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.     

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.     

Impact of a preventive social problem solving intervention on children's coping with middle-school stressors

Children receiving 1 year or 1/2 year of a preventive social problem solving program in elementary school were compared with each other and with a no-treatment group upon entry into middle school. One year of training was significantly related to reductions in the severity of a variety of middle-school stressors. Most importantly, a clear mediating role for social problem solving (SPS) skills was found. Children lacking in SPS skills were more likely to experience intense stressors; however, possessing the skills was not necessarily predictive of adjustment to stressors. The results are discussed in terms of the implications of this asymmetry and the strong support given to the value of social problem solving as a preventive intervention for children.     

Quality-of-life measures: hospital interview versus home questionnaire

Measures adapted from social survey research were used to assess the quality of life of 33 end-stage renal disease (ESRD) patients in a 2-week test-retest design that varied both location and format of administration (hospital interview vs. home self-administered questionnaire). The measures were found to have substantial consistency over time, location, and format. These results indicate that quality of life is a stable construct and support the usefulness of questionnaire quality-of-life measures for evaluating medical interventions.     

Health as a value: methodological and theoretical considerations

The concept of value placed on health is very important in several different theoretical approaches to the study of health behavior. In practice, however, health value is generally assumed to be universally high rather than being directly measured. If this assumption is incorrect, then theories that include health value have rarely been adequately tested. This paper presents a short 4-item Likert scale designed to measure the value placed on health. Norms from the utilization of this scale in five different samples are presented. Health value is found to increase with age among girls, but the increase apparently stops by late adolescence, before full adult levels of health value are achieved. Middle-aged women place a higher value on health than do middle-aged men, although no comparable sex difference appears in a sample of undergraduates. Consistent with theoretical predictions, both health locus of control beliefs and beliefs in the efficacy of certain preventive health behaviors correlate more highly with the performance of those same behaviors 5 to 9 months later among respondents who place a high value of health relative to those who do not value health so highly. However, this interaction is found only when it can be safely assumed that health is the primary value underlying the behavior. The importance of considering a variety of values in addition to health as possible motivators of preventive health behavior is stressed.     

Psychopathy: A psychobiological perspective

After critically examining the concept of psychopathy and reviewing the major existing theories of psychopathy in the light of a psychobiological conception of abnormal behaviour (Öhman, 1981), this paper attempts to present an integrated, psychobiological model of psychopathy. Essentially this analyses psychopathy in terms of the predisposing influences, the triggering environmental events which initiate psychopathic behaviour, and the neurophsychological mechanisms which mediate it. It is suggested that individuals who show chronic antisocial behaviour, conforming to the North American term ‘sociopath’, may demonstrate a maturational deficit but do not necessarily show a psychopathic personality disorder. The latter is said to be characterised, at a personality trait level, by high Impulsiveness and Psychopathy (Blackburn, 1982 a, b), reflecting interactive deficits in goal direction and affect. At a dynamic (state) level, a psychopathic personality disorder is said to be characterised by a lack of coping, reflecting either, in the case of the secondary psychopath, a deficit in primary appraisal, (over-perception of threat), or in the case of the primary psychopath, a deficit in secondary appraisal (low perceived control over aversive environmental events). It is further suggested that a genetic predisposition to social withdrawal and exposure to an uncontrollably aversive early environment may interact to predispose an individual to develop a psychopathic personality disorder in adulthood.     

Reactivity and response to pain

Male and female volunteers (N = 144) answered the Reactivity Scale (RS) and underwent testing for their perceived intensity and tolerance for finger-pressure pain. Half the Ss were randomly assigned to a low-intensity treatment (1150 g) and half to a high-intensity treatment (2300 g). Pain was rated at 30 and 60 sec., and Ss were asked to endure it as long as possible up to 5 min. The major findings were as follows: (1) women outscored men on reactivity; (2) the three pain measures intercorrelated highly; (3) high-intensity stimulation produced higher pain ratings and shorter tolerance than did low-intensity stimulation; (4) men gave lower intensity ratings than women and tolerated the pain longer; (5) reactivity related positively to judged pain at 30 and 60 sec, and negatively to pain tolerance; (6) there were no significant interaction effects among stimulus intensity, sex and reactivity for any pain measure; (7) the variance in the pain measures accounted for by stimulus intensity, sex and reactivity ranged from 26 to 32%. The implications were briefly discussed for the validity of the RS and factors explaining responses to experimentally-induced pain.     

Ulysses contracts

ABSTRACT 'Ulysses contracts' are an instrument through which a psychiatric patient may prearrange involuntary commitments to be put into effect if the patient satisfies certain diagnostic criteria in the future. Proposals for Ulysses contracts typically impose numerous safeguards. This paper argues against the intuitively plausible safeguard which permits only presently remitted patients to contract. Instead of requiring a patient's remission, it is argued that the appropriate safeguard is the patient's ability, whether remitted or not, to offer good reasons for wishing to contract. In short, what matters is not an executive's character, but an executive's reasons, and a bad executive may have good reasons. Attempts to deny the accessibility of good reasons in unremitted patients are rejected on the ground that psychiatric diagnosis requires psychiatrists to be able to distinguish between good and bad reasons in both remitted and unremitted patients. If psychiatrists cannot do that, psychiatric diagnosis is impossible.     

A note on modulation of gait in man: Effects of constraining stride length and frequency

In this study, our aim was to investigate the effect of an imposed stride-length on walking speed and stride-frequency, and the effect of an imposed stride-frequency on walking speed and stride-length. These variations were determined in relation to the values obtained by analysing the subject's preferred pace. In the first case, the subject had to step on transversal stripes on the floor; in the second case, he had to synchronize his stride with a regular auditory signal. The results obtained with 8 subjects show that speed was the most variable factor. Variations in speed were correlated with variations in the imposed parameter: whenever the subject lengthened his stride or increased his stride-frequency, his walking speed increased proportionally. These results point to a relative independence between stride-length and stride-frequency, and a strong correlation between each of these parameters and speed.