Pattern and process in the evolution of learning

A century after E. L. Thorndike's (1898) dissertation on the comparative psychology of learning, the field seems ready for a reassessment of its metatheoretical foundations. The stability of learning phenotypes across species is shown to be similar to that of other biological characters, both genotypic (e.g., Hox genes) and phenotypic (e.g., vertebrate brain structure). Moreover, an analysis of some current lines of comparative research indicates that researchers use similar strategies when approaching problems from either an ecological view (emphasizing adaptive significance) or a general-process view (emphasizing commonality across species). An integration of learning and evolution requires the development of criteria for recognizing and studying the divergence, homology, and homoplasy of learning mechanisms, much as it is done in other branches of biological research.     

The General Factor of Psychosocial Development and its relation to the General Factor of Personality and Life History strategy

It was hypothesized that the eight Eriksonian psychosocial stages form a single latent variable or General Factor of Psychosocial Development (GFPD) and that this latent factor is associated with the General Factor of Personality (GFP) and Life History (LH) strategy to the extent that the variables form a higher order Super-K factor. Correlational analyses and confirmatory factor analyses each supported the hypothesized GFPD. Additionally, correlational and confirmatory factor analyses supported the hypothesis that the three variables form a single Super-K factor. The results of Study 3 suggest that the relationship between the psychosocial stages and between the GFPD, GFP, and LH strategy remained after controlling for social desirable response biases.     

The effect of life expectancy on aggression and generativity: A life history perspective

Following a model that is inclusive of both dispositional and situational influences on life-history behaviors and attitudes, the effect of life expectancies on aggression and generativity was examined. Consistent with the hypotheses it was found that shorter life expectancies led to an increase in the desire to aggress and a decrease in the desire to engage in generative behaviors. The results are discussed in terms of how life history theory can be used to frame research on person-situation interactions.     

Survival of the partial reinforcement extinction effect after contextual shifts

The effects of contextual shifts on the partial reinforcement extinction effect (PREE) were studied in autoshaping with rats. Experiment 1 established that the two contexts used subsequently were easily discriminable and equally salient. In Experiment 2, independent groups of rats received acquisition training under partial reinforcement (PRF) or continuous reinforcement (CRF). Significant PREEs were observed whether extinction occurred in the same or in a different context. In Experiment 3, after PRF or CRF acquisition training, each group received extinction of the same conditioned stimulus in both the same and different contexts. PREEs were observed under both conditions, although extinction was accelerated after a contextual shift. These results were discussed in relation to the role of mediational states in the PREE.     

Successive negative contrast after partial reinforcement in the consummatory behavior of rats

Rats given access to a 32% sucrose solution later reject a 4% solution significantly more than controls that have only received the 4% solution. In Experiment 1, this consummatory successive negative contrast (cSNC) effect was attenuated by previous exposure to 50% partial reinforcement. Furthermore, recovery from cSNC was also facilitated by partial reinforcement. In Experiment 2, the attenuating effects of partial reinforcement on cSNC were eliminated by administration of the benzodiazepine anxiolytic chlordiazepoxide (5 mg/kg) before nonreinforced trials. In Experiment 3, the attenuating effect of partial reinforcement was greater after a shift from 32 to 6% solution, than after a shift from 32 to 2% solution. The parallels between the effects of partial reinforcement on consummatory and instrumental behavior are discussed.     

Familial correlates of sexually active pregnant and nonpregnant adolescents

The relationship of familial, demographic, and individual characteristics to the probability of pregnancy was examined among 124 sexually active adolescent females. Logistic regression analyses revealed that adolescent pregnancy status was a function of a combination of demographic and familial variables. Adolescents who were pregnant at the time of the study perceived their families as having low levels of family strength, perceived communication with parents as closed, came from homes characterized by family fragmentation (i.e., only one parent or no parent living in the home), came from low-income households, were unlikely to use any method of birth control, and were more likely to be married than their nonpregnant counterparts.     

The role of ego-identity status in mating preferences

This study was designed to examine the role ego-identity plays in the mating preferences of late adolescents. In addition to examining the variance in mating preferences explained by ego-identity status, it was hoped that the results could assist in testing the competing Sexual Strategies (Buss & Schmitt, 1993) and Social Role (Eagly & Wood, 1999) theories. Ego-identity and the sex of the participant accounted for a significant amount of variance in the number of sexual partners desired and the penchant for short-term mating. The sex of the participant was the lone predictor of the importance placed on the mate characteristics of physical attractiveness and earning capacity with females placing more emphasis on the former and males placing more emphasis on the latter characteristic.     

Grade, pubertal status, and gender-related variations in conflictual issues among adolescents

The purpose of this study was to describe adolescent perceptions of conflictual family issues, and to ascertain if the intensity of these issues is associated with adolescent grade in school, pubertal status, and gender. The sample was comprised of 279 junior high and senior high school students. Each participant completed a self-report measure of pubertal status, a demographic questionnaire, and the Issues Checklist. Principal factor analysis with varimax rotation of the Issues Checklist resulted in the retention of four factors accounting for 71.59% of the variance. Stepwise regression analyses were conducted for each emergent factor with grade in school, pubertal status, and gender serving as predictors. The results of these analyses indicated that the intensity of School Issues and Household Behavior Issues is greater among seventh and ninth graders than among eleventh graders. Self-Responsibility Issues were perceived as being most intense among transpubertal adolescents. Finally, boys perceived more intense conflict over Persistent Issues and Concerns than did girls.