Critical periods and catastrophic interference effects in the development of self-organizing feature maps

The use of self-organizing feature maps (SOFM) in models of cognitive development has frequently been associated with explanations of critical or sensitive periods. By contrast, error-driven connectionist models of development have been linked with catastrophic interference between new knowledge and old knowledge. We introduce a set of simulations that systematically evaluate the conditions under which SOFMs demonstrate critical/sensitive periods in development versus those under which they display interference effects. We explored the relative contribution of network parameters (for example, whether learning rate and neighbourhood reduce across training), the representational resources available to the network, and the similarity between old and new knowledge in determining the functional plasticity of the maps. The SOFMs that achieved the best discrimination and topographic organization also exhibited sensitive periods in development while showing lower plasticity and hence limited interference. However, fast developing, coarser SOFMs also produced topologically organized representations, while permanently retaining their plasticity. We argue that the impact of map organization on behaviour must be interpreted in terms of the cognitive processes that the map is driving.     

Evolution and development of boys’ social behavior

An evolutionary analysis of the dynamics of one-on-one and coalitional male–male competition provides a theoretical frame for conceptualizing the evolved functions and proximate developmental forms of the social behavior of boys, and for appreciating why the behavior of boys differs from that of girls. We propose the accompanying selection pressures favored the evolution of motivational and behavioral dispositions in boys and men that facilitate the development and maintenance of large, competitive coalitions and result in the formation of within-coalition dominance hierarchies. Empirical research on boys’ social development is reviewed using this frame and implications for interpreting boys’ social behavior are explored.     

The effect of social cues on the eating behavior of obese and normal subjects1

Schachter's externality hypothesis suggests that overweight individuals are more likely to be induced to eat by salient external cues than normal weight individuals. While a range of studies have demonstrated the plausibility of this hypothesis in the case of sensory stimuli (e.g., taste cues), there is little evidence that the hypothesis applies to social stimuli. The current study examines this latter proposition by exposing male and female, overweight and normal weight subjects to a same-sex or opposite-sex peer model. Under the guise of engaging in a taste experiment, the subjects were either exposed to a model who tasted experiment, the subjects were either exposed to a model who tasted no crackers (no eat), one cracker (low eat), or twenty crackers (high eat). In addition, control model-absent conditions were also run for purposes of establishing baseline eating rates. If the externality hypotheses were to prevail in social domains, one would expect overweight subjects to be more prone to model the cracker-eating behavior of the peer than normal weight individuals. However, the findings indicate that all subject groups regardless of weight evidence a rather clear modeling effect and all subjects evidence social inhibition effects on their eating behavior as well. Several intriguing interactions among subject sex, model sex, subject weight, and social condition were also found. The discussion explores the relevance of an externality model of overweight eating in social domains, and focuses upon the interesting and somewhat distinct pattern of socially mediated eating exhibited by overweight females.     

Gender-specific social experiences and the development of aggressive and sexual behavior in male mice

This study examined influences of gender-specific social experiences on the development of aggressive and sexual behavior in male mice. To determine the effects of gender-specific social experience three different types of groups were constituted after the animals had been weaned. The subjects were randomly assigned to different treatments. Female groups were composed of one experimental male and three female cohabitants. Male groups were composed of five experimental males each, and the mixed-sex groups were composed of two experimental males and of two females. The experimental subjects stayed in these groups until the age of approximately three months, when the testing for sexual and aggressive behavior commenced. For the sexuality tests, a receptive female was placed in the home cage of the experimental male for ten minutes. A nonaggressive male was placed in the home cage of the experimental male for seven minutes for the aggression tests. The experimental males were administered both sexuality and aggression tests, the sequence of testing sexual and aggressive behavior was systematically varied in order to control the influence of the two different types of behavioral tests. The results showed that males with only male social experiences showed fewer responses and were less active in both the aggression and sexuality tests than the males from the two other types of groups. Significant positive correlations between activity during aggression and sexual tests were obtained for all three groups. © 1994 Wiley-Liss, Inc.     

Pubertal development and behavior: Hormonal activation of social and motivational tendencies

Adolescence is a time of dramatic changes including rapid physical growth, the onset of sexual maturation, the activation of new drives and motivations, and a wide array of social and affective changes and challenges. This review focuses on behavioral changes in this interval and is organized by the claim that a key set of these adolescent changes are part of a more general re-orientation of social behavior. More specifically we hypothesize that pubertal maturation is associated with the activation of social and motivational tendencies, which in turn influence behavior and emotion in adolescence depending upon interactions with social context. We focus on evidence for two examples of these motivational changes: (1) increases in sensation-seeking (motivational tendency to want to experience high-intensity, exciting experiences) and (2) stronger natural interest in—and pursuit of—contact with peers and potential romantic partners. We consider how these motivational changes contribute to the broader social re-orientation of adolescence, including exploration of social experiences, development of skills and knowledge relevant to taking on adult social roles, individuation from family, and establishment of an individual identity, all of which represent core developmental tasks during this period in the life span ( 9, 16 and 62). The paper also emphasizes the importance of investigating and understanding the direct influences of puberty on behavior and disentangling these from the broader set of changes during adolescent development.     

