小孩和猩猩使用相同记忆法

Infants and apes apparently adopt the same tactics(1) for remembering where things are, but as children develop their strategies change, a new study shows.

The findings might reveal in part how the minds of our distant ancestors shifted gears(2) to embark(3) on the road toward humanity.

There are two basic strategies animals use to remember where things are. Either they remember a thing's features, such as whether it was a banana, or they remember its place in space, such as left.

All animals scientists have tested seem to employ both strategies. However, if experiments are rigged(4) such that animals had to choose between the tactics, some species, such as chickens and toads(5), prefer a feature-based strategy. Others, such as fish and dogs, favor a place-based strategy.

Researcher Daniel Haun at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany and his colleagues investigated orangutans(6), gorillas(7), bonobos(8), chimpanzees(9) and humans. They wanted to see whether humanity and its closest relatives all adopted the same strategies for remembering where things are. Any changes in strategy between species or within species would shed light on how they all evolved.

At the Leipzig Zoo, the scientists hid rewards such as grapes, banana slices or toy animals under either a hollow piece of wood, an imitation(10) bird's nest or an artificial hollow rock.

At times, the rewards were concealed(11) under the same object they were hidden beneath previously, whose place had changed. A feature-based strategy would best find these coveted items.

At other times, the rewards were hidden at the same place they were concealed before, but under a different object. A place-based strategy would best discover these items.

When human infants are a year old, they favor place-based strategies like all the other great ape species do. This suggests human and ape brains start out the same, at least when it comes to remembering where things are. The most recent common ancestors between humans and all the other great apes date back to about 15 million years ago, suggesting this common preference has been part of our brain structures since at least then.

However, three-year-old children preferred a feature-based strategy. The researchers noted this shift in strategy coincided with a period when humans are first drawn into social life and acquire skills such as spoken language.

1. tactics：战术、策略

2. gear：齿轮

3. embark：登上

4. rig：操纵

5. toad：癞蛤蟆

6. orangutans：猩猩，一种大型的树栖类人猿，产于波罗门和苏门答腊，有稀疏的红棕毛皮、很长的臂且无尾