Refreshing the conversation about adaptation and perceived numerosity: A reply to Yousif, Clarke and Brannon

Yousif et al. (2024) have raised a number of pertinent objections to the idea that number adaptation is a straightforward account of the readily-observable aftereffects that affect perceived numerosity. Their criticisms appear well-motivated, but their particular version of the old-news proposal, involving specific dots, may be insufficiently abstract given that adaptation accumulates. Two new experiments are presented that are meant to buttress their critique by (1) confirming their predictions concerning neutral adaptation, and (2) re-evaluating related claims concerning number vs. density comparisons that have been widely accepted. Present behavioral evidence dissociating effects of adapter size, adapter number and adapter density, supports the idea that density adaptation is implicated as a primary source of most phenomenologically-compelling aftereffects of perceived numerosity. Experiment 2 was preregistered on AsPredicted.org. The pre-registration is available at the following link: https://aspredicted.org/PC7_2ZB The full raw data sets for the two experiments reported her are available on OSF at the following links: Experiment 1: https://osf.io/b9qwy/?view_only=73beb62d9c2046c3aa08cdeb96cd5cca Experiment 2: https://osf.io/6ax5j/?view_only=723ceb0b44da47dba99e56db12db02a9.