Multidimensional scaling reveals two dimensions of thermal pain

The Individual Differences Scaling (INDSCAL) model of multidimensional scaling was used to explore the dimensions of thermal pain. The observers made 66 similarity judgments to all pairs of 12 different thermal stimulus intensities ranging from zero to noxious. Analysis of the data revealed a two-dimensional group stimulus space. The major dimension ordered the stimuli with respect to their intensity. This quantitative, strength-of-sensation dimension may be interpreted as indicating how weak or strong a stimulus feels, apart from any secondary qualities of warmth or pain. The second dimension was related to the qualitative aspects of the stimuli. This bipolar dimension contained two attributes: a pain attribute ranging from just detectable warmth to painful, and a warm-hot attribute running from just detectable warmth to hot. This study demonstrates the utility of the INDSCAL approach to the understanding of pain and offers a new technique for answering the age-old question concerning the number and qualities of the dimensions underlying the pain experience.     

The Zeigarnik effect and intrinsic motivation: Are they the same?

The present study focused on delineating the parameters under which intrinsic motivation leads an individual to reengage an activity from those that result in the Zeigarnik effect. In a posttask free-choice period, participants not completing the experimental task displayed more reengagement behavior than participants completing the task (the Zeigarnik effect). When participants were also provided self-efficacious performance feedback via a prearranged competitive outcome manipulation, there was no evidence of the Zeigarnik effect, while there was support for intrinsic motivation from competent self-efficacious performance feedback. Results were discussed in terms of distinguishing between intrinsic motivation and the Zeigarnik effect as sources of reengagement motivation. It was concluded that, in the presence of self-efficacious performance feedback, the competent-incompetent impression was more salient than task-completion feedback.Preparation of this article was supported by Texas Christian University grant TCU/RF 5-23757.     

Type A behavior,anger expression,and reactions to anger imagery

The experiment investigated the effects of Type A behavior, anger expression, and gender on perceptions of control and heart rate. Jenkins Activity Survey defined Type A and B subjects, categorized as either high or low in anger expression, were asked to recall, image, and generate self-referent statements about angry situations. State anger and heart rate were measured during all of the anger induction conditions, and ratings of imagery vividness and perceptions of control for self and others were taken following the recalled and imaged anger conditions. The results, with both the heart rate and self-report measures, indicated that the effects of the independent variables were interactive and situationally dependent. Type A behavior was associated with increased heart rate in two experimental conditions (mood anger and recalled anger), and, in one instance, this effect was amplified in male subjects (recalled anger). The self-report results yielded interactional effects that most commonly took the form of high anger expression, with male Type A's providing higher ratings of state anger, more vivid anger imagery, and lower perceived self-control ratings than did other categories of subjects. Taken together, these results suggest that anger expressiveness, particularly among males, amplifies the usual reactions attributed to Type A's, and that such effects are mediated by the threat of loss of control. Further, the observed interactive relationships limit the generalizability of A/B differences and raise definitional questions about Type A behavior.     

Weanlings' transfer of conditioned ethanol aversion from olfaction to ingestion depends on the unconditioned stimulus

Weanling (21-day-old) rats were exposed to an alcohol odor paired with either an interoceptive (apomorphine-induced illness) or exteroceptive (footshock-induced distress) reinforcer. Twenty-four hours later, ethanol preferences were measured in a locational olfactory test (ethanol vs lemon odor) or an ingestion test (5.6% v/v ethanol vs 0.25% v/v citric acid solution). Weanling rats expressed substantial olfactory aversions, independent of the reinforcer employed in conditioning. During the drinking test, however, only rats that had experienced the ethanol odor paired with internal malaise showed a significant reduction in the intake of the ethanol solution when compared to unpaired controls. Furthermore, rats that had experienced the ethanol odor paired with external distress drank significantly more of the ethanol solution than their controls. These results provide further evidence that olfactory experiences with ethanol can lead to changes in ethanol ingestion, and indicate that the nature of the unconditioned stimulus is critical in establishing the ingestive effect.     

