Differential rates of exhaustion and recovery of several parameters of male rat sexual behavior.

Sexual exhaustion of the male rat was studied with respect to several copulatory measures. The ejaculatory latency, intercopulatory interval, and intromission frequency demonstrate a U-shaped curve, exhibiting high values for the initial ejaculatory series, falling to a minimum at an intermediate ejaculatory series, and again increasing at exhaustion. The absolute refractory period of the postejaculatory interval (measured at vocalization termination) increases linerly, whereas the relative refractory period (the remaining portion of the postejaculatory interval) is a postively accelerating function. Partial recovery tests demonstrated that the preejaculatory measures and absolute refractory period have substantially returned to baseline values by Day 6, while the relative refractory period is still extended. The significance of these data to the theoretical modeling of sexual behavior is discussed.     

Parallel scanning of auditory and visual information

Two experiments involving memory retrieval of auditorilv and visually presented materials were performed. In Experiment I, subjects were presented with memory sets of 1, 2, or 4 stimuli and then with a test item to be classified as belonging or not belonging to the memory set. In Condition 1, each memory stimulus was a single, auditorily presented letter. In Condition 2, each memory stimulus was a visually presented letter. In Conditions 3 and 4, each memory stimulus was a pair of letters, one presented visually and the other auditorily. Mean reaction time (RT) for the classification task increased as a function of number of memory stimuli at equal rates for all four conditions. This was interpreted as evidence for a parallel scanning process in Conditions 3 and 4 where the auditory item and visual item of each memory stimulus pair can be scanned simultaneously. Experiment II compared memory retrieval for a simultaneous condition in which auditory and visual memory items were presented as pairs with a sequential condition in which mixed auditory-visual memory sets were presented one item at a time. RTs were shorter for the simultaneous condition. This was interpreted as evidence that parallel scanning may depend upon memory input parameters.     

AN ANALYSIS OF MULTIPLE MISPLACED PARENTAL SOCIAL CONTINGENCIES1

This study analyzed the training of a mother to modify five subclasses of her attention to her young child's noncompliance with instructions, and also displayed the changes in her child's behavior correlated with these events. Training in four subclasses consisted of teaching the mother to withhold various forms of social attention to her daughter's undesired behavior; training in the fifth subclass involved introduction of a brief room-timeout procedure for noncompliance. The effectiveness of the parent-training procedure, consisting of initial instructions and daily feedback, was demonstrated through a multiple-baseline design across the five subclasses of parent behavior. Sequential decreases in the first three subclasses of the mother's social attention to undesired child behavior resulted in incomplete improvements in some child responses; however, a decrease in the fourth subclass resulted in a significant increase in undesired child behavior. Complete remediation of all child behaviors was achieved following the training of a timeout procedure for noncompliance. Postchecks conducted up to 16 weeks later showed that these effects were durable.     

A SIMULTANEOUS DISCRIMINATION PROCEDURE FOR THE MEASUREMENT OF VISION IN NONVERBAL CHILDREN1

Few nonverbal developmentally disabled children ever receive adequate vision assessment because of their limited language skills. The present study details a simultaneous discrimination procedure for measuring subjective visual acuity in such children. A stimulus fading procedure was used to train a discrimination between Snellen Es differing in orientation, and a psychophysical tracking method was used to determine acuity thresholds. The procedure was tested with 11 nonverbal autistic and schizophrenic children and validated with four nonpsychotic children. Eight of the psychotic children were successfully examined in one to three sessions. Two of these children were identified as having significant acuity losses. The validity assessment showed that the experimental procedure resulted in thresholds equal to or slightly lower than those obtained with the Illiterate E chart.     

Age and task effects in short-term memory of children

Children of 4, 8, and 14 years performed a visual memory task with easy- or hard-to-label displays and with or without repetition of stimuli over trials. Eight pictures were displayed in serial order, and the task was to find the card in the array that matched an identical probe card. Performance improved with age, and strong serial position effects were obtained for all ages and tasks. In contrast to previous studies, primacy effects were obtained for the youngest children tested. Task difficulty increased with difficulty of labeling and with repetition, but order of task difficulty remained the same for all ages. The d’ measure, borrowed from signal detection theory, revealed differences in criterion levels over serial position, which in earlier studies had been confounded with strength of memory.