The role of brain stimulation priming effects in self-deprivation

Choice of brain stimulation reward (BSR) over biologically necessary substances in some self-stimulating animals is referred to as self-deprivation. In several recent papers, it has been argued that this phenomenon is produced by the rewarding aspects of the brain stimulation. This conclusion is partially based on data showing that self-deprivation and brain stimulation reward increase and decrease in a similar manner in response to changes in the brain stimulation parameters. However, the priming aspects of the brain stimulation also fluctuate with changes in stimulation parameters. Therefore, changes in the priming rather than the rewarding aspects of the brain stimulation could be responsible for self-deprivation. To determine whether the priming effects of brain stimulation play an important role in self-deprivation, rats with bipolar stimulating electrodes were given the choice between BSR and food. Time-outs were enforced within each BSR/food competition session. Since priming effects decay over time, increasing time-out length should have decreased self-deprivation due to decay of priming. It was found that time-out length did not affect the degree of self-deprivation. It was concluded that self-deprivation is not mediated by the priming aspects of brain stimulation.     

Hypothesis analysis of sameness-difference learning-set by capuchin monkeys

Sameness-difference discriminations were presented to capuchin monkeys and hypothesis analysis was applied to the data. Learners and nonlearners evidenced differences in overall performance and in relative strengths of hypotheses. Learners initially displayed markedly more random than position responding whereas nonlearners evidenced more position than random responding and remained particularly prone to position habits. Stimulus preference and aversion, suppressed by learners by the end of training, reemerged at the onset of two-object discriminations containing previously preferred and aversive stimuli. Hypothesis analysis indicated that when preferred stimuli were positive the correct hypothesis was more evidenced, and stimulus preference or aversion as well as random hypotheses were less evidenced, than when aversive stimuli were positive.     

Behavior modification consultation in a Mexican-American school

Following consultation by two psychologists with an elementary school populated primarily by Mexican-American students, absenteeism was chosen as the first problem area to attempt to change. A between-groups experimental design was used to evaluate the effect of contigent rewards on the students' attendance. Analysis of the data showed no improvement in attendance. The results of the study were discussed in terms of (1) a more thorough behavior analysis of the absenteeism problem, (2) methodological restraints of a between-groups experimental design, (3) the need for consultants to be familiar with the community in which they work, and (4) relatedly, the success of the local school psychologist in implementing behavior modification programs.     

Shape constancy and a perceptual bias towards symmetry

In attempting to judge whether a briefly presented rotated figure was symmetrical (circle or square) or asymmetrical (ellipse or rectangle), a bias towards perceiving symmetry was evident. This bias appears to be perceptual rather than judgmental in origin in that it was affected neither by variations in the probability of occurrence of symmetrical figures nor by familiarization with the stimuli. A characterization of the stimulus similarity space based on the shape-slant invariance hypothesis is presented, and a model which incorporates both the similarity space and the symmetry bias is proposed. The model can account for our paradoxical finding that the more asymmetrical some projected images, the more likely they will be perceived as symmetrical. This model can also account for Massaro’s (1973, 1975) results on shape constancy. However, Massaro’s theory was not supported in that extension in depth did not account for increased difficulty of shape judgments.     

The photo-lickerandum: A device for detecting the licking response,with capability for near-instantaneous programming of variable quantum reinforcement

A combined operandum-feeder is described that eliminates the necessity of passing an electrical sensing current through S while detecting and reinforcing tongue-licking responses. A glass nozzle for dispensing liquid reinforcers is situated just above a small separation in a loop of photo-conducting Sterite tubing; licks at a tiny area below the nozzle break a light beam and are detected via a photo-resistor and associated circuitry. Data are presented from a study in which rats worked at the operandum on a mult FR 40 ext schedule; performance and records are comparable to those obtained via conventional electronic sensing. Applications of the photo-lickerandum and an associated variable-quantum reinforcing system are suggested.     

“Anchor-range” results with “same” and “different” responses and similar and dissimilar stimuli

Summary Blocks of pairs of dissimilar (anchor-like) circles were unexpectedly followed by single pairs of similar circles and vice versa. The dissimilar circles were 3 and 10 mm in diameter, and the similar circles were 3 and 5 mm, 5 and 7 mm, and 7 and 10 mm in diameter. In a second experiment, the dissimilar and similar circles did not overlap in size (e.g., they were 1.5 and 5 mm and 7 and 10 mm, respectively). The same responses to the unexpected same pairs of similar circles were faster than the same responses to the identical pairs in the blocks. In contrast, the different responses to the unexpected different pairs of similar circles were slower than the different responses to the identical pairs in the blocks. Similar stimuli accelerate same responses and slow down different responses. So the time results (and the error results as well) suggest that the context of the block dissimilar circles increased the perceived similarity of the unexpected similar circles. These anchor-range results are not explained by Thurstonian theories, which are based on the absolute properties of stimuli. Instead, they imply that the relation between the similar circles in the context of the relation between the dissimilar circles affected performance.     

Personal striving differentiation and affective reactivity

Examined the relation between affective reactivity (intensity and variability of mood) and cognitive differentiation through the personal striving (Emmons, 1986) framework in order to test the hypothesis that affective reactivity underlies differentiation. 88 Ss in 2 samples listed 15 of their personal strivings and rated them with respect to 3 measures of striving differentiation (interdependence, dissimilarity, and plans for accomplishing each). Experience-sampling and daily mood ratings were used to assess affect intensity and affect variability over a 3-week period. Emotionally reactive Ss possessed a more differentiated striving system. However, they generated fewer plans for accomplishing each striving than did less reactive Ss. Results are interpreted in terms of Larsen and Diener's (1987) arousal regulation theory of affect intensity and Linville's (1982, 1985) self-complexity/affect-extremity model.