Our experiences in the first few years of our lives have enduring effects on the way we behave later. At that early age we have little or no control on what is going on. Of course, now that we’re grown up, we don’t recall much of those early days and would probably assume that it is our later experiences that mostly shape our behavior. But this may not be so.
A study by Feng et al from the Kunming Institute of Zoology report this week on a study of rhesus monkeys in which some youngsters who were separated from their mothers at birth, who were hand reared for the first month and then were reared with another youngster (1). The maternal separation was due to problems such as inexperienced moms not handling their babies properly, bad weather that is hazardous for young baby monkeys etc. and not for the purpose of studying the effects of the separation.
These peer-reared monkeys behave differently from those normally reared by their moms even three years later. They spent a lot of their time sitting around on their own and were generally less rhesus monkey-like.
When the monkeys were caught for check-ups, the control group, that is monkeys reared by their moms in the normal manner, responded with the release of cortisol. Cortisol, you’ll recall, helps us to get out there and fight for our survival. The guys who had been raised without their moms, had a much slower, and hence lower, cortisol release, so in a bad situation, they would be more likely to lose.
This effect of early life bad times is also seen in people. Published this week is a meta-data study of problems of depression in later life of children who had been maltreated and the depression treatments had poor outcomes. This work was carried out by Nanni et al from London’s King’s College (2).
Seriously scary to see how long term, permanent even, some of these effects can be on brain functionality.
- http://www.pnas.org/content/early/2011/08/12/1010943108.full.pdf+html
- http://ajp.psychiatryonline.org/cgi/content/abstract/appi.ajp.2011.11020335
