Assessment of the relative importance of S+ and S− in rats using differential training on intercurrent discriminations

The present studies assessed the degree of stimulus control exerted by S+ and S? without confoundings of stimulus novelty and stimulus ambiguity. In Experiment 1, rats were trained on two intercurrent simultaneous discrimination problems with nine times more training given on one than the other. Then the animals were given transfer tests with re-paired stimuli. The results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination. Experiment 2 provided a test of the possibility that the relative degree of control by S? varies with different amounts of training. Three groups were trained on two intercurrent simultaneous discrimination problems; each group was given 7, 11, or 15 times more training on one problem than the other. Then transfer tests were given with re-paired stimuli. Again the results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination.     

New assessments of weight-related body image derived from extant instruments

A study of 79 female college students examined the reliability and validity of two new size/weight-related measures of body image. The Body-size Appraisal Scale and the Overweight Preoccupation Scale were derived from existing instruments. Analyses supported the internal consistency and 2-wk. test-retest reliability of both new scales. Correlations of scores on each scale with measures of anxiety about being fat, negative body-image affect and avoidance, restrained and bulimic eating, and depression support their concurrent and construct validity. Scores on the Overweight Preoccupation Scale were also related to the extent of investment in physical appearance. Regression analyses indicated that each new scale could be predicted from several other conceptually relevant body-image attitudes, even after actual body weight was controlled.     

Recognition time for letters and nonletters: effects of serial position, array size, and processing order

Three experiments address the question of whether end-effects (the advantage for the first and last letters in multi-letter arrays) are due to sensory or cognitive factors. The basic strategy used was to compare letters with symbol stimuli that do not lend themselves to top-down processing. Serial position functions using central fixation were obtained in the first experiment for letters, digits, and symbols. End-effects were present with both letters and digits, indicating that processes limited to word recognition cannot be responsible for end-effects. Five-symbol arrays, however, yielded U-shaped reaction time functions, with poorest performance at the initial and terminal positions. The effects of array size and retinal placement were investigated with letters and symbols in a second experiment. Multi-letter and symbol arrays differed primarily in that letters showed end-effects that were independent of retinal placement, whereas symbols did not. The conclusion that multi-letter and symbol arrays are not processed in the same way was tested in a third experiment. Using a paradigm that eliminated processing order as a variable, the experiment obtained identical effects of ordinal position within an array for letters, digits, and symbols. It is concluded that sensory factors cannot provide a viable account of letter end-effects and that letter and nonletter comparisons can improve our understanding of the sensory and cognitive factors involved in letter perception.     

Contrasts in visual responsiveness and emotional arousal between rhesus monkeys raised with living and those raised with inanimate substitute mothers.

Rhesus monkeys were raised with dogs or inanimate surrogates in outdoor cages which provided them with complex, highly varied visual surroundings. Visual responsiveness to a variety of colored transparencies was investigated in three experiments, completed when the monkeys were between 18 and 30 mo old. Results indicated that the frequency and duration of looking at slides was significantly higher for dog-raised than for inanimate-surrogate-raised monkeys and that dog-raised monkeys were much more responsive to the novelty, complexity, ansal were obtained during the final experiment. Heart rate, vocalization, and changes in plasma cortisol were higher for monkeys raised with dogs. The frequency of most self-directed behaviors, however, was higher for monkeys raised with inanimate surrogates. Differences between rearing groups can only be the result of contrasts in attributes of the substitute mothers.     

Politics and school psychology: A case study

School psychology is one of several professions in education which offer services beyond the regular school curriculum and program. Psychologists who work in school systems have long recognized the need to cooperate with these other professionals in school settings. In addition, they have been aware of the pressures from parents, teachers, and community groups which can impinge upon their jobs. However, limited availability of funding, federally mandated services, and legislation regarding certification are rapidly placing local, state, and national politics into prominance for school psychologists. An example is provided using the Commonwealth of Kentucky.     

Long-term retention of a visually cued poison-based aversion in monkeys.

Retention of a poison-based aversion after a 3-yr. period by 8 vervet monkeys (Cercopithecus aethiops) was found. The color of the visual cue appeared to effect the retention of the aversion.     

Effects of selective forebrain noradrenaline loss on behavioral inhibition in the rat.

Virtually total depletion of cortical and hippocampal noradrenaline by stereotaxic injection of 6-hydroxydopamine into the fibers of the dorsal noradrenergic bundle produced no impairment in acquisition learning of a runway response for food reward. Extinction of this response, once learned, was markedly slower in the treated group than in controls, the treated animals perseverating in rapid running to the goal box even with no food present there. Similarly, no impairment was found on acquisition of a continuously reinforced lever-pressing response for food. Extinction of this response, however, was again slower in the treated group. Subsequent acquisition of a successive light-dark discrimination task was also slower in the treated group, with these animals perseverating in responding to the negative stimulus. Although selective forebrain noradrenaline loss does not impair the acquisition of appetitive responses, the suppression of responses in the absence of reward is impeded. A parallel is drawn with those effects found classically after surgical lesion to the hippocampus.