BEACHCOMBER 104 YEARS OLD AND BATTY ABOUT BATS...

IN 1974, the US philosopher Thomas Nagel published an influential paper with the title “What is it like to be a bat?” His argument was essentially that only a bat can answer that. Nagel’s paper raises profound questions on the nature of consciousness, but a paper in the current issue of the journal Animal Behaviour shows that bats may be more human that we thought.

Written by experts in the US and Panama – “Context-dependent Preferences in Wild Fruit Bats” – identifies a type of irrational behaviour in bats that had been seen as typically human. Known as “the decoy effect”, it is something we all experience when shopping and is a sneaky but effective marketing tool. Given a choice between two items A and B, we may without hesitation plump for B, but if a third item C is added to the range, it can change our preference to A.

Take wine for example. Bottle A is priced at £8, bottle B costs £15. The majority of people may choose A, seeing B as extravagant. But if we introduce bottle C at £20, giving people the choice of A, B or C, the majority preference shifts to B, which now looks like a bargain.

It’s the same with coffee; given a choice between a small cup for £2.50 or a large cup for £4, most choose the small cup. Add a medium-sized cup priced at £3.50, the majority now choose the £4 big cup, which suddenly looks better value. We now know that Jamaican fruit bats are much the same. Given the choice between ripe papaya and ripe banana, around half chose papaya while the other half chose banana, but when unripe banana was added, researchers saw a big preference for ripe banana. Like the expensive wine and medium coffee, the unripe banana acted as a decoy to change the bats’ preferences. Interestingly, a study in 2015 suggested frog-eating bats are rational in their choice of what frog to eat, based on volume and complexity of the frogs’ calls. They cannot be distracted by the decoy.

Yet female frogs can be decoyed when it comes to choosing a mate. Given a choice between a physically attractive frog and a fast-croaking frog, lady frogs went for the quick-croaker, but if a very slow croaker is added, she picks the attractive fellow.

In such circumstances, many humans, especially males, may think they know just what it is like to be a frog.