Primacy of functional knowledge in semantic representations: The case of living and nonliving things

In 3 experiments, participants decided whether sensory and functional features were true of living and nonliving concepts. In Experiments 1 and 2, concepts were presented twice: test phase followed study phase after either 3 min (Experiment 1) or 3 s (Experiment 2). At test, concepts were paired with the same feature as that at study, or a different feature from either the same modality (within-modality priming) or another modality (cross-modality priming). In both experiments functional decisions were faster than sensory decisions for living and nonliving concepts. Whilst no semantic priming occurred between study and test in Experiment 1, the shorter study–test interval of Experiment 2 did lead to test phase semantic priming. Here there was greater within- than cross-modality priming for sensory decisions, but equivalent within- and cross-modality priming for functional decisions owing to significantly greater facilitation of functional decisions from prior sensory decisions than vice versa. Experiment 3 involved a single verification phase: For half the participants the feature name preceded the concept name, and for half the concept name preceded the feature name. The functional processing advantage persisted irrespective of presentation order. Results suggest that functional information is central to the representation of all concepts: Function is processed faster than sensory information and is activated obligatorily.     

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.     

Semantic feature production norms for a large set of living and nonliving things

Semantic features have provided insight into numerous behavioral phenomena concerning concepts, categorization, and semantic memory in adults, children, and neuropsychological populations. Numerous theories and models in these areas are based on representations and computations involving semantic features. Consequently, empirically derived semantic feature production norms have played, and continue to play, a highly useful role in these domains. This article describes a set of feature norms collected from approximately 725 participants for 541 living (dog) and nonliving (chair) basic-level concepts, the largest such set of norms developed to date. This article describes the norms and numerous statistics associated with them. Our aim is to make these norms available to facilitate other research, while obviating the need to repeat the labor-intensive methods involved in collecting and analyzing such norms. The full set of norms may be downloaded from www.psychonomic.org/archive.     

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.     

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.     

Visual similarity is greater for line drawings of nonliving than living things: the importance of musical instruments and body parts

It has been argued that greater intra-category structural similarity for living things, and the subsequent "visual crowding," makes them more difficult to recognize and name for neurologically damaged individuals and normal subjects (Humphreys et al., 1988). Nevertheless, the precise meaning and quantification of structural similarity remains unclear, as does the rationale for why it necessarily should be greater for living things. We derived a new measure of visual overlap from the Snodgrass and Vanderwart corpus of line drawings: the degree of pixel overlap within subcategories (Euclidean distance: ED). Contrary to existing notions of visual crowding and extant measures of contour overlap, within-category ED indicated less within-category visual overlap for living things. Furthermore, musical instruments clustered with living things (having low overlap), while body parts clustered with nonliving things (having high overlap). These counter-intuitive findings accord with patient data and thus, provide evidence for the psychological reality and utility of ED.     

Semantic processing of living and nonliving concepts across the cerebral hemispheres

Studies of patients with category-specific semantic deficits suggest that the right and left cerebral hemispheres may be differently involved in the processing of living and nonliving domains concepts. In this study, we investigate whether there are hemisphere differences in the semantic processing of these domains in healthy volunteers. Based on the neuropsychological findings, we predicted a disadvantage for nonliving compared to living concepts in the right hemisphere. Our prediction was supported, in that semantic decisions to nonliving concepts were significantly slower and more error-prone when presented to the right hemisphere. In contrast there were no hemisphere differences for living concepts. These findings are consistent with either differential representation or processing of concepts across right and left hemispheres. However, we also found a disadvantage for nonliving things compared to living things in the left hemisphere, which is not consistent with a simple representation account. We discuss these findings in terms of qualitatively different semantic processing in right and left hemispheres within the framework of a distributed model of conceptual representation.     

Hearing living symbols and nonliving icons: Category specificities in the cognitive processing of environmental sounds

The neurocognitive processing of environmental sounds and linguistic stimuli shares common semantic resources and can lead to the activation of motor programs for the generation of the passively heard sound or speech. We investigated the extent to which the cognition of environmental sounds, like that of language, relies on symbolic mental representations independent of the acoustic input. In a hierarchical sorting task, we found that evaluation of nonliving sounds is consistently biased toward a focus on acoustical information. However, the evaluation of living sounds focuses spontaneously on sound-independent semantic information, but can rely on acoustical information after exposure to a context consisting of nonliving sounds. We interpret these results as support for a robust iconic processing strategy for nonliving sounds and a flexible symbolic processing strategy for living sounds.     

Geometric and featural representations in semantic concepts

We explore the adequacy of two types of similarity representation in the context of semantic concepts. To this end, we evaluate different categorization models, assuming either a geometric or a featural representation, using categorization decisions involving familiar and unfamiliar foods and animals. The study aims to assess the optimal stimulus representation as a function of the familiarity of the stimuli. For the unfamiliar stimuli, the geometric categorization models provide the best account of the categorization data, whereas for the familiar stimuli, the featural categorization models provide the best account. This pattern of results suggests that people rely on perceptual information to assign an unfamiliar stimulus to a category but rely on more elaborate conceptual knowledge when assigning a familiar stimulus.     

