The mental representation of living and nonliving things: Differential weighting and interactivity of sensorial and non-sensorial features

Warrington and colleagues (Warrington & McCarthy, 1983, 1987; Warrington & Shallice, 1984) claimed that sensorial and functional-associative (FA) features are differentially important in determining the meaning of living things (LT) and nonliving things (NLT). The first aim of the present study was to evaluate this hypothesis through two different access tasks: feature generation (Experiment 1) and cued recall (Experiment 2). The results of both experiments provided consistent empirical support for Warrington and colleagues' assumption. The second aim of the present study was to test a new differential interactivity hypothesis that combines Warrington and colleagues' assumption with the notion of a higher number of intercorrelations and hence of a stronger connectivity between sensorial and non-sensorial features for LTs than for NLTs. This hypothesis was motivated by previous reports of an uncrossed interaction between domain (LTs vs NLTs) and attribute type (sensorial vs FA) in, for example, a feature verification task (Laws, Humber, Ramsey, & McCarthy, 1995): while FA attributes are verified faster than sensorial attributes for NLTs, no difference is observed for LTs. We replicated and generalised this finding using several feature verification tasks on both written words and pictures (Experiment 3), including in conditions aimed at minimising the intervention of priming biases and strategic or mnemonic processes (Experiment 4). The whole set of results suggests that both privileged relations between features and categories, and the differential importance of intercorrelations between features as a function of category, modulate access to semantic features.     

Evaluating feature-category relations using semantic fluency tasks

The issue of the relationship between semantic features and semantic categories has been raised by Warrington and colleagues, who claimed that sensory and functional-associative features are differentially important in determining the meaning of living and nonliving things (Warrington & McCarthy, 1983, 1987; Warrington & Shallice, 1984). In the present study, the effectiveness of semantic memory search for living and nonliving things with sensory and functional-associative search cues was evaluated through eight different adaptations of the semantic fluency task. More living thing responses and clusters were generated from sensory than from functional-associative search cues, while the reverse pattern holds for nonliving things responses and clusters. The results thus provide consistent empirical support for the assumption that sensory properties are fundamental in the representation of living things, while functional-associative properties are fundamental in the semantic representation of nonliving things.     

Relational similarity and the nonindependence of features in similarity judgments

Four experiments examined the hypothesis that simple attributional features and relational features operate differently in the determination of similarity judgments. Forced choice similarity judgments ("Is X or Y more similar to Z?") and similarity rating tasks demonstrate that making the same featural change in two geometric stimuli unequally affects their judged similarity to a third stimulus (the comparison stimulus). More specifically, a featural change that causes stimuli to be more superficially similar and less relationally similar increases judged similarity if it occurs in stimuli that already share many superficial attributes, and decreases similarity if it occurs in stimuli that do not share as many superficial attributes. These results argue against an assumption of feature independence which asserts that the degree to which a feature shared by two objects affects similarity is independent of the other features shared by the objects. The MAX hypothesis is introduced, in which attributional and relational similarities are separately pooled, and shared features affect similarity more if the pool they are in is already relatively large. The results support claims that relations and attributes are psychologically distinct and that formal measures of similarity should not treat all types of matching features equally.     

Sometimes a noun is just a noun: comments on Bird, Howard, and Franklin (2000)

Bird, Howard, and Franklin (2000) have proposed a semantic-conceptual explanation of grammatical category-specific deficits that attributes impairments in noun and verb processing to two distinct mechanisms. According to their account, apparent deficits in verb production are not category specific, but rather result from the lower imageability of verbs compared to concrete nouns. Noun deficits are said to result from differences in the distribution of semantic feature types such that damage to sensory features results in disproportionate impairments in naming nouns, especially animate nouns, compared to verbs. However, this hypothesis, which we call the "extended sensory/functional theory" (ESFT), fails on several counts. First, the assumption that representations of living things are more heavily freighted with sensory features than are those of nonliving objects does not have any reliable empirical basis. Second, the ESFT incorrectly predicts associations between deficits in processing sensory features and living things or functional features and nonliving things. Finally, there are numerous cases of patients with grammatical category-specific deficits that do not seem to be consistent with damage at the semantic level. All of this suggests that the ESFT is not a useful model for considering grammatical (or semantic) category-specific deficits.     

Semantic memory: Complexity or connectivity?

