We are grateful to the late K. van der Walt for permission to conduct the study in his reserve. The authors would like to thank especially M. Bodin for collecting the focal data in one of the groups (NH), in addition of the other students and volunteers for their assistance in long term data collection at IVP, and the on-site manager A. van Blerk, for his great support. We thank A. Whiten for his useful comments on the manuscript.

Directed social learning suggests that information flows through social groups in a nonrandom way, with individuals biased to obtain information from certain conspecifics. A bias to copy the behaviour of more dominant individuals has been demonstrated in captive chimpanzees, but has yet to be studied in any wild animal population. To test for this bias using a field experiment, one dominant and one low-ranking female in each of three groups of wild vervet monkeys was trained on alternative methods of opening an 'artificial fruit'. Following 100 2 demonstrations from each model, fruits that could be opened either way were presented to each group and all openings were recorded. Overall, the dominant females were not attended to more than low-ranking females during the demonstrations, nor were their methods preferentially used in the test phase. We conclude that these monkeys show no overall bias to copy high-ranking models that would lead to a high-ranking model's behaviour becoming more prevalent in the group than a behaviour demonstrated by a low-ranking model. However by contrast, there were significant effects of observer monkeys' rank and sex upon the likelihood they would match the dominant model. Additionally we found that the dominant models were more likely to stick to their initially learned method than were low-ranking models.

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