and larger sized subsyllabic sound–spelling relationships, although the effect of phoneme-grapheme-sized relationships was always stronger and more reliable than larger sized subsyllabic sound–spelling relationships. Purely orthographic effects were also shown to affect word spelling, but no significant effects were found with nonword spelling. Together, the results support the hypothesis that a major constraint on spelling comes from phoneme-grapheme-sized relationships.

Semantic Richness Effects in Spoken Word Recognition: A Lexical Decision and Semantic Categorization Megastudy

A large number of studies have demonstrated that semantic richness dimensions [e.g., number of features, semantic neighborhood density, semantic diversity , concreteness, emotional valence] influence word recognition processes. Some of these richness effects appear to be task-general, while others have been found to vary across tasks. Importantly, almost all of these findings have been found in the visual word recognition literature. To address this gap, we examined the extent to which these semantic richness effects are also found in spoken word recognition, using a megastudy approach that allows for an examination of the relative contribution of the various semantic properties to performance in two tasks: lexical decision, and semantic categorization. The results show that concreteness, valence, and number of features accounted for unique variance in latencies across both tasks in a similar direction—faster responses for spoken words that were concrete, emotionally valenced, and with a high number of features—while arousal, semantic neighborhood density, and semantic diversity did not influence latencies. Implications for spoken word recognition processes are discussed.

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness

The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d') and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain.

Speed and accuracy of dyslexic versus typical word recognition: an eye-movement investigation

Developmental dyslexia is often characterized by a dual deficit in both word recognition accuracy and general processing speed. While previous research into dyslexic word recognition may have suffered from speed-accuracy trade-off, the present study employed a novel eye-tracking task that is less prone to such confounds. Participants (10 dyslexics and 12 controls) were asked to look at real word stimuli, and to ignore simultaneously presented non-word stimuli, while their eye-movements were recorded. Improvements in word recognition accuracy over time were modeled in terms of a continuous non-linear function. The words' rhyme consistency and the non-words' lexicality (unpronounceable, pronounceable, pseudohomophone) were manipulated within-subjects. Speed-related measures derived from the model fits confirmed generally slower processing in dyslexics, and showed a rhyme consistency effect in both dyslexics and controls. In terms of overall error rate, dyslexics (but not controls) performed less accurately on rhyme-inconsistent words, suggesting a representational deficit for such words in dyslexics. Interestingly, neither group showed a pseudohomophone effect in speed or accuracy, which might call the task-independent pervasiveness of this effect into question. The present results illustrate the importance of distinguishing between speed- vs. accuracy-related effects for our understanding of dyslexic word recognition.

Does viotin activate violin more than viocin? On the use of visual cues during visual-word recognition

The vast majority of neural and computational models of visual-word recognition assume that lexical access is achieved via the activation of abstract letter identities. Thus, a word's overall shape should play no role in this process. In the present lexical decision experiment, we compared word-like pseudowords like viotín (same shape as its base word: violín) vs. viocín (different shape) in mature (college-aged skilled readers), immature (normally reading children), and immature/impaired (young readers with developmental dyslexia) word-recognition systems. Results revealed similar response times (and error rates) to consistent-shape and inconsistent-shape pseudowords for both adult skilled readers and normally reading children - this is consistent with current models of visual-word recognition. In contrast, young readers with developmental dyslexia made significantly more errors to viotín-like pseudowords than to viocín-like pseudowords. Thus, unlike normally reading children, young readers with developmental dyslexia are sensitive to a word's visual cues, presumably because of poor letter representations.

Interactive Effects of Age-of-Acquisition and Repetition Priming in the Lexical Decision Task

The analysis of the interaction between repetition priming and age of acquisition may be used to shed further light on the question of which stages of elaboration are affected by this psycholinguistic variable. In the present study we applied this method in the context of two versions of a lexical decision task that differed in the type of non-words employed at test. When the non-words were illegal and unpronounceable, repetition priming was primarily based on the analysis of orthographic information, while phonological processes were additionally recruited only when using legal pronounceable non-words. The results showed a significant interaction between repetition priming and age of acquisition in both conditions, with priming being greater for late- than for early-acquired words. These findings support a multiple-loci account, indicating that age of acquisition influences implicit memory by facilitating the retrieval of both the orthographic and the phonological representations of studied words.

