Verb retrieval in brain-damaged subjects: 1. Analysis of stimulus, lexical, and conceptual factors

Verb retrieval for action naming was assessed in 53 brain-damaged subjects by administering a standardized test with 100 items. The goal of the study was to gain further insight into the nature of verb processing impairments by investigating the influence of several kinds of stimulus, lexical, and conceptual factors on the subjects' performance at the level of group tendencies and also at the level of individual differences. (1) Stimulus factors: visual complexity, familiarity, image agreement, and one vs. two pictures (which corresponds to ongoing vs. completed actions); (2) lexical factors: name agreement, verb frequency, and whether the root of the target verb has a homophonous noun; (3) conceptual factors: whether the action is done with the hand or the body, whether the action involves one or two core participants, whether the undergoer of the action has a change of internal state, whether the undergoer has a change of spatial location, and whether the actor makes use of an instrument in carrying out the action. The subjects were divided into an impaired group (n = 19) and an unimpaired group (n = 34) on the basis of their overall performance on the test. For both groups of subjects, verb retrieval was significantly affected by the following factors: familiarity, image agreement, name agreement, homophonous noun, and undergoer change of location. These results indicate that, at the level of group analysis, some factors have a stronger influence on verb retrieval for action naming than others. Moreover, the finding that the two groups exhibited the same general pattern of factor sensitivity suggests that although the processing efficiency of the mechanisms that subserve verb retrieval is degraded in the impaired group, the basic functional properties of these mechanisms may not be qualitatively very different from those of the unimpaired group. Further analyses were conducted at the level of individual subjects and revealed a considerable amount of variation with regard to factor sensitivity. Many patterns of associations and dissociations of factors were found across the subjects, which suggests that the task of retrieving verbs for naming actions is quite complex and that different subjects can be influenced by different properties of both the stimuli and the target verbs.     

Theoretical analysis of the cognitive processing of lexical and pictorial stimuli: reading, naming, and visual and conceptual comparisons

This article reviews the research literature on the differences between word reading and picture naming. A theory for the visual and cognitive processing of pictures and words is then introduced. The theory accounts for slower naming of pictures than reading of words. Reading aloud involves a fast, grapheme-to-phoneme transformation process, whereas picture naming involves two additional processes: (a) determining the meaning of the pictorial stimulus and (b) finding a name for the pictorial stimulus. We conducted a reading-naming experiment, and the time to achieve (a) and (b) was determined to be approximately 160 ms. On the basis of data from a second experiment, we demonstrated that there is no significant difference in time to visually compare two pictures or two words when size of the stimuli is equated. There is no difference in time to make the two types of cross-modality conceptual comparisons (picture first, then word, or word first, then picture). The symmetry of the visual and conceptual comparison results supports the hypothesis that the coding of the mind is neither intrinsically linguistic nor imagistic, but rather it is abstract. There is a potent stimulus size effect, equal for both pictorial and lexical stimuli. Small stimuli take longer to be visually processed than do larger stimuli. For optimal processing, stimuli should not only be equated for size, but should subtend a visual angle of at least 3 degrees. The article ends with the presentation of a mathematical theory that jointly accounts for the data from word-reading, picture-naming visual comparison, and conceptual-comparison experiments.     

Eye movements and lexical ambiguity resolution: investigating the subordinate-bias effect

Recent debates on lexical ambiguity resolution have centered on the subordinate-bias effect, in which reading time is longer on a biased ambiguous word in a subordinate-biasing context than on a control word. The nature of the control word--namely, whether it matched the frequency of the ambiguous word's overall word form or its contextually instantiated word meaning (a higher or lower frequency word, respectively)--was examined. In addition, contexts that were singularly supportive of the ambiguous word's subordinate meaning were used. Eye movements were recorded as participants read contextually biasing passages that contained an ambiguous word target or a word-form or word-meaning control. A comparison of fixation times on the 2 control words revealed a significant effect of word frequency. Fixation times on the ambiguous word generally fell between those on the 2 controls and were significantly different than both. Results are discussed in relation to the reordered access model, in which both meaning frequency and prior context affect access procedures.     

Cumulating retrieval inhibition in semantic and lexical domains

In 3 experiments the authors examined changes in successive exemplar generation percentages within categories defined semantically (e.g., fruit-P, fruit-A, fruit-M) and by 1st letter (e.g., insect-C, sport-C, car-C), with a mixed control condition (e.g., fruit-P, insect-C, disease-M). Retrieval success declined across 12 successive items in both semantic and letter categories, with no change for the mixed condition. This retrieval inhibition is unrelated to taxonomic frequency of exemplars within either letter or semantic categorical structures. Furthermore, semantic retrieval inhibition appears to be long lasting, suggested by the decline in retrieval percentage across successive 12-item blocks in both the mixed and letter conditions. The authors suggest that different mechanisms underlie the inhibition found in the semantic (suppression) and letter (interference) conditions.     

