Ever wondered why New Year’s resolutions to work out so often fail? It could be because people set goals that are too precise, according to business professor Baba Shiv.

In a forthcoming paper for the next issue of Psychological Science, Shiv says numerical ranges and vague deadlines are more effective at sustaining motivation than precise numbers and deadlines because they give people more psychological leeway.

“The individual desires a biased outcome,” Shiv said. “The brain functions on that which is favorable out of a desired range. But if I force the individual to look at all the precise measures and information, then the brain will tend to focus on the negative.”

In other words, if people see their targets as spectrums, their minds will focus on the more easily attainable portions of those spectrums, Shiv said. They will perceive their goals as within reach, and they will stay motivated.

By contrast, if sprinters, for example, are reminded of their precise previous performances and told to shoot for precise improvements, they will tend to focus on the negative, Shiv said. That attitude will lead them to interpret any minor setbacks as discouragement or failure, and they will lose motivation.

“Precise information doesn’t allow the individual the leeway to process the information in a biased fashion,” he said.
In addition, Shiv said, frequent updates can only discourage. “There is evidence that the more people keep track of their exact progress, the more likely they are to give up,” he said.

Shiv conducted several studies from late 2009 to early 2011 that led him to draw these conclusions about the relationship between the language of goal-setting and sustained motivation as a function of success.

In one study, Shiv told 106 participants that flavanol, a chemical present in cocoa, aids mental acuity, adding that one gram of cocoa was necessary for the effect to manifest. He gave identical chocolate candy bars to all the test subjects. Half of the participants were told that the bar contained exactly one gram of cocoa, while the other half were told that the bar contained between 0.5 and 1.5 grams.

All the participants then completed several exercises in Brain Games, a program that assesses and trains mental capacity.
“I observed that the people who were told that their bar contained a range had brain age scores that were more favorable than those who were told their bar contained exactly one gram,” Shiv said.

The data suggest that those who believed their bar could have contained up to 1.5 grams assumed the maximum and were subsequently inspired, validating the hypothesis that people respond more positively to vaguely presented information.

“It’s a classic placebo effect,” Shiv said, “which gives rise to a self-fulfilling prophecy.”

In another study, Shiv brought in 39 participants and evaluated them on the fictional “Holistic Health Index” scale, telling all of them that they exceeded the desired value, between 45 and 55. However, he told half the subjects their exact scores at the start, and half a rough range that captured their scores. The participants all attempted to lose weight through their own means.

Shiv found that, like in the cocoa study, the recipients of the vague information were more successful at their respective goals: they lost more weight on average than the group who were given an exact figure.

These ideas have far-reaching implications in the fields of business, education, athletics and general life strategies, Shiv said.

“These days, it’s all about numbers—course evaluations, employee evaluations…those are the instances when precise information can end up hurting rather than helping.”