The nature of infant color categorization: evidence from eye movements on a target detection task

Infants respond categorically to color. However, the nature of infants' categorical responding to color is unclear. The current study investigated two issues. First, is infants' categorical responding more absolute than adults' categorical responding? That is, can infants discriminate two stimuli from the same color category? Second, is color categorization in infants truly perceptual? Color categorization was tested by recording adults' and infants' eye movements on a target detection task. In Experiment 1, adults were faster at fixating a colored target when it was presented on a colored background from a different color category (between-category) than when it was presented on a colored background from the same color category (within-category), even when within- and between-category chromatic differences were equated in CIE (Committee International d'Eclairage) color space. This category effect was found for two chromatic separation sizes. In Experiment 2, 4-month-olds also responded categorically on the task. Infants were able to fixate the target when the background color was from the same category. However, as with adults, infants were faster at fixating the target when the target background chromatic difference was between-category than when it was within-category. This implies that infant color categorization, like adult color categorization, is truly perceptual.     

The psychometric properties of the Interpersonal Sensitivity Measure in social anxiety disorder

The Interpersonal Sensitivity Measure (IPSM) was developed to assess hypersensitivity to interpersonal rejection, a suggested trait of depression-prone personality (Aust NZ J Psychiatry 23 (1989) 341). Although studies of the IPSM and interpersonal rejection sensitivity have primarily been conducted in depressed populations, it is important to investigate interpersonal rejection sensitivity as a relevant construct in the assessment of social anxiety. This study examined the psychometric properties of the IPSM in treatment-seeking individuals with social anxiety disorder. The results of this investigation support the convergent and divergent validity and internal consistency of the IPSM in socially anxious individuals. An exploratory factor analysis of the scale was also conducted after the original factor and subscale structure was shown to be a poor fit for the present data. Three factors emerged (Interpersonal Worry and Dependency, Low Self-Esteem, and Unassertive Interpersonal Behavior), and 29 items were retained. Because they demonstrated negative factor loadings on Factor 2, it is suggested that the scoring for four items of the original IPSM be reversed. In summary, the revised IPSM assesses three aspects of interpersonal rejection sensitivity and appears to be a valid and reliable instrument for its assessment in social anxiety disorder.     

A taxometric analysis of the MMPI-2 Depression scales

The MMPI (Hathaway & McKinley, 1943) and MMPI-2 (Butcher et al., 2001) have long been used as measures of psychopathology. Both clinicians and researchers have noted the widespread existence of negative affectivity on the MMPI and MMPI-2 that may elevate scale scores and eclipse the tests' ability to differentiate depression from other clinical disorders. Using taxometric analyses, in this study we sought to test directly whether the MMPI-2 depression scales could differentiate patients with depressive symptoms from patients with other disorders. A large psychiatric sample (N = 2,000) was utilized and analyses were run separately for men and women. Taxometric analyses did not find a MMPI-2 Depression scale cut point that categorizes patients with depressive symptoms from other patients. Rather, these findings support previous studies finding an underlying dimensionality of depression. We discuss implications for MMPI-2 scale use and depression nosology in light of these findings.     

The two sides of beauty: Laterality and the duality of facial attractiveness

We hypothesized that facial attractiveness represents a dual judgment, a combination of reward-based, sexual processes, and aesthetic, cognitive processes. Herein we describe a study that demonstrates that sexual and nonsexual processes both contribute to attractiveness judgments and that these processes can be dissociated. Female participants rated the general attractiveness of faces presented in either their left or right visual field. In order to examine sexual and nonsexual components of these judgments, general attractiveness ratings were correlated with ratings of these same faces made by two independent groups of raters in two specific contexts, one sexual and one nonsexual. Based on an items analysis, partial correlation coefficients were computed for each individual and used as the dependent variable of interest in a 2 (laterality: right, left) by 2 (context: sexual, nonsexual) ANOVA. This analysis revealed an interaction such that faces rated in a sexual context better predicted attractiveness ratings of faces shown in the left than right visual field, whereas faces rated in a nonsexual context better predicted attractiveness of faces shown in the right than left visual field. This finding is consistent with the assertion that sexual and nonsexual preferences involve predominantly lateralized processing routes that independently contribute to what is perceived to be attractive.     

