Dolphins, chimps display powers of recall

  • 13/08/2013

Elephants have always been touted as having great memories, but new research suggests dolphins could give them a run for their money.

So where do humans rank? Possibly beneath chimpanzees.

A new study has shown dolphins can remember the sounds other dolphins make – possibly for their whole lives.

"We've had anecdotal evidence for a long time that dolphins are intelligent and possible have long memories, but it wasn't until this study… that we really had the ability to add a timeline to that," says director of the Institute for Applied Ecology at AUT, Professor Steve Pointing.

"In the US, dolphins in zoos were often transported between zoos for breeding purposes – so a male and female could be separated and then not see each other again, possibly for the rest of their lives.

"What these investigators did was recorded the unique call signs of all the dolphins around the country, and then went and played them back intermixed with other non-familiar sounds to dolphins, and remarkably dolphins that had been separated for so long were able to recognise – with a friendly display – the call signs of dolphins they once shared time with."

But it's not just dolphins that have been impressing with their powers of recall – a Japanese study on chimps suggests when it comes to short-term memory, they're at least our equal, if not superior.

"These chimps were effectively given an iPad-like device where a numeric sequence was displayed, but also with a spatial dimension to it," says Prof Pointing.

"The chimps – in almost every scenario – were better able to repeat the pattern than the human subjects. To put this in context, a chimp's brain is about a third the size of ours, and although they're our closest living relative, we last shared an ancestor well over 4 million years ago.

"These are fundamentally simpler creatures on paper, yet they do have this amazing short-term memory."

He says it's probably an evolutionary consequence of living in the wild.

"Chimps living in the wild have to multitask, so this sort of working memory, this short-term memory is really useful when you're swinging through the trees in what's a very three-dimensional environment, and also when you're having to avoid predators, make decisions on food and also deal with really big, complex social groups."

So what can humans do to catch up with chimps? The answer, surprisingly, might be to drink champagne.

Whilst having too much has obvious negative effects on memory, having a few glasses of bubbles a week could do the opposite.

"The study was carried out on rats, but I'm sure they were quite happy rats," says Prof Pointing.

"Essentially, two groups of rats – one group of rats fed regular rat food, the other had food supplemented with about three glasses of champagne, a week. Those rats developed the ability in a maze where they had to memorise the direction that they had to take in order to find a treat or a reward.

"The rats that had the champagne diet had a 50 percent higher chance of navigating the maze through memory than the rats that didn't have the champagne diet."

The study took place over three weeks – which is about three years in human terms, says Prof Pointing.

"It's a nice, long period of champagne drinking."

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source: newshub archive