The effect of abnormal displacement of the retinal image during eye movements

The displacement of the images on the retina that results from a turning of the eye does not lead to an apparent motion of what is seen, It has been generally assumed that this is due to a compensating process which takes eye movement into account and serves to discount those image displacements that result from eye movements, It follows from this view that an abnormal image displacement, that is, an image displacement that is larger or smaller than the causing eye movement would warrant, should lead to an experienced displacement of the target. Abnormal image displacement was produced by placing the eye in the converging or diverging bundle of rays from a point source that form behind a strong positive lens; this arrangement yielded a disc-shaped image, the projection of the pupil onto the retina, which displaced abnormally during eye movements. By changing the position of the eye along the axis of the lens in relation to the crossing point of the bundle, the degree to which the displacement was abnormal could be varied, For various displacement rates ranging from 25% to 120 and 400% of normal, abnormal displacements produced by incidental eye movements remained unnoticed, Only where eye movements were intentional did some of our Ss report shifts of the perceived image. It is suggested that the organism copes with the image displacement resulting from the ever-present incidental eye movements not by compensation but by ignoring them.     

Correlates of organizational commitment: Differences in the public and private sector

Private and public sector managers were compared regarding their job characteristics and organizational commitment. We hypothesized that job characteristics would be positively related to commitment and that sector would moderate that relationship. Moderated regression analyses revealed partial support for both hypotheses. The existence of clarity and challenge were positively related to commitment. Job characteristics demonstrated a stronger relationship with commitment among private sector managers. Explanations for these findings and directions for future research are discussed.     

Improved standards for laboratory animals?

In February 1993, Judge Charles R. Richey of the United States District Court issued a summary judgment in the case of Animal Legal Defense Fund, et al. v. The Secretary of Agriculture, et al. The decision, which was in favor of the Animal Legal Defense Fund, requires the U.S. Department of Agriculture to withdraw its current regulations governing exercise for dogs and the psychological well-being of nonhuman primates used for biomedical research and to issue new regulations containing only minimum, measurable standards. Both plaintiffs and defendants contended that they were seeking the best interests of the laboratory animals. The issue at stake is whether animals are better protected if the government establishes limited minimal standards or is allowed to require institutions to provide additional standards, which will be judged on the basis of their effectiveness in maintaining healthy animals. The Court avoided this dispute, however, by placing primary emphasis on applying the Administrative Procedures Act and stating that it was merely interpreting the "plain meaning" of the Animal Welfare Act, as amended. In this article, arguments are presented for interpreting the law in a far more flexible way than Judge Richey did. The conclusion is also reached that there were no winners in the Animal Legal Defense Fund case and that the real losers are the laboratory animals.     

Properties of spatial representations: Data from sighted and blind subjects

Five questions concerning the properties of spatial representations are explored. (1) How accurately does a spatial representation correspond to the true scene? (2) If inaccurate, how does it differ? (3) Are representations of a familiar scene more accurate than those of an unfamiliar one? (4) Do representations of a scene currently in view differ from those retained in memory? (5) Do the representations of the blind have properties comparable to those-of the sighted? Seven sighted and 7 highly mobile blind subjects, all familiar with a room, and 6 sighted subjects unfamiliar with it, were asked to estimate the absolute distances between 10 salient objects in the room. The 14 familiar subjects made their estimates twice: while they were in the room, and while they were remote from it. Regression analyses showed that the estimates of all subjects had strong metric properties, being linearly related to true distance, with a true zero point; and multidimensional scaling showed that all subjects produced distance estimates that could be scaled in two dimensions to closely match the actual locations of the objects. Familiarity had no effect. The effect of location of testing was the same for both the sighted and the blind: all subjects displayed better spatial knowledge when tested in the room; and all subjects underestimated true distance substantially when tested out of the room. The results showed no qualitative differences as a function of blindness, at least for these highly skilled blind travelers.     

The use of partial temporal information in dating personal events

Memory & Cognition - The use of different types of partial temporal information is shown to affect dating accuracy and the distribution of errors in event dating. Several different types of...