Science

The neuroscience of pessimism: Why some people always focus on the negative

The neuroscience of pessimism:...
New research may have homed in on the precise brain region that causes pessimistic decision making
New research may have homed in on the precise brain region that causes pessimistic decision making
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New research may have homed in on the precise brain region that causes pessimistic decision making
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New research may have homed in on the precise brain region that causes pessimistic decision making

Are you a glass half full or a glass half empty kind of person? Some people seem to inherently focus on the negative when faced with a decision-making situation, and new research from a team of MIT neuroscientists has identified exactly what region of the brain may be inducing these pessimistic decisions.

The researchers at MIT have been examining the neuroscience of decision making for several years. Previous work has revealed that cost-benefit decisions are mediated by a brain circuit that runs from the medial prefrontal cortex to a specific cluster of neurons located in the striatum. It was found that when this circuit is disrupted, an animal would be more likely to make a high-risk, high-reward decision such as traversing past unpleasant bright light for stronger chocolate milk, instead of a less-concentrated but easily accessible milk reward.

An interesting outcome of this prior research was that when the test animals were chronically stressed, they displayed similar high-risk, high-reward behavior, suggesting that risker decisions may be made under the influence of stress and anxiety. The researchers hypothesized that it is this process that may help explain how the stress of addiction can lead to substance abuse.

The new research set out to focus on the area of the brain where negative weighting is generated in the decision making process. The study focused on the caudate nucleus, a small structure making up part of the dorsal striatum, a component of the basal ganglia. The experiments stimulated the caudate nucleus in macaque monkeys with a small electric current.

The animals were presented with a decision, a reward of juice was paired with an unpleasant puff of air to the face – a simple cost-benefit decision. What degree of negative stimulus will the animal put up with to get the reward? The experiment intriguingly showed that when the caudate nucleus was stimulated the animals began to avoid choosing the reward, when previously they would have put up with the unpleasant stimulus.

"This state we've mimicked has an overestimation of cost relative to benefit," explains Ann Graybiel, senior author on the new research.

Essentially, the research reveals that pessimistic decision-making can potentially be tied to an overactive caudate nucleus. Graybiel is turning her focus to validating these findings in human subjects, working with patients suffering from anxiety and depression to find out whether abnormal activity in the caudate nucleus can be specifically seen during negative decision-making.

As well as offering a compelling insight into how our brains weigh positive or negative outcomes when making a decision, the research hopes to help direct scientists toward better treatments for people suffering from depression and anxiety. For some people with extreme neuropsychiatric disorders, a crippling pessimistic worldview can be overwhelming, and this discovery may help focus treatments on an area of the brain that can modulate those negative sensations.

The research was published in the journal Neuron.

Source: MIT News

5 comments
CraigAllenCorson
I am a "glass is simultaneously half-full and half-empty" kind of person. Any word on what part of the brain does THAT?
dfmd
Neuro-phrenology lives on. From the compassion bump of the 18th century, we leap to the midbrain meanness lump. An essential tool for this is the MRI which unfortunately has a resolution of only an eighth inch while the processes they wouldst discern are a million times smaller. They should instead focus on finding the Homunculus in us. Obama showered "resurchers" with hundreds of millions to play with MRI machines. Psychiatrists need new toys. Emotions are created at the submicron level by cytokines et al inside the wireless mind.
Doug Nutter
I had a friend who was the poster boy for pessimism. I always got a chuckle out of his response. "If something goes like I think it will, it's expected. If it goes better than expected, it's a pleasant surprise."
Jay_Wilson
or it could be the times we're living in...
aviatrix
The saying, "Ignorance is bliss" is absolutely correct. I'm one of the pessimists, because I've got a clue what's going on. I've studied and worked in so many industries with about every kind of person, so I don't expect sunshine where stupidity reigns. I can see failures before most, so I analyze and solve a problem before jumping in, where most blindly jump in and are completely surprised by failure. I guess I see how clueless and mindless the human race is, and don't have any hope for us to improve.