Reduced chromatic discrimination in children with autism spectrum disorders

Atypical perception in Autism Spectrum Disorders (ASD) is well documented ( Dakin & Frith, 2005 ). However, relatively little is known about colour perception in ASD. Less accurate performance on certain colour tasks has led some to argue that chromatic discrimination is reduced in ASD relative to typical development ( Franklin, Sowden, Burley, Notman & Alder, 2008 ). The current investigation assessed chromatic discrimination in children with high-functioning autism (HFA) and typically developing (TD) children matched on age and non-verbal cognitive ability, using the Farnsworth-Munsell 100 hue test (Experiment 1) and a threshold discrimination task (Experiment 2). In Experiment 1, more errors on the chromatic discrimination task were made by the HFA than the TD group. Comparison with test norms revealed that performance for the HFA group was at a similar level to typically developing children around 3 years younger. In Experiment 2, chromatic thresholds were elevated for the HFA group relative to the TD group. For both experiments, reduced chromatic discrimination in ASD was due to a general reduction in chromatic sensitivity rather than a specific difficulty with either red–green or blue–yellow subsystems of colour vision. The absence of group differences on control tasks ruled out an explanation in terms of general task ability rather than chromatic sensitivity. Theories to account for the reduction in chromatic discrimination in HFA are discussed, and findings are related to cortical models of perceptual processing in ASD.     

Sparse distributed memory for ‘conscious’ software agents

In this work we are reporting a case study on the use of SDM as the associative memory for a software agent, CMattie, whose architecture is modeled on human cognition. Sparse distributed memory (SDM) is a content-addressable memory technique that relies on close memory items tending to be clustered together. In this work, we used an enhanced version of SDM augmented with the use of genetic algorithms as an associative memory in our ‘conscious’ software agent, CMattie, who is responsible for emailing seminar announcements in an academic department. Interacting with seminar organizers via email in natural language, CMattie can replace the secretary who normally handles such announcements. SDM is a key ingredient in a complex agent architecture that implements global workspace theory, a psychological theory of consciousness and cognition. In this architecture, SDM, as the primary memory for the agent, provides associations with incoming percepts. These include disambiguation of the percept by removing noise, correcting misspellings, and adding missing pieces of information. It also retrieves behaviors and emotions associated with the percept. These associations are based on previous similar percepts, and their consequences, that have been recorded earlier. SDM also possesses several key psychological features. Some enhancements to SDM including multiple writes of important items, use of error detection and correction, and the use of hashing to map the original information into fixed size keys were used. Test results indicate that SDM can be used successfully as an associative memory in such complex agent architectures. The results show that SDM is capable of recovering a percept based on a part of that percept, and finding defaults for empty perception registers. The evaluation of suggested actions and emotional states is satisfactory. We think that this work opens the door to more scientific and empirical uses for SDM.     

Structural Priming as Implicit Learning: A Comparison of Models of Sentence Production

Structural priming reflects a tendency to generalize recently spoken or heard syntactic structures to different utterances. We propose that it is a form of implicit learning. To explore this hypothesis, we developed and tested a connectionist model of language production that incorporated mechanisms previously used to simulate implicit learning. In the model, the mechanism that learned to produce structured sequences of phrases from messages also exhibited structural priming. The ability of the model to account for structural priming depended on representational assumptions about the nature of messages and the relationship between comprehension and production. Modeling experiments showed that comprehension-based representations were important for the model's generalizations in production and that nonatomic message representations allowed a better fit to existing data on structural priming than traditional thematic-role representations.