Table 1.

Mean percentage of correct responses (+sem) for discriminations of rhesus faces, chimpanzee faces and houses in five orientation angles

Stimulus type	Training trials	Angle of rotation (°)
		0°	45°	90°	135°	180°
Rhesus faces	136	83.6	83.4	73.3	68.0	72.6
Sem	29.93	2.8	2.8	3.5	3.7	4.6
Houses	184	83.68	84.68	74.00	68.66	72.00
Sem	82.56	2.36	3.42	5.31	3.10	3.43
Chimpanzee faces	150	83.68	79.33	65.33	56.67	70.53
Sem	48.00	0.98	3.23	4.16	2.11	4.86

The performance listed under 0° is the overall mean for control trials of that stimulus type. The number of trials required (in 40 trial blocks) for subjects to reach above 80% correct during the upright training is also given for each stimulus category