Developmental trends in the use of perceptual and conceptual attributes in grouping,clustering, and retrieval

In Experiment I, two tasks were administered to children aged 4, 5, and 9 in order to investigate preference for perceptual versus conceptual attributes in grouping of common objects, and in various aspects of memory. The grouping task revealed a clear chronological progression: color and form determined the youngest children's grouping about equally; form dominated in the 5-year-olds; and most of the oldest children grouped primarily by conceptual attributes. In the memory task, three lists—one organized by color, one by form, one by superordinate category—were presented for free, followed by cued recall. Clustering showed the developmental shift from color to form to concept, while cued recall showed conceptual superiority at all ages. Experiment II replicated the memory task, yielding the same results. The results were discussed in terms of the relative abstractness and predictability of conceptual versus perceptual attributes and the difficulty of abstraction in encoding and the function of predictability in retrieval.     

The effects of communication,resource feedback,and identifiability on behavior in a simulated commons

This study examined the effects of communication, feedback, and identifiability on behavior in a simulated commons. To do this, 64 mixed-sex groups of four introductory psychology students participated in a commons dilemma simulation for 50 trials or until the group exhausted the commons pool. Half of the groups played under a free communication condition, while the other half were prohibited from communicating. Half of the groups in both communication conditions received visual feedback about the amount of the commons' resource (money) which remained after each trial while the other half received no feedback. Finally, half of the groups in each of these four conditions were made highly identifiable by the use of the name tags and feedback about the choices of each player. The remaining groups were assigned to a low identifiability condition in which no name tags were used, no feedback given and group members were separated by wooden dividers to prevent visual contact. Results showed that groups having the opportunity for resource feedback or for communication achieved greater total money harvests and maintained the commons for a greater number of trials than groups having neither. As expected, the largest totals and longest commons maintenance were achieved by groups having both. Identifiability had no influence on the length of commons maintenance except when there was neither resource feedback nor communication opportunities. When both were unavailable, groups in the high identifiability condition harvested more money and maintained the commons longer.     

Self-punitive behavior in humans: Effects of a self-fulfilling prophecy

Human subjects were exposed to contingencies which programmed aversive tones (100 db). Two types of contingencies were employed: self-confirming (i.e., self-fulfilling prophecies), in which the aversive tone was occasioned by the prediction it was about to occur; and self-disconfirming, in which the tone was probable when subjects predicted it would not occur. Experiments 1 and 2 used a modified classical conditioning paradigm, and demonstrated that a self-confirming contingency maintained reliable self-punitive responding, i.e., subjects consistently predicted and therefore obtained tones on every trial. Subjects in Experiment 3 were instructed to express predictions continuously throughout four sessions to ensure adequate sampling of the various predictions. Subjects exposed to a self-disconfirming contnngency reliably evidenced awareness of the contingency in effect (judged by answers on a postexperimental questionnaire), whereas subjects exposed to a self-confirming contingency failed to show effective avoidance behavior or contingency awareness. Experiment 4 investigated free-operant self-punitive behavior, utilizing a single prediction response button, which subjects depressed repeatedly. Subjects were exposed to either periodic or aperiodic punishment schedules over as many as four sessions. In general, more persistent self-punitive responding was found in the groups receiving periodic punishment. The results from the four experiments show that self-confirming contingencies can effectively prolong self-punitive responding in human subjects. The findings are consistent with a blocking interpretation of self-punitive behavior, which asserts that when an aversive event is already predicted by stimuli in the situation (including temporal cues), the association between a response and punishment is impaired, and self-punitive responding is likely to be maintained. An integration of human and animal self-punitive research is proposed.     

Attention as a predictor of learning in infants

A total of 240 fourteen-week-olds were rewarded with a pattern of lights and tones for kicking. The reward display interrupted a background of random alternation between two lights and tones. In experiment 1, attention to this background stimulus during a 1-min baseline was assessed using the number of fixations of alternating lights. During 6 min of reward, high-attention subjects showed significantly greater changes in kicking rate from baseline than low-attention subjects. In experiment 2, the proportion of subjects with low attention ratings increased dramatically during an extended 5-min baseline period, and those subjects with low attention ratings at the end of baseline did not show an increase in kicking from baseline to the reward phase, while high-attention subjects did show evidence of learning. Thus, an objective measure of attention, empirically separate from the dependent learning measure, provided a significant prediction of the effectiveness of subsequent reinforcement, and could be manipulated simply by extending the baseline by as little as 4 min.     

Event knowledge,elaborative propensity,and the development of learning proficiency

An experimental test was made of two hypotheses formulated to account for age differences across adolescence in the learning of arbitrary associations. One hypothesis ascribes such differences to two factors: the propensity to elaborate coherent relationships among initially disparate items, and accessibility to event knowledge that can form the bases of such relationships. The other hypothesis assumes that propensity remains constant across age, and that development stems entirely from increases in the accessibility of relevant event knowledge. These hypotheses are evaluated with reference to the performance of 11- and 17-year-olds in learning relationships among paired nouns. The results discredited both hypotheses, instigating the formulation of a revised conception of the relationship between knowledge and propensity as developmental determinants.     

Divided attention: Evidence for coactivation with redundant signals

Many models of divided attention assume that signals presented on different channels produce separate activations, any one of which can initiate a response. According to these models, detection responses are especially fast when signals are presented on two channels at the same time because the system can detect a signal in either of two ways. Such models predict a testable relation among reaction time distributions for conditions in which a single signal is presented as compared with a condition in which two signals are presented, and this prediction is tested in two tasks. A bimodal detection task required a simple speeded response to either a visual or an auditory signal. A letter search task required a choice response depending on whether or not a two-letter display included the signal letter “A.” Data from both tasks are inconsistent with the prediction. When two signals are presented, responses are faster than separate-activation models can explain. The results favor “coactivation” models, in which signals presented on different channels contribute to a common pool of activation that initiates a response.