Parallel distributed processing and neuropsychology: A neural network model of Wisconsin card sorting and verbal fluency

Neural networks can be used as a tool in the explanation of neuropsychological data. Using the Hebbian Learning Rule and other such principles as competition and modifiable interlevel feedback, researchers have successfully modeled a widely used neuropsychological test, the Wisconsin Card Sorting Test. One of these models is reviewed here and extended to a qualitative analysis of how verbal fluency might be modeled, which demonstrates the importance of accounting for the attentional components of both tests. Difficulties remain in programming sequential cognitive processes within a parallel distributed processing (PDP) framework and integrating exceedingly complex neuropsychological tests such as Proverbs. PDP neural network methodology offers neuropsychologists co-validation procedures within narrowly defined areas of reliability and validity.     

Characteristics of Calls to Israeli Hotlines During the Gulf War

The current study presents results of a survey of 3,215 calls received at seven centers of telephone emergency services (TES) in Israel during the Gulf War, when citizens of Israel experienced severe stress resulting from SCUD missile attacks. Whereas former surveys have shown that characteristics of calls to TES in Israel are generally not affected by external stressogenic events, a remarkable change was recorded in both the quantity and quality of calls received in TES centers in Israel during the Gulf War. The relative frequencies of problem categories presented by callers during the Gulf War revealed a significant increase in environmental pressures, a category that reflected the stressful situation of the war, as opposed to intra- or interpersonal problems typical of peacetime calls. A comparison between this group of war calls and a control group of nonwar calls, revealed that the two groups represented populations of callers differing in sociodemographic characteristics, expectations, and benefits from the calls. Results are discussed in reference to the unique role of TES as a source of psychological first-aid in a community crisis situation.     

The effects of situational variations in role-play scenes on assertive behavior

The study was conducted to determine the extent to which variations in the situational parameters of role-play scenes affect subjects' levels of assertiveness. Thirty-six psychology undergraduate students were randomly assigned to one of three role-play conditions that differed in the situation-setting characteristics presented in the scenes: a Difficult condition, designed to inhibit assertive responding; an Easy condition, designed to facilitate assertive responding; and a Neutral condition. Subjects also completed a self-report assertion inventory. Videotapes of the role-played interactions were rated for a variety of component responses. Results indicate that subjects responded differently in the three conditions. Subjects in the Difficult and Neutral conditions were more compliant, and those in the Easy and Difficult conditions were more fluent. It is suggested that failure to specify the situational parameters of role-play scenes may affect the validity of this assessment procedure.This research was supported in part by NIMH Grant, MH28279 to the third author.     

Integrated-structure emergence and its mechanistic explanation

Synthese - This paper proposes an integrated-structure notion of interlevel (part-whole) emergence, from a dynamic relational ontological perspective. First, I will argue that only the...     

the role of dimensional distinctiveness in children's and adults' artifact categorization

There are conflicting results as to whether preschool children categorize artifacts on the basis of physical or functional similarity. The present study investigated the effect of the relative distinctiveness of these dimensions in children's categorization. In a physical-distinctive condition, preschool children and adults were initially asked to categorize computer-animated artifacts whose physical appearances were more distinctive than their functions. In a function-distinctive condition, the functional dimension of objects was more distinctive than their physical appearances. Both conditions included a second stage of categorization in which both dimensions were equally distinctive. Participants in a control condition performed only this stage of categorization. Adults in all conditions and stages consistently categorized by functional similarity. In contrast, children's categorization was affected by the relative distinctiveness of the dimensions. Children may not have a priori specific beliefs about how to categorize novel artifacts, and thus may be more susceptible to contextual factors.     

Children's reliance on creator's intent in extending names for artifacts

When children learn a name for a novel artifact, they tend to extend the name to other artifacts that share the same shape—a phenomenon known as the shape bias. The present studies investigated an intentional account of this bias. In Study 1, 3-year-olds were shown two objects of the same shape, and were given an explanation for why the objects were the same shape even though they were intended to be different kinds. The shape bias disappeared in children provided with this explanation. In Study2, 3-year-olds were shown triads of objects, and were either given no information about the function of a named target object, told the function that object could fulfill, or told the functions all three objects were intended to fulfill. Only in the third condition did children overcome a shape bias in favor of a function bias when extending the name of the target object. These findings indicate that 3-year-olds' shape bias results from intuitions about what artifacts were intended to be.