SOCIAL-LEARNING IN SIBLING PIGS

Three experiments were designed to assess the extent to which pigs can acquire information from their siblings. In Experiment 1, pigs were p re-exposed to the sight and smell of a novel diet, or to a sibling dem onstrator eating the novel diet, or to a sibling demonstrator eating a familiar diet. In subsequent individual feeding trials, pigs from the first two treatment groups showed an enhanced preference for the nove l diet relative to the third (control) group, but did not differ signi ficantly from each other. In Experiment 2, food was hidden in three di stinctly coloured and positioned troughs. Individual pigs observed a s ibling demonstrator feed from one trough. In subsequent tests, ten out of 24 individuals discovered that food was available in the test room . Eight of these ten made their initial discovery of food in the same trough that their demonstrator had used. Thus, some combination of cue s resulted in a significant bias in food searching behaviour towards a site where a demonstrator had previously eaten. In Experiment 3, pigs observed a trained sibling demonstrator press one of two panels for f ood reward during ten daily sessions. Control groups observed untraine d siblings in the same apparatus. In subsequent tests, there were no s ignificant effects of observation experience on rewarded panel pressin g, but pigs that had observed demonstrators spent significantly more t ime facing the operant panels and directed more non-rewarded presses a t the operant panels than controls. They also showed a significant dis crimination for making non-rewarded presses at a panel of the same col our/position as that used by their demonstrator. Visual cues appeared to be more important than residual olfactory cues in attracting non-re warded panel presses.