Elicitation and punishment of intraspecies aggression by the same stimulus

Fighting responses were elicited in pairs of rats by shocks over a period of 46 days. During certain blocks of these days, “punishing” shocks were made contingent on the shock-elicited fights. Fighting frequency was reduced as a direct function of the intensity of the contingent shocks. Fighting frequency recovered completely when contingent shocks were removed.     

Failure to replicate visual discrimination learning with a 1-min delay of reward

Two experiments were carried out in an attempt to replicate Lett's (1974) demonstration of visual discrimination learning with a 1-min delay of reward. In Experiment 1, controls for olfactory cues were introduced by testing animals in different orders from day to day and by reversing the positions of the discrimination chambers within days; also, secondary reinforcement effects were precluded by the use of opaque rather than transparent doors to the discrimination chambers. No evidence of learning was found either in a group of rats returned to the home cage during the delay or in a group left in the apparatus during the delay. It was hypothesized that the failure to find improvement in Experiment 1 might have resulted from either the controls for odor cues or from a lack of memory retrieval cues provided by the apparatus. In Experiment 2, both of these hypotheses were tested and neither was supported. The Lett group in Experiment 2 was run according to the exact procedures used by Lett and still no learning was demonstrated. It was concluded that further demonstrations of visual discrimination learning with a 1-min delay of reward will be necessary for the acceptance of the validity of this phenomenon.     

Lifting movements in the size-weight illusion

The occurrence of the size-weight illusion is related to the manner in which-objects are lifted. When the SWI occurs, the larger of two objects of equal objective weight is usually lifted with greater acceleration, deceleration, and maximum velocity than the smaller one, but to approximately the same height. These differences are not present when the cans feel equally heavy. The relationship of lifting movements to judgments is consistent with the known behavior of proprioceptors which provide sensory input about muscular and movement events.     

The effects of prior task experience in the modeling situation

An investigation was made into the effects of observers' previous experience with the experimental task on acquisition and subsequent performance of modeled task behavior. The task was socially neutral and the subjects were second grade boys and girls. Recall of modeled actions increased with prior experience, indicating greater acquisition. This finding supports Bandura's (1973) assertion that task familiarity may enhance attentiveness to the model. Contrary to previous research, performance of imitation did not decrease with experience. The present performance results are possibly due to the ambiguity of the preexperience and novelty of the experimental task.     

The inheritance of cognitive interest styles among twins

Through twin studies, research in behavioral genetics has demonstrated significant genetic components in many personality traits. Less research has been done on inheritance of vocational interest preferences, partially because of the lack of a wholistic conceptual model for understanding the relationships among diverse occupational interests. With the development of scales for the Strong Vocational Interest Blank (SVIB) to measure the six cognitive interest styles propounded by Holland, a parsimonious and comprehensive mapping of the occupational world was available and lent itself to the study of measuring inheritance of vocational preferences among twins. Median intraclass correlations for 409 pairs of monozygotic males, tested with the SVIB, was r = .50; for 570 pairs of monozygotic females, r = .55; for 237 pairs of dizygotic males, r = .27; and for 370 pairs of dizygotic females, r= .27.