Our weekly round-up of the best psychology coverage from elsewhere on the web

There’s not much evidence that brain training apps really improve our cognitive abilities – so why do so many people use them? Sabrina Weiss at Wired has the answers.

More colour-related research this week: people who live in grey, rainy countries far away from the equator are more likely to associate yellow with joy, reports Eva Frederick in Science. Most people in Finland, for instance, felt that yellow was related to the feeling of joy, while very few of those in countries like Egypt and Saudi Arabia made that association.

Humans can sometimes be aggressive, xenophobic creatures — but we also have the capacity to be pretty welcoming to outsiders. Our flexible approach to outgroups seems unique amongst primates, and may have an evolutionary basis, writes former Digest editor Christian Jarrett at Aeon.

We already knew that bees can count up to four and understand the concept of zero – now researchers have used a classic bit of behavioural psychology to push the insects’ maths skills even further. Bees who received a training regime that included both rewards and punishments — rather than only rewards — ended up being able to identify numbers even higher than four, reports Jason Arunn Murugesu at New Scientist.

Whether it’s the final episode of a TV show or the parting of two lovers, there’s a certain amount of melancholy associated with endings. But endings aren’t all bad, according to a nice little round-up of “ending”-related research by Ben Healy at The Atlantic. Football players score more goals in the second half of a game, for instance, while the end of a relationship can also be an important period of growth.

“The only remaining option was an operation to remove the tumour from inside his brain, something that had never been done before. The terrible risks were made clear to Henderson, but he waved off the medics’ concerns: it was a chance he was willing to take.” Thomas Morris has written a fascinating account of the first operation to remove a brain tumour, and the neuroscience research that led to the momentous occasion, for the Wellcome Collection’s website.

An investigation by Kings College London has concluded that a number of papers by the psychologist Hans Eysenck are “unsafe” – including many long-criticised studies that claimed there is a strong link between personality and cancer risk, reports Sarah Boseley in the Guardian. Over at Retraction Watch, James Heathers ponders what will now happen to these papers.

Compiled by Matthew Warren (@MattbWarren), Editor of BPS Research Digest