Nutritious and delicious: The effect of informational social norms and
affective appeals in public health campaigns on intended food choice
Megan Nicole Harris Student Number: 10426353
Master’s Thesis University of Amsterdam Graduate School of Communication Master’s programme Communication Science
Gert-Jan de Bruijn June 27, 2014
Abstract
Decisions regarding eating behavior are something that we experience on a regular basis, decisions which are often influenced by several different factors such as social influence, or simply because they make us feel good. An online study examined whether the combination of two types of informational social norms (descriptive and injunctive) and two types of affective appeals (positive and negative) had a greater influence on an individuals intentions to eat fruits and vegetables. While this study had insignificant results, descriptive norms with or without an affect appeal were found to elicit greater behavioral intentions than injunctive norms did. The addition of an affective appeal proved to be more successful when a positive affective appeal was used. These results can be explained by the amount of processing they elicit, which is known to be minimal processing. Eating behavior has been known to be a sensitive topic for many as obesity has evolved into a widespread epidemic.
Introduction
We are faced with decisions about what, where, and how much to eat on a daily basis. While there are several factors known to effect such decisions, such as economic factors, social influence has been consistently found to have an affect on intended food choice, whether they are healthy or unhealthy choices. With a drastic increase in availability and consumption of energy dense foods, obesity rates have skyrocketed in many countries around the world, resulting in an obesity epidemic. Therefore, the need for effective public health campaigns are at an all time high. Impressive health gains can be achieved with even small changes in behavior, therefore this study seeks to examine an effective strategy by testing the
combination of informational social norm messages with an affective appeal, as pubic health campaigns can benefit from such campaign strategies aimed towards decreasing obesity rates around the world.
It is said that eating behavior is often transmitted socially, meaning that an individual’s eating behavior often reflects the eating behavior that individual has viewed others doing. Social norms have been said to have a powerful influence on several health behavior’s, more specifically social behaviors. Research suggests that individuals’ use other’s behavior as a guide for determining how they should behave, even when not in the presence of others. The former is best known as informational social influence, which is best understood as, if
everyone else is doing it, then it must be good (Robinson, Thomas, Aveyard, & Higgs, 2013). Informational social influence is commonly communicated through explicit written
information or cues. Often health campaigns communicate a descriptive norm, as they are known to require minimal processing and rely on heuristic cues, which have been found to influence the consumption of unhealthy food choices. Therefore, health campaigns need to
adapt a new strategy in which communicating an injunctive norm, which requires more processing, could encourage more healthy food choices.
There is a plentiful amount of scientific evidence indicating that a diet rich in fruits and vegetables significantly lessens the risk of developing several chronic diseases, such as heart disease, stroke, diabetes, and various forms of cancer (Herbert, Butler, Kennedy, and Lobb, 2010; Joshipura et al., 2001), however worldwide insufficient consumption of fruits and vegetables still remains at alarming rates (World Health Organization, 2003). There is clear evidence showing that high-energy foods, such as processed foods high in fats and sugars promote obesity compared to low-energy foods like fruits and vegetables (World Health Organization, 2003). It is recommended for adults that consuming 400 grams or 5 pieces per day of a variety of fruits and vegetables will minimize the risk of developing the previously mentioned chronic diseases (World Health Organization, 2003). A study by Krebs-Smith et al., (1995) found that having some knowledge of the recommended daily portion size of fruits and vegetables and the health benefits of such food is a key factor in determining food choice when it comes to fruits and vegetables.
Social norms in regard to eating behavior have been found to inform individuals eating behavior in regards to food intake and food choice. In most societies there is a general consensus on the societal injunctive norm regarding food choices, which is people should eat healthy foods, such as fruits and vegetables, and should limit the amount of unhealthy foods in their diet. Though the norm regarding food choice is quite clear, the consumption of unhealthy foods remains high. Research has shown that this could be a result of the power of influence social norms have on an individuals eating behavior (Robinson et al., 2013). Therefore, the research question this study will attempt to answer is if normative influence is
powerful enough on it’s own to influence behavioral intentions or if a combination approach which makes use of emotional appeals through affect proves to elicit a greater impact on behavioral intentions, specifically fruit and vegetable consumption.