The complexity hypothesis predicts that concept-feature verification times should be directly related to the number of features associated with a concept (the fan effect). Conversely, the connectivity hypothesis predicts that for interconnected semantic relationships, this verification time should be inversely related to the number of closely associated features (the reversed fan effect). In the present experiments, although the time required for episodic recognition memory decisions tended to be directly related to the number of features associated with a concept, semantic verification times were inversely related to the complexity of the concept. In addition, the concept's complexity was at least as good a predictor of performance in semantic tasks as was the strength of association between the concept and feature. Both of these results are interpreted in terms of the connectivity hypothesis.     

Names,concepts, features and the living/nonliving things dissociation

The present paper evaluates different hypotheses for explaining the living/nonliving things dissociation phenomenon in terms of feature type, considering the role of this dimension in the organization of conceptual semantic representations and in the activation of name representations. For this purpose we used Sloman and associates' (Memory and Cognition 27(3) (1999) 526; Cognitive Science 22(2) (1998) 189) name centrality and conceptual centrality tasks and asked subjects to judge functional and perceptual/visual features of living and nonliving items. Conceptual centrality results are more in accordance with a "single feature-domain connection hypothesis" where visual features are more important than functional features for the representation of living things and no feature type advantage is found for nonliving things. Name centrality results show that functional features are more important than sensory/visual features overall, a result that is not predicted by any of the hypotheses considered. The fact that the two judgments diverge emphasizes their importance for evaluating the role of feature type in the living/nonliving dissociation. Implications for explaining this phenomenon are also discussed.     

Learning about the internal structure of categories through classification and feature inference

Previous research on category learning has found that classification tasks produce representations that are skewed toward diagnostic feature dimensions, whereas feature inference tasks lead to richer representations of within-category structure. Yet, prior studies often measure category knowledge through tasks that involve identifying only the typical features of a category. This neglects an important aspect of a category's internal structure: how typical and atypical features are distributed within a category. The present experiments tested the hypothesis that inference learning results in richer knowledge of internal category structure than classification learning. We introduced several new measures to probe learners' representations of within-category structure. Experiment 1 found that participants in the inference condition learned and used a wider range of feature dimensions than classification learners. Classification learners, however, were more sensitive to the presence of atypical features within categories. Experiment 2 provided converging evidence that classification learners were more likely to incorporate atypical features into their representations. Inference learners were less likely to encode atypical category features, even in a “partial inference” condition that focused learners' attention on the feature dimensions relevant to classification. Overall, these results are contrary to the hypothesis that inference learning produces superior knowledge of within-category structure. Although inference learning promoted representations that included a broad range of category-typical features, classification learning promoted greater sensitivity to the distribution of typical and atypical features within categories.     

Causal status as a determinant of feature centrality

One of the major problems in categorization research is the lack of systematic ways of constraining feature weights. We propose one method of operationalizing feature centrality, a causal status hypothesis which states that a cause feature is judged to be more central than its effect feature in categorization. In Experiment 1, participants learned a novel category with three characteristic features that were causally related into a single causal chain and judged the likelihood that new objects belong to the category. Likelihood ratings for items missing the most fundamental cause were lower than those for items missing the intermediate cause, which in turn were lower than those for items missing the terminal effect. The causal status effect was also obtained in goodness-of-exemplar judgments (Experiment 2) and in free-sorting tasks (Experiment 3), but it was weaker in similarity judgments than in categorization judgments (Experiment 4). Experiment 5 shows that the size of the causal status effect is moderated by plausibility of causal relations, and Experiment 6 shows that effect features can be useful in retrieving information about unknown causes. We discuss the scope of the causal status effect and its implications for categorization research.     

Response-effect compatibility in manual choice reaction tasks

This study investigated whether compatibility between responses and their consistent sensorial effects influences performance in manual choice reaction tasks. In Experiment 1 responses to the nonspatial stimulus attribute of color were affected by the correspondence between the location of responses and the location of their visual effects. In Experiment 2, a comparable influence was found with nonspatial responses of varying force and nonspatial response effects of varying auditory intensity. Experiment 3 ruled out the hypothesis that acquired stimulus-effect associations may account for this influence of response-effect compatibility. In sum, the results show that forthcoming response effects influence response selection as if these effects were already sensorially present, suggesting that in line with the classical ideomotor theory, anticipated response effects play a substantial role in response selection.     

Attentional resource demands of visual word recognition in naming and lexical decisions.

