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.
In each display, the unique item was the target (square in the shape example, left pointing cow in the cow example). On half the trials, one of the remaining items (the singleton) moved back and forth. Images not to scale.
