Cotton-top tamarins (Saguinus oedipus) fail to show mirror-guided self-exploration.

To investigate the problem of inter- and intraspecific differences on the mirror test, we conducted two experiments on cotton-top tamarins. Experiment 1 employed a technique similar to one used recently on chimpanzees, and provided no evidence of mirror-mediated touching of the marked area. In a control condition, involving colored dye applied to one arm, two subjects also failed to show self-directed touching, even though they clearly looked at their newly dyed arm. Under these test conditions, cotton-top tamarins fail to show mirror-guided self-exploration. Experiment 2 examined whether this failure was due to insufficient mirror exposure, as well as other details of the testing conditions. In particular, we replicated the design of a previously successful experiment on mirror-mediated recognition in tamarins [Hauser et al., 1995], providing four new animals with a protracted period (three weeks) of mirror exposure prior to dying their hair. In parallel with results from Experiment 1, we observed no evidence of mirror-mediated behavior (recognition) in Experiment 2.