The scanning of compound figures by young infants

We studied infants' scanning of two compound stimuli, in each case by presenting features inside a frame, the frame alone, and the features alone. One stimulus was composed of squares and was like that studied by P. Salapatek (in L. Cohen & P. Salapatek (Eds.), New York: Academic Press, 1975); the other was a schematic face. Newborns and 1-month-olds looked at the small square when it was presented alone, but rarely looked at it when it was framed by the larger square. In contrast, 2-month-olds looked at the small square for long periods whether or not it was framed. However, when newborns and 1-month-olds were shown a schematic face, they looked at its internal features at least half the time. Thus, young infants show no external bias when scanning a schematic face.     

Developmental differences in reactions to children labeled mentally retarded

In an attempt to examine age-related differences in response to the mental retardation label, 48 4th and 5th graders and 48 11th and 12th graders were told of a child of their own age and sex who was either labeled mentally retarded or unlabeled and who performed either competently or incompetently in giving a report. Incompetent target children were viewed more negatively than competent ones at both grade levels. The mental retardation label had less generalized impacts, leading girls but not boys (a) to cite lack of ability as the reason for a retarded child's failure, and (b) to hold low expectations that retarded targets would hold jobs, marry, or have children. A developmental shift in responses to the label was evident only on a trait perception measure; younger children stigmatized retarded targets, while older children granted special dispensation of a failing retarded child by viewing him or her more positively than a similarly incompetent but unlabeled child. Since only adolescent boys showed special dispensation, even though girls were more generally attentive to the label, both sex and age differences warrant further examination.     

Kinematic information feedback for learning a rapid arm movement

The experiments reported examine the notion that knowledge of results (KR) about the outcome of a response does not provide the necessary information for optimizing performance in many skilled activities. The effect of traditional KR was contrasted with various kinematic feedback parameters in the acquisition of a single degree of freedom response requiring the minimization of movement time. Experiment 1 showed that the presentation of discrete kinematic information feedback (peak accelaration, time to peak accelaration, and velocity at the target location) did not facilitate performance over movement-time KR. Experiment 2 revealed that presentation of a computer generated velocity-time representation of the movement as terminal information feedback improved performance over movement-time KR. This facilitation occured even without knowledge of the kinematics for optimal performance. The findings suggest that the task criterion specifies the appropriate information feedback for skill learning in that the information feedback must match the constraints imposed upon response output.     

The effects of a discriminative cue and an incompatible activity on generalized imitation

Four noncompliant retardates were observed in a generalized imitation study. Two variables were studied: provision of a competing reinforced activity, and use of a cue to aid discrimination between reinforced and nonreinforced imitations. Both variables were found to increase the rate of discrimination between the two sets of stimuli. Greatest discrimination occurred when both cue and alternative task were present. Discrimination decreased when the variables were removed. Results are interpreted as implying that imitation of nonreinforced cues in generalized imitation procedures varies with the degree to which reinforcement is available for other activity, as well as with the complexity of the discrimination problem. These results help indicate conditions under which the generalized imitation effect may be observed in more naturalistic settings.     

Short-term memory in the pigeon with presentation time precisely controlled

Delayed matching-to-sample was studied in the pigeon using a procedure which precisely controlled the presentation time of the sample stimulus. Experiments 1 and 2 revealed that (a) accuracy of matching increased as a negatively accelerated function of presentation time, (b) accuracy declined when an interstimulus interval was introduced between successive presentations of the sample stimulus, and (c) the rate at which accurate matching was restored after an interstimulus interval was greatest when the initial presentation of the sample was short and the interval was long. It was concluded that a theory of STM based on the growth and decay of trace strength could account adequately for all of these findings. Experiment 3 studied trace interaction by presenting two sample stimuli first in succession and then simultaneously for choice. Predictions from trace competition theory about the specific lengths of presentation of these stimuli at which choice of the second stimulus should be 50% or deviate systematically below 50% were not supported. It appears that a recency mechanism in addition to competition is necessary to explain trace interaction effects.     

Reconstruction from the mental image

In three experiments young children were asked to reconstruct an array of objects after they had imagined its appearance following either a rotation of the array or a change in their own position (Huttenlocher & Presson, 1973). In reconstructing arrays, subjects first positioned that object which would be most prominent to an observer following the imagined transformation. Surprisingly, this occurred even when subjects made an egocentric error by reconstructing a copy of the original array. Hence young children, although apparently egocentric, can imagine themselves in a new position with a new perspective. The mental operations which underlie imagined spatial transformations are discussed in light of the results.     

Male versus female Siamese fighting fish as reinforcing stimuli for conspecific males in single- and two-choice operant situations

Two experiments attempted to determine the reinforcing effectiveness of visual exposure to a female versus a male stimulus in male Siamese fighting fish (Betta splendens). This was accomplished by making male or female presentation contingent upon an operant ring swimming response in single- (Experiment 1) and two-choice (Experiment 2) continuous reinforcement operant situations for 1 hr per day. It was found that visual exposure to a female stimulus was behaviorally reinforcing in a way comparable to that typically found in intermale studies. If given a choice, male test subjects were observed to demonstrate a consistent preference for the female as opposed to the male stimulus. The results are discussed in terms of stimulus discrimination and approach-avoidance conflict as differentially elicited by male and female target stimuli.     

An organizational analysis of the form class effect

The paper reports eight experiments concerning the form class effect. If verb connectives enhance organization between pairs of nouns more than do conjunction connectives, then (a) the form class effect should obtain in cued but not free recall, (b) interactive imagery instructions should raise performance with conjunctions, removing the effect, (c) separation imagery instructions should reduce performance with verbs, removing the effect, and (d) prepositions implying spatial contact should be superior as mediators for cued recall compared with less suggestive prepositions. The results of the experiments confirm the predictions, except that grade 3 children do not perform as expected with the instructional variables.     

The repetition effect in time judgments is not a function of the intensity of the stimulus defining the interval: implications for an arousal theory

College students (N = 17 per group) estimated the durations of time intervals ranging from 8 to 20 sec. Intervals were defined by tones of 35, 55, and 75 db for each of three groups. The estimates of all groups declined across trials, but the degree of decline did not differ as a function of stimulus intensity. These data call into question the view that the repetition effect is attributable to a decrement in general arousal.