DURHAM — Your favorite teacher from high school probably motivated you with kindness and a can-do attitude. But you may also recall a strict teacher, one who motivated with the blackmail of bad grades.

It turns out each teacher was engaging different parts of your brain – and you probably learned more from the nice one.

Scientists at Duke have shown that for simple learning, rewards are actually better motivators than threats. Their recent paper has further uncovered that the two types of learning use separate brain circuits. The work was led by Alison Adcock, a professor of psychiatry and behavioral sciences, and published in The Journal of Neuroscience.

The Duke researchers’ most recent work focuses on threat-motivated learning. Subjects were asked to memorize pictures, then tested the following day. A sequence of landscapes flashed before their eyes. Occasionally, an image was tagged as important, and they were told if they failed to remember it they would be punished.

The punishment? A mild electric shock.

“College students will come (participate in a study) even when there is shock involved,” laughed Vishnu Murty, Adcock’s graduate student and the first author of the paper.

The threats were empty; no one was shocked, as the subjects learned after they had seen all the images. The motivation during the learning process was what mattered.

The threat of punishment proved to be compelling. The subjects learned the tagged images better.

During the learning process, functional magnetic resonance images (fMRI) were taken, creating a 3-dimensional map of the subjects’ brains. Their fMRI was tuned to detect oxygen, which is used as fuel in firing neurons. Bright spots in the images show active areas of the brain.

In the fMRI, the amygdala, a region of the brain associated with stress, lit up when tagged images were shown. An instant later, the bright spots appeared in the hippocampus, which is responsible for crafting a short-term memory that can be saved in other regions of the brain.

Adcock did an identical study on reward-motivated learning in 2006. Subjects were offered money for their memory. Similar to the threat study, the rewarded images were remembered at a better rate.

But the fMRI told a different story. The ventral tegmental area (VTA), not the amygdala, was active with the hippocampus. The VTA is a region of the brain associated with reward and is where many feel-good dopamine-making neurons reside.

The team published a study in 2011 comparing reward-motivated and punishment-motivated people. People who were told they would be rewarded learned a maze more quickly than those threatened with punishment.

They also learned the maze more completely, remembering finer detail.

The 2012 work shows that these different outcomes are likely related to the different brain circuitry involved. Our brains can see two different versions of the same events, depending on whether we feel threatened or not.

“Threat-based motivation seems to lead to a narrow, stereotyped view, while reward leads to a broader, more nuanced view,” said Murty. This would explain why in the 2011 maze experiment, rewards yielded better results than threats.

But this does not mean the narrow view is not useful, especially for survival. “Like when recognizing a snake in the grass, or a fearful face in the crowd,” says Murty.

Further, this type of research has been done only for simple learning. The team studied declarative memory, the memory of things that can be described such as facts, events, and pictures. Learned skills, such as writing, playing a sport, or playing an instrument, are infinitely complicated.

So while reward incentives might help you learn the rules of football, your cantankerous coach may have your best interests at heart.

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