Decoding semantic representations in mind and brain

A key goal for cognitive neuroscience is to understand the neurocognitive systems that support semantic memory. Recent multivariate analyses of neuroimaging data have contributed greatly to this effort, but the rapid development of these novel approaches has made it difficult to track the diversity of findings and to understand how and why they sometimes lead to contradictory conclusions. We address this challenge by reviewing cognitive theories of semantic representation and their neural instantiation. We then consider contemporary approaches to neural decoding and assess which types of representation each can possibly detect. The analysis suggests why the results are heterogeneous and identifies crucial links between cognitive theory, data collection, and analysis that can help to better connect neuroimaging to mechanistic theories of semantic cognition.     

Priming of semantic autobiographical knowledge: a case study of retrograde amnesia

The case of a 36-year-old man who suffers dense retrograde and anterograde amnesia as a result of closed-head injury that caused extensive damage to his left frontal-parietal and right parieto-occipital lobes is described. Patient K.C. has normal intelligence and relatively well-preserved perceptual, linguistic, short-term memory, and reasoning abilities. He possesses some fragmentary general knowledge about his autobiographical past, but he does not remember a single personal event or happening from any time of his life. He has some preserved expert knowledge related to the work he did for 3 years before the onset of amnesia, although he has no personal recollections from that period. Some features of K.C.'s retrograde amnesia can be interpreted in terms of the distinction between episodic and semantic memory, and in terms of the distinction between episodic and semantic autobiographical knowledge. K.C.'s semantic knowledge, but not his episodic knowledge, showed progressive improvement, or priming, in the course of the investigation.     

Primacy of emotional vs. semantic scene recognition in peripheral vision

Emotional scenes were presented peripherally (5.2° away from fixation) or foveally (at fixation) for 150 ms. In affective evaluation tasks viewers judged whether a scene was unpleasant or not, or whether it was pleasant or not. In semantic categorisation tasks viewers judged whether a scene involved animals or humans (superordinate-level task), or whether it portrayed females or males (subordinate-level task). The same stimuli were used for the affective and the semantic task. Results indicated that in peripheral vision affective evaluation was less accurate and slower than animal/human discrimination, and did not show any advantage over gender discrimination. In addition, performance impairment in the peripheral relative to the foveal condition was greater or equivalent for affective than for semantic categorisation. These findings cast doubts on the specialness and the primacy of affective over semantic recognition. The findings are also relevant when considering the role of the subcortical "low route" in emotional processing.     

Primacy of emotional vs. semantic scene recognition in peripheral vision

Emotional scenes were presented peripherally (5.2° away from fixation) or foveally (at fixation) for 150 ms. In affective evaluation tasks viewers judged whether a scene was unpleasant or not, or whether it was pleasant or not. In semantic categorisation tasks viewers judged whether a scene involved animals or humans (superordinate-level task), or whether it portrayed females or males (subordinate-level task). The same stimuli were used for the affective and the semantic task. Results indicated that in peripheral vision affective evaluation was less accurate and slower than animal/human discrimination, and did not show any advantage over gender discrimination. In addition, performance impairment in the peripheral relative to the foveal condition was greater or equivalent for affective than for semantic categorisation. These findings cast doubts on the specialness and the primacy of affective over semantic recognition. The findings are also relevant when considering the role of the subcortical “low route” in emotional processing.     

Usage of semantic representations in recognition memory

Meanings of words facilitate false acceptance as well as correct rejection of lures in recognition memory tests, depending on the experimental context. This suggests that semantic representations are both directly and indirectly (i.e., mediated by perceptual representations) used in remembering. Studies using memory conjunction errors (MCEs) paradigms, in which the lures consist of component parts of studied words, have reported semantic facilitation of rejection of the lures. However, attending to components of the lures could potentially cause this. Therefore, we investigated whether semantic overlap of lures facilitates MCEs using Japanese Kanji words in which a whole-word image is more concerned in reading. Experiments demonstrated semantic facilitation of MCEs in a delayed recognition test (Experiment 1), and in immediate recognition tests in which participants were prevented from using phonological or orthographic representations (Experiment 2), and the salient effect on individuals with high semantic memory capacities (Experiment 3). Additionally, analysis of the receiver operating characteristic suggested that this effect is attributed to familiarity-based memory judgement and phantom recollection. These findings indicate that semantic representations can be directly used in remembering, even when perceptual representations of studied words are available.     