Pupil-BLAH-metry: cognitive effort in speech planning reflected by pupil dilation

In reading research, a longstanding question is whether any stages of lexical processing require central attention, and whether such potential demands are frequency-sensitive. In the present study, we examined the allocation of cognitive effort in lexical processing by examining pupil dilations and naming latencies in a modified delayed naming procedure. In this dual-task/change procedure, participants read words and waited for various delays before being signaled to issue a response. On most trials (80%), participants issued a standard naming response. On the remaining trials, they were cued to abandon the original speech plan, saying "blah" instead, thereby equating production across different words. Using feature-matched low- and high-frequency words, we observed the differences in pupil dilations as a function of word frequency. Indeed, frequency-sensitive cognitive demands were seen in word processing, even after naming responses were issued. The results suggest that word perception and/or speech planning requires the frequency-sensitive allocation of cognitive resources.

Losing the sound of concepts: damage to auditory association cortex impairs the processing of sound-related concepts

Conceptual knowledge is classically supposed to be abstract and represented in an amodal unitary system, distinct from the sensory and motor brain systems. A more recent embodiment view of conceptual knowledge, however, proposes that concepts are grounded in distributed modality-specific brain areas which typically process sensory or action-related object information. Recent neuroimaging evidence suggested the significance of left auditory association cortex encompassing posterior superior and middle temporal gyrus in coding conceptual sound features of everyday objects. However, a causal role of this region in processing conceptual sound information has yet to be established. Here we had the unique chance to investigate a patient, JR, with a focal lesion in left posterior superior and middle temporal gyrus. To test the necessity of this region in conceptual and perceptual processing of sound information we administered four different experimental tasks to JR: Visual word recognition, category fluency, sound recognition and voice classification. Compared with a matched control group, patient JR was consistently impaired in conceptual processing of sound-related everyday objects (e.g., "bell"), while performance for non-sound-related everyday objects (e.g., "armchair"), animals, whether they typically produce sounds (e.g., "frog") or not (e.g., "tortoise"), and musical instruments (e.g., "guitar") was intact. An analogous deficit pattern in JR was also obtained for perceptual recognition of the corresponding sounds. Hence, damage to left auditory association cortex specifically impairs perceptual and conceptual processing of sounds from everyday objects. In support of modality-specific theories, these findings strongly evidence the necessity of auditory association cortex in coding sound-related conceptual information.

Phonological universals in early childhood: Evidence from sonority restrictions

Across languages, onsets with large sonority distances are preferred to those with smaller distances (e.g., bw>bd>lb; Greenberg, 1978). Optimality theory (Prince & Smolensky, 2004) attributes such facts to grammatical restrictions that are universally active in all grammars. To test this hypothesis, here, we examine whether children extend putatively universal sonority restrictions to onsets unattested in their language. Participants (M=4;04 years) were presented with pairs of auditory words-either identical (e.g., lbif→lbif) or epenthetically related (e.g., lbif→lebif)-and asked to judge their identity. Results showed that, like adults, children's ability to detect epenthetic distortions was monotonically related to sonority distance (bw>bd>lb), and their performance was inexplicable by several statistical and phonetic factors. These findings suggest that sonority restrictions are active in early childhood and their scope is broad.

Integrating trait and social-cognitive views of personality: neuroticism, implicit stress priming, and neuroticism-outcome relationships

The trait perspective of personality emphasizes the broad role of traits in outcome prediction, whereas the social-cognitive perspective emphasizes the importance of if-then intrapsychic associations. Three studies (N = 188) were conducted to reconcile these alternative views of personality in the context of stress-related behaviors. Implicit priming tasks were used to quantify the extent to which stress primes activated thoughts of aggression (Studies 1 and 2) or eating (Study 3), and trait levels of neuroticism were also assessed. Neuroticism did not consistently predict stress-related implicit associations, consistent with the independence of these predictors. Of more importance, such implicit associations predicted problematic outcomes (e.g., physical aggression), but only to the extent that relevant individuals were also high in neuroticism. The results highlight an interface of trait and social-cognitive views of personality and do so in the context of understanding stress-reactivity processes, a topic of importance to multiple literatures.

