Aggressive behavior inhibition by serotonin and quipazine injected into the amygdala in the rat

The effects on aggressive behavior, open-field activity, and pain threshold of bilateral microinjections of serotonin (20 micrograms) and quipazine (20 micrograms), the direct serotonergic receptor agonist, into the cortico-medial amygdala were investigated in Wistar rats. Both drugs significantly prolonged the attack latency in isolated killer rats (predatory aggression model), and suppressed the incidence of aggressive postures/attacks in shock-induced fighting test (affective aggression). The only difference in the open-field behavior was the lower number of central square entries in drug-treated compared to saline-injected rats. None of the substances produced any significant change in jump threshold. It is concluded that stimulation of serotonin receptors within the amygdala produces inhibition of affective and muricidal behavior in isolated rats. The effect does not seem to be dependent on changes in general activity and pain sensitivity.     

The use of computer networks in data gathering and data analysis

In our research, the data are gathered in the laboratory on a DEC PDP-11/24 minicomputer. Once the data are gathered, they are analog-to-digital (A/D) converted and sent by the PDP to an IBM 370-3031. The data are submitted to a Fast Fourier Transform (FFT) on the IBM computer. Once the FFT is completed, the data are accessed by an IBM PC-XT that is equipped with an IRMA system. The PC is used in its emulation mode to access the data in the mainframe. In the mainframe, SPSS or SAS is used to do the initial statistical analyses. When necessary, subsets of the data are transferred to the PC, where other computer programs are used to analyze the data. In many instances, they are returned to the mainframe from the PC, where they are submitted to multivariate statistical analysis. Finally, all of the data are stored on floppy disks, which are prepared on the PC.     

Frequency of neurologic-psychiatric findings in the late phase following minor and medium severe blunt craniocerebral injuries

The authors present a short review of the pertinent literature and report on their own neuropsychiatric findings following internal craniocerebral injuries, at the same time drawing attention to the necessity of psychological examination. Statistical comparisons with the international literature are complicated owing to the different classifications used for craniocerebral injuries.     

Interpersonal attraction,social identification and psychological group formation

Two perspectives on the nature of the social group and psychological group formation are discussed. The traditional social cohesion approach traces group formation to processes of interpersonal attraction, while the social identity approach defines the group in cognitive terms and considers identification, or self-categorization, to be the mechanism of psychological group formation. On the basis of an experiment by Turner, Sachdev and Hogg (1983) it is hypothesized that interpersonal attraction (positive or negative) is related to group formation only in so far as it enhances intergroup distinctiveness. This hypothesis is experimentally tested in a 2 × 3 (interpersonal liking/disliking per se versus no explicit categorization/random categorization/criterial categorization on the basis of affect) factorial design employing the ‘minimal group’ paradigm. People who like each other and were not explicitly categorized formed a group. This effect was enhanced by criterial categorization but disappeared when categorization was random. Although the results do not support the hypothesis, they are not explicable in social cohesion terms. A social identity explanation is furnished—attraction influences group formation by acting, under certain specifiable conditions, as a cognitive criterion for common category membership. This explanation is located in current theorizing and is proposed as part of a reconceptualization of the relationship between interpersonal attraction and group formation.     

Prejudice,categorization and particularization: From a perceptual to a rhetorical approach

This paper seeks to offer an alternative approach to the study of prejudice than that based upon the notion of categorization which is currently influential in cognitive social psychology. It is argued that the categorization approach assumes the inevitability of prejudice and ignores the issue of tolerance. The assumptions of the categorization approach are criticized, and it is suggested that, by focusing on categorization as a cognitive process, it has overlooked an opposing process—that of particularization. The result has been a rather mechanical and bureaucratic model of cognition. A less mechanical view is possible if the relations between the two processes of categorization and particularization are considered from a rhetorical perspective, which examines the argumentative nature of thought. For theoretical and empirical reasons, this perspective does not equate prejudiced thinking with rigid categorization; instead a rhetorical approach permits a distinction between prejudice and tolerance on the basis of content, rather than form, and thereby avoids assuming the inevitability of prejudice.