Anxiety-related differences in affective categorizations of lexical stimuli

Effects of emotional valence on attention have been shown to occur even when stimuli are presented outside awareness. The impact of negative valence on stimulus processing has been demonstrated to be particularly salient in anxiety. Therefore, it has been hypothesized that compared to nonanxious individuals, anxious individuals have an enhanced ability to detect the valence of negative stimuli. However, it remains unclear whether anxious individuals are better at identifying the valence of threatening stimuli or, rather, more likely to label ambiguous stimuli as threatening. To investigate these hypotheses, high and low anxious participants categorized lexical stimuli as "safe" or "dangerous." Stimuli were presented at durations that allowed for both conscious (unmasked) and nonconscious (masked) processing. Results show that on masked trials, anxious individuals evidenced an enhanced ability to correctly classify threatening information, whereas nonanxious participants demonstrated an enhanced ability to correctly classify neutral or positive information. Signal detection analyses indicated results were explained by a response bias, whereby anxious individuals were more likely than nonanxious individuals to categorize masked words as threatening and nonanxious individuals were more likely to categorize masked words as nonthreatening. No group differences for nonword stimuli emerged, suggesting that anxiety-related response bias tendencies are activated only after detection of a weak semantic signal.     

Focused attention in the perception and retrieval of multidimensional stimuli

This paper reports some further experiments on successive matching of multidimensional stimuli in which the correct conjunctions of features must be specified; it also modifies and extends the model proposed earlier by Treisman, Sykes, and Gelade (1977). The results obtained in the previous experiment were replicated despite a change from fixed to varied targets, and from spatial to temporal separation of the targets, thus extending their generality. The modified conjunction-matching model proposes that the subject progressively narrows his focus of attention, first to deal with a single display stimulus at a time and finally, if necessary, to a single target. The model was tested quantitatively by simulating the separate stages hypothesized to underlie conjunction-matching in some simpler, single-attribute-matching conditions, and using the differences between latencies in these conditions to predict differences between latencies in the appropriate conjunction-matching conditions. The results were consistent with the general hypothesis that one important role of focused attention and serial processing is to integrate separable attributes or features into the correct conjunctions, which correspond to the objects actually presented or stored.     

Semantic priming and retrieval from lexical memory: Evidence for facilitatory and inhibitory processes

Immediately prior to each visually presented target letter string to which the subject made a speeded word-nonword classification response, a visually presented prime to which no overt response was required was shown for 360, 600, or 2,000 msec. For word (W) target trials, the priming event was either a semantically neutral warning signal (Condition NX), a word semantically related to the target word (Condition R), or a word semantically unrelated to the target word (Condition U); for nonword (N) target trials, the priming event was either the neutral warning signal (Condition NX) or a word prime (Condition WP). For the W target trials, reaction times (RTs) were slower in Condition U than in Condition NX and equally so for all three prime durations; RTs were faster in Condition R than in Condition NX and to a greater degree for the 600- and 2,000-msec prime durations than for the 360-msec prime duration. For the N targets, RTs were faster in Condition WP than in Condition NX and equally so for all prime durations. These results were interpreted within the framework of a two-factor theory of attention proposed by Posner and Snyder (1975a).     

Conscious and unconscious lexical retrieval blocking in younger and older adults

The effects of orthographically overlapping prime words in a word fragment completion task (modified from S. M. Smith & D. R. Tindell, 1997) were studied in younger and older adults. Participants studied words and then completed word fragments corresponding to those words. Fragments were preceded by a blocking, unrelated, or neutral prime. In Experiment 1, all participants were slower and less likely to complete the word fragments correctly in the blocking prime condition. Older adults also were more likely to use the blocking prime to incorrectly complete the word fragment compared with younger adults, even when warned against doing so (Experiment 2). Experiment 3 used a masked priming paradigm in younger adults to examine whether conscious processing of the prime word was necessary to produce blocking effects. Reliable blocking effects were obtained, including an intrusion rate similar to that observed in older adults in the first two experiments. These results suggest that certain aspects of word-finding failures in normal aging may be related to the reduced ability to control the activation of a lexical competitor when attempting to retrieve a target word.     

Space aliens and nonwords: stimuli for investigating the learning of novel word-meaning pairs.

We describe a set of pictorial and auditory stimuli that we have developed for use in word learning tasks in which the participant learns pairings of novel auditory sound patterns (names) with pictorial depictions of novel objects (referents). The pictorial referents are drawings of "space aliens," consisting of images that are variants of 144 different aliens. The auditory names are possible nonwords of English; the stimulus set consists of over 2,500 nonword stimuli recorded in a single voice, with controlled onsets, varying from one to seven syllables in length. The pictorial and nonword stimuli can also serve as independent stimulus sets for purposes other than word learning. The full set of these stimuli may be downloaded from www.psychonomic.org/archive/.     