Attentional demands of lexical access were assessed with dual-task methodology. Subjects performed an auditory probe task alone (single-task) or combined (dual-task) with either a lexical decision or a naming task. In Experiment 1, probe performance showed a decrement from single- to dual-task conditions during recognition of words in both lexical decision and naming tasks. In addition, decrements in probe performance were larger during processing of low-frequency compared with high-frequency words in both of the word recognition tasks. Experiment 2 showed that the time course of frequency-sensitive demands was similar across lexical decision and naming tasks and that attention is required early in the word recognition sequence. The results support the assumption that lexical access is both frequency sensitive and attention demanding.     

Hemispheric activation increases positive manifold for lateralized cognitive tasks: an extension of Stankov's hypothesis

Stankov (1983a, Journal of Educational Psychology, 75, 471-490) suggests that the dual task paradigm, requiring the division of attention, increases positive manifold (i.e., positive intercorrelations) for cognitive tasks relative to the single task paradigm. Two dual task studies are reported. Unimanual finger-tapping served as the primary task and the short-term retention (20 sec) of digit or spatial-location sequences served as the secondary tasks. When both tasks were lateralized to the same hemisphere (digits and right-hand tapping or spatial locations and left-hand tapping), highest memory task intercorrelations (Experiment 1) and better retention of sequences (Experiments 1 and 2) resulted. Left-hand tapping produced more leftward looking and right-hand tapping more rightward looking (Experiment 2). Overflow from lateralized finger-tapping may shift the gradient of attentional activation toward the contralateral hemisphere, producing the homolateral gaze direction, the increase in positive manifold, and the better retention of sequences lateralized to that hemisphere.     

Analyzing feature distinctiveness in the processing of living and non-living concepts in Alzheimer’s disease

The conceptual structure account (CSA) is a model specifying the role of the living and non-living domain dichotomy in the structure of semantic memory. According to this model, feature distinctiveness and the perceptual–functional inter-correlation of concepts are assumed to play a major role in impairing the ability to discriminate between living and non-living concepts in Alzheimer’s disease (AD). The hypothesis was tested in this study by using naming and sorting tasks traditionally considered as assessing distinctiveness, and a property verification task where distinctiveness and perceptual–functional inter-correlation were objectively controlled against norms especially created for this purpose. Alzheimer’s patients (n = 59) with minimal, mild or moderate dementia and normal elderly adults (n = 31) participated in the study. Overall, the findings did not support the CSA predictions. They revealed a distinctiveness effect on response accuracy with shared features dominating distinctive features regardless of domain. They also revealed more difficulties in the tasks involving effortful processes. The results stress the need to consider both cognitive demands of tasks and structural aspects of knowledge in the evaluation of semantic memory in AD.     

Semantic and visual relatedness of distractors impairs episodic retrieval of pictures in a divided attention paradigm

We used a divided attention (DA) paradigm to infer the representational codes needed to support episodic retrieval of pictures, by measuring susceptibility to memory interference from different distracting tasks. Participants made recognition memory decisions to semantically categorized sets of pictures while simultaneously making size judgments to a set of visually-presented distractor pictures. Recognition accuracy was worse and response times were slower under DA conditions relative to full attention (FA), regardless of semantic relatedness of distractors to targets (Experiment 1). Similarly, we found no differential memory interference under DA relative to FA when distractor pictures were either visually (but not semantically), semantically (but not visually), or unrelated to the targets (Experiment 2). In Experiment 3, memory interference was significantly larger under DA at retrieval when distractors were both semantically and visually similar to the targets. Findings suggest episodic memory for pictures requires access to either visually- or semantically-based representations for optimal performance.     

Exploring the identification-production hypothesis of repetition priming in young and older adults

The identification-production hypothesis of age-related differences in repetition priming predicts reduced priming in older adults on indirect memory measures that require stimulus production (production priming) together with age constancy on indirect measures that require stimulus identification, verification, or classification processes (identification priming). Although some evidence is consistent with this hypothesis, comparisons of identification and production priming in young and older adults often confound stimulus, subject, and dependent measure factors across tasks. Consequently, repetition priming has yet to be assessed in healthy young and healthy older adults using identification and production tasks that control for these factors. The identification-production hypothesis was tested using verb generation as a measure of production priming (Experiments 1-3) and semantic classification (Experiment 1) or semantic verification (Experiments 2 and 3) as the measure of identification priming. Contrary to the identification-production hypothesis, no age-related diminutions in identification or production forms of priming were found.     

