Symbolic Representation by Pigeons

The capacity for symbolic representation is a prerequisite for the development of human language because words, the basic units of language, are symbols that represent things. But symbolic representation may also serve a nonlinguistic role of organizing events into categories having the same meaning, and such a capacity could have considerable survival value for many species. In a number of experiments, my co-workers and I have found that pigeons that are trained to treat two different stimuli similarly also learn that those stimuli are commonly represented and, thus, that they have the same meaning. We have demonstrated evidence for such common representations in a number of ways, but perhaps the most convincing is when pigeons learn a new association involving one of the presumed commonly represented stimuli, and without further training demonstrate that they have learned a similar association involving the other stimulus. Furthermore, we have found that when pigeons are trained to treat two stimuli similarly, one of those stimuli is represented in terms of the other. These results have implications not only for the generality of cognitive processes across species, but also for the generality of symbolic representation beyond language use.     

A comparison of self-report and interview diagnoses of DSM-III-R personality disorders

A total of 73 psychiatric inpatients, all of whom (but two) fulfilled criteria for at least one specific personality disorder (PD) on SCID-II PQ, were interviewed with the help of PDE. The self-report PD diagnosis was confirmed in 35 (48 per cent) patients. The diagnostic agreement between the two instruments was poor, yielding an overall weighted kappa of 0.22. Levelling off the PD base rates by increasing or decreasing the diagnostic threshold of SCID-II PQ and PDE respectively increased the overall weighted kappa to 0.38 in both instances. 70 per cent of SCID-II PQ but only 29 per cent of PDE personality disorders were of extensive type. Most frequent important co-occurrences occurred between individual PD types within cluster 2. On the whole, the results confirmed the relatively poor agreement between self-report and interview PD diagnoses. The utilization of self-report questionnaires in a clinical practice remains a controversial issue. © 1998 John Wiley & Sons, Ltd.     

A comparison of noncontingent reinforcement,other competing stimulation,and liquid rescheduling for the treatment of rumination

Modified versions of three popular nonaversive treatments for rumination in a person with profound developmental delay were evaluated using an alternating treatments design (ATD) as a component of an ABAB design. Results showed that the most effective intervention involved noncontingent feeding every 20 s for the 30 min immediately following a meal. Further analysis demonstrated that no significant increase in rumination occurred during the 60 min after the treatment procedure had expired, thus indicating that rumination was not merely postponed. Results are discussed in terms of their relation to currently popular (satiation) interventions for the treatment of rumination in individuals with developmental disability. Future research needs are proposed from an analysis of known behavioral and physiological variables and their possible interactions. ©1997 by John Wiley & Sons, Ltd.     

Topics in semantic representation

Processing language requires the retrieval of concepts from memory in response to an ongoing stream of information. This retrieval is facilitated if one can infer the gist of a sentence, conversation, or document and use that gist to predict related concepts and disambiguate words. This article analyzes the abstract computational problem underlying the extraction and use of gist, formulating this problem as a rational statistical inference. This leads to a novel approach to semantic representation in which word meanings are represented in terms of a set of probabilistic topics. The topic model performs well in predicting word association and the effects of semantic association and ambiguity on a variety of language-processing and memory tasks. It also provides a foundation for developing more richly structured statistical models of language, as the generative process assumed in the topic model can easily be extended to incorporate other kinds of semantic and syntactic structure.     

Genetic and environmental influences on the positive traits of the values in action classification,and biometric covariance with normal personality

Virtually all human individual differences have been shown to be moderately heritable. Much of this research, however, focuses on measures of dysfunctional behavior and relatively fewer studies have focused on positive traits. The values in action (VIA) project is a comprehensive and ambitious classification of 24 positive traits, also known as character strengths (Peterson, C., & Seligman, M. E. P. (2004). Character strengths and virtues: A handbook and classification. Washington, DC: American Psychological Association), the majority of which have received no behavior genetic attention. Using a sample of 336 middle-aged twins drawn from the Minnesota Twin Registry who completed the VIA inventory of strengths, we detected significant genetic and non-shared environmental effects for 21 of 24 character strengths with little evidence of shared environmental contributions. Associations with a previously administered measure of normal personality found moderate phenotypic overlap and that genetic influences on personality traits could account for most, but not all, of the heritable variance in character strengths.