A Healthy Nudge.

HealthifyMe, an online fitness planner and calorie counter which helps people adhere to a health and weight loss regime, often sends its users email reminders to follow up on their health plan. I couldn’t help but notice that some of these reminders have behavioural nudges hidden in them. Here’s a peek at one of the emails, followed by my interpretation of the influence attempt:


1) Social Norms: “623 people tracked 4951 meals on HealthifyMe yesterday! We noticed you weren’t one of them”.

Using descriptive social norms to change behaviour is a commonly used behaviour change strategy. Telling people what others are doing influences them to conform to the norm or “join the herd”. According to this theory, an influence tactic which points out that many people in one’s community engage in undesirable behaviour can be particularly destructive (e.g. telling teenagers how many other teenagers in their school smoke is likely to increase smoking). On the other hand, pointing out a community’s desirable behaviour can be surprisingly effective.

By claiming that 623 people tracked meals on the website yesterday, and stressing that I clearly wasn’t one of them, HealthifyMe is not only activating feelings of guilt at failing to keep my healthy lifestyle commitment, it is also telling me that I’m not doing what the other members are doing: consciously working on my nutrition plan. I’m now in the “out-group”.

2)  Similarity: “Check out healthy choices that were logged on HealthifyMe yesterday by people just like you: Roti, Apple, Green tea without milk (sugar free), Lentil Dhal and boiled egg white.”

Human beings have a tendency to favour things (and people) that are similar to themselves. By telling members that people “just like them” have been searching for specific types of food/drink items, HealthifyMe is tapping into the similarity bias.  There’s a pattern here: while the social norms message above relates to a broad population of individuals who tracked meals on the website, the similarity message narrows it down to a specific sample of people who are “similar” to the user based on individual demographics and HealthifyMe search behaviour.

There’s another Nudge in there….leave a comment if you can spot it!


2 thoughts on “A Healthy Nudge.

  1. Chandreyee

    Good catches there, K. I had only guessed at the power of descriptive values in a nebulous way until the Atlantic Monthly Article last year about Prescriptive vs Descriptive. Makes total sense. Similarity bias does too. Is the third nudge the one about being able to start-over? I don’t know what behavioural science jargon fits but it seems like a not-so-subtle hint that mortality is creeping up and there’ s a chance for a do-over still. Good pacing too – pointing out how you’ve failed followed by how you can still redeem yourself. Stick followed by a carrot. Then the promise of validation from your peers in the similarity thing. Interesting that we all sub-conscious function along these lines of essential human wrangling……all nudges, all the way. 😉

    1. karishmarajaratnam Post author

      Ooh yes, there is a bias called the fresh start bias, which suggests that people tend to engage in desirable behaviours on the start of a new period, which is why new years resolutions are so popular (whether they keep up with these resolutions or not is a different story). But this can also be a motivational thought at the start of the week, start of the month etc. “The every day is a new day” sentence is a fresh-start driver.Good spot, thank you! 🙂


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