A team of researchers at Toronto’s Hospital for Sick Children “taught mice of different ages to associate a particular environment with a mild electric shock.” They then gave some of the younger mice a drug that slows the formation of new neurons, while they had some of the older mice run on a wheel in order to encourage new neuron growth. When the mice reentered the dangerous environment, the younger ones who received the drug were more likely to remember the shock, and the older ones who had exercised on the wheel were more likely to forget the shock.
What’s the Big Idea?
Both results point to a reason for why so few adults can remember anything that happened prior to their third birthday: In the young brain, the process of new neuron formation — neurogenesis — is so rapid that any already-stored memories are likely to be disrupted and eventually forgotten. This theory behind the phenomenon known as childhood amnesia “might be an interesting avenue to pursue” but it’s only one of several other possible explanations that exist, says City University London memory researcher Mark Howe.
According to the "rice theory," Asian societies evolved to be more cooperative, and Western societies more individualistic, because of the type of work needed to farm rice and wheat respectively. A recent study seems to lend credence to this theory.