One difficulty plaguing research on dispositional optimism and health is whether optimism and pessimism are bipolar opposites or constitute distinct constructs. The present study examined the Life Orientation Test to determine whether the two-factor structure is explained by method bias (due to measurement) or substantive differences. The authors compared three measurement models: bipolar, bivariate, and method artifact. Optimism and pessimism emerged as distinct constructs due to substantive differences. The authors also considered the validity of optimism and pessimism, examining their relations with psychological and physical health outcomes. Optimism and pessimism were more similar in relation to psychological health than to other health-related behavior or physical health outcomes. However, a strongly interpretable pattern for the relation of optimism and pessimism to the health outcomes did not emerge. Further research may benefit from considering optimism and pessimism as bivariate and also should consider the conceptual components and behavioral mechanisms specific to each variable.

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A HOUGH reports about people insensitive to pain are increasing in number (5,6,8), they are still rare (about 15 in the literature) and only one, McMurray (6), includes psychological data on a subject congenitally insensitive to pain. While Mc-Murray referred to Rorschach and TAT examinations in his report, these data were neither presented nor discussed. The present report, about a 19-year-old college girl congenitally insensitive to pain, includes psychological projective and objective test data in addition to the neurological and medical data which have been reported in abstract elsewhere (4).The subject (S) was first brought to the attention of one of the authors (Kipnis) when she responded without evidence of pain to the removal of large sections of adhesive tape while being seen in the Duke University Student Health Center. Later, after an auto accident, she complained of a swelling of her ankle which had prevented her from putting her shoe on, but had not interfered with her participating in the festivities associated with a weekend football game and dance. X ray revealed a slight fracture. Following this introduction to the S, she was tested over a period of nine months during which a wide variety of medical, physiological, and psychological experiments and examinations were conducted. The history and background information were secured primarily from the S, although some details were made available by her mother.Background. The S's birth and delivery are described as normal, as was her behavioral development-walking, talking, play habits, feeding, etc. Impaired pain perception was first noted during infancy by her parents when 5 sustained severe burns over the left forearm and wrist without reacting as expected. Later, at 18 months, she took a series of 17 rabies

A "Symposium on Sensory Deprivation" was held at Harvard Medical School in Boston on 20 and 21 June 1958. The meeting was jointly sponsored by the Physiological Psychology Branch of the Office of Naval Research, the Harvard Medical School, and the Boston City Hospital. The meeting consisted of a working group of some 80 scientists working directly or indirectly with problems of sensory deprivation, isolation, and confinement.An outstanding feature of the meeting was the fact that representatives of a wide variety of disciplines and interests, ranging from neurophysiology, psychiatry, psychoanalysis, and psychology to biochemistry, pharmacology, mathematics, and engineering, could meet together and communicate meaningfully about a problem of common interest.Sensory deprivation is the term applied to various experimental techniques designed to isolate the subject from his natural environment through the elimination, reduction, or stereotyping of sensation from vision, hearing, and touch. The effects of sensory deprivation have long been known in the accounts of explorers and shipwrecked sailors, more recently in "brainwashed" prisoners-ofwar. They are varied and include boredom, restlessness, oppression, mental inefficiency, and aberrations in thinking. The specific determinants and consequences of sensory deprivation have recently come in for increasing systematic study in the laboratory.Findings were reported at the symposium relevant to the effects of deprived or restricted environments upon intellectual function, opinions and attitudes, perceptual performance, reaction time, electroencephalograms, and physiological reactivity, as well as upon personality and emotions. The relevance of sensory deprivation to a variety of practical situations was examined, including its role in the treatment of psychiatric disorders, its effects on the performance of aviators, and its special utility in the study of stress. The particular relevance of questions raised by research in sensory deprivation for concepts, techniques, and theory in psychoanalysis was also discussed.The mental disturbances produced by sensory deprivation were thought to be explained best in terms of interference with previously little understood neural mechanisms essential to alertness and attentiveness. The mind does not seem to

The binocular summation experiment provides one way of deciding between central and peripheral accounts of the visual threshold. Occurrence of a significantly lower binocular than monocular threshold implies that the threshold events are not exclusively retinal in origin. However, Pirrenne (8) has pointed out that, even on the assumption that the two eyes operate independently, the binocular threshold should be lower than the monocular by the rule for combination of independent but nonmutually exclusive probabilities. Thus a demonstration of summation requires that monocularbinocular threshold differences exceed the value expected on the combination of independent probabilities.In previous studies all possible outcomes have been obtained: no differences between monocular and binocular thresholds, the differences expected by the combination of independent probabilities, and differences exceeding that expected by the combination of independent probabilities (4). This diversity of results led to a study (4) which carefully controlled the variables most often related to the failure or success in demonstrating summation, e.g., fixation, differential accommodation, differential pupil size, and stimulation of noncorresponding retinal points. In order to evaluate Pirenne's hypoth- 1 The experiment reported in this paper was performed at Duke University and was supported by a grant from the Duke University Council on Research.