Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a) Sample stimuli. Both whistles can be moved by hand, but only the whistle with the string attached can be picked up with a hook. (b) The proportion of time spent looking at the competitor goal when the presence or absence of an instrument makes the competitor action-compatible or action-incompatible.