More Memory Bang for the Attentional Buck: Self-Protection Goals Enhance Encoding Efficiency for Potentially Threatening Males

When encountering individuals with a potential inclination to harm them, people face a dilemma: Staring at them provides useful information about their intentions but may also be perceived by them as intrusive and challenging-thereby increasing the likelihood of the very threat the people fear. One solution to this dilemma would be an enhanced ability to efficiently encode such individuals-to be able to remember them without spending any additional direct attention on them. In two experiments, the authors primed self-protective concerns in perceivers and assessed visual attention and recognition memory for a variety of faces. Consistent with hypotheses, self-protective participants (relative to control participants) exhibited enhanced encoding efficiency (i.e., greater memory not predicated on any enhancement of visual attention) for Black and Arab male faces-groups stereotyped as being potentially dangerous-but not for female or White male faces. Results suggest that encoding efficiency depends on the functional relevance of the social information people encounter.

Individual differences in the joint effects of semantic priming and word frequency: The role of lexical integrity

Word frequency and semantic priming effects are among the most robust effects in visual word recognition, and it has been generally assumed that these two variables produce interactive effects in lexical decision performance, with larger priming effects for low-frequency targets. The results from four lexical decision experiments indicate that the joint effects of semantic priming and word frequency are critically dependent upon differences in the vocabulary knowledge of the participants. Specifically, across two Universities, additive effects of the two variables were observed in participants with more vocabulary knowledge, while interactive effects were observed in participants with less vocabulary knowledge. These results are discussed with reference to Borowsky and Besner's (1993) multistage account and Plaut and Booth's (2000) single-mechanism model. In general, the findings are also consistent with a flexible lexical processing system that optimizes performance based on processing fluency and task demands.

Emphasizing Nonword Decisions in Word-Decision Performance

A robust finding in the lexical decision literature is that decisions to words are made more quickly and accurately than decisions to nonwords. When instructions are presented to participants prior to an experiment, an emphasis is usually placed on identifying words. This study assessed whether instructing participants to emphasize nonword decisions would affect the performance of the speed and accuracy of identification. A total of 98 individuals took part, 49 in a Word Instruction condition and 49 in a Nonword Instruction condition. Analysis indicated changes in emphasis on words versus nonwords decreased the difference in mean reaction time between word and nonword decisions. An interesting finding is that the manipulation of instructions affected reaction times to words but not to nonwords. The analysis of accuracy yielded no significant comparisons. Further research is required to assess the importance of the finding that the manipulation of instructions affects only word decisions.

Are CORNER and BROTHER Morphologically Complex? Not in the Long Term

Previous studies haves shown that under masked priming conditions, CORNER primes CORN as strongly as TEACHER primes TEACH and more strongly than BROTHEL primes BROTH. This result has been taken as evidence of a purely structural level of representation at which words are decomposed into morphological constituents in a manner that is independent of semantics. The research reported here investigated the influence of semantic transparency on long-term morphological priming. Two experiments demonstrated that while lexical decisions were facilitated by semantically transparent primes like TEACHER, semantically opaque words like CORNER had no effect. Although differences in the nonword foils used in each experiment gave rise to somewhat different patterns of results, this difference in the effects of transparent and opaque primes was found in both experiments. The implications of this finding for accounts of morphological effects on visual word identification are discussed.

A model of the go/no-go task

In this article, the first explicit, theory-based comparison of 2-choice and go/no-go variants of 3 experimental tasks is presented. Prior research has questioned whether the underlying core-information processing is different for the 2 variants of a task or whether they differ mostly in response demands. The authors examined 4 different diffusion models for the go/no-go variant of each task along with a standard diffusion model for the 2-choice variant (R. Ratcliff, 1978). The 2-choice and the go/no-go models were fit to data from 4 lexical decision experiments, 1 numerosity discrimination experiment, and 1 recognition memory experiment, each with 2-choice and go/no-go variants. The models that assumed an implicit decision criterion for no-go responses produced better fits than models that did not. The best model was one in which only response criteria and the nondecisional components of processing changed between the 2 variants, supporting the view that the core information on which decisions are based is not different between them.

