A new study in the oft-overlooked field of hamster research tries to get at that nagging question: Can hamsters be happy? Two researchers with Liverpool John Moores University found that hamsters, like other animals, may exhibit judgment bias, according to Phys.org, which boils that down to the idea that we behave "more optimistically when [we feel] good emotionally." Emily Bethell and Nicola Koyama devised a study in which 15 Syrian hamsters were placed in enriched cages featuring gnaw sticks, huts, and extra bedding, while 15 other hamsters lived in basic cages. Both types of cage contained water bottles that held sugar water in some cases, and bitter-tasting quinine water in others.
More bottles were then added, with the researchers looking to see whether the hamsters who led the "better" life would be more likely to sample the new bottles in hopes of tasting sugar water. Indeed, those in the better cages were more likely to test the waters, while the less-enriched hamsters pretty much stuck with the bottles they knew contained sugar water. The researchers acknowledge they "cannot say whether the hamsters in our study felt happy in their enriched housing," adding "it is difficult to interpret animals as categorically 'optimistic' or 'pessimistic' as there is no reference baseline against which to assess this." Still, they write in Royal Society Open Science that "the changes in cognitive processing of ambiguous cues certainly suggests enriched hamsters became more optimistic." Theirs is the "first study to report evidence for emotion-mediated judgement bias in a species of hamster." (France was threatened with a $24 million fine for not helping its hamsters).