Figure 5.

Transfer of motion direction learning between first- and second-order motion signals. A, One sample frame of the first-order (luminance-modulated) motion stimulus. The green dot served as a fixation through the trial. B, One sample frame of the second-order (contrast-modulated) motion stimulus. C, Left, Session-by-session thresholds. Right, Learning of second-order motion direction (“Training1”) and its transfer to first-order motion stimuli (“Transfer”), as well as the effect of further training with the first-order stimuli (“Training2”). D, Left, Session-by-session thresholds. Right, Learning of first-order motion direction and its transfer to second-order motion stimuli (“Training1” and “Transfer”); the impact of exposure to the second-order stimuli through contrast discrimination training (“Exposure”); and the effect of further training with the second-order stimuli (“Training2”). E, Effect of exposure of second-order stimuli alone without initial first-order motion direction training. F, Analysis of eye movement patterns in individual observers (n = 4) during a training session (10 staircases) of the first-order motion discrimination task. Eye traces during each stimulus presentation were projected to the axes along and orthogonal to the motion direction and the maximal magnitudes of eye movements along these two axes were computed, respectively, and then averaged across trials for each observer. G, Effects of adaptation to the second-order stimulus on the perceived speed of the first- or second-order stimulus. The adaptation effect, or speed PSE reduction, is defined as follows: 100*(baseline_PSE − adaptation_PSE)/baseline_PSE. Error bars indicate ±SEM.