Object permanence tests on gibbons (Hylobatidae)

Anna Fedor, Gabriella Skollár, Nóra Szerencsy, Mária Ujhelyi
2008 Journal of Comparative Psychology  
Ten gibbons of various species (Symphalangus syndactylus, Hylobates lar, Nomascus gabriellae, and Nomascus leucogenys) were tested on object permanence tasks. Three identical wooden boxes, presented in a linear line, were used to hide pieces of food. The authors conducted single visible, single invisible, double invisible, and control displacements, in both random and nonrandom order. During invisible displacements, the experimenter hid the object in her hand before putting it into a box. The
more » ... t into a box. The performance of gibbons was better than expected by chance in all the tests, except for the randomly ordered double displacement. However, individual analysis of performance showed great variability across subjects, and only 1 gibbon is assumed to have solved single visible and single invisible displacements without recourse to a strategy that the control test eliminated.
doi:10.1037/0735-7036.122.4.403 pmid:19014264 fatcat:q2qbi6n6dnaplf6r7xujq6lxgy