Stick Motivates Physical Activity Better than Carrot, Says Study

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We've recently described studies in which researchers tried to physically motivate people without much success to alter their behavior by giving them financial rewards if they reached set goals. A new study depicts the result of the opposite approach financial loss if participants don't reach their goals. And it appears that the stick just might work better than the carrot.

Dr. Mitesh S. Patel of the Perelman School of Medicine at the University of Pennsylvania and colleagues investigated the efficacy of financial incentives to increase physical activity in overweight and obese adults. The participants in their study were 281 overweight or obese employees (based on having a BMI of over 27 kgm/m2) of the University of Pennsylvania. They were given an activity goal of 7,000 steps per day, and activity was monitored by means of an application on participants' smart phones. Each person was randomly assigned to one of four incentive groups as follows:

  • Group 1: Control no financial incentive
  • Group 2: Gain Incentive: each person received $1.40 for each day they met the 7,000 step goal
  • Group 3: Lottery Eligibility worth $1.40 per day for each day goal was met
  • Group 4: Loss Incentive from a $42.00 per person fund, a participant lost $1.40 each day the goal was not met

The participants were followed for 13 weeks, and given daily feedback on their performance. At the end of that time, they were followed for an additional 13 weeks during which they were still given daily feedback, but any incentives or penalties were discontinued. The primary endpoint of the study was the proportion of participant days the activity goal was met. A secondary endpoint was the proportion of days that the goal was met during the follow-up period, as well as the average number of steps the participants took during both intervention and follow-up periods.

Only the Loss Incentive group (No. 4) met the activity goal a significantly greater proportion of days than did the control group. However, the difference from controls group's average number of steps taken didn't differ significantly overall. And during the follow up period, there were no significant differences from the control group compared to any other group the number of steps decreased for all groups.

Thus, while the loss incentive was most effective in changing activity levels in this study, once the incentive ended, the activity levels fell. While this loss incentive had some use, it seems that its effect was not long-lived.

More research is obviously needed before any type of incentive can be said to be effective in motivating individuals to change their behavior to improve health.