Two experiments were conducted in an attempt to occasion both positive and negative contrast effects. The primary purpose was to occasion both decrements and increases in responding following planned shifts in quality or magnitude of reinforcement. Participants were children ages 7 to 16 years who were receiving therapy using Applied Behavior Analysis (ABA) and had a prior diagnosis of autism. In Experiment I, changes in responding were measured following manipulations of reinforcer quality. Results indicated response patterns consistent with negative contrast effects following shifts from high quality to low quality reinforcers, and positive contrast effects following shifts from low quality to high quality reinforcers. That is, responding in sessions following shifts from high to low magnitude reinforcers was lower than rates of responding in previous low quality conditions. Positive contrast was less consistently observed, but was seen as responding at higher rates during a second high-quality condition relative to the first following exposure to a low-quality condition. In Experiment II, responding was measured following shifts in reinforcer magnitude using a similar sequence of schedules as Experiment I. Both positive and negative contrast effects were observed, although less consistently than in Experiment I. Overall, the findings were consistent with the phenomena of positive and negative contrast effects in that one schedule of reinforcement produced changes in responding for a different schedule of reinforcement. Results were discussed in relation to the ideas of behavioral contrast and studies of intrinsic motivation.

Blood pressure (BP) in healthy individuals typically exhibits normal diurnal variation ("nocturnal dipping"), with nighttime systolic reductions of 10-20%. Having sustained BP levels, without normal nocturnal dipping, has been associated with increased risk for cardiovascular disease and poorer performance on memory measures especially within the context of hypertension. A positive family history of hypertension has also been related to poorer performance on neuropsychological tests of visuospatial/constructional ability, verbal learning, attention, and memory. The present study investigated the effect of nocturnal BP dipping status in hypertensive and normotensive individuals, with and without a family history of hypertension, to determine if these factors contributed to declines in cognition and brain atrophy over a two-year period in otherwise healthy older adults. Eighty-one neurologically healthy older adults aged 68-89 received a battery of neuropsychological tests, 24-hour ambulatory BP monitoring, structural magnetic resonance imaging, health screening and questionnaires at baseline. Two-years later participants received follow-up neuropsychological testing and structural magnetic resonance imaging. Analysis of variance investigated the effects of age, nocturnal BP dipping status, hypertension, and family history of hypertension on residualized change scores for measures of memory, executive function, and processing speed. Additionally, multivariate analysis of variance was used with region of interest measures of brain structure to evaluate the effects of age, nocturnal BP dipping status, hypertension, and family history of hypertension on brain atrophy. Results indicated main effects for dipping status with non-dippers showing poorer performance on measures of memory compared to dippers. An interaction between nocturnal BP dipping and hypertension status was also observed on a test of executive functioning, with non-dipping hypertensives performing more poorly than the dipping groups, indicating that the combination of hypertension and non-dipping nocturnal BP was associated with poorer cognitive performance. Results indicated that non-dipping BP status was related to greater decline in cingulate volume and the combination of non-dipping and hypertension was related to greater decline in right hemisphere frontal surface area measures. These results provide some support indicating that having sustained diurnal systolic BP without normal nocturnal reductions in hypertension may be an important vascular risk factor influencing the course of cognitive and brain aging.

Efforts to understand the evolution of modern mammalian brains are undertaken through comparative studies of cortical organization. Here, we have used a comparative approach in studying multiple species to understand more about the organization of the visual system across different mammalian orders. Primates are notable for their large brains, and every primate species has an average brain size larger than then 0.4 g mouse brain, the animal model most commonly used in laboratory studies. Neurons are the building blocks of neocortex, and an accurate estimate of the total number of neurons in a brain can reveal information concerning the specializations of cortex. In this collaborative effort, we determined the total numbers of cells and neurons within the neocortex of the adult chimpanzee and macaque brains. These are species that have relatively large brains compared to most mammals, and to the proposed brain size of our earliest mammalian ancestors. We found the same pattern of overall neuronal density described in all other primate species, in which primary visual cortex and primary somatosensory cortex contain higher-than-average neuron densities and primary motor cortex contains lower-than-average neuron densities. It is also important to look to species that also, independently of the primate lineage, came to evolve large brains. As such, we examined the visual neuroanatomy of the California sea lion and northern elephant seal using immunohistochemistry in coronal sections and other reconstruction methods. We found that the visual neuroanatomy is more similar in structure to other carnivores, such as cats, as opposed to primates, which is expected given these speciesâ phylogenetic position within the Carnivora order.

