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Subjects were required to make easy pitch discriminations at four frequency levels. In a counterbalanced design, for half their judgements they were required to choose the higher of the pair of tones, and for the other half, the lower. It was found that subjects were quicker at choosing the higher than the lower of two high tones, but quicker at choosing the lower than the higher of two low tones. This 'cross-over' effect was found to be graded across the stimulus levels intermediate in the series, the intersection point being somewhat below the geometric mean of the series of frequencies used. While latencies tended to decrease during the course of an indiviual session, the cross-over effect was consistently observable in an analysis that controlled for such practice effects. Whether the tone responded to was the first or the second of the pair discriminated was found to be a significant variable. The 'cross-over' phenomenon was only consistently effective when the second tone was chosen. Linking these findings to similar phenomena previously demonstrated in brightness discrimination, theoretical suggestions are advanced which are relevant to all judgemental processes. [ABSTRACT FROM AUTHOR]

It is hypothesized that the speed with which a relative judgement is made between two stimuli on any given dimension depends upon the relation between the general position of the stimuli on the dimension and the direction of the required judgement along this. Experiments involving the discrimination of light patches of different luminance are reported which support this hypothesis. They show that subjects are quicker at choosing the brighter than the darker of two relatively intense stimuli but quicker at choosing the darker of two relatively dark stimuli. A provisional explanation of the phenomenon in terms of a response competition theory of choice behaviour is offered. Some alternative hypotheses are considered and analogies are made with other psychological phenomena. It is concluded that this is a judgemental phenomenon of some considerable generality. [ABSTRACT FROM AUTHOR]

There is a major gap in knowledge as regards the epidemiology and nature of medical accidents. Major studies, such as the Harvard Medical Practice Study, are required in the UK and elsewhere to identify common accidents and assess the needs of the patients involved. Such work would also provide an estimate of the likely cost of a no-fault compensation scheme. The study of critical incidents and "near misses" should form a regular part of clinical audit, as should the study of communications among medical staff and between care staff and patients. Existing work points to the need to review the training needs of junior doctors, especially in relation to the provision of consultant supervision, and to the need for counselling of all the parties, doctor and patient alike, who are involved in medical accidents.