Injunctive Data vs. Descriptive Norms… Creating the Optimal Discrepancy

April 21, 2014 (old blog)

Last week’s blog highlighted why we want RIPPLE to produce a cognitive discrepancy… let’s take it one step further and ask how we plan to create the optimal cognitive discrepancy.

Once parents respond to two brief questions about their child’s lifestyle behaviours (e.g., daily screen time, portion sizes), their responses will be contrasted against descriptive (normative data from the Canadian population; for example, the Canadian Health Measures Survey; CHMS) or injunctive data (national guidelines; for example, Canada’s Food Guide).

Here’s an example:

“On a typical day, how many minutes of moderate-to-vigorous physical activity does your child get?”

[Mum selects “16-30 minutes per day”]

Now, mum’s response could be contrasted against descriptive data (CHMS):

“You said your child typically gets 16-30 minutes of MVPA per day. Did you know that Canadian children of the same age and sex as your child typically get 47 minutes of MVPA per day?”

Or, her response could be contrasted against injunctive data (Canadian guidelines):

“You said your child typically gets 16-30 minutes of MVPA per day. Did you know that Canadian guidelines recommend that children should get 60 minutes of MVPA per day?”

Which type of feedback, descriptive or injunctive, do you think will produce the optimal cognitive discrepancy? My prediction has always favored descriptive data. Why?

  1. It is likely that parents encounter national guidelines and recommendations on a routine basis from many sources (e.g.,health professionals, media, schools) and over time the saliency of this information may decrease. Conversely, parents might not encounter descriptive norms all that often, potentially representing a more novel source of information.
  2. In comparison to injunctive data which is often generalized, descriptive data can be personalized by age and sex, and thus parents may resonate more with normative data if they perceive the information to be relevant to their child.

Studies have highlighted mixed results associated with the power of descriptive and injunctive data. For example, in a recent paper by Staunton et al. (2014), authors’ highlighted that participants’ intentions to eat healthily were strongest when either injunctive or descriptive data were presented alone (red); however, notable is that intention to change decreased when descriptive and injunctive data were combined together (blue). [7=strong intention to change].

Stay tuned next week for other factors that may influence intention to change… perceived behavioural control, self-efficacy, and threat perception are just a few to name.

Staunton M, Louis WR, Smith JR, Terry DJ, McDonald RI. (2014). How negative descriptive norms for healthu eating undermine the effects of positive injunctive norms. Journal of Applied Social Psychology, 44(4):319-330.

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