Successive episodes produce direction contrast effects in motion perception

Abstract

Motion coherence thresholds decline with an increase in the number of frames in a random dot kinematogram (RDK), indicating that motion information can be integrated across successive frames. We investigated whether such temporal integration would be disrupted by a brief interval (32-600 msec) inserted into a motion sequence, perceptually dividing it into two successive episodes. Both episodes consisted of only a few frames (between 3 and 15), with the first episode being 100% coherent and the coherence of the second episode being adjusted to determine threshold. In four experiments we observed that coherence threshold for motion in the second episode was elevated if the directions in the two episodes matched, was lowered if they were opposite, and was unaffected if they were orthogonal. This successive direction contrast effect did not vary with the duration of the interval, suggesting that it is not an adaptation effect. The result of varying the number of frames in the second episode suggests that these effects are not due to alterations in cooperative activity among motion detectors. We suggest that successive direction contrast effects may reflect activity of higher-order perceptual organization mechanisms.

Practice-Related Improvement in Working Memory is Modulated by Changes in Processing External Interference

“…However, the lack of correlation between probe N1 amplitude and WM performance and lack of correlation between changes in probe N1 amplitude and improved WM performance across blocks argues against this possibility. Furthermore, while adaptation has been reported for motion stimuli (Raymond and Isaak 1998), to our knowledge, the effect of motion adaptation on discrimination has not been reported for stimuli moving in different directions (i.e., the cue and probe stimuli are linear motion, while the interruptors are circular motion).…”

Neural strength of visual attention gauged by motion adaptation

“…Other evidence, however, implies that brief bursts of motion on the order of a second can produce significant adaptation in cortical motion mechanisms, as revealed by MAEs 14 and by elevations of motion-coherence thresholds 18 . Moreover, because of storage, the adaptation produced by intermittent, weak motion bursts persists and accumulates until it is tapped by a static test figure 19,20 .…”

The effect of perceptual load on attention-induced motion blindness: The efficiency of selective inhibition.

“…When less than 100% of the available dots are moved coherently, the remainder on screen move randomly. Normal observers can perceptually group or integrate the coherently moving dots despite this random noise, and can report the overall global motion direction, even as coherence levels fall substantially below 100% (Raymond & Isaak, 1998), although with reductions in Figure 8. Experiment 4-Mean motion discrimination following speeded response to single or flanked cues for trials both with distractors and without distractors.…”