Modality-independent involvement of the left BA 44 during lexical decision making

During a lexical decision task, lexical decision making can be distinguished from lexical retrieval. Lexical decision making is independent of stimulus modality and not reflected in the decision times, whereas the opposite holds for lexical retrieval. In neuroimaging studies investigating lexical decision tasks with either visual or auditory stimuli these two processes have so far been confused. Therefore, it is not clear whether the activation of Broca's region, consisting of the left Brodmann's area (BA) 44 and BA 45, reported in such studies really reflects lexical decision making. The present event-related fMRI study investigated the role of Broca's region in lexical decision by analyzing brain activation that is independent of stimulus modality or decision times. Twenty-two healthy participants performed lexical decisions on visual and auditory real words and pseudo-words. The left BA 44 was conjointly activated during visual and auditory lexical decisions as compared to rest indicating the modality-independent involvement of BA 44 in lexical decision tasks in general. To identify brain activation related to lexical decision making rather than lexical retrieval the decision times were entered as covariates into the fMRI analysis. In this analysis, the left BA 44 was activated for visual and for auditory lexical decision making. These results indicate that the left BA 44 as a distinct sub-part of Broca's region plays an important role in lexical decision making independently of stimulus modality and decision times.

The role of orthography in speech production revisited

The language production system of literate adults comprises an orthographic system (used during written language production) and a phonological system (used during spoken language production). Recent psycholinguistic research has investigated possible influences of the orthographic system on the phonological system. This research has produced contrastive results, with some studies showing effects of orthography in the course of normal speech production while others failing to show such effects. In this article, we review the available evidence and consider possible explanations for the discrepancy. We then report two form-preparation experiments which aimed at testing for the effects of orthography in spoken word-production. Our results provide clear evidence that the orthographic properties of the words do not influence their spoken production in picture naming. We discuss this finding in relation to psycholinguistic and neuropsychological investigations of the relationship between written and spoken word-production.

Brain Activation for Lexical Decision and Reading Aloud: Two Sides of the Same Coin?

This functional magnetic resonance imaging study compared the neuronal implementation of word and pseudoword processing during two commonly used word recognition tasks: lexical decision and reading aloud. In the lexical decision task, participants made a finger-press response to indicate whether a visually presented letter string is a word or a pseudoword (e.g., “paple”). In the reading-aloud task, participants read aloud visually presented words and pseudowords. The same sets of words and pseudowords were used for both tasks. This enabled us to look for the effects of task (lexical decision vs. reading aloud), lexicality (words vs. nonwords), and the interaction of lexicality with task. We found very similar patterns of activation for lexical decision and reading aloud in areas associated with word recognition and lexical retrieval (e.g., left fusiform gyrus, posterior temporal cortex, pars opercularis, and bilateral insulae), but task differences were observed bilaterally in sensorimotor areas. Lexical decision increased activation in areas associated with decision making and finger tapping (bilateral postcentral gyri, supplementary motor area, and right cerebellum), whereas reading aloud increased activation in areas associated with articulation and hearing the sound of the spoken response (bilateral precentral gyri, superior temporal gyri, and posterior cerebellum). The effect of lexicality (pseudoword vs. words) was also remarkably consistent across tasks. Nevertheless, increased activation for pseudowords relative to words was greater in the left precentral cortex for reading than lexical decision, and greater in the right inferior frontal cortex for lexical decision than reading. We attribute these effects to differences in the demands on speech production and decision-making processes, respectively.