Theoretical Framework
Normative influence
Informational social influence is best understood as when individuals use the behavior of those around them to decide whether they will do something or not, essentially following the idea of “if they’re doing it, it must be good” (Deutsche & Gerard, 1955). Informational eating norms are information regarding people’s eating habits communicated through either explicit written information, or cues about other people’s typical eating behavior (Roth, Herman, Pliner, 2001). A number of investigations into how people make decisions regarding their eating behavior suggest that social influence plays an important role in peoples eating behavior (Burger et al., 2010). It has been found that when deciding on how much to eat and what to eat, people often rely on social norms (Burger et al., 2010). Though there are few studies that have investigated whether informational eating norms influenced intended
choice, significant results have been found, indicating that when presented with informational food choice norms, their intended food choice and type of food intake is positively effected. Therefore, eating norms can guide behavior through informational social influence processes. This can be understood through the Theory of Planned behavior, which highlights the
importance of social acceptability of behaviors and emphasizes how approval from those around us, within our social network, can impact behavioral intentions (Ajzen, 2012).
There have been mixed findings for normative influences on eating behavior. Informational food choice norms have been found in several studies to have a consistent effect on food
choice (Berger & Heath, 2008; Croker et al., 2009; Burger et al., 2010). While injunctive norms are essentially communicating the same behavior as descriptive norms, injunctive norms refer more to norms about social approval, essentially representing societal standards for what is appropriate behavior (Robinson et al., 2013). There have been several studies that have examined social approval on adherence to a descriptive norm for eating behavior, concluding that what others eat had a greater influence on food choice rather than what others approve of eating did (Robinson et al., 2013).
The processing of norms
While descriptive norms are found to be processed more peripherally and typically rely on heuristics, injunctive norms have been found to illicit a more careful and thoughtful evaluation of the message (Frewer et al., 1997). This can be understood through the
Elaboration Likelihood Model (ELM), which posits that there are two routes of processing that can occur, the central route, which requires extensive cognitive evaluation of a
persuasive message, and the peripheral route, which requires minimal processing of a persuasive message (Henningsen et al., 2003). Injunctive norms communicate what others approve of and could be seen as more informational norms, whereas descriptive are about what others do, which could be seen as more normative. Several studies have found that when presented with an informational influence, an individual becomes highly involved with the message and therefore processes it more extensively in terms of whether adopting the behavior would benefit them (Henningsen et al., 2003; Dennis, 1996; Kaplan, 1989; Mongeau, Hale, & Smith, 1993). Petty, Gleicher, and Baker (1991) propose that when the elaboration of a message is increased, the quality of the issue-relevant arguments presented have a greater impact on attitudes, which in turn has been found to impact intentions to adhere to a behavior. Therefore, this study proposes that communicating an injunctive norm
about healthy food choices will require greater cognitive processing of that norm, causing an individual to think more in depth about the food choice they make, leading to a greater increase in healthy food choices than communicating a descriptive norm would.
When it comes to food choices, individuals have the tendency to use impulsive decision-making strategies, such as relying on heuristics (Ridder et al., 2014). Heuristics are believed to serve as mental shortcuts for decision-making requiring minimal cognitive processing and low involvement, providing an automatic and simple decision. One of the main principles underlying external influence heuristics is social proof, which is the tendency to adopt the option preferred by others (Ridder et al., 2014). Descriptive norms are a form of social proof heuristics because they communicate what others are doing and can therefore be translated into a tactic for making the norm salient (Ridder et al, 2014). Descriptive norms are believed to be processed heuristically because individuals can look to what others are doing to
determine what they should be doing, rather than having to cognitively process what should be done. This tactic is often used within the food industry, which often promotes unhealthy food choices through means of a social proof heuristic (i.e., limited edition). Therefore, this study proposes that a message containing a descriptive norm may serve as a heuristic and cause an individual to be low involved and have minimal processing about their food choice, leading to a greater chance of unhealthy food choices.
H1: Injunctive norm messages will be a greater predictor of intentions to eat fruits and vegetables than descriptive norm messages will be on an individual’s intention to eat fruits and vegetables.
