Randomly Presented Face Patterns, Newsprint, Bull's-Eye Patterns, or Colored Circles

Multiple Choice

randomly presented face patterns, newsprint, bull's-eye patterns, or colored circles in a looking chamber and then measured how long an infant fixated on each item.What was the independent variable in this study?

A) time the infant fixated on an item
B) age of the infants when they could see the patterns
C) number of items presented
D) type of item presented (face pattern, newsprint, etc.)