Tag: Monkeys

Drunken monkeys reveal how binge-drinking harms the adolescent brain

By Ed Yong | May 31, 2010 3:00 pm

Hangover

Most of us will be all too familiar with the consequences of night of heavy drinking. But alcohol’s effects on our heads go well beyond a mere hangover. The brain suffers too. A penchant for incoherent slurring aside, alcohol abusers tend to show problems with their spatial skills, short-term memory, impulse control and ability to make decisions or prioritise tasks. Many of these skills are heavily influenced by a part of the brain called the hippocampus. Now, Michael Taffe and researchers from the Scripps Research Institute have shown how binge-drinking during adolescence can cause lasting damage to this vital area.

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Monkeys fall into the uncanny valley

By Ed Yong | October 13, 2009 9:30 am

In the movie industry, special effects and computer-generated imagery are becoming better and more realistic. As they’d improve, you’d expect moviegoers to more readily accept virtual worlds and characters, but that’s not always the case. It turns out that people are incredibly put off by images or animations of humans that strive for realism, but aren’t quite there yet.

A character like Wall-E is lovable because he’s clearly not human but has many human-like qualities and expressions. In contrast, the more realistic CG-characters of Beowulf or The Polar Express are far closer to reality but somehow less appealing because of they haven’t tripped the finish line. This phenomenon is called the “uncanny valley” – it’s the point where, just before robots or animations look completely real, they trigger revulsion because they almost look human but are just off in subtle but important ways.

This isn’t just a quirk of humans – monkeys too fall into the uncanny valley. Shawn Steckenfiner and Asif Ghazanfar from Princeton University showed five macaques a set of faces of real or CGI faces, pulling a few different expressions. They found that all five macaques consistently reacted more negatively to realistic virtual monkey faces than to either real or completely unrealistic ones. They spent much less time looking at the realistic avatars than the other two options, particularly if the faces were moving rather than static.

Steckenfiner and Ghazanfar say that the simplest explanations is that the monkeys “are also experiencing at least some of the same emotions” as humans. But for the moment, we can’t say if the monkeys felt the queasy disgust that humans do when we fall into the valley, or whether they were simply more attracted to the other two options.

The best way to do that would be to repeat these experiments while looking for possible signs of unease – sweaty skin, dilated pupils or clenched facial muscles, as examples. Steckenfiner and Ghazanfar also want to see if combining fake faces with real voices would put the macaques are greater or lesser ease.

For the moment, the duo hopes that macaques will be able to help us understand why the uncanny valley exists, or what goes on in the brains of people who feel its characteristic revulsion. For a start, it’s not about movement. The realistic virtual faces were only marginally less attractive to the monkeys when they moved compared to when they were static.

Steckenfiner and Ghazanfar’s favoured idea is that the part of our brains (and those of macaques) responsible for dealing with faces fires up when it sees realistic animations. But the features of these avatars fail to meet the expectations that we’ve built up through a lifetime of experience. Perhaps their skin colour is slightly off making them look anaemic. Perhaps their skin is too smooth, or their features out of proportion.  Whatever the clash, the idea is that the increased realism lowers our tolerance for these anomalies.

Reference: doi: 10.1073/pnas.0910063106



MORE ABOUT: Monkeys, uncanny valley

Monkey see, monkey calculate statistics

By Ed Yong | April 3, 2009 8:30 am

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Blogging on Peer-Reviewed Research Say the word ‘statistician‘ and most people might think of an intelligent but reclusive person, probably working in a darkened room and almost certainly wearing glasses. But a new study shows that a monkey in front of a monitor can make a reasonably good statistician too.

Rhesus macaques can compute statistics in a simple psychological task.Tianming Yang and Michael Shadlen from the University of Washington found that rhesus macaques can perform simple statistical calculations, and even watched their neurons doing it. Psychologists often train animals to learn simple tasks, where the right choice earns them a reward and the wrong one leaves them empty-handed or punished. But real life, of course, is not like that.

Mostly, there are risks and probabilities in lieu of guarantees or right answers. Animals must weigh up the available information, often from multiple sources, and decide on the course of action most likely to work out in their favour.

Yang and Shadlen tested this decision-making ability in two rhesus macaques using a variation of the well-known weather prediction task used to test human volunteers. In the human version, people are shown a series of cards that represent various probabilities of good or bad weather. After some training, they are shown combinations and asked to predict the likely weather from these.

The monkeys had a slightly simpler task – they had to look at either a green or a red target. If they picked the right one (which changed from trial to trial), they were rewarded with a tasty drink. To help the monkeys choose, Yang and Shadlen showed them a series of shapes that represented the probability that the rewarding target was red or green.

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