If there’s any molecule that is consistently viewed through rose-tinted glasses, it’s oxytocin. This simple hormone has earned misleading but charmingly alliterative nicknames like “hug hormone”, “cuddle chemical” and “moral molecule”. Writers love to claim, to the point of absurdity, that oxytocin increases trust, generosity, cooperation and empathy, among a slew of other virtues.
These lines of evidence might seem contradictory, but only if we hold the naive view that oxytocin is a chemical force for good. Instead, many scientists have suggested that, rather than some positive panacea, it’s more of a general social substance. It directs our attention towards socially relevant information – everything from facial expressions to posture – or drives us to seek out social interactions.
Now, Adam Reddon from McMaster University has found more evidence to support this idea by studying the daffodilcichlid, a beautiful African fish. When he injected them with isotocin – the fish version of oxytocin – he found that they became more responsive to social information. They were more sensitive to an opponent’s size before a fight, and they behaved more submissively when they themselves were challenged.