Attending to the big picture: mood and global versus local processing of visual information

Two experiments employed image-based tasks to test the hypothesis that happier moods promote a greater focus on the forest and sadder moods a greater focus on the trees. The hypothesis was based on the idea that in task situations, affective cues may be experienced as task-relevant information, which then influences global versus local attention. Using a serial-reproduction paradigm, Experiment 1 showed that individuals in sad moods were less likely than those in happier moods to use an accessible global concept to guide attempts to reproduce a drawing from memory. Experiment 2 investigated the same hypothesis by assessing the use of global and local attributes to classify geometric figures. As predicted, individuals in sad moods were less likely than those in happier moods to classify figures on the basis of global features.     

Distinctiveness and correlation in conceptual structure: behavioral and computational studies

Patients with category-specific deficits have motivated a range of hypotheses about the structure of the conceptual system. One class of models claims that apparent category dissociations emerge from the internal structure of concepts rather than fractionation of the system into separate substores. This account claims that distinctive properties of concepts in the living domain are vulnerable because of their weak correlation with other features. Given the assumption that mutual activation among correlated properties produces faster activation in the normal system, the authors predicted a disadvantage for the distinctive features of living things for unimpaired adults. Results of a speeded feature verification study supported this prediction, as did a computational simulation in which networks mapped from orthography to semantics.     

Violations of implicit theories and the sense of prediction and control: implications for motivated person perception

Beginning with the assumption that implicit theories of personality are crucial tools for understanding social behavior, the authors tested the hypothesis that perceivers would process person information that violated their predominant theory in a biased manner. Using an attentional probe paradigm (Experiment 1) and a recognition memory paradigm (Experiment 2), the authors presented entity theorists (who believe that human attributes are fixed) and incremental theorists (who believe that human attributes are malleable) with stereotype-relevant information about a target person that supported or violated their respective theory. Both groups of participants showed evidence of motivated, selective processing only with respect to theory-violating information. In Experiment 3, the authors found that after exposure to theory-violating information, participants felt greater anxiety and worked harder to reestablish their sense of prediction and control mastery. The authors discuss the epistemic functions of implicit theories of personality and the impact of violated assumptions.     

See what I mean? An ERP study of the effect of background knowledge on novel object processing

Two event-related potential (ERP) experiments were used to examine the representation of object feature information and background knowledge in semantic memory. Participants were trained on novel object categories with three features and were tested with new exemplars that were complete or were missing one to two features that were essential or nonessential to object function. In both a category membership judgment task (Experiment 1) and a parts detection task (Experiment 2), the N400, a functionally specific measure of semantic access, was graded with feature number but was insensitive to knowledge-based feature importance. A separable ERP effect related to knowledge was seen in Experiment 1 as an enhanced frontocentral negativity (beginning ∼300 msec) to exemplars missing a nonessential versus an essential feature, but this effect did not manifest when background knowledge was less task relevant (Experiment 2). Thus, similarity- and knowledge-based effects are separable, and the locus of knowledge effects varies with task demands but does not seem to arise from facilitated semantic access.     

汉语词汇习得的年龄效应：语义假设的证据

通过三个实验考察了词汇加工中的习得年龄效应。实验一对比了汉字命名和图片命名中词汇习得的年龄效应,发现图片命名中存在着较大的词汇习得的年龄效应,汉字命名中没有出现这种效应。实验二和实验三分别采用语义范畴判断任务和图片语义分类任务,两个实验均发现了词汇习得的年龄效应。实验结果说明,词汇习得的年龄效应至少部分来源于语义加工的层次,结果支持了语义假设的观点     

Independent dimension-weighting mechanisms for visual selection and stimulus identification

Observers respond faster when the task-relevant perceptual dimension (e.g., color) repeats across consecutive trials relative to when it changes. Such dimension repetition benefits (DRBs) occur in different tasks, from singleton feature search to feature discrimination of a stimulus presented on its own. Here, we argue that the DRBs observed in different tasks originate from distinct mechanisms: preselective weighting of dimension-specific feature contrast signals and, respectively, postselective stimulus processing. The multiple-weighting-systems hypothesis predicts significant DRBs across trials of different tasks that share the same weighting mechanism, but not across tasks involving different mechanisms. Experiments 1, 2, and 3 examined DRBs across localization and detection tasks (both involving feature contrast computations); across detection and identification tasks (which presumably involved different weighting systems); and across identification and discrimination tasks (both involving stimulus identification). As expected, significant DRBs were observed across different tasks in Experiments 1 and 3, but not in Experiment 2. These findings support the multiple-weighting-systems hypothesis.