杏吧原创

A MOSQUITO FISH approaches predators more boldly if it has a pal
alongside鈥� especially if its buddy is on the left.

Small fish, such as the mosquito fish Gambusia holbrooki, tend to
pair up to check out predators. Previous studies have shown that when a mirror
is placed parallel to a single fish in a tank, so that its reflection looks like
a cooperative partner, the fish ventures closer to a predator than if the mirror
is angled to show the illusory partner swimming away.

Now Angelo Bisazza and his colleagues at the universities of Padua and
Trieste in Italy have found that the fish are braver when they see their partner
with their left eye and the predator with their right鈥攅ven when the
partner is swimming away (Animal Behaviour, vol 57, p 1145). This
follows on from work last year, in which Bisazza鈥檚 team discovered that mosquito
fish prefer to eye up potential mates with their left eye and possible predators
with their right.

These findings add to a growing body of evidence that, in birds and mammals
as well as fish, the right brain, which gets input from the left eye,
specialises in recognising members of the same species. Lateralisation may have
evolved to make signal processing in the brain more efficient, say the
researchers.

鈥淎rtificial neural networks crash more easily if some specialisation is not
built in,鈥� says Richard Andrew of the University of Sussex in Brighton, who has
done similar experiments with birds. He thinks such lateral specialisation in
early animal brains has persisted in mammals, which might explain why speech and
other skills are preferentially handled by the right or left brain in humans.