Search efficiency is usually improved by presenting observers with highly detailed target cues (e.g., pictures). However, in the absence of accurate target cues, observers must rely only on categorical information to find targets. Models of visual search suggest that guidance in a categorical search results from matching categorically-diagnostic target features in the search display to a top-down attentional set (i.e., the search template), but the mechanisms by which such attentional set is constructed have not been specified. The present investigation examined the influences of both semantic and episodic memory on search template formation. More precisely, the present study tested whether observers incorporated a recent experience with a target-category exemplar into their search template, instead of relying on long-term learned regularities about object categories (Experiment 1) or on the semantic context of the search display (Experiment 2). In both experiments participants completed a categorical search task (75% of trials) in conjunction with a dot-probe response task (25% of trials). The dot-probe response task assessed the contents of the search template by capturing spatial attention if the dot-probe was presented at an inconsistent location relative to objects matching the search template. In Experiment 1 it was shown that observers include recently encoded objects into their search templates, when given the opportunity to do so. Experiment 2, however, showed that observers rely on context semantics to construct categorical search templates, and they continue to do so in the presence of repeated target cues related to different contexts. These results suggest that observers can, and will, rely on episodic representations to construct categorical search templates when such representations are available, but only if no external cues (i.e., scene semantics) are present to identify criterial target feature.

Research finds high-shy persons participate minimally in interactions, withhold ideas from their groups, and negatively evaluate their performance. While commonly true, high-shy persons do not always interact less and it has been suggested (Efran & Korn, 1969) that high-shy persons may dominate a discussion if they can find a "safe" topic. The current study examined whether perceptions of perceived competence can produce this effect and increase the performance level of high-shy persons in a problem-solving group above the performance level of low-shy persons. One hundred and four women, ages 18 to 24, at Virginia Commonwealth University participated. Subjects completed a shyness measure and a simulated creative problem-solving ability measure. Subjects were then placed into nominal brainstorming groups of three to six persons and were asked to generate solutions to a problem. They were led to believe their solutions would be evaluated by their group in preparation for a discussion where the group would select the best solution. Before beginning, subjects were told creative problem-solving ability predicted their performance and that their ability was either significantly below average (low self-competence condition), average (average self-competence condition), or significantly above average (high self-competence condition). After brainstorming, subjects selected their best solution and made a brief tape recording describing their solution. Subjects were told the tape would be played for the group prior to the discussion (neither occurred).

In today's complex society, no one can be independent and survive; people must help others. There appear to be limits on help giving or at least some conditions under which help is not given. For example, why did thirty-eight people stand silently and watch Kitty Genovese being murdered without one person calling the police or offering any assistance? In addition to making people more interdependent, our rapidly expanding technological society may also account for increased im-personalization and accompanying apathy and alienation. However, the research which has been done in the area of altruism or helping behavior seems to indicate that the variables involved are more complex than these"explanations" would indicate. Funk and Wagnall's dictionary defines altruism as "devotion to the interests of others: disinterested benevolence.”1 Berkowitz and Daniels (1963, 1964) as well as Hornstein (1968) assume the existence of what they term a "social responsibility norm," while Leeds (1963) calls it the "norm of giving." Latane and Darley (1970) feel that many discussions of altruism have basic questions which must be separated if we are to explain this phenomenon adequately. The first of these questions is, "What is the underlying force in mankind toward altruism?" or "What motivates helping?" The second, which is more specific, asks, "What determines in a particular situation whether one person will help another?" Schwartz (In Macaulay and Berkowitz) suggests that there is a three-step decision process which leads to behavior that is congruent with moral norms. First of all, the person must recognize the dependence of another on him by becoming aware that a potential action has consequences for the other. Secondly, he must have knowledge of the moral norms pertinent to this action and its consequences; and finally, he must ascribe some responsibility to himself for the action. Similarly, Darley and Latane (1968) have outlined a series of steps which describe the process of deciding to intervene in an emergency. He must notice that something is happening, interpret the event as an emergency, and decide that he has personal responsibility for coping with it. If any of these steps is omitted, then the bystander will remain inactive. However, they also point out that although many theories use the concept of norms to account for variations in helping from one situation to another, there is little evidence that people actually think about norms when choosing a course of action but instead seem guided by their first reactions.

