An analysis of aftereffects in the measurement of the correction effect

Ss, under prismatic viewing, aligned a spot of light to the apparent straightahead first in the dark and then under illumination. Ss made these judgments either by controlling the spot themselves or by directing E in moving it. For both types of alignment procedures, judgments were significantly more veridical in the illuminated room (correction effect). Aftereffects, measured after both the spot alignment in the dark and in the light, were found to be significant only when S moved the stimulus. These results contradict the argument that the egocentric localization processes involved in the production of the correction effect itself are the basis of the aftereffects obtained.     

Elevator illusion: Influences of otolith organ activity and neck proprioception

Each of nine Ss experienced gravitational-inertial forces (GIFs) of 1.00, 1.25, 1.50, and 1.75 G_z with his head erect and pitched forward at angles of 15 and 30 deg. The magnitude of the elevator illusion was shown to depend on both the intensity of the GIFs and the orientation of the head. Contributions of otolith organ activity and of neck proprioception to the illusion were examined, and theoretical baseg for their influences were discussed.     

Pictorial target control of schedule-induced attack in White Carneaux pigeons

Three pigeons with a history of attacking a mirror target, and two of six pigeons with no prior exposure to targets, attacked a colored photograph of a conspecific during exposure to intermittent schedules of reinforcement for key pecking. Rate of attack on the photograph decreased when the reinforcement schedule was removed. The topography, temporal pattern, and locus of attack on the picture were comparable to schedule-induced attack on live, stuffed, and mirror targets. When silhouette, outline, and plain paper targets were used, schedule-induced attack was more sensitive to a change in target characteristics with a concurrent target-preference procedure than with an analogous successive-testing procedure. The combined results of the two testing procedures indicated that an “upright” white-on-black silhouette of a pigeon with or without an eye was more effective in controlling attack than was a comparable “inverted” silhouette, an outline of a pigeon, or a piece of colored paper.     

Correcting for unreliability in nonlinear models of attitude change

The paper opens with a brief discussion of the problems in testing nonlinear models of attitude change. The regression artifacts produced by unreliability are shown in both the linear and nonlinear case. Classical solutions for the linear case are quickly reviewed. A new solution to the linear case is presented and applied to the nonlinear case. It is shown to work well under a broad set of conditions. Regression artifacts in bivariate regression are then discussed. If the predictors are independent, then the univariate correction procedure can be applied to each predictor separately. But if the predictors are correlated, a joint correction procedure must be used. One such procedure is defined and shown to work perfectly in the case of linear regression and reasonably well in a broad set of conditions in which the regression is nonlinear.     

Variables affecting establishment of schedule-induced attack on pictorial targets in White King pigeons.

White King pigeons exposed to food schedules before introduction of a colored photograph of a pigeon showed sustained schedule-induced attack on that image; additional birds given an early introduction to both the photograph and the schedule subsequently attacked the image at lower rates. Other pigeons attacked a second photograph of a pigeon regardless of whether it was introduced early or late. The late-introduction procedure was also effective in establishing attack on a projected image of a conspecific. The combined results showed that 14 of 17 White King pigeons given a late introduction to a pictorial target exhibited sustained attack against it and that a pigeon's initial reaction to a photograph of a conspecific when introduced early was a good predictor of subsequent schedule-induced attack on it.     

Differential sample response schedules in the acquisition of conditional discriminations by pigeons

Pigeons were trained on four matching-to-sample tasks with various schedule requirements in effect on the sample key. Differential sample-schedule requirements (a differential-reinforcement-of-low-rates of 3 sec in the presence of one sample and a fixed-ratio 16 in the presence of the other) produced rapid rates of acquisition that did not differ across tasks. Nondifferential sample-schedule requirements (fixed-ratio 1, fixed-ratio 16 or a differential-reinforcement-of-low-rates of 3 sec in the presence of both samples) produced slower rates of acquisition, which depended on the difficulty of the discriminations between samples and between comparisons. Patterns of stimulus and position preferences were influenced both by the comparison stimuli in each task and by the sample-schedule requirements. Detailed analyses of acquisition revealed frequent instances of complete differential sample control of comparison responding at intermediate levels of overall “accuracy”.