Results for Experiment 1:

<p>TAEs induced in all-white test lines (<b>A</b>) and one-alternating polarity test lines (<b>B</b>), by all-white (white bars), all-dark (black bars), one-alternating (light gray bars) and two-alternating polarity (dark gray bars) line adaptors, for each observer and the average across observers. (<b>C–D</b>) Normalized TAE obtained for each ‘different’ adaptor-and-test condition to the after-effect obtained using the ‘same’ adaptor-and-test condition, for each observer and the average across observers. One can think of this measure as the amount of transfer of the after-effect in the ‘different’ condition. Transfer of TAE obtained in the different adaptor-and-test condition normalized to the after-effect obtained with (<b>C</b>) all-white adaptor-and-test condition and (<b>D</b>) one-alternating polarity adaptor-and test condition. A transfer value of 1 (dashed lines) indicates that the after-effects obtained in the ‘different’ and ‘same’ adaptor/test conditions are similar in magnitude.