Barr – infant crying

That’s a terrific question about infant crying. We have essentially very little idea about why some infants cry much more than others. Except for some very obvious truths which is that there’s hardly a behavioral or a biologic or morphologic characteristic that we know about in humans or any other species that doesn’t have a huge range of variation and why we shouldn’t expect that for crying is really not such a surprising answer in a way. There is a huge variation in height, there’s huge variation in skin color, there’s huge variation in all kinds of functions that we know about. And there’s huge variation in the amounts infants cry. Interestingly, anything that has a huge variation like that has context in which it can be beneficial and context in which it’s not beneficial.  

So we can illustrate that by the wonderful story of Martin deVries’ observations in the Masai infants where he took a sample of infants and rated them according to temperament characteristics and then came home and found out that just like in North American infants you have some infants that cry a lot and some that cry less. The ones that cry a lot are called difficult temperament infants and the ones that cry less are called normal or slow to warm up infants. And then when he was away from the Masai they happened to suffer from famine that occurred during the winter and he went back the next summer and looked up all of the infants and as you might expect from the context of the story that I’m telling, the infants who were the difficult crying infants were more likely to have survived the famine. In that context crying a lot was life saving for those infants, relatively speaking.