Date of Award


Degree Type


Degree Name

Master of Arts (MA)



First Advisor

Sarah Brosnan

Second Advisor

Michael Beran

Third Advisor

Heather Kleider-Offutt


Change blindness is a phenomenon in which individuals fail to detect seemingly obvious changes in their visual fields. Like humans, several animal species have also recently been shown to exhibit change blindness; however, no species of New World monkey has been tested to date. Nine capuchins (Cebus [Sapajus] apella) were trained to select whether or not a stimulus changed on a computerized task. In four phases of testing, the search display and mask durations were varied systematically. Only one phase yielded significant results, with subjects detecting changes most accurately with longer search displays and, perplexingly, least accurately when there was no mask. No interactions between search display and mask durations were found in any test phase, suggesting that the relationship between the two parameters may be less important to how capuchins perceive changes.