Experimenter bias and subliminal perception.

It has been suggested that subliminal perception phenomena may be in part due to experimenter bias effects. Two studies that obtained positive evidence of subliminal perception were therefore replicated with experimenters tested under blind and not blind conditions. There was only marginal support for the subliminal perception hypothesis and, although there were fairly clear indications of diffuse experimenter effects, the evidence for the experimenter bias explanation of subliminal perception was not strong. The need for more extensive replications of subliminal perception researches is noted. It is argued that the experimenter bias hypothesis lacks detail and generality; it is essential for it to be examined in the context of theoretically substantial issues.     

Sex differences in verbal skills: Use of spelling-sound and lexical information

An experiment is described in which possible sex differences in lexical and phonological skills were investigated. A spelling test was used which could not be done on a phonological basis alone and which entailed lexical access for good performance. Women were judged on the evidence for this task to have better lexical ability than men, but no difference was found on a task designed to tap knowledge and use of phonological information in the form of spelling-sound correspondences.     

Spatial and movement-based heuristics for encoding pattern information through touch

Seven experiments investigated the heuristics people use to encode spatial pattern information through touch. Observers traced a tangible pathway with one hand and then answered questions about either the euclidean line between the pathway endpoints or the pathway itself. Parameters of the euclidean line were held constant, while characteristics of the felt pathway were manipulated. Experiments 1-4 showed that blindfolded sighted and blind observers increasingly overestimated the length of the euclidean line as the length of the explored pathway increased. This indicates a movement-based heuristic for encoding distance. Experiments 5-7 indicated that judgments of the position of the euclidean line did not vary with the position of the felt pathway or the extent to which it deviated from that line. Instead, the results indicated that observers relied on implicit spatial axes, which are movement independent, to judge position. These and other results have implications for theories of haptic encoding of spatial pattern and for the construction of tangible graphics displays.     

Activity measures in stress-attenuated novelty tests as possible analogues for extraversion in rats: Some experimental results

In an attempt to extend and validate Garcia-Sevilla's (1974) hypothesis proposing ambulation in a non-stressful open field (OF) as an animal analogue of human extraversion, ambulatory behaviour and rearing behaviour were studied and compared in several experiments with genetically-unselected rats. The effects of variation of OF auditory stimulation level, the correlation with a two-way avoidance-learning situation and the effects of a stimulant dose of d-amphetamine and an anxiolytic one of diazepam upon rearing and ambulatory behaviours were studied. All in all, our results support some of the requirements of the hypothesis, but also generate some additional problems. The results show that the number of rearings could be a better and more sensitive measure of variations in the level of arousal and a better predictor of shuttle-avoidance conditioning than ambulation. However, all activity measures are at least moderately intercorrelated, and they become grouped when results are factor analysed. All the results are discussed with reference to Eysenck's personality theory and Gray's anxiety theory, and it is concluded that these measures are too multidetermined and too poorly controlled to represent correctly and in a direct form a personality dimension such as Extraversion. Anyway, this attempt could be a good point of departure for discovering more efficient animal behavioural measures of arousability.     

A parametric study of learned helplessness in humans

In two experiments designed to assess the effect of varying amounts of exposure to noncontingency training, it was discovered that performance decrements could be produced after relatively brief training and again after extended training. Between these conditions was a period of recovery during which no performance deficits were evident. There was also a tendency for individual differences in motivation to moderate deficits following brief but not extended training. A four-stage model is proposed to account for these results. In response to uncontrollable outcomes, individuals are said to pass through a phase of no effect, followed by temporary helplessness, recovery, and final helplessness. The model also proposes that motivational differences and perceptions of noncontingency exert independent and opposing influences on learned helplessness deficits.