On sensitive rank tests for comparing the effects of two treatments on a single group

The rank testR _n of Cronholm and Revusky [1965] in effect doubles the number of comparisons carried out in the Mann-Whitney test between Treated and Control subjects chosen from a single group ofn and triples the asymptotic Pitman efficiency against shift alternatives by using a series ofn — 1 subexperiments. However, the full series can be too costly or time-consuming. It is shown thatj appropriately chosen subexperiments will permit one to make at leastj/(j+1) of the number of comparisons possible underR _n, with large sample efficiency ofj/(j+2) relative toR _n against shift alternatives and small sample efficiency greater than that,j=2, 3, ...,n — 2. The resulting test criterion is a sum ofj independent Mann-Whitney test statistics. Its null distribution is tabulated forn10 and small sample efficiency comparisons are carried out forn=10.     

On counteradaptation

Often adaptation to artificially altered stimulation takes place because veridical stimulation that produces the same perceptual property that is produced by the altered stimulation is also received. In these cases, an assimilation of the two perceptual processes produced by the two different stimulations (the altered and the veridical) is supposed to be responsible for the adaptation that is achieved. This hypothesis, which was formulated by Wallach and Karsh (1963), would be confirmed by demonstrating a modification of the perceptual process produced by veridical stimulation rather than the one produced by the altered stimulation. We demonstrated this by having S observe in the dark for 20 min a luminous figure that objectively expanded as it moved toward S and contracted as it moved away. But instead of testing for changes in size perception as such, we tested for a change in the relation between accommodation and convergence on the one hand and registered distance on the other. In one experiment, such a change was measured by obtaining estimates of perceived size and depth before and after the adaptation period. Highly significant changes of size and significantly greater changes of stereoscopic depth were obtained. Inasmuch as stereoscopic vision was totally absent from the adaptation conditions, the change in stereoscopic depth that was larger than the size change can only be ascribed to a change in registered distance. In another experiment, we tested for a change in distance by having S point from the side to a vertical line, before and again after the adaptation period, under conditions where only accommodation and convergence could serve as distance cues. Significant changes in the pointing distance were measured, indicating more directly a change in the relation between these oculomotor adjustments and perceived distance. We propose the term counteradaptation for such modification of a perceptual process away from veridicality.     

Visual and proprioceptive adaptation to altered oculomotor adjustments

Adaptation to spectacles that alter in equivalent amounts the accommodation and the convergence with which objects are viewed was produced under two conditions. In one, S alternately pushed away or pulled toward him a screen that exhibited only a single vertical contour while wearing glaaaes that caused decreases in accommodation and convergence equivalent to 1.5 lens diopters. Here kinesthesis for these arm movements provided the only veridical distance cues, A small, but highly significant, adaptation effect was obtained with a teat in which S, before and after the adaptation period, pointed to the location of a test line in the distance dimension. Corresponding tests consisting in size and in depth estimates did not show an adaptation effect. In the other condition of adaptation, S moved objects by hand toward and away from himself while wearing spectacles that increased accommodation and convergence by the equivalent of 1.5 lens diopters. In addition to the altered oculomotor cues, some veridical visual cues for distance such as are caused by perspective were present. This condition yielded changes in size and depth estimates indicative of an adaptation in visual distance perception and a larger effect of adaptation measured by the pointing test. We concluded that the excess of the adaptation effect measured by pointing over that measured by size estimation represents an adaptation in proprioception, as did the pointing effect produced by our first adaptation condition.     

Primate learning tasks reveal strong impairments in patients with presenile or senile dementia of the Alzheimer type

Eight subjects with the likely diagnosis of presenile or senile dementia of the Alzheimer type were tested on two frequently used primate learning tasks: a concurrent object discrimination task and a delayed non-match-to-sample task. In addition, various tests for cognitive, mnemonic, perceptual, and language functions were applied. The results suggest a severe decline of the Alzheimer subjects in all measures when compared with 10 control subjects matched for age, gender, and education. The two animal learning tasks revealed strong impairments, thus demonstrating a high sensitivity for the detection and assessment of human amnesic disorders. Implications of these findings for human neuropsychological, and especially comparative neuropsychological, research are discussed.     

Conceptualizations of responses to stress

The article presents the concepts and methodologies used in a series of studies on responses to stress in different areas of life and in different age and social groups. The studies described include findings of the Bonn Longitudinal Study of Aging and several studies on reactions to stress, e.g. coping with chronic disease and other distressing life situations. The discussion of the empirical findings presented focuses on the concept of ‘response hierarchy’ and its possibilities for examining consistency in reactions to stress across time and different situations. The data presented emphasize the need for a process-centred view on stress and responding to stress in the context of a cognitive theory of personality comprehending the individual and her/his world as an undivisible dynamic unit.     

Kurt Lewin's early intentions (dedicated to his 100th birthday)

This article deals with Lewin's early intentions to promote applied psychology, especially with his essay ‘Die Sozialisierung des Taylorsystems’ (The Socialisation of the Taylor System). The authors point out that certain characteristics of Lewin's social psychological approach can already be seen in this early article. Furthermore, they want to show how important the role of applied psychology has been in the development of Lewin S scientific work.     

The effect of prolonged practice of pursuit eye movement

Prolonged exposure to a reciprocating motion that is tracked by the eyes results in diminished extent of perceived motion. Investigation of this effect showed that it becomes manifest only in perceived motion that is caused by ocular pursuit, but that it is not an eye muscle effect. It may consist in a changed evaluation of eye movements. The results throw some light on the relations between the processes that are caused by different stimuli for motion.     

Slope of regard as a distance cue

It is proposed that some distance cues are learned when a perceptual parameter that varies with observation distance is regularly associated with objects whose distances are perceived because another distance cue operates. If that is the way distance cues can come into existence, it may be possible to identify a parameter that varies with distance but is not a known distance cue and to show that it functions as one. The slope of regard with which an object on the ground is viewed is such a potential distance cue. Its angle varies approximately with the reciprocal of distance. An experiment was done that showed that this slope angle functions as a distance cue. Subjects who looked through a device that altered slope angles gave estimates of the dimensions of an object on the ground. Perceived sizes, which vary inversely with distance, were found to be altered in accordance with the altered slope angle.     

A theory of behavior interaction in dyads: A structuralist account

A theory from the behavioral and social sciences is presented from the structuralist point of view. A more comprehensive theory-net is outlined, some basic terms and core assumptions are formulated, and an expansion of the theory towards two intended applications is given. Finally, some results of a first empirical test of the theory are reported. The aim of the paper is to show that the structuralist account of scientific theories is not confined to mathematical theories from the natural sciences, but can also be applied to relatively informal constructions of the behavioral and social sciences.