There is growing research that accentuates the importance of affective attitudes as a key correlate of a variety of health behaviors, such as physical exercise (Conner et al., 2011). However, there is still a minimal amount of research investigating whether messages, which target affective attitudes, can be used to successfully change behavior. Health promotion messages often focus more on targeting cognitive attitudes even though there is strong evidence showing larger effects for affective attitudes than for cognitive in predicting
exercise behavior, which is a health behavior that is socially known as being good for you but does not always get done (Blanchard et al., 2008; Conner et al., 2011; Courneya, Conner, & Rhodes, 2006; Eves, Hoppe, & McLauren, 2003; Lowes, Eves, & Carroll, 2002; Rhodes & Courneya, 2003).
Affect is a general term for a range of positive and/or negative feelings and emotions, and is often used by theorists to refer to messages and responses to messages that include a
subjective feeling component (Monahan, 1995). Affect can be conceived in two ways, as residing within a person, which is something that can occur within the individual in response to a campaign, and as the emotional valence of a message (Monahan, 1995).
The use of affect in health messages has been found to play an important role in guiding judgments about a behavior (Lawton et al., 2009). A study by Zajonc (1980) found that the immediate, automatic feelings/emotions experienced when exposed to an affective appeal guide an individuals evaluation of that behavior, ultimately influenced the decision making process. Affective messages, both positive and negative, in health messages have been found to elicit a certain mood in an individual, which in turn impacts their decision making process (Lawton et al., 2009). Therefore, when it comes to physical exercise or eating behavior, an individual will exert less energy processing whether eating a piece of fruit or vegetable is
good for them, but rather focus on whether eating that piece of fruit or vegetable makes them happy or makes them feel good. According to Bublitz and colleagues (2013), promoting a healthy relationship with food must go beyond the consideration of cognitive information, as often consumers base food choice decisions on what feels right based on emotional
information, rather then thinking it through based on cognitive information.
The amount of effort an individual expends on processing a message is critical because it can affect an individual’s attitude, their intentions to comply with the message, and their recall of the message (Monahan, 1995). Similar to the processing of norms, the depth of processing of affective health messages can differ depending on the valence of the affect (positive vs. negative). Affective appeals that use negative messages typically promote more elaborate, detailed, and analytical processing strategies, which result in more in depth processing (Monahan, 1995). This is because negative affect informs the audience that the current situation is problematic and causes audiences to focus more on the bad feelings elicited by aspects of the situation (Monahan, 1995). Affective appeals that use positive messages often require the use of less elaborate or more heuristic strategies for processing (Monahan, 1995). Positive affect is believed to inform the audience that the current situation is nonthreatening by fostering good feelings and therefore, does not require extensive attention or processing (Monahan, 1995).
H2: Positive affective messages with a descriptive norm will be a greater predictor of intentions to eat fruits and vegetables than negative affective messages with an injunctive norm will be on an individual’s intention to eat fruits and vegetables.
While there is limited research surrounding the interaction between social norms and affective appeals on eating behavior, separately both have been found to have a direct influence on several health issues, such as physical activity, smoking, and eating behavior (Conner et al., 2011; Lawton et al., 2009; Bublitz et al., 2013). Research has suggested that emotional components of decision-making can be influenced by social influence and that social influence has an emotional component in the sense that those around them socially influence individuals especially when it comes to eating behavior (Bublitz et al., 2013). According to Bublitz and colleagues (2013), social influence and emotions impact food choices because individuals want to be accepted by others and therefore will alter their food choices to reflect those around them to avoid feelings of guilt or shame, and when they make the same food choices as those around them, they are more likely to feel positive emotions that do not make them feel rejected. Therefore, this study proposes that a health message that combines social influence in terms of informational social norms with affective appeals will have a greater influence on an individual’s intention to make a healthy fruit or vegetable choice (i.e. eat a piece of fruit versus a bag of chips).
H3a: An injunctive norm message combined with a negative affective appeal will have a positive influence on an individual’s intention to eat fruits and vegetables compared to an injunctive norm message only.
H3b: A descriptive norm message combined with a positive affective appeal will have a positive influence on an individual’s intention to eat fruits and vegetables compared to a descriptive norm message only.
