LEARNING FROM OTHERS MISTAKES - A PARADOX REVISITED

Some researchers have reported the paradoxical finding of enhanced soc ial learning when naive observers learn from unskilled rather than ski lled demonstrators, particularly in discrimination tasks. In two exper iments with starlings, Sturnus vulgaris, I considered whether this enh anced learning is because the observer (1) sees incorrect responses on ly, (2) sees both correct and incorrect responses or (3) sees an incre ase in the proportion of correct responses over trials. In experiment 1, individual starlings observed a demonstrator bird perform multiple simultaneous discrimination tasks. In one group, the demonstrator alwa ys picked the correct stimulus; in another group, the demonstrator alw ays picked the incorrect stimulus; in a third group, the demonstrator consistently picked the correct stimulus 50% of the time. Those subjec ts that observed only incorrect choices performed significantly better than the other two groups, but none of the birds achieved the 90% cor rect performance criterion. Experiment 2 involved a single discriminat ion task; thus, a fourth group was added to control for individual lea rning. Again, subjects that observed only incorrect responses learned the discrimination significantly more quickly than the other three gro ups. Subjects that observed the demonstrator make both correct and inc orrect responses were equally likely to select the same (correct) or o pposite (incorrect) stimulus when the demonstrator picked the correct stimulus. When the demonstrator picked the incorrect stimulus, however , these subjects were significantly more likely to pick the opposite ( correct) stimulus. These findings suggest that when learning a discrim ination problem, observing a foraging companion's lack of success is m ore informative than observing its success. (C) 1998 The Association f or the Study of Animal Behaviour.