Anticipation of pain can be worse than pain itself - health - 22 November 2013 - New Scientist

"The only thing we have to fear is fear itself," said Franklin D. Roosevelt. He might have been onto something: research suggests that the anticipation of pain is actually worse than the pain itself. In other words, people are happy to endure a bit more pain, if it means they spend less time waiting for it.

Classical theories of decision-making suppose that people bring rewards forward and postpone punishments, because we give far-off events less weight. This is called "temporal discounting". But this theory seems to go out the window when it comes to pain.

One explanation for this is that the anticipation of pain is itself unpleasant, a phenomenon that researchers have appropriately termed "dread".

To investigate how dread varies with time, Giles Story at University College London, and his colleagues, hooked up 33 volunteers to a device that gave them mild electric shocks. The researchers also presented people with a series of choices between more or less mildly painful shocks, sooner or later.

During every "episode" there was a minimum of two shocks, which could rise to a maximum of 14, but before they were given them, people had to make a choice such as nine extra shocks now or six extra shocks five episodes from now. The number of shocks they received each time was determined by these past choices.

No pain, no gain

Although a few people always chose to experience the minimum pain, 70 per cent of the time, on average, participants chose to receive the extra shocks sooner rather than a smaller number later. By varying the number of shocks and when they occurred, the team was able to figure out that the dread of pain increased exponentially as pain approached in time. Similar results occurred in a test using hypothetical dental appointments.

"This study demonstrates that the fear of anticipation is so strong it can reverse the usual pattern of time discounting," says George Loewenstein, a professor of economics and psychology at Carnegie-Mellon University in Pittsburgh, Pennsylvania. "It's probably not an exaggeration to say that as much, or more, of the pains of life come from anticipation and memory than from actual experience."

The study could well have implications for medicine and health policy, because an understanding of how people judge pain is important for presenting them with options about potentially painful treatments.

"You should avoid emphasising waiting times," says Story. "And if you can make something seem unavoidable, people may be more likely to confront it to minimise dread."

Story hopes that this kind of psychological study will aid the development of diagnostic tools. "Looking at these kinds of preferences might help predict whether people will make healthy or unhealthy choices," he says.

Journal reference: PLoS Computational Biology, DOI: 10.1371/journal.pcbi.1003335


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