Perception and recognition memory of words and werds: two-way mirror effects

We examined associative priming of words (e.g., TOAD) and pseudohomophones of those words (e.g., TODE) in lexical decision. In addition to word frequency effects, reliable base-word frequency effects were observed for pseudohomophones: Those based on high-frequency words elicited faster and more accurate correct rejections. Associative priming had disparate effects on high- and low-frequency items. Whereas priming improved performance to high-frequency pseudohomophones, it impaired performance to low-frequency pseudohomophones. The results suggested a resonance process, wherein phonologic identity and semantic priming combine to undermine the veridical perception of infrequent items. We tested this hypothesis in another experiment by administering a surprise recognition memory test after lexical decision. When asked to identify words that were spelled correctly during lexical decision, the participants often misremembered pseudohomophones as correctly spelled items. Patterns of false memory, however, were jointly affected by base-word frequencies and their original responses during lexical decision. Taken together, the results are consistent with resonance accounts of word recognition, wherein bottom-up and top-down information sources coalesce into correct, and sometimes illusory, perception. The results are also consistent with a recent lexical decision model, REM-LD, that emphasizes memory retrieval and top-down matching processes in lexical decision.

Repetition proportion biases masked priming of lexical decisions

Although subjects have little or no awareness of masked primes, Bodner and Masson (2001) found that priming of lexical decisions is often enhanced when masked repetition primes occur on a high proportion of trials. We used baseline prime conditions to specify the locus of this repetition proportion (RP) effect. In Experiments 1A and 1B, a .8-RP group showed more priming than did a .2-RP group, and this RP effect was due to both (1) increased facilitation from repetition primes and (2) increased interference from unrelated primes. In Experiment 2, we used the baseline condition to show that subjects are sensitive to RP rather than to the proportion of unrelated primes. Direct comparisons of a given prime condition (repetition, unrelated) across RP conditions were more stable than were comparisons relative to the baseline condition. The increased costs and benefits of repetition priming when RP is higher implicate a context-sensitive mechanism that constrains accounts of masked priming.

Phonological neighbors speed visual word processing: evidence from multiple tasks

The author investigated the role of phonological neighborhood on visual word recognition. Using a lexical decision task, the author showed in Experiment 1 that words with large phonological neighborhoods were processed more rapidly than those with smaller phonological neighborhoods. This facilitative effect was obtained even when the nonword fillers had the same number of phonological neighbors as the words. This finding indicates that phonological neighbors speed processing within the phonological system. In the next 2 experiments, this claim was further tested using the naming and semantic categorization tasks. In both experiments, the effect of phonological neighborhood was found to be facilitative. The results across all 3 experiments indicate that phonology is central to visual word recognition and that phonological neighborhood provides a reliable measure of phonological processing.

How lexical decision is affected by recent experience: Symmetric versus asymmetric frequency-blocking effects

In a lexical decision task (LDT) in which list composition is manipulated, a typical finding to date has been a slowdown for easy items (e.g., high-frequency words) but little speedup for hard items (e.g., low-frequency words) when they are mixed together. This asymmetric frequency-blocking effect contrasts with the symmetric pattern (both a speedup for hard items and a slowdown for easy items when they are mixed together) observed with the naming task. In the present study, we investigated the mechanism responsible for the asymmetric blocking effect in the LDT within a model of blocking effect proposed by Mozer, Kinoshita, and Davis (2003), termed the adaptation-to-the-statistics-of-the-environment (ASE) model. Experiments 1A and 1B showed that when the same high- and low-frequency words were used, consistent with the existing literature, an asymmetric blocking effect was found in the LDT and a symmetric blocking effect was found in the naming task. Within the ASE model, a symmetric versus asymmetric blocking effect can be explained in terms of different asymptotic rates in subjective estimates of error probability. Experiments 2 and 3 tested and confirmed a prediction of the model based on this assumption that a speedup of hard items would be observed in an LDT with hard items whose subjective error probability asymptotes near zero (low-frequency words with high familiarity ratings that subjects could be certain were words). Implications of the model for task differences in reaction times are discussed.

Masked inhibitory priming in English: Evidence for lexical inhibition

Predictions derived from the interactive activation (IA) model were tested in 3 experiments using the masked priming technique in the lexical decision task. Experiment 1 showed a strong effect of prime lexicality: Classifications of target words were facilitated by orthographically related nonword primes (relative to unrelated nonword primes) but were inhibited by orthographically related word primes (relative to unrelated word primes). Experiment 2 confirmed IA's prediction that inhibitory priming effects are greater when the prime and target share a neighbor. Experiment 3 showed a minimal effect of target word neighborhood size (N) on inhibitory priming but a trend toward greater inhibition when nonword foils were high-N than when they were low-N. Simulations of 3 different versions of the IA model showed that the best fit to the data is produced when lexical inhibition is selective and when masking leads to reset of letter activities.