Methodology Design
The design of this study was a 2 (Informational social norm: descriptive vs. injunctive) x 2 (affect: positive vs. negative) between-subjects experimental design. Participants were randomly exposed to four different types of advertisements: descriptive informational norms, injunctive informational norms, a combination of descriptive informational norms and
positive affect, and a combination of injunctive informational norms and negative affect.
Sample
The only criterion for participation in this study was that individuals were over the age of 18 years old. Overall, a total of 189 adults participated in this study (female = 73%). The age of participants ranged from 18 to 74 years old (M = 38.88, SD = 12.14). The sample was an international sample, with participants from a total of 17 different countries (USA = 49.7%). Majority of the sample is employed full time (n = 90). Also, majority of the sample is married (n = 99). The sample was highly educated with the majority holding a bachelors degree or higher (n = 147). To improve the representativeness of the sample, this study aimed to recruit both male and female participants of varying ages. Participants were recruited through various online forums, Facebook, and email. This study made use of a snowball technique in order to gather participants. Of the whole sample, only 38.1% of participants indicated that on average they consume the recommended 5 pieces of fruits and vegetables per day.
Procedure
An online study was designed to manipulate each of our independent/dependent variables through separate advertisements. As this study did not take place in a controlled laboratory setting, the potential threats to the internal validity of the design were taken into
which their fruit and vegetable consumption generally takes place. Therefore, the internal validity was compromised because of the lack of close control that could have been possible in a laboratory setting, however, this study believes that the external validity was
strengthened because it allowed participants to complete the study in a location convenient for them and closer to the environment in which they usually consume fruits and vegetables.
The online study first started with an informed consent form, in which participants were asked to give their consent for participation in this study. This online study aimed to keep participants informed throughout the entire process in hopes of maintaining the participants attention, therefore, descriptions were provided prior to each section. Following the consent and explanation, participants were asked a series of demographic questions such as age, country of origin, marital status, education level, etc. as well as questions regarding their current fruits and vegetables intake. The online study continued by presenting participants with one of the four conditions at random, which were presented through online
advertisements. Participants were asked to examine the advertisements very closely before proceeding to the next section, where participants were asked to evaluate the advertisement they had just viewed. The remaining sections consisted of several questions regarding participants attitudes toward eating fruits and vegetables, the type of affect
(positive/negative) they feel they would experience when eating fruits and vegetables on a daily basis, and questions regarding their consumption of fruits and vegetables being socially influenced by asking questions pertaining to both descriptive and injunctive norms. The online study concluded with a series of questions regarding participants intended fruit and vegetable consumption in the future, which was used to later determine their behavioral intentions.
Design stimuli
Four different advertisements were created for this study to represent the four conditions. The first advertisement represented the first condition, which was a descriptive informational social norm only. This condition presented participants with a descriptive norm message which states that a certain percentage of adults between the age of 20 and 60 eat at least 5 pieces of fruits and vegetables per day. The second advertisement, representing the second condition, was an injunctive informational social norm only, which presented participants with an injunctive norm message that states that most adults between the age of 20 and 60 should eat at least 5 pieces of fruits and vegetables per day. The third advertisement, representing the third condition, was a combination of a descriptive informational social norm and positive affect and presented participants with a descriptive norm message which states that a certain percentage of adults between the age of 20 and 60 eat at least 5 pieces of fruits and vegetables per day, as well as a positive affect message which states that you will feel good by eating fruits and vegetables. The fourth and final advertisement, representing the fourth condition, was also a combination of an injunctive informational social norm and negative affect. This advertisement presented participants with an injunctive norm message, which says that most adults between the age of 20 and 60 should eat at least 5 pieces of fruits and vegetables per day, and a negative affect message stating that you will feel miserable if you don’t eat your daily serving. This advertisement depicted an individual with a frown, where as the third advertisement depicted an individual with a smile. Participants were randomly assigned to one of these four conditions.
Participants were asked to answer a series of questions regarding demographics such as age, gender, country of origin, marital status, education level, income level, and number of people in their household.
