Human choice in concurrent ratio-interval schedules of reinforcement.

Seven undergraduates participated in a concurrent-choice experiment with monetary reinforcers. Response-independent analogues of variable-interval and variable-ratio schedules were used to assess whether subjects would maximize reinforcement rate. The optimal pattern of behavior, in terms of maximizing reinforcement rate, involved a large bias toward the ratio alternative, with only occasional sampling of the interval schedule. Most experiments with pigeons, however, demonstrate matching of response rates to reinforcement rates, with only slight biases for the ratio schedule. Although subjects in the present experiment allocated more time to the ratio alternative than required by matching, the magnitude of the bias did not approximate that predicted by a maximizing account. After exposure to clock stimuli correlated with the operation of each schedule, 1 subject's behavior did show a substantial level of bias, increasing the total number of reinforcers obtained, and lay at a point between the predictions of matching and maximizing. The other subjects, however, continued to respond less optimally. The present results can be accounted for by a view of matching that incorporates the effects of delayed reinforcement.     

Patterns of 4-month-old infant responses to hidden silent and sounding people and objects

Responses of 4-month-old infants to hidden people and objects were investigated with equated task demands. Twenty-one 4-month-old infants were administered a combined task, in which they were shown a sounding stimulus that continued to sound after hiding, an auditory task, in which sound was the only source of information about the position of the object in space, and a vision task, in which a silent stimulus was shown to the infants prior to hiding. Five infant behaviours were coded: reaching, gazing, body movements, vocalizations and smiles. The infants reached significantly more for hidden objects than for people, to whom they vocalized instead. They further smiled, and moved their bodies more towards their invisible mother than to the other stimuli. Thus infants responded differentially to people and objects whether the stimuli were soundless (so that there was no cue to their presence) or not. This suggested that infants appreciated (a) that an object had been hidden; (b) this object was either animate or inanimate; and (c) different procedures were appropriate for the retrieval of, or for interacting with animate and inanimate objects. Discussion centres on the underlying representational system that allows for such appreciation.     

REPEATED EXPOSURE TO SUGGESTION AND THE CREATION OF FALSE MEMORIES

Abstract— The purpose of the present study was to extend research on repetition and illusory truth to the domain of eyewitness suggestibility. Specifically, we assessed whether repeated exposure to suggestion, relative to a single exposure, facilitates the creation of false memory for suggested events. After viewing a video of a burglary, subjects were asked questions containing misleading suggestions, some of which were repeated. Their memory for the source of the suggestions was tested. The results show that following repeated (relative to a single) exposure to suggestion, subjects were more likely to (a) claim with high confidence that they remembered the suggested events from the video (Experiment 1) and (b) claim that they consciously recollected witnessing the suggested events (Experiment 2). The effects of repeated exposure were highly reliable and were observed over retention intervals as long as I week.     

Learning capacities during sleep: A preliminary study in a group of schizophrenic inpatients

The relationship between sleep and learning processes is analysed in a sample of schizophrenic patients, starting from more recent hypotheses about the function of REM sleep in learning and memory processes. This is done by means of two experiments: in the first AA. evaluate the possibility to elicit a simple motor conditional reflex acquired during daytime in different sleep stages. With the second experiment daytime learning performances are evaluated with and without a reinforcement administered during REM sleep. Results for the first experiment underline a qualitative difference between REM and nREM sleep in a reflexological perspective. In nREM sleep the conditional response is better maintained than in REM sleep. The second experiment confirms the possibility to improve daytime learning performances after an additional presentation of learning material in REM. The joint study of sleep abnormalities and learning and cognitive impairment in schizophrenic patients is finally suggested.     

Personality Factors Related to Black Teenage Pregnancy and Abortion

Forty-eight pregnant adolescents who applied for therapeutic abortions (TAs) were compared with 55 adolescents who planned to have their babies (Terms) and 67 adolescents who were not pregnant (Controls) on the California Psychological Inventory (CPI). All the subjects were single, Black, and aged 15 or 16. CPI results point to psychological differences with the Controls being most socialized, followed by the TAs, and then the Terms. Term girls seem to be experiencing a void and appear to be trying to fill it and assume an adult role by having a baby; the TAs do not seem to have these same needs. In addition, girls who became pregnant and described the relationship with the putative father as casual, appear on the CPI to have more daily problems, lack socialization, be less clear thinking, and have poor self-control. Pregnant girls who have good communication with their mothers showed no differences on the CPI from girls with poor communication with their mothers.     

Differential effects of identification with family and peers on coping with developmental tasks in adolescence

Adolescents from three Italian cities responded to a questionnaire concerning the particular peer-group with which they were associated and identification with their family, aspects of the process of coping with seven developmental tasks, and demographic characteristics. The participants were 1600 male and female teenagers, with a mean age of 16.28 years, who were approached at schools and various meeting places in three Italian cities. The study shows that effective coping with developmental tasks depends largely on the degree of identification with both family and peer-group. Those who identify with both social groupings show advantages in various critical situations. Adolescents only identifying with either family or peers get emotional and instrumental support from that group but not from the other, thus, they are supported in some critical situations but not in others. Adolescents who are unwilling or unable to identify with their family and/or their peers are less successful in managing the transition to adulthood than others who are close to their parents and peers. Consistent with the findings of previous studies, the type of group adolescents join, be it a formal group or an informal street group, has no significant effect on their coping strategies.     

Semantic congruity effects in judgments of loudness

This research uses comparative judgments of the relative loudness of sounds to make a critical test of one theory of the mental representation of continuous physical attributes. The first two experiments find a semantic congruity effect, which is an interaction such that subjects can pick the louder of two loud sounds faster than the softer, and the softer of two quiet sounds faster than the louder. According to the theory under test, physical quantities are stored as points on a representational continuum, with a variance as well as a mean placement on it. The theory predicts the semantic congruity effect by assuming that the variance of placement of intensities on the representational continuum is a function of the direction of judgment: a soft sound will have less variance than a loud one when judged for softness and more when judged for loudness. Since the speed of making a judgment increases as variance decreases, the theory predicts a semantic congruity effect. However, for loudness, it can be shown that variance does not change in the manner assumed. The finding of a semantic congruity effect therefore disconfirms the theory. Alternative models are discussed. This research was supported by NSF Grant BNS 78-17442.     

Cross-cultural model testing: toward a solution of the etic-emic dilemma

A model for the prediction of behavior from attitudinal components, developed by Triandis, was tested with samples of U.S. and Mexican women, and with fertility relevant behaviors. The elements of the model are etic, but the operationalizations of the various variables were done emically. Results support the model in both cultures. While the predictive utility of the model is equivalent in two cultures, there are social class differences on which component of the model is most emphasized. The U.S. upper-middle-class sample and the Mexican upper-middle-class sample emphasized the person's attitude toward the act, while the Mexican lower SES (socio-economic status) sample emphasized the person's normative beliefs (moral obligations).