Monday, 5 August 2013

Less is more when it comes to beating bad habits

An evidence-backed way to break habits involves forming what's known as "if-then" implementation intentions that target the situational cues to temptation. "If I am feeling bored then I will eat an apple" would be a plan designed to break the automatic link between boredom and unhealthy snacking. Most research in this area has focused on the benefits of just one plan. Of course, in reality, our bad habits often have multiple cues. It's not just boredom that prompts a mindless grope for the cookie jar, but also the taste of tea or coffee, watching TV, or the after-buzz of a gym visit. A new paper examines the effectiveness of forming multiple if-then plans, one for each habit-provoking prompt.

Aukje Verhoeven asked 63 young women to keep a snacking diary for three days. They then used these records to identify cues to their unhealthy snacking and to form either one or three if-then plans for replacing cue-snacking routines with healthier behaviours. There was also a control group who simply thought of healthy snack alternatives. All the participants then kept a record of their unhealthy snacking for three further days.

The take-home result? The women in the single if-then plan condition and those in the control condition showed a reduction in their snacking from baseline to follow-up (2.01 to 1.47 average daily snacks, and 2.45 snacks to 1.45, respectively). By contrast, the women in the multiple if-then plan group showed no significant reduction in snacking (1.95 daily snacks at baseline vs. 1.83 at follow-up).

A second study aimed to find out why forming multiple if-then plans for a single overarching goal (in this case reducing snacking) is counter-productive. If-then plans work by replacing the cue-habit association with a new healthier cue-behaviour link. Perhaps forming multiple if-then plans backfires because multiple new cue-behaviour links interfere with each other in memory. Unlike in the situation with a single if-then plan, maybe none of them form a strong enough association to dislodge the original, unwanted cue-habit link.

To test this, 93 men and women formed either one or three if-then plans related to breaking unhealthy snacking habits. Another "mixed" group formed one if-then plan related to snacking and two further if-then plans related to an unrelated aspect of life - academic achievement. The crucial test was a word task on a computer. An initial (prime) word was flashed - this was one of the cues, such as "boredom", that triggered a bad habit. Then either a new word or a nonsense word appeared on-screen and the participants had to indicate as fast as possible whether it was a real word or not. Real words were taken from a list of bad snacking habits or the healthy behaviours used in the if-then plans.

The key finding here was that participants in the single if-then plan condition and participants in the mixed condition showed faster responding to words pertaining to healthy snacking than to bad habits - a sign that they'd successfully replaced the link between a cue and habit with a healthier option. No such progress was observed among the participants who'd formed three if-then plans related to snacking. This suggests multiple if-then plans targeting the same overarching goal are ineffective because none of the intended healthy behaviours is linked strongly enough with the relevant situational cues.

"Although multiple plans for the target behaviour should intuitively provide people with more opportunities to successfully act upon one's intentions, the present findings show, both with behavioural and cognitive measures, that formulating multiple implementation intentions is ineffective when fighting unhealthy snacking habits," the researchers said.


Aukje A. C. Verhoeven, Marieke A. Adriaanse, Denise T. D. de Ridder, Emely de Vet, and Bob M. Fennis (2013). Less is more: The effect of multiple implementation intentions targeting unhealthy snacking habits. European Journal of Social Psychology DOI: 10.1002/ejsp.1963

--Further reading--
7 ways to be good (near the bottom of the post)

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.


Anonymous said...

Who decided that 63 was the ideal sample size for this study? Did they just get to 63 and say "eh, that's probably big enough"? Seems fishy to me.

Anonymous said...

It was probably the biggest sample they could get a hold of (or afford to monitor). Most studies don't have round-number sample sizes.

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