Preserved spatial memory in old rats survives 10 months without training

Aged rats with extensive prior training on the radial maze retain the capacity for accurate spatial working memory (WM) for at least 3 months without practice. To investigate the temporal limits of this influence of prior experience we compared the reacquisition of spatial WM by a group of experienced 21.5-month-old rats to the original acquisition by naive 3-month-old rats. The aged rats had received 225 radial maze tests between 3 and 11 months of age. Despite 10 months without practice the old rats rapidly reacquired critical performance. Their reacquisition was markedly superior to original learning by the young rats, even when delays as long as 5 h were imposed between the rats' fourth and fifth choices during the daily tests in the eight-arm maze. Additional tests showed that neither young nor old rats employed a response strategy to maintain accurate spatial WM performance. Experience clearly confers long-lived protection against the otherwise deleterious effects of aging on spatial WM, but the mechanism by which this influence arises is unknown.     

Value Development During the College Years: A Cause for Concern and an Opportunity for Growth

The authors examine and propose a synthesis of the theoretical tenets of ecumenical religious principles and cognitive-developmental stages of moral reasoning as a basis for value development. Because the college years represent a major opportunity for such value development, a case is made for formal programs and curriculum development for this period and an example is provided of coursework designed to promote systematic consciousness and the process of value growth.     

Successive, simultaneous, and anticipatory contrast in the consumption of saccharin solutions

Contrast effects were obtained in rats in the consumption of saccharin solutions in three different paradigms. Degree of negative contrast varied as a function of concentration disparity, but not equally in the three procedures. Successive negative contrast occurred following shifts from 0.15% to either 0.075% or 0.05% saccharin but did not occur following shifts to 0.10% or 0.125% saccharin. Some degree of simultaneous contrast was obtained with all four concentration disparities. Anticipatory contrast, where the intake of the first substance is suppressed by a more preferred second substance, occurred only in the case of the 0.05%-0.15% difference in concentrations. It was suggested that the several contrast paradigms engage somewhat different psychological processes differentially involving emotional, sensory, and associative mechanisms, but all lead to behavior based on relative value. A modification of Toates's (1981) incentive model of ingestive behavior was suggested to incorporate relativity effects based on both associative and nonassociative factors in the consumption of both nutritive and nonnutritive substances.     

Categorical shape and color coding by pigeons

Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical.     

Initial environment influences amphetamine-induced stereotypy: subsequently environment change has little effect

Saline-treated and amphetamine-treated (7 mg/kg, ip, immediate) male rats from a Sprague-Dawley substrain were observed in two test environments designed to elicit different investigative responses in normal rats. Snout contact with the substrate was generated by placing the rat in a small enclosed cage. Absence of snout contact was induced by placement of the rat on a square elevated platform. Detailed ethological records were kept of locomotion, rearing, sitting, grooming, gnawing, and sleeping throughout the 90-min session. Amphetamine-treated rats incorporated environmentally contingent bodily postures into their forms of stereotyped behavior. The postures were characteristic of those evinced initially by the saline-treated rats in the same test environment. The control rats showed appropriate changes in their investigative behavior when the apparatus was changed at 10 and at 30 min postinjection. The amphetamine-treated rats, however, were completely unresponsive to such changes at 30 min and only partially so at 10 min postinjection. It was concluded that there is a temporal gradient of decreasing readiness to modify repetitive behavior after a single, large dose of amphetamine.     

Incidental learning,distraction, and sustained attention in hyperactive and control subjects

Thirty-two children designated as hyperactive (ADD) were compared with an equal number of control subjects who were matched for age, sex, and verbal IQ. The subjects were tested on (1) a component selection task, measuring serial memory and incidental learning and (2) a cancellation task, assessing attentional variables and distractibility. No straightforward group differences were found on the component selection task, whereas hyperactive subjects made more omission and commission errors than controls on the cancellation task. It was concluded that a deficit in sustained attention and impulsivity best described the group differences. Age was also found to influence performance on a number of variables, including incidental learning on the component selection task and response rate and omission errors on the cancellation task. Because subjects in the hyperactive group were rated as extreme on a number of subscales not necessarily related to hyperactivity, the data were reexamined by multiple regression analyses. Subscales considered to be related both to hyperactivity and to conduct disorder were associated with different performance variables, indicating that each of these subscales provided some unique information.This study was supported by a grant from the Medical Research Council of New Zeland to the first author. The authors would like to thank the pupils and staff of Mt. Eden Normal Primary School and Newmarket School for taking part in the study, and the Auckland Education Board for granting approval for the study. We also thank Prof. J. S. Werry, Dr. J. Reeves, and Mrs. G. Elkind for assistance in locating some of the control subjects. Special thanks goes to Gail Elkind for assistance with the statistical analysis.