Matching to Sample
Using this test, we ask our monkeys to recognize a stimulus they've previously seen. In the example on the left, the monkey has to remember which face he studied. By manipulating aspects of the stimuli or conditions during study/delay/test, we can see how recognition is affected and infer characteristics of monkey memory.
Click the picture to try a matching to sample test for yourself. Or see a video of a monkey doing this task.
With this test, we can assess how monkeys categorize objects according to perceptual similarity. Monkeys see images from different categories and must learn to pair each category with an arbitrary symbol. We can then test new images from the trained categories or manipulate perceptual features of the images (e.g., desaturate them, make them into line drawings, etc.) and use performance on these transfer tests to infer characteristics of the categories that the monkeys have formed.
Click on the picture to try a categorization test for yourself. Or see a video of a monkey and an orangutan doing this task.