Auditory temporal discrimination by trained listeners

Previous reports from this laboratory have shown that untrained listeners cannot name the order of sounds in extended sequences of unrelated items such as hisses, tones, and buzzes at item durations of 200 msec, even though identification of order for the sounds of speech and music is accomplished readily at much shorter item durations. The present study indicates that under appropriate conditions subjects can be trained to distinguish between and to identify permuted orders within sequences of nonrelated sounds each lasting only 10 msec or less. Evidence is presented suggesting that much of what passes for direct identification of order is actually based on prior identification of a larger pattern. Two principal mechanisms seem to mediate discrimination of auditory temporal order: (1) fine resolution (requiring prior training) permitting identification of over-all patterns and capable of operating with item durations of only a few msec; (2) coarse resolution (special prior training not required) allowing naming of order of items having minimal durations usually above 200 msec for unfamiliar sequences.     

The effects of exposure duration and practice on the immediate memory spans of children and adults

Immediate memory spans for alphabetic items were determined for second-grade, fifth-grade, and adult subjects. Subjects were tested on three days, ten trials per day at each of three exposure durations: 15, 50, and 200 msec. One half of the subjects were presented with exposure durations in an ascending order, the other half in a descending order. The results indicated that immediate memory span increases with age and practice. The exposure duration effect depended on the order and day in which durations were presented. There was a suggestion that the exposure duration effect was also dependent upon the age and sex of the subject. The ordering of array positions from most accurately reported to least accurately reported was identical for all three age levels, indicating that scanning strategies are well established at an early age.     

Observing behavior in the albino rat: a within-subjects' comparison of increasing levels of visual complexity.

54 male CD strain Charles River albino rats were tested for complexity preference using a non-locomotor response. Each subject was presented an array of photographic slides containing an incremental series of complexity elements, i.e., 1, 2, 5 and 25 elements. All photographic slides were randomized both within and across subjects. Each photographic slide of each level of complexity was repeated three times. Results of an analysis of covariance, with luminance as the covariate, showed that cummulative viewing time increased with an increase in stimulus complexity. The relationship between looking and level of complexity was shown to be different when covariance procedures were used than without them.     

Pain cues and uncertainity as determinants of aggression in a situation involving repeated instigation.

In contrast to the Buss aggression paradigm, a situation was employed in which subjects were given an expanded range of response options and were exposed to instigation throughout their response period. It was found that (a) despite these changes pain cues depressed aggressiveness in the present situation as they generally do in the Buss paradigm, but that this effect only occurred where the subjects' aggression was initially ineffective in changing their target's behavior; (b) situational uncertainity, which is minimal in a Buss-type situation, was related to aggressiveness; (c) subjects tended to match rather than attempt to control the responses of the target; and (d) the present paradigm is capable of isolating a personality variable related to overall aggressiveness. These data are discussed in terms of other recent paid cue studies that deviate from the standard Buss situation. Generally, the findings suggest the potential of increasing the range of situations in which aggression is studied.     

The effect of adults' eating on young children's acceptance of unfamiliar foods

Adults presented unfamiliar foods to 14- to 20- and 42- to 48-month-old children individually in their homes. More children put the food in their mouths when the adults also were eating than when the adults simply were offering the food. More children put food in their mouths when their mothers were the source than when the source was a friendly adult “visitor”. However, even when alone with a child, the visitor's eating elicited reliably more tasting. Analysis of requesting behavior indicated that the adults' eating aroused a desire to eat in the children. There were no consistent sex differences or interactions between sex of visitor and sex of child in children's food acceptance. There was a suggestion that younger children were more affected by repeated offerings than were older children. It is concluded that a relatively “low level” form of observational learning—“social facilitation”—can account for the data.     

The effect of a teacher's presence on the classroom behavior of conduct-problem children

Six institutionalized conduct-problem children performed in a classroom under three reinforcement conditions: (1) noncontingent reinforcement: (2) reinforcement for being on task and (3) reinforcement for the accuracy and rate fo their academic behavior. Within each of these conditions, the teacher was either present throughout the class session or absent for a portion of the session. In the teacher's absence, on-task behavior was markedly reduced and disruption was markedly increased, regardless of the reinforcement condition in operation. In contrast, the teacher's absence had no effect on academic accuracy and had a major effect on academic rate only when reinforcement was delivered noncontingently. Furthermore, the extent to which the children became disruptive in the teacher's absence was reduced when reinforcement was contingent upon academic accuracy and rate, instead of being contingent upon being on task or delivered noncontingently. It is suggested that the reinforcement of academic behavior, rather than on-task behavior or classroom social behavior, not only will improve the latter behaviors as well, but possibly also make them less dependent upon the presence and continued surveillance of the teacher.