Artificial visual stimuli for animal experiments: An experimental evaluation in a prey capture context with common marmosets (Callithrix jacchus).

Experimenters often use images of real objects to simulate interactions between animal subjects or visual stimuli on a touchscreen to test animal cognition. However, the degree to which nonhuman animals recognize 2-D images as representing the corresponding real objects remains debated. The common marmoset monkey ( Callithrix jacchus ) has been described as a species that spontaneously shows natural behaviors to 2-D images, for example, grasping behaviors to insects and fear responses to snakes. In this study, we tested 10 monkeys with their favorite food item (crickets), 2-D images (a photo and videos of a cricket), and a 3-D plastic model to reevaluate marmoset's spontaneous responses to 2-D images and to explore which artificial visual stimuli can motivate spontaneous interactions. The monkeys showed grasping behavior to the real cricket and the 3-D plastic model, but to none of the 2-D images. Our experiment suggests that depth information is the most important factor eliciting predatory behavior from the marmosets, and, therefore, a stimulus produced by a 3-D printer could be a good alternative when a spontaneous interaction or a convincing stimulus is required. Furthermore, this work serves as a cautionary tale for those using 2-D image presentations with marmosets, and perhaps other animal species. (PsycINFO Database Record