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Is the trough half full or half empty?

PIGS feel optimistic or pessimistic about life depending on how pleasant their environment is, researchers at Newcastle University have found.

A technique has been developed to “ask” the animals about their mood, the BBC reports.

They were put in two groups, one with more space and toys, then taught to associate one noise with a treat and another with something less pleasant.

When a new noise was played, pigs in the better environment were more likely to approach expecting a treat.

Half the pigs were placed in an enriched environment - more space, freedom to roam in straw and play with “pig” toys - while the other half were placed in a smaller, boring environment - no straw and only one non-interactive toy.

In both cases, a note from a glockenspiel was followed by an apple but a dog training clicker led to something mildly unpleasant - the rustling of a plastic bag.

The new and ambiguous sound was a squeak.

Dr Catherine Douglas, who led the experiment, said: “We found that almost without exception, the pigs in the enriched environment were optimistic about what it could mean and approached expecting to get the treat.

“In contrast, the pigs in the boring environment were pessimistic about this new strange noise and, fearing it might be the mildly unpleasant plastic bag, did not approach for a treat.”

She said the results were similar to a “glass half empty versus glass half full” interpretation of life, where feelings affect judgement of events.

This was posted in Bdaily's Members' News section by Ruth Mitchell .