The effects of prohibiting gestures on children's lexical retrieval ability

Two alternative accounts have been proposed to explain the role of gestures in thinking and speaking. The Information Packaging Hypothesis (Kita, 2000) claims that gestures are important for the conceptual packaging of information before it is coded into a linguistic form for speech. The Lexical Retrieval Hypothesis (Rauscher, Krauss & Chen, 1996) sees gestures as functioning more at the level of speech production in helping the speaker to find the right words. The latter hypothesis has not been fully explored with children. In this study children were given a naming task under conditions that allowed and restricted gestures. Children named more words correctly and resolved more 'tip-of-the-tongue' states when allowed to gesture than when not, suggesting that gestures facilitate access to the lexicon in children and are important for speech production as well as conceptualization.     

Introduction to special issue of Cognition on lexical and conceptual semantics.

It is the fate of those who dwell at the lower employments of life, to be rather driven by the fear of evil, than attracted by the prospect of good; to be exposed to censure, without hope of praise; to be disgraced by miscarriage, or punished for neglect, where success would have been without applause, and diligence without reward. Among these unhappy mortals is the writer of dictionaries ... (Preface, Samuel Johnson's Dictionary, 1755).     

Dyslexia, dysnomia, and lexical retrieval: a longitudinal investigation

Results from a 3-year longitudinal investigation of confrontation naming in 98 children (75 average readers, 14 severely impaired readers, 9 bilingual readers) indicate: kindergarten performance on confrontation naming predicts Grade 2 reading performance, particularly reading comprehension; confrontation naming differentiates average from severely impaired readers; and lexical retrieval, not vocabulary knowledge, is the major source of difference between reading groups. Findings on lexical retrieval are integrated with research on naming access speed. The implications of these results for specification of dyslexia subgroups are discussed.     

Modeling lexical decision and word naming as a retrieval process.

We argue that rule-like phenomena in naming and lexical decision reflect the collapsing of information that occurs during retrieval from the lexicon, and that complex patterns in performance reflect the pattern of correlation that exists in the reader's lexicon rather than mapping rules wired into, or learned by, the processing apparatus. By using a lexicon built to scale, we show that simple retrieval operations applied to a large corpus of words correctly predict an interaction of word frequency by spelling-to-sound regularity in naming, a frequency main effect in lexical decision, sensitivity to orthographically defined syllable-like structures in lexical decision, and an interaction of number of syllables with word frequency in naming.     

Age differences in recognition of emotion in lexical stimuli and facial expressions

Age differences in emotion recognition from lexical stimuli and facial expressions were examined in a cross-sectional sample of adults aged 18 to 85 (N = 357). Emotion-specific response biases differed by age: Older adults were disproportionately more likely to incorrectly label lexical stimuli as happiness, sadness, and surprise and to incorrectly label facial stimuli as disgust and fear. After these biases were controlled, findings suggested that older adults were less accurate at identifying emotions than were young adults, but the pattern differed across emotions and task types. The lexical task showed stronger age differences than the facial task, and for lexical stimuli, age groups differed in accuracy for all emotional states except fear. For facial stimuli, in contrast, age groups differed only in accuracy for anger, disgust, fear, and happiness. Implications for age-related changes in different types of emotional processing are discussed.     

Situation-evoking stimuli,domain of reference,and the incremental interpretation of lexical ambiguity

In two experiments, we examined the influence of situation-evoking stimuli on the resolution of lexical ambiguity. In Experiment 1, we examined situation-evoking stimuli at an early NP position. Readers were asked to establish whether specific entities were likely to participate as agents in contextually defined situations. Naming latencies demonstrated that defined situations headed by likely agents evoked a domain of reference that included only the situation-appropriate meaning of a targeted lexical ambiguity. In contrast, defined situations headed by unlikely agents evoked a domain of reference that did not include either meaning of the intended ambiguous word. In Experiment 2, we examined situation-evoking stimuli at a later direct object position. The specificity of the theme/patient role filler was manipulated, where the linguistic expressions were either specific or general with respect to a given contextual situation. The results showed that contexts with specific situation-evoking stimuli were rated as strongly biased and provided a domain of reference for the immediate resolution of lexical ambiguity, whereas contexts with nonspecific role fillers were rated as ambiguous and provided a domain of reference that was supportive of both meanings of an ambiguous word. The results were discussed within a contextual-feature-sensitive model of language processing.     