Exogenous testosterone and social experience each enhance the development of aggressive behavior in Cyprinodon variegatus

The combined effects of testosterone and social experience from the time of hatching on development of aggressive behaviors in Cyprinodon variegatus were investigated. Social experience was defined as a rearing condition allowing visual, tactile, chemosensory, and auditory contact with zero, three, or 15 additional conspecifics. Behaviors were videotaped once weekly from 3 weeks to 4 months post-hatching, using the focal animal method, and an ethogram was constructed. At 3 months post-hatching, half the fish were injected once with testosterone propionate (2 μg/g b. w., i. p., vehicle-Ringer's solution) and the other half were injected with Ringer's isotonic saline solution. Testosteronetreated subjects showed significantly greater frequencies and durations of behaviors that may be related to aggression than did saline controls. Two weeks after the treatments, a round-robin tournament was conducted between testosterone- and saline-treated fish from each rearing condition. Testosterone-treated fish won significantly more encounters than did saline-treated subjects over all rearing conditions. Furthermore, significantly more aggressive acts were displayed by fish raised in the groups of 16 and the groups of four than did the Isolates. Although the number of aggressive acts exhibited by the group of 16 was greater than the group of four, the difference was not statistically significant.     

Quantification of rats' behavior during reinforcement periods

What is treated as a single unit of reinforcement often involves what could be called a reinforcement period during which two or more acts of ingestion may occur, and each of these may have associated with it a series of responses, some reflexive, some learned, that lead up to ingestion. Food-tray presentation to a pigeon is an example of such a “reinforcement period.” In order to quantify this behavior, a continuous-reinforcement schedule was used as the reinforcement period and was chained to a fixed-ratio schedule. Both fixed-ratio size and reinforcement-period duration were manipulated. Rats were used as subjects, food as reinforcement, and a lever press as the operant. Major findings included (a) a rapid decline in response rates during the first 15 to 20 seconds of the reinforcement periods, and (b) a strong positive relationship between these response rates and the size of the fixed ratio. Also revealed was a short scallop not normally found in fixed-ratio response patterns, whose length was a function of fixed-ratio size and reinforcement-period duration. It is suggested that rapidly fluctuating excitatory processes can account for many of these findings and that such processes are functionally significant in terms of behavioral compensation.     

Self-efficacy and social behavior

Data regarding the relationship between self-efficacy and social behavior are limited, and questions remain about how to interpret the relationship of self-efficacy to phobic behavior in general. The current study includes data regarding the relationship between self-efficacy ratings and social behavior. The data also allow tests of an alternative hypothesis that self-efficacy ratings represent a general prediction regarding the likely outcome regarding a task. If this hypothesis is correct, the relationship of self-efficacy to behavior should be moderated by task familiarity. The study involved 124 socially anxious participants who gave at least partial data on a variety of measures, including three speaking tasks. In accordance with the alternative hypothesis, self-efficacy ratings best predicted behavior in reference to a familiar speaking task. Overall, self-efficacy showed only a moderate tendency to predict behavior.     

Further development and restandardization of an approach to the diagnosis of aggressive social behavior in childhood

The present paper continues and concludes an investigation into the restandardization of a first attempt, checked in respect of content and method, at the diagnosis of aggressive social behavior initially concentrating on the 9-11 age group. The work has its origin in a paper by Petermann and Petermann (1980), which we consider could be of significance to gradual restandardization, both in methodological research and in practical clinical application. A previous article demonstrated under various aspects the fundamental suitability of the attempt to restandardization. Arising out of this and the present analysis, some fundamental consequences, both in content and in method, of a fuller development and the therapy oriented employment of the attempt are discussed.     

Factors affecting the social validity of a role-play test of children's social skills

The social validity of a role-play test of children's social skills, the Social Skills Test for Children (SST-C), was evaluated by 63 subjects (33 adults and 30 children) who subjectively judged the quality of three children's role-play performances. The three children were selected as having high, medium, or low social skill based upon their performance on the SST-C. Assessment of the effects of subject characteristics upon judgments of social skill suggested that similarities in age and race between the subjects and the three children tended to diminish perceived differences in social skill among the three children. It was concluded that the social validity of the role-play test was supported only if the persons evaluating social behavior were dissimilar in age and racial characteristics from the persons who were being evaluated.     

Anticipating the consequences of social behavior

Some forms of psychological theory explain behavior in part by its consequences. The consequences are called reinforcing if the behavior is strengthened; punishing if the behavior is weakened. Through repetition, the consequences eventually become generalized or anticipated. While social psychology has used consequences extensively in its manipulations, this has been implicit rather than explicit. This paper reviews ten such manipulations over ten areas of social psychology for the first time and shows how implicit consequences can determine social behavior. The problems with executing and interpreting these manipulations are extensively discussed. It is concluded that the notion of “anticipating the consequences of social behavior” can bring unity to many areas of social psychology and provide a sound motivational basis.