Number adaptation survives spatial displacement

Canonical visual adaptation effects, such as those observed for color or orientation, are spatially specific, consistent with their locus in early, retinotopically organized visual areas.^1,2 In contrast, number adaptation effects have been localized to the intraparietal sulcus (IPS), a higher-level region of the dorsal visual pathway involved in (among other things) tracking objects as they move across space and time.^3,4,5 This suggests that number may be a crucial test case for adaptation more generally, potentially revealing non-retinotopic adaptation effects. We predicted that number adaptation effects should persist even when the spatial positions of adapted and test stimuli are constantly changing. Six experiments measured adaptation when (1) adapted and tested dots were presented within constantly translating visible discs, (2) adapted and tested dots moved about constantly within the visibly translating discs, and (3) adapted and tested dots moved about constantly within bounded invisible translating discs. In all cases, we found object-specific number adaptation-as if adaptation travels with an object or bounding region. Additionally, we found that adaptation was specific to target objects-i.e., it did not transfer to other objects within the same hemifield-and that the size of the adaptation effect was equally large for moving and static stimuli. Unlike the retinotopic adaptation effects characteristic of other early visual features,^1,2 number adaptation can be bound to moving objects.