Automatic Priming of Semantically Related Words Reduces Activity in the Fusiform Gyrus

We used rapid, event-related fMRI to identify the neural systems underlying object semantics. During scanning, subjects silently read rapidly presented word pairs (150 msec, SOA = 250 msec) that were either unrelated in meaning (ankle-carrot), semantically related (fork-cup), or identical (crow-crow). Activity in the left posterior region of the fusiform gyrus and left inferior frontal cortex was modulated by word-pair relationship. Semantically related pairs yielded less activity than unrelated pairs, but greater activity than identical pairs, mirroring the pattern of behavioral facilitation as measured by word reading times. These findings provide strong support for the involvement of these areas in the automatic processing of object meaning. In addition, words referring to animate objects produced greater activity in the lateral region of the fusiform gyri, right superior temporal sulcus, and medial region of the occipital lobe relative to manmade, manipulable objects, whereas words referring to manmade, manipulable objects produced greater activity in the left ventral premotor, left anterior cingulate, and bilateral parietal cortices relative to animate objects. These findings are consistent with the dissociation between these areas based on sensory-and motor-related object properties, providing further evidence that conceptual object knowledge is housed, in part, in the same neural systems that subserve perception and action.

An fMRI investigation of strategies for word recognition

A common procedure used to study visual word recognition is the lexical decision task (LDT). Behavioral studies have demonstrated that overall performance in this task is modulated by the type of foils presented. There are divergent claims about the impact of different types of foils on overall processing strategies in the LDT: some researchers claim that pseudohomophone foils (e.g., BRANE) encourage participants to selectively de-emphasize phonological processing, while other researchers claim that pseudohomophone foils encourage participants to engage in more extensive processing of all types (orthographic, phonological, and semantic). To evaluate these claims, we conducted a functional magnetic resonance imaging study. Participants (N = 18) completed three lexical decision tasks, each with a different foil type: consonant strings (e.g., BVRNT), pseudowords (e.g., BLINT), and pseudohomophones (e.g., BRANE). We presented homophones (e.g., MAID) and nonhomophones (e.g., MESS) on word trials in order to be able to calculate the homophone effect as a marker of phonological processing for word stimuli in each foil condition. Comparison of behavioral results in the different foil conditions showed that reaction times were longest, error rates were highest, and homophone effects were largest in the LDT with pseudohomophones. Imaging results showed the greatest magnitude of activity in several regions, including the inferior frontal cortex, during the LDT with pseudohomophone foils. A comparison to inferior frontal activity produced during an additional task (rhyme judgment) supported the conclusion that LDT with pseudohomophone foils is a difficult task in which readers engage in an overall response strategy involving extensive processing of phonological information.

Evidence for several components of word familiarity

Familiarity with a word can be divided into two main components: familiarity with the form of the word (due to both its lexicality and its specific form) and familiarity with its meaning. In this study, ratings of familiarity were compared for words whose meaning was unknown to participants (UM words), for words of known meaning (KM words), and for unknown words (U words). Linguistic and experiential frequencies were equivalent. Rated familiarity was lower for UM than KM words and even lower for U words. Next, we built pseudowords from these stimuli by changing one letter and submitted them to two familiarity rating tasks that differed in the nature of the additional stimuli: either only nonwords or nonwords plus words. It was assumed that familiarity ratings would be lower for pseudowords built from UM words than for pseudowords built from KM words. The data were consistent with this assumption, and ratings depended on the initial categories of stimuli. These results support the view that usual word familiarity has two components, familiarity with form and familiarity with meaning, and a double source, processing of word form and processing of word meaning. The full set of these materials and norms may be downloaded from www.psychonomic.org/archive.

