A diver's face-mask produces an optical distortion of the relationship between size and distance under water, with the result that objects normally appear further than the optical distance and enlarged. Adaptation to size enlargement was examined by obtaining size estimates in air and water, before and after a period of 20-40 min. underwater activity in which objects of known size were handled. Size estimates were obtained by adjusting a line to an est,imated length of 12 in. Initial estimates in water indicated that novices experienced more size enlargement than experienced divers. Both groups of divers showed significant aftereffects in air, indicating that some size adaptation had occurred. The aftereffect declined rapidly, and was significant for only the first two trials. A second experiment showed that the greater accuracy of experienced divers also occurred when looking into water through a porthole: it was not, therefore, 'situationcontingent' in the sense that it depended upon wearing a face-mask in water.

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Objects viewed through a facemask under water appear larger and closer than when viewed in air. Divers' adaptation to this distortion was measured by obtaining estimates of the size and distance of an array of targets before and after a 20-min underwater dive. A negative correlation between size-and distance-adaptation scores indicated that most divers adapted to one dimension by counteradapting to the other. For example, some Ss adapted to size by increasing the distortion of apparent distance and some the other way around. The results were discussed in relation to the size-distance invariance hypothesis. Recent experiments by Rock (1965. 1966) have confirmed Stratton's (1903) prediction of adaptation to a size-distorted retinal image. Rock found thaI viewing objects through a convex mirror, which minified their retinal image but which left distance undistorted, resulted in adaptation in the direction of veridical size perception. Ross, Franklin. Welt man. & Lennie (1970) found size adaptation following a period of underwater viewing in which both size and distance are usually perceived as distorted. Underwater distortion of size and distance occurs when a diver views objects through a facemask which introduces a water-glass-air interface between the eyes and an underwater object. Since the refractive index of water is 4/3 that of air, light rays passing from water into air are refracted away from the normal. This produces a virtual image at approximately 3/4 of the object's physical distance (the location of the virtual image is referred to as the optical distance), with an angular magnification of abou! 4/3 that wh ich occurs in air. These effects obtain for objects viewed normally to the mask; objects in the periphery undergo greater distortion. According to the size-distance invariance hypothesis, there are alternative ways of perceiving the retinal image of an underwater object. An object viewed thr"ugh a facemask under water should appear its correct size if perceived at i ts optical distance (3/4 physical distance), 4/3 enlarged if perceived at the physical distance, and proportionately enlarged if it appears between the optical and physicaI distance. The latter case occurs for most

100 freshman college women from a residence hall were randomly assigned to 1 of 3 conditions expected to affect need for affiliation (n Affiliation) or to a control group. In agreement with previous research on male Ss, 2 of the conditions-being rated by peers and being rejected by peers-resulted in arousal of TAT n Affiliation. No effect of the 3rd condition, social acceptance, was obtained. Implications for a 2-factor theory of n Affiliation were discussed.Although the fantasy measure of need for affiliation (n Affiliation) described by Heyns, Veroff, and Atkinson (19S8) has been widely employed in research, some basic assumptions concerning its validity have not been put to adequate empirical test. The present study attempts to determine the applicability of the measure to female subjects and to evaluate some theoretical inferences that were drawn in initial validation experiments.According to McClelland (1958, p. 9), a minimal requirement for the validation of a measure of motivation is that it reflect the presence or absence of the motive in the individual. Experimental arousal commonly has been used as a direct method of determining whether fantasy measures of motivation are sensitive to gross variations in motive strength. Although experimental arousal of n Affiliation has been demonstrated repeatedly in male samples (Atkinson, Heyns, & Veroff, 1954; French & Chadwick, 1956; Shipley & Veroff, 1952) there are no published reports of attempts to arouse n Affiliation in women. Yet female subjects often have been used in correlational studies employing the projective measure of n Affiliation. One aim of the present study is to determine whether n Affiliation can be aroused in women by the techniques that have proved successful in previous studies of men.The present study also is concerned with the degree of support provided by the earlier experimental studies for a two-factor theory of n Affiliation. Following McClelland's (1951) general distinction between approach and avoidance motives, Shipley and Veroff (1952) suggested that the tendency to seek affiliation (n Affiliation) is a function of two subdispositions-the ap-