“Are you a dog person… or a cat person?”

It’s a question that may forever divide the nation, but at least now we can put to rest any doubts about which of the two species loves us humans more.

Read more: The health benefits of owning a dog

A study (which aired as part of the show Cats V. Dogs on BBC Two)  decided to pit dogs and cats against one another in terms of their affection for humans. Researchers did this by measuring how much oxytocin – the so-called ‘love hormone’ – the two animals produced when they interacted with their owners.

Led by neuroscientist Dr Paul Zak, scientists then measured how much of the hormone both animals had in their saliva 10 minutes before a play session, and how much it had risen immediately afterwards.

"We have pretty good evidence that dogs actually love their humans,” said Dr Zak. "A couple of small-scale studies have shown that when owners interact with their dogs, the human and their dog appear to release oxytocin. 

"It’s one of the chemical measures of love in mammals. Humans produce the hormone in our brains when we care about someone. For example, when we see our spouse or child the levels in our bloodstream typically rise by 40-60 per cent.”

Read more: Why every office should allow dogs

But, while a number of studies have proven that both owners and their dogs produce oxytocin when spending time together, no previous research has ever examined whether or not this phenomenon occurs in cats, toio.

Until now, that is.

The study has found that dogs reciprocated these high hormone levels after interacting with their owner. The oxytocin in their blood increased by an average of 57.2% after play, while in cats it rose around 12%.

As such, this confirms that dogs are capable of feeling more love towards their owners, but it also confirms that cats really do feel some affection for their owners – contrary to assumptions that they’re aloof.

“I was really surprised to discover that dogs produced such high levels of oxytocin… the dog level of 57.2% is a very powerful response,” Zak commented.

“It shows these dogs really care about their owners. It was also a nice surprise to discover that cats produce any at all. At least some of the time, cats seem to bond with their owners,” he added.

Images: iStock