There's a new twist to the perennial argument about which is smarter, cats or dogs.

It has to do with their brains, specifically the number of neurons in their cerebral cortex: the little grey cells associated with thinking, planning and complex behavior — all considered hallmarks of intelligence.

The first study to actually count the number of cortical neurons in the brains of a number of carnivores, including cats and dogs, has found that dogs possess significantly more of them than cats.

As far as dogs and cats go, the study found that dogs have about 530 million cortical neurons while cats have about 250 million, compared with 16 billion in the human brain.

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"I believe the absolute number of neurons an animal has, especially in the cerebral cortex, determines the richness of their internal mental state and their ability to predict what is about to happen in their environment based on past experience," said study leader Suzana Herculano-Houzel, an associate professor of psychology and biological sciences at Vanderbilt University in the United States.

The researchers analysed the brains of one or two specimens from each of eight carnivore species: ferret, mongoose, raccoon, cat, dog, hyena, lion and brown bear.

They expected that their measurements would confirm the intuitive hypothesis that the brains of carnivores should have more cortical neurons than the herbivores they prey upon.

That was because hunting is more demanding, cognitively speaking, compared with the herbivore's primary strategy of finding safety in sheer numbers.

However, that proved not to be the case.

The researchers determined that the ratio of neurons to brain size in small and medium-sized carnivores was about the same as that of herbivores, suggesting that there is just as much evolutionary pressure on the herbivores to develop the brain power to escape from predators as there is on carnivores to catch them.

In fact, for the largest carnivores the neuron-to-brain-size ratio was actually lower.

They found that the brain of a golden retriever has more neurons than a hyena, lion or brown bear, even though the bigger predators have brains up to three times as large.

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"I'm 100 per cent a dog person," she added, "but, with that disclaimer, our findings mean to me that dogs have the biological capability of doing much more complex and flexible things with their lives than cats can.

"At the least, we now have some biology that people can factor into their discussions about who's smarter, cats or dogs."

Why being media-savvy makes you more sceptical

The more you know about the news media and how it works, it appears, the less likely you are to believe conspiracy theories - even ones you might find politically tempting. Photo / 123RF
The more you know about the news media and how it works, it appears, the less likely you are to believe conspiracy theories - even ones you might find politically tempting. Photo / 123RF

The more you know about the news media and how it works, it appears, the less likely you are to believe conspiracy theories - even ones you might find politically tempting.

US researchers surveyed nearly 400 participants online in spring 2016 to gauge how their news media literacy - measured as a combination of news media knowledge and psychological traits connected with processing news messages - might relate to their endorsement of conspiracy theories.

The researchers found that "individuals who give credence to conspiracy theories know comparatively little about how the news media work".

They also found that the greater one's knowledge about the news media - from the kinds of news covered, to the commercial context in which news is produced, to the effects on public opinion news can have - the less likely one will fall prey to conspiracy theories.

Study leader Stephanie Craft, a journalism professor at the University of Illinois, said this applied even where conspiracy theories resonated with an individual's political beliefs.

The study asked participants about the strength of their belief in any of 10 conspiracy theories, split evenly between those associated with liberal and conservative perspectives.

It also asked separate questions to determine participants' ideological beliefs.

The researchers found that liberals with higher news media literacy were less likely to believe any or all of the five liberal conspiracy theories - among them that the federal government knew about the 9/11 terrorist attacks beforehand, that Republicans stole the 2004 presidential election through voter fraud in Ohio, and that there's a link between childhood vaccines and autism.

Likewise, conservatives with higher news media literacy were less likely to believe five conspiracy theories commonly associated with conservatives - among them that Barack Obama was not born in the US, that global warming is a hoax, and that the 2010 health care law authorised government panels to make end-of-life decisions for people on Medicare.

Contrary to popular conception, believing in conspiracy theories was "not the sole province of the proverbial nut-job", the researchers wrote.

Conspiracy theories were "almost by definition 'good' (ie, enticing) stories" and even reasonable individuals can buy into theories not supported by the best evidence, they note.

"The power of a compelling narrative and one's pre-existing biases are often no match for conflicting information."

Yet, given those factors and others that might play a part in conspiracy theory endorsement, Craft said she was encouraged to find that promoting greater news media literacy might have a small-but-significant effect.

"To the extent that we've hit on one thing that seems to matter in a nontrivial kind of way, that represents some sort of progress."

It was also something we could do something about, Craft said, rather than trying to change set beliefs, alter news habits or complain about "fake news".

Educators could promote news media literacy in schools, Craft said, and journalists could play a part "by being more open about how they do what they do".

"One of the tricky areas for people in the news literacy area is you want to encourage scepticism, you want to encourage people to be actively thinking about news, not just consuming it like candy," she said.

"But there's kind of a fine line between being a sceptical news consumer and a cynical one, where the cynical one would just think, 'Oh well, they all make stuff up, they all do it, it's all wrong.'

"That doesn't serve anyone, either."