Tuesday, September 8, 2009

An Interesting Example Of Evolution Among Dogs.

The blog 80beats pointed out a study in Science that compliments a comment made on my strawman post.

For those who don't know, dogs and wolves share a common ancestorThey evolved from the same animal.   However, man domesticated some of these Grey Wolves many years ago and the modern differences between dogs and wolves are the results of evolution.

From the above linked article:
Ten-month-old infants persistently search for a hidden object at its initial hiding place even after observing it being hidden at another location. Recent evidence suggests that communicative cues from the experimenter contribute to the emergence of this perseverative search error. We replicated these results with dogs (Canis familiaris), who also commit more search errors in ostensive-communicative (in 75% of the total trials) than in noncommunicative (39%) or nonsocial (17%) hiding contexts. However, comparative investigations suggest that communicative signals serve different functions for dogs and infants, whereas human-reared wolves (Canis lupus) do not show doglike context-dependent differences of search errors. We propose that shared sensitivity to human communicative signals stems from convergent social evolution of the Homo and the Canis genera.
In a nutshell, (you can read 80beats above for more information), these researchers found that dogs think like ten-month old infants in certain respects and wolves don't.

However, there's always the nature versus nurture problem: is this biological or the result of how the animals were raised?  To overcome this problem, the researchers only used wolves raised by humans.  The study thus removes any nurture bias in the conclusions.  What is left is nature.

Therefore, this study is a clear example a real biological difference between dogs and wolves.  A difference that did not exist many years ago when these two creatures were the same animal. 

But now for the important question of the post: What about domestication would cause this particular biological change in dogs?  Your thoughts are welcome.


  1. I think it's because dogs had to dumb down for them to be our best friends. =:)

    I wonder if this study accounted for breed variation. Some dogs are "smarter" than others and I have a vague personal anecdote to prove it! When I was a kid I had an Australian Shepherd, a "smart" dog. I remember playing a game where I would run around a central obstacle and she would chase me. I would stop on one side and she on the other as we eyed each other, then the chase continued. One time I tried doubling back on her, counter to the pattern I had established, and she anticipated that move and we met in the middle for some play fighting. I remember being astounded at how she beat me at my own game. I suppose that kind of activity matches well with her herding instincts, but it seems somewhat close to the experiment in this study. My point is that some dog breeds do certain things better than others. Was this variability accounted for?

  2. Stan, testing for breed variation would have been interesting. I'm not sure if they did that or not.


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