Neonatal responsiveness as a function of maternal contact and obstetrical drugs

This work was designed to study changes in neonatal behavior during the first two days of life. Infants in Part I were from middle-class backgrounds. Half of these infants had unrestricted maternal contact during the first two days of life, the other half had contact with their mothers only at feeding time. Infants in Part II were from low socio-economic backgrounds. They were cared for entirely by the nursery staff during the first two days of life, so that differences in maternal style did not affect their behavior. Half of these babies were born to mothers who received 50 mg meperidine during labor, half to mothers who received no meperidine. This work provided evidence for the sensitivity of the neonate during the first two days of life. Both those infants who received unrestricted maternal contact and those whose mothers had received no obstetrical drugs exhibited more behavioral change than those who received low maternal contact or whose mothers had received meperidine during labor. High maternal contact and absence of obstetrical drugs also resulted in increased sensitivity to some environmental stimuli.     

Choice as a function of local versus molar reinforcement contingencies.

Rats were trained on a discrete-trial probability learning task. In Experiment 1, the molar reinforcement probabilities for the two response alternatives were equal, and the local contingencies of reinforcement differentially reinforced a win-stay, lose-shift response pattern. The win-stay portion was learned substantially more easily and appeared from the outset of training, suggesting that its occurrence did not depend upon discrimination of the local contingencies but rather only upon simple strengthening effects of individual reinforcements. Control by both types of local contingencies decreased with increases in the intertrial interval, although some control remained with intertrial intervals as long as 30 s. In Experiment 2, the local contingencies always favored win-shift and lose-shift response patterns but were asymmetrical for the two responses, causing the molar reinforcement rates for the two responses to differ. Some learning of the alternation pattern occurred with short intertrial intervals, although win-stay behavior occurred for some subjects. The local reinforcement contingencies were discriminated poorly with longer intertrial intervals. In the absence of control by the local contingencies, choice proportion was determined by the molar contingencies, as indicated by high exponent values for the generalized matching law with long intertrial intervals, and lower values with short intertrial intervals. The results show that when molar contingencies of reinforcement and local contingencies are in opposition, both may have independent roles. Control by molar contingencies cannot generally be explained by local contingencies.     

Choice for signalled over unsignalled shock as a function of shock intensity

Choice between a signalled shock schedule and an unsignalled one was examined at various shock intensities. Three rats were given the opportunity to change from the unsignalled schedule to the signalled one at intensity values between 0.15 mA and 1.0 mA. Steps were usually 0.15 mA and both ascending and descending series were given. For two other rats, shock intensity increased from 0.20 mA to 1.0 mA in 0.20-mA increments; for two additional rats, shock intensity was first 3.0 mA and was then reduced to 1.0 mA. Subjects tended to remain in the unsignalled schedule at the lower shock intensities, but spent most of each session under the signalled schedule at the higher intensities (1.0 mA and 3.0 mA). In addition, the time spent in the signalled schedule tended to vary systematically with shock intensity over at least part of the range of intensity values. It was concluded that the relationship between shock intensity and choice behavior is similar to the relationship between intensity and behavior in procedures involving avoidance, escape, and punishment.     

Quality of college students' same-sex friendships as a function of personality and interpersonal competence

The aim of the current study was to investigate personality traits and interpersonal competencies as predictors of the quality of same-sex friendships in young adulthood. Undergraduate students (N = 176), who attended a mid-Atlantic U.S., medium-sized university, completed self-report surveys on their personality, interpersonal competence, and friendship quality. Sex, class status, extraversion, agreeableness, and interpersonal competencies were associated with higher friendship quality, but only the interpersonal competence of self-disclosure significantly predicted friendship quality after controlling for sex, class status, and the five personality factors.     

Choice for signaled over unsignaled shock as a function of signal length.

Subjects chose between signaled and unsignaled shock conditions while signal length was varied between .5 and 2.0 seconds in steps of .5 seconds in both ascending and descending series. Preference for the signaled condition failed to develop initially for five of six subjects when signals were .5 or 1.0 seconds but became strong for all subjects when signals were 2.0 seconds (ascending series). Preference declined when signals were shortened, but for most subjects this decline was small (descending series). Since discriminable shock-free periods were present in the signaled condition at all signal lengths, these results suggest that safety may not be a sufficient condition for preference to develop for signaled shock.