Determining the dimensionality in spatial representations of semantic concepts

When multidimensional scaling solutions are used to study semantic concepts, the dimensionality of the optimal configuration has to be determined. Several strategies have been proposed to choose the appropriate dimensionality. In the present paper, the traditional dimensionality choice criteria were evaluated and compared to a method based on the prediction of an external criterion. Two studies were conducted in which typicality of an exemplar within a semantic concept was predicted from its distance to the concept centroid. In contrast to the low-dimensional solutions selected by the traditional methods, predictions of an external criterion improved with additional dimensions up till dimensionalities that were much higher than what is common in the literature. This suggests that traditional methods underestimate the richness of semantic concepts as revealed in spatial representations derived from similarity measures.     

How do young children deal with hybrids of living and non‐living things: The case of humanoid robots

In this experiment, we tested children's intuitions about entities that bridge the contrast between living and non‐living things. Three‐ and four‐year‐olds were asked to attribute a range of properties associated with living things and machines to novel category‐defying complex artifacts (humanoid robots), a familiar living thing (a girl), and a familiar complex artifact (a camera). Results demonstrated that 4‐year‐olds tended to treat the category‐defying entities like members of the inanimate group, while 3‐year‐olds showed more variability in their responding. This finding suggests that preschoolers' ability to classify complex artifacts that cross the living–non‐living divide becomes more stable between the ages of 3 and 4 and that children at both ages draw on a range of properties when classifying such entities.     

Musical instrument naming impairments: the crucial exception to the living/nonliving dichotomy in category-specific agnosia

In category-specific agnosia (CSA) patients typically have more trouble naming animals, fruits, and vegetables than tools, furniture, and articles of clothing. A crucial exception to this living vs nonliving rule involves the category of musical instruments. Patients with problems naming living objects often repeatedly fail to name musical instruments. In CSA it is crucial to equate living and nonliving object lists on object name frequency, complexity, and familiarity. The present study shows, however, that even the most rigorously controlled object lists can lead to erroneous conclusions if nonliving stimuli contain an overrepresentation of musical instruments. Naming capabilities of a herpes encephalitis patient were assessed using matched lists of living and nonliving objects and showed no indication of category-specific deficits. When exemplars were separated into biological objects, musical instruments and man-made artifacts, strong category-specificity emerged: artifact naming was flawless whereas musical instrument and biological object naming were both severely impaired. It is concluded that CSA is a veridical phenomenon but that our understanding of CSA is limited by adhering to the spurious living/nonliving distinction.     

Organisation and evocation of the semantic knowledge: a non-abstractive approach

The majority of the models which attempt to explain category-specific deficits are based on the assumption that the conceptual knowledge is represented in a permanent way in memory (abstractive view). showed that a non-abstractive view would be more suitable to account for some of these cases. The present study aims to assess the hypotheses on the meaning evocation process as formulated by these authors, using a property verification task conducted on healthy subjects. The data were in agreement with these hypotheses and would be more hardly accounted in the frame of the abstractive view.     

Estimating the average need of semantic knowledge from distributional semantic models

Continuous bag of words (CBOW) and skip-gram are two recently developed models of lexical semantics (Mikolov, Chen, Corrado, & Dean, Advances in Neural Information Processing Systems, 26, 3111–3119, 2013). Each has been demonstrated to perform markedly better at capturing human judgments about semantic relatedness than competing models (e.g., latent semantic analysis; Landauer & Dumais, Psychological Review, 104(2), 1997 211; hyperspace analogue to language; Lund & Burgess, Behavior Research Methods, Instruments, & Computers, 28(2), 203–208, 1996). The new models were largely developed to address practical problems of meaning representation in natural language processing. Consequently, very little attention has been paid to the psychological implications of the performance of these models. We describe the relationship between the learning algorithms employed by these models and Anderson’s rational theory of memory (J. R. Anderson & Milson, Psychological Review, 96(4), 703, 1989) and argue that CBOW is learning word meanings according to Anderson’s concept of needs probability. We also demonstrate that CBOW can account for nearly all of the variation in lexical access measures typically attributable to word frequency and contextual diversity—two measures that are conceptually related to needs probability. These results suggest two conclusions: One, CBOW is a psychologically plausible model of lexical semantics. Two, word frequency and contextual diversity do not capture learning effects but rather memory retrieval effects.     

Accessing the asymmetrical representations of causal relations and hierarchical relations in semantic memory

In a speeded aiming task, participants were trained to move a cursor with a mouse from a start position to target locations when the mouse–cursor relationships were either normal or reversed (vertically, horizontally, or both vertically and horizontally). Testing, which occurred after a 5-min delay, involved either the same or a different reversal condition. Response times improved across training, but no transfer occurred when reversal conditions were changed between training and testing. Specificity of training effects extended even to performance with the highly familiar normal mouse. Normal mouse use was slowed by a factor of two to three with training on a reversed mouse although the effect was transient in that case. To contend with a reversed mouse, participants apparently adopt a global inhibition strategy, suppressing all normal movements (and replacing them with sensorimotor remapped movements) but disinhibiting movements along any nonreversed dimension (selectively disengaging the sensorimotor remapping).