Number Adaptation: A critical look
This page contains selected demos from the paper Number Adaptation: A critical look, co-authored with Sam Clarke and Elizabeth Brannon. We have also created comprehensive bibliography of existing number adaptation studies, so that others may easily reference the work to which we respond. The purpose of this page is to display some key demos. These demos are most compelling if viewed in a maximized window!
Demo #1: Canonical Number Adaptation
This is a canonical demonstration of number adaptation. Putatively, because you adapted to a large number on the right side, you experienced a repulsive aftereffect on number causing you to perceive few items in the test display. The original demonstration from Burr & Ross (2008) can be seen here.
Demo #2: ‘news’ influences adaptation
On the alternate view that we advance, this putative adaptation to number may be explained in part because of the correspondence between adaptors and test stimuli. If that’s true, the degree of spatial overlap between the two should influence the extent of adaptation. That seems to be true. Dots on the right side overlap more with each other, so are more likely to fade from awareness and thus be perceived as less numerous.
Demo #2.1: 0% overlap
Here, there is only a single adaptor. That adaptor has 0% overlap with its corresponding test stimulus. However, you will notice that some dots still fade from awareness. This demonstrates that it is difficult (if not impossible) to fully eliminate any correspondence between adaptors/targets. Especially farther in the periphery, the visual system may still treat nearby dots as identical, thereby causing them to fade from awareness even when there is no direct overlap.
Demo #3: Color swap
The previous demo showed that spatial overlap influences adaptation. How does this interact with color? Here, both sides have 100% spatial overlap, but on one side all the dots swap color (and on the other side they do not). Although subtle, there is a slight tendency to perceive the side on which the colors swap as more numerous.
Demo #4: Dynamic stimuli
Number adaptation should be observed in dynamic displays. But on the alternate view that we advance, we may not expect adaptation in this case. In fact, there seems to be little or no effect of adaptation here.
Demo #5: ‘Reverse’ adaptation
The traditional number adaptation view predicts bi-directional effects: Large numbers should make middling numbers look smaller and small numbers should make middling numbers look larger. However, there is no clear effect of adaptation when adapting to only a small number.
Demo #6: Cross-modal adaptation
In these trials, the observer would be tasked with estimating the number of tones that they heard. Unlike other kinds of adaptation, cross-modal adaptation cannot be experienced as a demo. This is because there is no direct comparison in the display. The purpose of this demonstration is just to convey what trials in this experiment are like. Notice: As an observer, you can easily count the relevant stimuli.
Demo #7: Retin0topy
Some work on number adaptation (see Anobile et al., 2014; DeSimone et al., 2020) controls for certain features (e.g., area, density) by manipulating the spatial envelope in which dots appear. The assumption is that because number adaptation is spatiotopic, this is acceptable. What this demonstration shows is that retinotopy matters: Dots selectively disappear from awareness in the places where you adapt to other dots.