Conformity in wild vervet monkeys? Possibly not.

Comment on van de Waal, E., Borgeaud, C., & Whiten, A. (2013). Potent social learning and conformity shape a wild primate’s foraging decisions. Science, 340(6131), 483-485.

Written by:

Claudio Tennie, Julia Fischer, Daniel B. Haun & Bennett G. Galef

 

[This was written, submitted and appeared on Science magazine online at the time – but somehow its now lost there. So, rather than resubmit etc etc its now simply here]

 

The conclusion [1] that vervets exhibit “conformity” is, we believe, premature (even though methodologically this study is superior to a previous study making a similar claim in chimpanzees [2]).

Conformity – adjusting ones behaviour to that of a majority – characterizes human cultural learning. Consequently, conclusive evidence of conformity in a non-human primate would increase understanding of the evolution of human culture.

In [1], groups of wild monkeys were trained to avoid one of two different foods. Males subsequently migrating between groups with different food preferences reversed their food choices to match that of the group into which they migrated. The authors concluded that the migrants conformed to the majority [1].  However, socially induced biases other than conformity can account for the reported effect.

Norway rats trained to avoid one of two foods preferred that food after interacting with a single conspecific eating it [3]. Similarly, migrating vervet males might have copied the food choices of a few individuals (e.g females [4])– or even a single other individual (e.g. a dominant) rather than copied the majority. Consistent with the latter hypothesis, the single migrant that did not change food preference was immediately of highest rank in the group he joined [1]. In any case, there is no need to invoke “conformity” to explain the behaviour of migrating males [5, 6].

While it is indeed interesting that social learning can result in stable variation in food choices of vervet social groups, the mechanisms of such social learning may well differ from those supporting analogous behaviour in humans. “Conformity,” particularly normative conformity [7], remains to be demonstrated in non-human primates.

 

  1. van de Waal, E., Borgeaud, C. and Whiten, A. (2013). Science 340, 483-485.

 

  1. Whiten, A., Horner, V. and de Waal, F. B. M. (2005). Nature 437, 737-740.

 

  1. Galef, B. G. and Whiskin, E. E. (2008). Anim. Behav. 75, 2035-2039.

 

  1. van de Waal, E., Renevey, N., Favre, C. M. and Bshary R. (2010). Proc. R. Soc. B 277, 2105-2111.

 

  1. Haun, D. B., Leeuwen, E. J. V. and Edelson, M. G. (2013). Dev. Cogn. Neurosci. 3, 61-71.

 

  1. Leeuwen, E. J. V. and Haun, D. B. (2013). Evol. Hum. Behav. 34, 1-7.

 

  1. Deutsch, M. and Gerard, H. B. (1955). J. Abnorm. Soc. Psych. 51, 629-636.
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