Instructions and Word Bias in a Lexical Decision Task

During a lexical decision task, identification of words is usually faster and more accurate than identification of nonwords. Normally, when instructions are presented to participants, an emphasis is placed on identifying words. The purpose of this study was to assess whether changing the instructions so emphasis is placed on identifying nonwords would change this word versus nonword effect. For 48 participants, 24 in the Word Instruction Type condition and 24 in the Nonword Instruction Type condition a significant word versus nonword main effect was found, but no interaction between type of instruction (word vs nonword focus) and type of item (word vs nonword). This indicates that participants' bias towards making word decisions may be very strong and may be based on prior experience and hence not easily affected by the kind of instructions given. Methodological issues for research are discussed.

Distinct Brain Systems for Processing Concrete and Abstract Concepts

Behavioral and neurophysiological effects of word imageability and concreteness remain a topic of central interest in cognitive neuroscience and could provide essential clues for understanding how the brain processes conceptual knowledge. We examined these effects using event-related functional magnetic resonance imaging while participants identified concrete and abstract words. Relative to nonwords, concrete and abstract words both activated a left-lateralized network of multimodal association areas previously linked with verbal semantic processing. Areas in the left lateral temporal lobe were equally activated by both word types, whereas bilateral regions including the angular gyrus and the dorsal prefrontal cortex were more strongly engaged by concrete words. Relative to concrete words, abstract words activated left inferior frontal regions previously linked with phonological and verbal working memory processes. The results show overlapping but partly distinct neural systems for processing concrete and abstract concepts, with greater involvement of bilateral association areas during concrete word processing, and processing of abstract concepts almost exclusively by the left hemisphere.

Human cognition and a pile of sand: a discussion on serial correlations and self-organized criticality

Recently, G. C. Van Orden, J. G. Holden, and M. T. Turvey (2003) proposed to abandon the conventional framework of cognitive psychology in favor of the framework of nonlinear dynamical systems theory. Van Orden et al. presented evidence that "purposive behavior originates in self-organized criticality" (p. 333). Here, the authors show that Van Orden et al.'s analyses do not test their hypotheses. Further, the authors argue that a confirmation of Van Orden et al.'s hypotheses would not have constituted firm evidence in support of their framework. Finally, the absence of a specific model for how self-organized criticality produces the observed behavior makes it very difficult to derive testable predictions. The authors conclude that the proposed paradigm shift is presently unwarranted.

Selective and Nonselective Transfer: Positive and Negative Priming in a Multiple-Task Environment

Processing of a probe stimulus can be affected either positively or negatively by presenting a related stimulus immediately before it. According to structural accounts, such effects occur because processing of the prime activates or inhibits the mental representation of the probe before it is presented. In contrast, transfer-appropriate processing accounts suggest that success in processing a probe depends on resources made available by earlier experiences of related stimuli. The authors manipulated the similarity between the prime and probe on color, lexical status, and orthographic structure, requiring either lexical decision or color identification on each. The authors observed a complex pattern of positive and negative transfer that cannot easily be explained through activation-inhibition of mental structures. Instead, that pattern provides evidence in favor of transfer-appropriate processing.

Blocking by word frequency and neighborhood density in visual word recognition: A task-specific response criteria account

Effects of blocking words by frequency class (high vs. low) and neighborhood density (high vs. low) were examined in two experiments using progressive demasking and lexical decision tasks. The aim was to examine the predictions of a task-specific response criteria account of list-blocking effects. Distinct patterns of blocking effects were obtained in the two tasks. In the progressive demasking task, a pure-list disadvantage was obtained to low frequency-high density words, whereas high frequency-low density produced a trend toward a pure-list advantage. In lexical decision, high-frequency words showed a pure-list advantage that was strongest in high-density words, whereas low frequency-low density words produced a trend toward a pure-list disadvantage. A simulation study implementing task-specific response criteria within the framework of the multiple read-out model provided an accurate description of the blocking effects obtained in the experiments. It is argued that adjustments of task-specific response criteria determine changes in list-blocking effects across different tasks.

Serial mechanisms in lexical access: the rank hypothesis

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.