Pediatric constipation can lead to various negative emotional and physical consequences including abdominal pain, painful defecation, toileting fears, anxiety about pain and intestinal dysfunction. In addition, constipation can lead to socially compromising and embarrassing situations due to associated overflow incontinence. These unpleasant physical and emotional symptoms may in tum lead to conditioned avoidance behaviors, which serve to further maintain the cycle of stool retention and constipation. Presently, there have not been any studies directly addressing the role of conditioned aversion in the etiology and maintenance of constipation. This study examined the psychometric properties of the Defecation Anxiety Scale (DAS)- a scale designed to assess subjective fear and anxiety that children with chronic constipation may experience regarding toileting. A reliable and valid measure of toileting fears for this population would be useful in determining the possible contribution of conditioned- aversion in the etiology and maintenance of chronic constipation. Three samples of children were recruited to examine the reliability and validity of the measure: (1) children with chronic constipation, (2) a normal control sample from a wellness clinic, and (3) a pediatric asthma sample. The study population consisted of children between the ages of 5 and 16 years of age. Parents and children in each group completed the Defecation Anxiety Scale. Results indicated that parents and children in the constipation group had significantly higher scores in the DAS relative to either control group. Having experienced pain significantly impacted DAS scores. The number of subjects reporting painful bowel movements was significantly higher for the constipation group. A preliminary examination of the interrater reliability of the DAS showed that the scale has high stability across parent and child ratings for the constipation group. Internal consistency for the total score suggested a high level of reliability for the scale. The validity of the DAS was assessed via comparisons with previously standardized measures of anxiety. Correlations between general anxiety scores and the DAS were low for the ratings made by the constipation group; therefore, fear and anxiety tapped by the DAS is specific to toileting.

This research investigated the influence of two social situational factors, anonymity and expected audience, on the expression of criticism and subsequent physiological and psychological response. The expression of criticism towards a disagreeable stranger was studied under the provision of either anonymity or no anonymity to the critic factorially combined with an expected audience for the criticism of either the person criticized (criticism-relevant expected audience), or someone who knew neither the critic or the person criticized (criticism-irrelevant expected audience). A series of hypotheses were derived from Zillman's (1972) two factor theory of aggressive responding concerning the expression of criticism and subsequent physiological and psychological response. In general, it was expected that criticism would be greatest, and subsequent physiological response least, when the critic was anonymous with a criticism-irrelevant expected audience. The opposite pattern of response was predicted for critics who were nonanonymous with a criticism-relevant expected audience. Subjects were 54 female students enrolled at a large urban university who were told that they were participating in a study concerned with the physiological and psychological correlates of critical thinking and expression. All subjects heard an audiotape of an obnoxious, though not personally insulting, confederate student at the same university. Two-thirds of the subjects were then randomly assigned to one of the four treatment conditions of anonymity or no anonymity with a criticism-relevant or irrelevant expected audience and asked to make a critical evaluation of the student. The remaining subjects were assigned to two control group conditions in which they did not criticize but were given an unrelated task involving verbalization. Forty-two subjects participated in a second session under the same treatment condition as the first session. Dependent measures consisted of an independently rated score for the criticalness of each subject's evaluation of the obnoxious student, frequency of skin resistance response (SRR), range-corrected skin conductance level (SCL) and heart rate (HR), and responses to a postsession Self-Report Questionnaire which asked the subjects to rate themselves, the obnoxious student, and their criticism on various scales. Results indicated no differences in the expression of criticism or subsequent physiological response as a function of the anonymity and expected audience factors. However, significant differences were noted on the anonymity factor for items on the Self-Report Questionnaire. Anonymous subjects reported less dislike of the confederate student and greater feelings of restraint in criticizing than the nonanonymous subjects. All subjects who expressed criticism gave themselves significantly less positive self-evaluations than those who did not. Physiological responding on SRR and HR was also found to vary significantly in the second session prior to criticizing when subjects received instructions which identified the particular treatment condition to which they had been assigned. Subjects in the anonymous, criticism-irrelevant treatment group showed the greatest arousal while subjects in the nonanonymous, criticism-irrelevant group displayed the least. Results were discussed as reflecting an interaction between the potential threat of retaliation which subjects may have attributed to the various treatment conditions, and the social inappropriateness of expressing criticism towards a peer under conditions of low provocation. Modifications to the design of the present study were suggested to overcome these problems.

