Abstract
Many have argued that adaptation effects, some resulting from negative aftereffects from viewing of a stimulus tilted in a certain way or a stimulus moving in a particular direction, reflect that the visual system adjusts its responses to the statistics of the input at any given time. I will review results from my laboratory on such effects, which show that discrimination around the level of an adapting stimulus (e.g., a particular motion direction, a certain tilt, or the midpoint of brightness variation) improves with prolonged adaptation to such a stimulus. So, for example, orientation discrimination thresholds around the adapted orientation decrease with increased viewing of a Gabor varying in phase over time. Similar improvements of discrimination of brightness changes are reported for a stimulus varying sinusoidally in luminance over time and for adaptation to motion. The results show how adaptation can lead to better discrimination around the level of the adapting stimulus itself, and that discrimination performance improves steadily with increased adaptation. The results show how the visual system adjusts its response characteristics to the properties of the visual input at a given time.