Attachment behavior: a validation study in two age groups.

To assess the validity of attachment scores derived from the Ainsworth "strange situation," 56 1-year-olds and 79 2-year-olds accompanied by either the mother, the father, or a brief acquaintance were studied. Proximity to the adult, duration of play, crying, activity, and the incidence of looks and distance bids were measured. 1-year-olds were more secure with their parents: they were more active, played more, cried less, and stood closer to their parents than to an acquaintance. 2-year-olds accompanied by their parents were less settled in the presence of a stranger than children accompanied by the acquaintance. The adequacy of current conceptions and measures of attachment was discussed in light of these results.     

Perceptual training of height and brightness seriation in kindergarten children.

A study of seriation was conducted from the perspective of Gibson's theory of perceptual development. Kindergarten children who evidenced little seriation of height or brightness were assigned to either 1 of 3 perceptual training conditions or to a fourth, control condition. Training consisted of nonreinforced same-different judgments to wooden dowels varying in height, or in brightness, or simultaneously in height and brightness. The theoretical rationale for this training was that it would facilitate perception of the stimulus dimension(s) on which the dowels differed. It was found that perceptual training did facilitate seriation, particularly if both the height and brightness dimensions varied simultaneously in training.     

Dimensional salience and judgments of bigness by three-year-old children.

3-year-olds were shown triads of rectangles and asked to select the "big" one, where the biggest rectangle in each triad was neither the tallest nor the widest. Dimensional salience and response choice were highly related. In addition, as saliency of a particular dimension increased relative to the other dimension, significantly more responses were based on that dimension. The results support the notion that the young child does not rely on 1 specific dimension to make judgments of bigness but, rather, attends to the most salient differences among stimuli.     

Reversal of visual discrimination problem and differential frustration effects in dominant and submissive rats

Two experiments are reported comparing performance in dominant and submissive rats as determined by a food-competition procedure. Ss in Experiment I were either trained to criterion or overtrained before being reversed on a visual discrimination task. Although the two groups did not differ significantly in learning the initial task, the dominant Ss were significantly slower on reversal than the submissives. Experiment II, which utilized a tandem runway, showed that when the reinforcer which maintained the running response was not available in the first goalbox, submissive rats responded with a greater increase in running speed in the second runway than dominant rats. These findings were discussed as reflecting motivational differences between dominant and submissive rats.     

Successive acquisition and extinction in a runway with the domestic Muscovy duck (Cairina moschata)

Twenty domestic Muscovy ducks were trained to traverse a runway for food reward. Subjects were then randomly assigned to treatments. In one treatment, subjects received six nonrewarded trials followed by six rewarded trials every day for 12 days; and, in the other treatment, subjects received six rewarded trials followed by six nonrewarded trials every day for 12 days. These successive acquisition and extinction (SAE) treatments were selected because different extinction rates on the nonrewarded trials are expected on the bases of previous research performed with rats. Analyses of variance revealed the former treatment yielded significantly greater resistance to extinction than did the latter treatment. It was concluded that ducklings performed similarly to rats in the above SAE situation.     

Self-punitive responding in rats with goal shock and color change

After acquisition avoidance training, rats were assigned on the basis of matched run speed to the following groups: (1) maintenance of avoidance training, (2) extinction procedures with the addition of a brief shock in the goalbox, and (3) regular extinction procedures. Each group was further divided into two minor groups which experienced either change or no change in goalbox color. The results indicated : (1) that self-punitive responding was increased by goal shock, (2) that self-punitive responding was reduced by goalbox color change, and (3) that generalization of goal shock to the startbox and runway areas is a factor in self-punitive responding.