Does jugde activate COURT? Transposed-letter similarity effects in masked associative priming

Transposed-letter (TL) nonwords (e.g., jugde) can be easily misperceived as words, a fact that is somewhat inconsistent with the letter-position-coding schemes employed by most current models of visual word recognition. To examine this issue further, we conducted four masked semantic/associative priming experiments, using a lexical decision task. In Experiment 1, the related primes could be words, TL-internal nonwords, or replacement-letter (RL) nonwords (e.g., judge, jugde, or judpe, respectively; the target would be COURT). Relative to an unrelated condition, masked TL-internal primes produced a significant semantic/associative priming effect, an effect that was only slightly smaller than the priming effect for word primes. No effect, however, was observed for RL-nonword primes. In Experiment 2, the TL-nonword primes were created by switching the two final letters of the primes (e.g., judeg). The results again showed a semantic/associative priming effect for word primes, but not for TL-final nonword primes or for RL-nonword primes. Experiment 3 replicated the associative/semantic priming effect for TL-internal nonword primes, with, again, no effect for TL-final nonword primes. Finally, Experiment 4 again failed to yield a priming effect for TL-final nonword primes. The implications of these results for the choice of a letter-position-coding scheme in visual word recognition models are discussed.

A diffusion model account of the lexical decision task

The diffusion model for 2-choice decisions (R. Ratcliff, 1978) was applied to data from lexical decision experiments in which word frequency, proportion of high- versus low-frequency words, and type of nonword were manipulated. The model gave a good account of all of the dependent variables--accuracy, correct and error response times, and their distributions--and provided a description of how the component processes involved in the lexical decision task were affected by experimental variables. All of the variables investigated affected the rate at which information was accumulated from the stimuli--called drift rate in the model. The different drift rates observed for the various classes of stimuli can all be explained by a 2-dimensional signal-detection representation of stimulus information. The authors discuss how this representation and the diffusion model's decision process might be integrated with current models of lexical access.

Semantic and phonological influences on the processing of words and pseudohomophones

In two experiments, we investigated the relationship between semantics and phonology in the lexical decision task. In the first experiment, lexical decisions to words with large semantic neighborhoods were faster than those to words with sparse semantic neighborhoods. Conversely, this effect of semantic neighborhood was reversed for pseudohomophones (e.g., nale). That is, pseudohomophones based on words with large semantic neighborhoods took longer to reject than did those based on words with sparse semantic neighborhoods. In the second experiment, we found the magnitude of the semantic neighborhood effect for words to be a function of nonword foil type. Taken together, these results indicate that semantic neighborhood size affects processing of both words and pseudohomophones, and that the effect of semantic neighborhood size for words is more pronounced when pseudohomophone foils are employed. These effects are discussed in terms of a model in which the orthographic, phonological, and semantic systems are fully interactive.

Neural correlates of lexical access during visual word recognition

People can discriminate real words from nonwords even when the latter are orthographically and phonologically word-like, presumably because words activate specific lexical and/or semantic information. We investigated the neural correlates of this identification process using event-related functional magnetic resonance imaging (fMRI). Participants performed a visual lexical decision task under conditions that encouraged specific word identification: Nonwords were matched to words on orthographic and phonologic characteristics, and accuracy was emphasized over speed. To identify neural responses associated with activation of nonsemantic lexical information, processing of words and nonwords with many lexical neighbors was contrasted with processing of items with no neighbors. The fMRI data showed robust differences in activation by words and word-like nonwords, with stronger word activation occurring in a distributed, left hemisphere network previously associated with semantic processing, and stronger nonword activation occurring in a posterior inferior frontal area previously associated with grapheme-to-phoneme mapping. Contrary to lexicon-based models of word recognition, there were no brain areas in which activation increased with neighborhood size. For words, activation in the left prefrontal, angular gyrus, and ventrolateral temporal areas was stronger for items without neighbors, probably because accurate responses to these items were more dependent on activation of semantic information. The results show neural correlates of access to specific word information. The absence of facilitatory lexical neighborhood effects on activation in these brain regions argues for an interpretation in terms of semantic access. Because subjects performed the same task throughout, the results are unlikely to be due to task-specific attentional, strategic, or expectancy effects.