Re: Macaque culture was: Dawkins' Mutation Test for Replicators

Bill Spight (
Tue, 31 Aug 1999 09:32:29 -0700

Date: Tue, 31 Aug 1999 09:32:29 -0700
From: Bill Spight <>
Subject: Re: Macaque culture was: Dawkins' Mutation Test for Replicators

Dear Derek,

My own secondary source for this is:

King, Barbara J (1991) Social information transfer in monkeys, apes and hominids. Yearbook of Physical Anthropology 34, 97-115.


Thanks much for the reference. <s>

I have done a bit more looking around about this. As I understand it, the question of social transmission is under debate. I doubt we can resolve the issue here. <g>

Just a few remarks:

Barbara King (p105):

"Even the classic example, [ie on 'the role of information transfer in primate foraging'], sweet potato washing by Japanese macaques Macaca fuscata, following the technique's invention by the young female Imo, has been questioned. First during at least some years, the
human caretaker at Koshima reinforced those monkeys that exhibited washing behaviour by giving the sweet potatoes only to them."


I think that "caretaker" is the wrong word. These are wild monkeys. As I understand it, researchers constructed feeding stations because the monkey troops moved around too much and too quickly to be easy to follow and watch. At theses stations, they were not under any human's care. They got food. Also, since these were feeding stations, I doubt that the other monkeys did not get fed (although maybe not with the sweet pototoes).

The reinforcement may have been for behavior which was already learned, merely strengthening an existing habit. As anyone who has grown his own vegetables knows, washing them carries its own rewards. Still, this reinforcement contaminates the data about the macaques involved, and that data should not be considered. However, at this point, that is only a small part of the data.

Barbara King:

"Second, the average interval between the invention of sweet potato washing and its acquisition by other individuals the same age as the innovator, or older, was 2.2 years. This may be too long a time for social mechanisms to be operating."


May be. Still, as you have pointed out, Derek, there are early adapters and late adapters.

It also raises questions about any learning mechanism. One would expect human training to take a shorter time, as well.

I suspect that the main thing it indicates is that these macaques already had well-established feeding habits. To replace an established habit is more difficult than simply learning a new habit de novo.

And again, we are talking about a relatively small number of macaques.

Barbara King:

"Third infants ate potatoes from the water all along as they grew up, raising the possibility that individual acquisition of potato washing was facilitated by early experience and was not related to social transmission."


I think that this is the most serious objection. It applies to all the macaques in the troop after Imo. But the question is not whether early experience facilitates learning the behavior (I expect that it does), but whether it is sufficient for that learning (given the opportunities).

If it is sufficient, then why was Imo the first macaque to wash her potatoes? Was she simply the first one to be observed? If so, why did it take so long for her age cohort and elders to learn? If now, most or all of the youngsters learn to wash potatoes on their own, why did their ancestors in the same habitat (who presumably had similar early experiences) not do so?

Also, none of these objections applies to "panning" wheat (throwing it in the water and eating what floats).


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