Connectionist models of neuropsychological disorders

Artificial neural networks ('connectionist models') embody aspects of real neuronal systems. But does studying the breakdown of performance in such models help us to understand cognitive impairments in humans following brain damage? Here we review recent attempts to capture different neuropsychological disorders using connectionist models with simulated lesions. We show how such lesion studies can be used to evaluate some of the standard assumptions made in neuropsychological research, concerning both double dissociations and associations between patterns of impairment. We also illustrate how lesioned models, like humans, can sometimes be more impaired on the easier of two tasks and demonstrate that connectionist models can incorporate forms of internal structure. Finally we discuss the utility of the models for understanding and predicting the effectiveness of different rehabilitation strategies. Future questions concern the role and possible development of internal structure within these models, whether the models can be generalized to larger-scale simulations, and whether they can accommodate higher-order linguistic disorders.     

The Preconditions and Consequences of Relative Deprivation: Two Field Studies1

Two field studies assessed the preconditions and behavioral consequences of relative deprivation. A sample of single mothers receiving government assistance participated in Study 1, and a sample of working women participated in Study 2. We found general support for a 2-factor model of the preconditions of relative deprivation, in which wanting the desired state and deserving the desired state were the best predictors of discontent. In both studies, discontent regarding the status of one's group (i.e., single mothers or working women) was specifically predictive of reports of group-directed protest behaviors. In Study 2, discontent regarding one's own status was specifically predictive of willingness to engage in self-improvement behaviors. Participants in both studies reported more group discontent than personal discontent. These findings provide support from naturalistic settings for the construct of relative deprivation.     

Empowerment praxis in community coalitions

Community coalitions address a wide variety of community problems, espousing a community development processes that promotes individual and collective self-determination. They offer a promising venue for the study of empowerment of individuals and organizations. This study utilizes data from members of 35 community coalitions organized for the prevention of alcohol and other drug problems to address the following questions: What individual characteristics are related to the psychological empowerment of coalition members? What organizational characteristics are related to the collective empowering of members? What organization characteristics are related to a coalition being organizationally empowered to succeed in achieving its objectives? At the individual level, psychological empowerment was most strongly related to individuals' participation levels, sense of community, and perceptions of a positive organizational climate. At the group level, the strongest predictors of collective empowering (our operationalization of the empowering organization) were net benefits of participation, commitment, and positive organization climate. Psychological empowerment and positive organizational climate were the two predictors of organizational effectiveness (the empowered organization). Implications and limitations of these findings are discussed.     

PREDICTORS OF RESPONSES TO UNWANTED SEXUAL ATTENTION

Data were collected from 4,011 male and female university students, faculty, and staff regarding responses to unwanted sexual attention. Women and undergraduate students reported the highest incidence of unwanted sexual attention; most harassers were peers. Ignoring the behavior was the most common response, followed by avoiding the harasser and talking to others about the harassment. Harassment severity was the strongest predictor of responses, with more direct responses being made to more severe harassment. Bivariate correlational analyses suggested that unwanted sexual attention was rated as more distressing by women than by men, by faculty/staff than by students, by individuals with less tolerant attitudes toward harassment, and when the harasser was in a position of authority or when the harassment was of longer duration. In path analyses, only the relations between attitudes and responses were mediated by differences in perceived severity. The gender and status (i.e., student vs. faculty/staff) of the harassee, the duration of the harassment, and whether the harasser was in a position of authority had direct effects on responses not attributable to perceived severity. Implications for policy and future research are discussed.     

The effects of sex-role taking on children's responses to aggressive conflict situations

The effects of sex-role taking on children's responses to aggressive conflict situations were investigated in the present study. Subjects were 40 boys and girls aged 8–9, who were asked to take the role of boy and girl story characters involved in the following kinds of aggressive situations: victim of a verbal attack, victim of a physical attack, and witness to an attack upon a friend. A significant interaction effect between type of conflict situation and sex of story character was obtained. Subjects expected boy characters to retaliate more strongly than girl characters when intervening in an attack upon a friend, and girl characters to retaliate more strongly than boy characters when being verbally or physically assaulted. These findings suggest the importance of situational factors in determining children's sex-stereotyped expectations for aggressive retaliation.     

Dyslexic and normal readers' eye movements

Dyslexic and normal readers' eye movements were compared while tracking a moving fixation point and in reading. Contrary to previous reports, the dyslexic and normal readers did not differ in their number of saccades, percentage of regressions, or stability of fixations in the tracking task. Thus, defective oculomotor control was not associated with or a causal factor in dyslexia, and the dyslexics' abnormal eye movements in reading must be related to differences in higher cognitive processes. However, individual differences in oculmotor efficiency, independent of reading ability, were found within both the dyslexic and normal groups, and these differences were correlated in reading and tracking tasks.