Albino rats were injected with various doses of d-amphetamine (.02 mg/kg- 9 mg/kg) and subjected to 4 hours restraint in a cold (+5 degrees C) environment. Differential effects on ulceration were observed as a function ot the d-amphetamine dose level. Pretreatment with a .50 mg/kg injection of d-amphetamine significantly inhibited ulceration over that of saline injected, control animals, while a 9 mg/kg dose injection of the drug significantly facilitated it. Such results were explained in terms of a model interaction between sympathetic and parasympathetic nervous system activity, and the effect that such activity has on gastric conditions conducive to ulceration. A second experiment was conducted to further delineate the properties of the proposed theoretical model using drugs which were known to deplete norepinephrine. Differential effects of disulfiram and guanethidine on ulceration were observed and these results were discussed in reference to the theoretical model. Alternative explanations for these results were also presented.

Hypochondriasis is a disorder that may affect ten percent of all individuals seeking medical care. This places a great burden on the health care resources that are currently available. Unfortunately, very few of these individuals come to the attention of mental health professionals. Various models have attempted to conceptualize hypochondriasis. These include the psychiatric model, the psychodynamic model, the social learning and the perceptual or cognitive abnormality model. The perceptual or cognitive abnormality model suggests that individuals who are hypochondriacal misinterpret and/or amplify normal bodily sensations. These processes lead the individuals to believe they are suffering from a serious disease. Few empirical studies have been conducted to confirm this model, and no research has been conducted testing this model using psychophysiological measures to test whether or not these indices are indeed different for non-hypochondriacal persons. Pain is a symptom often reported by hypochondriacs and this is what usually brings them into contact with the health care system. Being able to measure how hypochondriacs react to the experience of pain would give insight into whether or not they react more strongly to pain than do non-hypochondriacal persons. Although the objective measurement of pain has been considered difficult in the past, recent work by researchers using visual analogue scales have shown them to be valid and reliable instruments for measuring both the sensory and affective dimensions of the pain experience. The present study tested the perceptual and cognitive abnormality model of hypochondriasis using painful physical stimuli (heat stimulation and a cold pressor task) to measure subjects' pain tolerance and to rate their experience of pain. Subjects rated their pain experience on both sensory (intensity) and affective (unpleasantness) dimensions using visual analogue scales. The model was also tested using a psychological stressor, a visualization task which incorporated everyday life events. The psychophysiological measure heart rate was continuously recorded to assess subjects' physiological activity to stress. It was hypothesized that hypochondriacal individuals would withdraw their feet from the cold water bath, before being instructed to, at a significantly higher rate than the control group. It was also hypothesized that visual analogue scale ratings of intensity and unpleasantness would be significantly higher for the hypochondriacal group than for the control group for both cold pressor and thermal radiant heat. Further, it was hypothesized that the hypochondriacal group would exhibit increased heart rate, as well as a longer return to baseline time compared to the control group. In general, the data offered little support for the hypotheses used to test the amplification/misinterpretation components of the perceptual and cognitive abnormality model. Methodological problems with the study were discussed and improvements suggested. Also, problems and advantages of the present model were noted.