These experiments provide converging evidence of an automatic, direct causal link between food advertising and greater snack consumption, and further contradict industry claims that advertising affects only brand preferences and not overall nutrition (Young, 2003
). Overall, the findings were highly consistent. In both studies, and across diverse populations, food advertising that promoted snacking, fun, happiness and excitement (i.e., the majority of children’s food advertisements) directly contributed to increased food intake. In addition, as previously found by Halford et al. (2004
), similarity between the foods provided and those advertised was not required. Finally, these effects occurred regardless of participants’ initial hunger, and amount consumed after viewing snack advertising was completely dissociated with adult participants’ reported hunger.
The potential health consequences of these naturally-occurring advertising priming effects on overall diet and attempts to control unhealthy eating are far-reaching. Children may be most consistently affected, yet snack advertising also increased adult consumption, especially for men and those attempting to diet. In addition, the effects persisted after the viewing session. Therefore it may not be possible for one to avoid influence simply by not snacking while watching television; television viewing could also lead to increased consumption during a subsequent snack or meal.
One limitation of our findings (as with most laboratory experiments) is that real-world exposure to advertising stimuli occurs in a wide variety of contexts, and we cannot be certain that other situational factors (e.g., viewing with others, viewing at other times of the day, or viewing for other purposes) would not have moderated the advertising effects. To optimize both external and internal validity, however, we imitated natural television-viewing conditions, as closely as possible, within a controlled setting. We feel confident, therefore, that the increased snacking was due to the advertising, and that these effects do occur during real-world viewing.
Although our findings are consistent with a number of potential priming mechanisms, the specific mechanisms through which food advertising increased automatic eating behavior cannot be identified with certainty. As many potential intervening variables did not
moderate the advertising-eating effects, much of the effect probably occurred directly upon perceiving the eating behavior of people in the ads and/or activating concepts associated with consumption (e.g., Dijksterhuis & Bargh, 2001
). A motivational explanation is also quite viable (Bargh, Gollwitzer, Lee-Chai, Barndollar, & Troetschel, 2001
; Shah & Kruglanski, 2002
). Snack advertising may have primed a short-term hedonic, enjoyment goal, whereas nutrition advertising primed a long-term goal of healthy eating, leading to corresponding behaviors. In reality, the power of advertising may be its ability to prime behaviors through multiple mechanisms at the same time.
Another limitation of our findings is that we cannot pinpoint the specific advertising features that affected eating behaviors. To increase the ecological validity of the findings, we utilized actual advertising stimuli. As a result, the stimuli may have conflated the benefits promoted in the ads (i.e., snacking, fun and excitement vs. nutrition) with positive associations toward the types of foods typically promoted in ads with those messages (i.e., nutrient-poor foods vs. “healthier” options). Our findings suggest, however, that the effect of priming product benefits was more powerful than the effect of priming specific types of foods: The snack ads increased consumption of all foods, including the healthier options, and the nutrition message did not increase consumption of the healthier foods (in fact, consumption of all foods was lowest in this condition). Further research is required to confirm that priming snacking versus nutrition benefits, and not other features of the advertisements, including specific types of foods or brands, triggered the effects on consumption behaviors. In addition, the messages used to frame food consumption in advertising are also likely to create powerful effects on consumption, and these could be profitably examined in future research.
Defending against advertising influence
Further understanding of the mechanisms that produced these priming effects is also needed to enable educators and parents to more effectively protect children (and themselves) against unhealthy food advertising influence. Wilson and Brekke (1994)
proposed that defense against unconscious “mental contamination” requires awareness and understanding of how unwanted external influences might affect us, as well as the motivation and ability to defend against influence. As most adults in our study did not recognize the potential influence of food advertising on their eating behaviors, increased awareness will be an important first step. These findings also highlight the need for media literacy programs that go beyond teaching children how to analyze and evaluate advertising messages, and increase the public’s understanding of how advertising may affect them outside of their awareness (Livingstone & Helsper, 2006
Additional studies could also examine contexts that might affect motivation and ability to defend against food advertising priming effects. According to Baumeister and colleagues, self-regulatory resources are limited and can become depleted and unavailable for subsequent self-regulatory tasks (Muraven & Baumeister, 2000
). Food advertising effects could be especially pronounced, therefore, in the evening ‘prime-time’ hours when most adult television viewing occurs, following a day of self-control efforts. Perhaps, under such ego-depletion or cognitive load conditions, snack advertising might also affect female unrestrained eaters. Additional studies could also examine whether advertising that utilizes other consumption messages (e.g., satisfaction or indulgence), would differentially affect motivations to consume.
Another important direction for future research will be to examine the priming effects of other forms of food advertising. Increasingly, food companies are replacing television advertising with more subtle marketing strategies (Chester & Montgomery, 2007
). Future studies could examine whether consumption behaviors modeled during television programming and movies (through product placements) or interactive websites involving food products also prime automatic consumption behaviors. Other priming studies suggest that even exposure to less overt food cues, (e.g., brand logos that appear on signs or websites), could affect food consumption (e.g., Strahan et al., 2002
; Winkielman et al., 2005
In summary, our results demonstrate that television food advertising increases snack consumption and may contribute to the obesity epidemic, and that efforts to reduce unhealthy food advertising to children are urgently needed. In addition, they highlight the need to increase awareness of the potential automatic effects of food advertising on eating behavior. Current industry efforts to self-regulate television food advertising to youth are limited to children 12 years and under (Council of Better Business Bureaus, 2006
), but the present findings suggest that reduced exposure to unhealthy food advertising would be beneficial for all