Descriptive norm
Descriptive normative influence was measured using a 5-point Likert scale ranging from 1 = strongly disagree to 5 = strongly agree. Four items were used to represent descriptive
normative influence (i.e. I eat fruits and vegetables because people close to me (friends, family, colleagues) eat them. The additional three items can be viewed in Appendix B.
Injunctive norm
Injunctive normative influence was measured using a 5-point Likert scale ranging from 1 = strongly disagree to 5 = strongly agree. Four items were used to represent injunctive
normative influence such as, I eat fruits and vegetables because I am supposed to eat it. The additional items can be found in Appendix B.
Affect
Positive and negative affect was measured using a 5-point Likert scale ranging from 1 = strongly disagree to 5 = strongly agree for four of the items used to measure positive and negative affect. The four items representing positive and negative affect consisted of ‘eating fruits and vegetables makes me feel good’ or ‘eating fruits and vegetables makes me feel miserable’. Four additional items were used to measure positive and negative affect, such as ‘eating 5 pieces of fruits and vegetables per day would be …’. These four items were
measured using a 5-point Likert scale ranging from 1 = completely unsatisfying to 5 = completely satisfying.
Behavioral intention
Behavioral intention was conceptualized as participants’ intention to consume 5 pieces of fruits and vegetables in the near future and was measured through three different items.
Participants indicated their level of agreement, using a 5-point Likert scale ranging from 1 = strongly disagree to 5 = strongly agree, to one statement, which was ‘I can see myself eating at least 5 pieces of fruits and vegetables per day on a regular basis’. The additional two items asked participants to indicate how many pieces of fruits and vegetables they planned to eat in the next 24 hours and in the next four weeks. Scores for each of the three items were
combined to determine participants overall behavioral intention score. Therefore, the higher the score, the higher a participants intention to consume fruits and vegetables is.
Attitudes
Attitude towards eating fruits and vegetables was measured using a 5-point Likert scale ranging from 1 = strongly disagree to 5 = strongly agree. Attitudes were represented by six items, and consisted of statements such as, ‘eating fruits and vegetables is important to stay in shape’. The additional items can be found in Appendix B.
Results
Preliminary analyses
Female participants (M = 3.13, SD = 0.84), compared with male participants (M = 3.07, SD = .85), expressed greater intentions to eat 5 pieces of fruits and vegetables per day. However, this difference was not significant t(187) = 0.42, p > 0.05.
Principle component analysis and reliability
A principle component analysis (PCA) was conducted in order to assess whether the three items used to measure behavioral intentions (intentions to eat 5 fruits and vegetables per day) are able to load onto one factor, essentially representing the same concept. The results first show through the Kaiser-Meyer-Olkin measure that the sample size of this study is sufficient enough for a principle component analysis (KMO = 0.66). In addition, the principle
component analysis shows that all three items indeed load on to one factor (EV = 1.91, R2 = 0.63), therefore confirming that all three items effectively measure the same concept of behavioral intention. Before a new variable representing behavioral intention can be
constructed, it is necessary to conduct a reliability test. The results of the reliability test show that the scale for behavioral intention is dependable (α = 0.71), and that no items should be excluded.
An additional PCA was conducted in order to assess whether the five items used to measure
descriptive normative influence are able to load onto one factor to represent the same
concept. The first results show that the sample size is adequate for a PCA (KMO = 0.86). The PCA results show that all five items load onto one factor (EV = 3.40, R2 = 0.68). The results of the reliability test show that the scale for descriptive normative influence is dependable (a = 0.88), and that no items need to be excluded. A PCA was also conducted to assess the five items used to measure injunctive normative influence to determine if they represent the same concept. The first results show that the sample size is adequate for a PCA (KMO = 0.78). The PCA results show that all five items load onto one factor (EV = 2.49, R2 = 0.50). The results of the reliability test show that the scale for injunctive normative influence is dependable (a = 0.84), and that no items should be excluded.