Quantitative numerical and lexical knowledge: evidence of double dissociation

The aim of this work was to explain the involvement of a specific brain injury in the numerical processing and calculation system. The method employed was > analysis and the administration of various cognitive neuropsychology tests. The results of this study revealed a double dissociation between quantitative numerical knowledge and qualitative or lexical numerical knowledge. Patient M.C. preserved quantitative numerical knowledge, as indicated by the results obtained in the numerical comprehension and calculation tasks. However, she showed a drastic deficit in qualitative numerical knowledge. On the other hand, patient M.L. preserved qualitative numerical knowledge, but she had serious problems in all the abilities that require internal manipulation of magnitude; that is, quantitative numerical knowledge. These results have two important implications, as conclusions: firstly, quantitative numerical knowledge may be made up of different elements susceptible to damage independently. And secondly, quantitative and qualitative numerical knowledge were functionally independent.     

Integrating conceptual knowledge within and across representational modalities

Research suggests that concepts are distributed across brain regions specialized for processing information from different sensorimotor modalities. Multimodal semantic models fall into one of two broad classes differentiated by the assumed hierarchy of convergence zones over which information is integrated. In shallow models, communication within- and between-modality is accomplished using either direct connectivity, or a central semantic hub. In deep models, modalities are connected via cascading integration sites with successively wider receptive fields. Four experiments provide the first direct behavioral tests of these models using speeded tasks involving feature inference and concept activation. Shallow models predict no within-modal versus cross-modal difference in either task, whereas deep models predict a within-modal advantage for feature inference, but a cross-modal advantage for concept activation. Experiments 1 and 2 used relatedness judgments to tap participants’ knowledge of relations for within- and cross-modal feature pairs. Experiments 3 and 4 used a dual-feature verification task. The pattern of decision latencies across Experiments 1–4 is consistent with a deep integration hierarchy.     

The impact of retrieval suppression on conceptual implicit memory

ABSTRACT

When people suppress retrieval of episodic memories, it can induce forgetting on later direct tests of memory for those events. Recent reports indicate that suppressing retrieval affects less conscious, unintentional retrieval of unwanted memories as well, at least on perceptually-oriented indirect tests. In the current study we examined how suppressing retrieval affects conceptual implicit memory for the suppressed content, using a category verification task. Participants studied cue-target words pairs in which the targets were exemplars of 22 semantic categories, such as vegetables or occupations. They then repeatedly retrieved or suppressed the targets in response to the cues for some of those pairs. Afterwards, they were exposed to the targets intermixed with novel items, one at a time, and asked to verify the membership of each of the words in a semantic category, as quickly as possible. Judgment response times to studied words were faster than to unstudied exemplars, reflecting repetition priming, as has been previously observed. Strikingly, the beneficial effects of prior exposure on response time were eliminated for targets that had been suppressed. Follow-up explicit memory tests also demonstrated that retrieval suppression continued to disrupt episodic recall for the items that had been just been re-exposed on the category verification test. These findings support the contention that the effects of retrieval suppression are not limited to episodic memory, but also affect indirect expressions of those memories on conceptually oriented tests, raising the possibility that underlying semantic representations of suppressed content are affected.     

Taxonomic and thematic organisation of proper name conceptual knowledge

We report the investigation of the organisation of proper names in two aphasic patients (NBC and FBI). The performance of both patients on spoken word to written word matching tasks was inconsistent, affected by presentation rate and semantic relatedness of the competing responses, all hallmarks of a refractory semantic access dysphasia. In a series of experiments we explored the semantic relatedness effects within their proper name vocabulary, including brand names and person names. First we demonstrated the interaction between very fine grain organisation and personal experience, with one patient with a special interest in the cinema demonstrating higher error rates when identifying the names of actors working in a similar film genre (e.g., action movies: Arnold Schwarzenegger, Bruce Willis, Sylvester Stallone, Mel Gibson) than those working in different genres (e.g., Arnold Schwarzenegger, Gregory Peck, Robin Williams, Gene Kelly). Second we compared directly two potential principles of semantic organisation - taxonomic and thematic. Furthermore we considered these principles of organisation in the context of the individuals' personal knowledge base. We selected topics matching the interests and experience of each patient, namely cinema and literature (NBC) and naval history (FBI). The stimulus items were arranged in taxonomic arrays (e.g., Jane Austen, Emily Bronte, Agatha Christie), thematic arrays (e.g., Jane Austen, Pride and Prejudice, Mr Darcy), and unrelated arrays (e.g., Jane Austen, Wuthering Heights, Hercule Poirot). We documented that different patterns of taxonomic and thematic organisation were constrained by whether the individual has limited knowledge, moderate knowledge or detailed knowledge of a particular vocabulary. It is suggested that moderate proper name knowledge is primarily organised by taxonomy whereas extensive experience results in a more detailed knowledge base in which theme is a powerful organising principle.