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Unintended consequences? Food ads automatically prime eating in children and adults

October 2, 2013 0 Comments

girl-watching-tv-w-popcornA really fascinating, and in several ways disturbing study recently crossed my desk. Authored by Jennifer Harris, John Bargh, and Kelly Brownwell, the article is called “Priming Effects of Television Food Advertising on Eating Behavior”. It was published earlier this this year in Health Psychology.  Abstract and online access are available here.

The study shows in undeniable terms that advertising is a powerful real-world prime for both children and adults.  But if the purpose of advertising is to increase favorability toward and/or consumption of the product advertised, then this study also shows an unexpected effect.

The advertising definitely primed eating, but the eating was not directed at the product advertised, or even at the category of the product advertised.  People just ate more of whatever was put in front of them.  So in a very real sense, the advertising failed in two critical ways:  it did not influence behavior in the intended direction (toward the product advertised) and it did influence behavior is a troubling, unintended direction, by stimulating indiscriminate eating in general, unrelated to the product being advertised.

The study design is an excellent example of using unobtrusive measures to capture automatic, nonconscious responses to stimuli.  In a first experiment, about 120 grade school students were shown a kids’ cartoon show.  Half of the children saw snack food ads during the show, the other half saw ads not associated with food.  Children watched alone, not in groups.  While watching, the children were given a bowl of “goldfish” crackers.  The snack was not among the foods advertised.  The dependent variable was the amount of goldfish crackers consumed during the show.

In a second experiment, about 100 adults watched a TV show with advertising breaks.  Some saw consumption-oriented snack food ads, some saw nutrition-oriented food ads, and some saw only non-food ads.  No snacks were offered during viewing, but after the viewing session subjects were invited to a “separate” experiment in which they were interviewed about some unrelated consumer products.  During those interviews, several snacks were provided – from healthy (carrots and celery) to moderately healthy (trail mix and multi-grain tortilla chips) to nutrient-poor (mini chocolate chip cookies and cheesy snack mix).  The dependent variable was the amount and type of food consumed during the interview.

Kids who watched snack ads during the cartoon show consumed 45% more crackers than kids who watched non-food ads.  Adults who watched snack ads during their show consumed significantly more food during their later interviews – both healthy and non-healthy – than adults who watched non-food or nutritionally-oriented ads.

What was going on here?

First, advertising is a prime.  The authors provide a cogent summary of what priming is, and how it works:

In priming studies, relevant mental representations are activated in a subtle, unobtrusive manner in one phase of an experiment, and then, the unconscious, unintended effects of this activation are assessed in a subsequent phase …. Priming research has already demonstrated that a variety of complex social and physical behaviors—such as aggression, loyalty, rudeness, and walking speed—can be activated by relevant external stimuli (i.e., the primes) without the person’s intent to behave that way or awareness of the influence …. The mechanism through which behavior priming operates appears to be an overlap or strong association between representations activated by the perception of a given type of behavior, and those used to enact that type of behavior oneself … – the same mechanism that creates tendencies toward imitation and mimicry in adults … and which serves as a vital support for vicarious learning in young children …. (emphasis added)

They then describe how advertising operates in a similar way:

Advertising for food and beverages communicates potentially powerful food consumption cues, including images of attractive models eating, snacking at nonmeal times, and positive emotions linked to food consumption …. We propose that the messages presented in TV food advertising similarly have the power to act as real-world primes and lead to corresponding eating behaviors. Given the types of foods and consumption benefits typically promoted in food advertising, what is primed is usually snacking on unhealthy foods and beverages ….

Second, the priming effect was exactly what would be expected from the literature.  The ad-as-prime activated an implicit motivational goal – to eat – and that goal was pursued automatically, in one case immediately and in the other case with a delay.  As soon as a path to goal satisfaction was made available (the presence of snacks), goal pursuit was initiated.  All without any conscious awareness of the processes at work.

Third, whatever conscious, persuasive messages these ads were meant to convey, they apparently played no discernible role in the behaviors observed.  Advertising, as we saw in our post on Robert Heath, is supposed to present a persuasive message that is later recalled in a buying situation to facilitate a purchase of the advertised product.  But here we see the ad is being processed much more implicitly and emotionally than explicitly and rationally.  Advertisers should obviously be concerned that their ads are contributing to automatic and inadvertent eating in children and adults, but they should also be concerned that their ads are not achieving their real purpose, building a brand or facilitating consumption intent.

What was especially interesting from the point of view of TV advertising “theory” was the fact that the priming was indiscriminate.  Watching low-nutrition snack ads did not just stimulate low-nutrition snacking, it stimulated more healthy snacking as well.  If the advertising was meant to target the consumption of the product advertised, it failed in this goal:

We also demonstrated that the influence of the snack ads continued after exposure (such that they carried over to the subsequent “second experiment”), and that participants were not aware that they were affected. In addition, as in the children’s experiments, advertising effects could not be accounted for by participants’ hunger, and the effects transferred to products that were not advertised during the TV segments viewed by the participants. Snack advertising also increased consumption of healthier snack options, including vegetables, further supporting the automatic nature of the advertising effects. (emphasis added)

The authors note that the study raises many intriguing questions that can be addressed in later research.  In particular, what are the specific mechanisms by which the priming effect is obtained?  They discuss two possible mechanisms, and acknowledge that they both may be operating in advertising:

  1. A mimicry effect, in which eating behavior was instigated “directly upon perceiving the eating behavior of people in the ads and/or activating concepts associated with consumption.”
  2. An implicit motivational effect, in which snack food advertising “may have primed a short-term hedonic enjoyment goal, whereas nutrition advertising primed a long-term goal of healthy eating.”

Understanding the underlying mechanisms at work is of course essential to fixing both problems revealed by this study.  First, that the advertising is having a negative, unintended effect, and second, that it is not having its intended effect.

For example, advertising that utilized a different consumption message – perhaps something as simple as showing people being sated and satisfied after eating, rather than hungry and motivated before eating – could produce different behavioral priming effects, without damaging the intentional goals of the ad, such as increasing brand favorability or purchase intent.

If food advertisers want to do the right thing, for themselves and their consumers, they should think seriously about incorporating neuroscience and cognitive psychology insights such as these into their thinking about when, where and how they advertise their products.

Research methods that directly measure  nonconscious influences and effects are the only way to reliably tackle these critical questions.

Harris JL, Bargh JA, & Brownell KD (2009). Priming effects of television food advertising on eating behavior. Health psychology : official journal of the Division of Health Psychology, American Psychological Association, 28 (4), 404-13 PMID: 19594263

Originally published in my earlier blog, October 29, 2009.

About the Author:

Steve is a pioneer in the field of neuromarketing. He founded one of the first neuromarketing research firms in 2006 and published the first comprehensive overview of the field, Neuromarketing for Dummies, in 2013. He established Intuitive Consumer Insights in 2012 to help clients, vendors, and industry associations navigate the opportunities and challenges neuromarketing presents to the marketing and market research communities.

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