A PCA was also conducted in order to assess whether the six items used to measure positive
affect are able to load onto one factor. The first results show that the sample size is sufficient
enough for a PCA (KMO = 0.85). The PCA results show that all six items load onto one factor (EV = 4.14, R2 = 0.68). The results of the reliability test show that the scale for positive affect is dependable (a = 0.91). A final PCA was conducted in order to assess whether the six items used to measure negative affect are able to load onto one factor. The results first show
that the sample size is sufficient for a PCA (KMO = 0.81). The results of the PCA show that all six items load onto one factor (EV = 3.67, R2 = 0.61). The results of the reliability test show that the scale for negative affect is dependable (a = 0.70). Therefore, new variables were computed for behavioral intention, descriptive normative influence, injunctive normative influence, positive affect, and negative affect.
Manipulation check
In order to examine whether an informational social norm combined with an affect message has an effect on intended fruit and vegetable consumption, a manipulation check was used in which participants were exposed to one of four conditions: either the descriptive norm only condition, the injunctive norm only condition, descriptive norm/positive affect condition, or the injunctive norm/negative affect condition. Therefore, an analysis of variance (ANOVA) was conducted to see how scores for behavioral intention differed between the four
conditions. As you can see in Table 2, the scores per condition differed slightly, however, this difference is not significant (F (3, 185) = 0.79, p > 0.05.
Hypotheses testing
This study first hypothesized that injunctive norm messages will be a greater predictor of intentions to eat fruits and vegetables than descriptive norm messages will be on an
individual’s intention to eat fruits and vegetables. H1 was investigated using an independent samples t-test, in which participants’ behavioral intention when exposed to a descriptive norm message was compared with participants’ behavioral intention when exposed to an injunctive norm message. On average, participants had a slightly greater intention to eat fruits and vegetables when exposed to a descriptive norm message (M = 3.19, SE = 0.09), than to an injunctive norm message (M = 3.06, SE = 0.07). Lavene’s test was statistically significant
(F = 4.41, p < 0.05), indicating that equal variances cannot be assumed. However, the results of the t-test were not significant t(182) = -0.99, p > 0.05. Also, the effect size was very small (r = 0.07). Therefore, no main effects were found. H1 is not supported and must be rejected.
The second hypothesis proposed by this study was that positive affective appeals with a descriptive norm will be a greater predictor of intentions to eat fruits and vegetables than negative affective appeals with an injunctive norm will be on an individual’s intention to eat fruits and vegetables. To test this, an independent samples t-test was conducted, in which participants’ behavioral intentions when exposed to a positive affective appeal combined with a descriptive norm message were compared to participants’ behavioral intentions when exposed to a negative affective appeal combined with an injunctive norm message. On average, participants had a greater intention to eat fruits and vegetables when exposed to a positive affective message combined with a descriptive norm (M = 3.18, SE = 0.13) than when exposed to a negative affective message combined with an injunctive norm (M = 2.95,
SE = 0.09). Lavene’s test was statistically significant (F = 6.98, p < 0.05), indicating that
equal variances are not assumed. The results of the t-test were not significant t(84) = 1.32, p > 0.05. The effect size was very small (r = 0.01). Therefore, H2 is not supported and must be rejected.
The third hypothesis was broken down into two parts. The first part of H3 proposed that an injunctive norm message combined with a negative affective appeal would have a positive influence on an individual’s intention to eat fruit compared to an injunctive norm message only. The differences in behavioral intention scores per condition can be seen in Table 1. To test this, an independent samples t-test was conducted to compare participants’ behavioral intention for the two conditions. Participants had a greater behavioral intention when exposed
to an injunctive norm message only (M = 3.16, SE = 0.12) compared to participants’ behavioral intention when exposed to a combination of an injunctive norm message and a negative affective appeal (M = 2.95, SE = 0.09). Lavene’s test was not significant (F = 3.47,
p > 0.05), indicating equal variances are assumed. The results of the t-test were not
significant t(92) = -1.32, p > 0.05. Again, the effect size was very small (r = 0.01). As a result, H3a is not supported and must be rejected.
Table 1. Behavioral intention scores per condition
The second part of H3 proposed that descriptive norms combined with a positive affective appeal will have a positive influence on an individual’s intention to eat fruit compared to a descriptive norm only. In order to test this, an independent samples t-test was again
conducted. On average, there was no difference between participants’ behavioral intentions when exposed to a descriptive norm message combined with a positive affective appeal (M = 3.18, SE =0.13) and when exposed to a descriptive norm message only (M = 3.18, SE = 0.12). Lavene’s test was not significant (F = 0.18, p > 0.05), indicating equal variances are
assumed. The results of the t-test were not significant t(93) = 0.02, p > 0.05. The effect size was again very small (r = 0.04). Therefore, H3b is also not supported and must be rejected.
Behavioral Intention Score
Conditions
Condition1 Condition 2 Condition 3 Condition 4 Total 1 2 3 4 5 2 1 2 1 17 14 17 19 21 20 16 24 7 11 9 3 1 0 3 1 6 67 81 30 5 Total 48 46 47 48 189
Lastly, to test the main effects and interaction effect of the combination of social norm messages with affective appeals, a two-factor analysis of variance (ANOVA) was used to assess the influence of exposure to a combination message in conjunctive with behavioral intention. The results show that there was no main effect of message type (F (3, 185) = 0.79,
p = 0.496) on behavioral intention. The mean scores for each condition in relation to
behavioral intention can be seen in Table 2. Next to main effects, the results show that there was no significant interaction effect of affective appeals on the effects of norm type on behavioral intention (F (3, 185) = 0.79, p = 0.496, η2 = 0.00). Therefore indicating that the type of combination appeal does not differ for behavioral intention.
Table 2. Mean scores per condition
Condition
Mean Score
Standard
deviation N 1. Descriptive norm message
3.18 0.89 48
2. Injunctive norm message
3.16 0.83 46 3. Descriptive norm message +
positive affective appeal
3.18 0.95 47
4. Injunctive norm message + negative affective appeal
2.95 0.68 48
Discussion
The aim of this study was to investigate the effect of informational social norm messages, descriptive compared to injunctive, on an individual’s intention to consume the
recommended daily amount of fruits and vegetables, and whether adding an affective appeal, positive or negative, to create a combination message elicits greater behavioral intentions. This study is unique in the sense that it is the first to examine the effects of combining informational social norms with affective appeals to influence eating behavior.
While several studies have found that what others are eating (descriptive norm) is a greater predictor of eating behavior than what others approve of eating (injunctive norm), this study examined both types of norms in regards to behavioral intention and did not find a significant difference between descriptive and injunctive norms. With similar findings for both types of norms, it could be concluded that individuals are easily socially influenced regardless of the type of norm they are presented with.
While the results of this study were insignificant, it should be noted that out of the four conditions, the condition which exposed participants to a descriptive norm message combined with a positive affective appeal showed to have the highest behavioral intention scores. The results of this study can be explained through the Elaboration Likelihood Model (ELM). The model states there are two routes of processing that can occur, the central route, which requires extensive cognitive evaluation of a persuasive message, and the peripheral route, which requires minimal processing of a persuasive message (Henningsen et al., 2003). As descriptive norms are believed to require minimal processing, as they often serve as heuristic cues when deciding what to do, this study aimed to see if an injunctive norm could achieve the same results as past studies have found with descriptive norms by encouraging more in depth processing. However, this study can attest to past findings that descriptive norms are more successful in changing behavior, showing that when it comes to certain health behaviors, people do not want to think in depth about such decisions, they prefer to not have to exert a lot of energy when deciding what to eat and being presented with what others are already doing promotes the idea that if others are doing it and it is good for them then it must be food for me (Henningsen et al., 2003; Dennis, 1996; Kaplan, 1989; Mongeau, Hale, & Smith, 1993).
The same can be concluded for affective appeals, as Monahan (1995) states, positive affective appeals typically require less elaboration when it comes to processing. Positive affective appeals have been found to enhance the use of heuristic strategies for processing, and simply tell the individual that what they see is nonthreatening and will in fact make them feel good (Monahan, 1995). This study found greater intentions to consume fruits and
vegetables when participants were presented with the positive affective appeal than when presented with a negative appeal. This could be because negative affective appeals require more extensive processing and tell the individual that what they are doing now is not good. Therefore, rather than processing why their behavior is threatening to their health, they instead focus on something that will make them feel good because individuals often try to avoid situations that will make them feel bad (Monahan, 1995).
Implications
Though this study did not find significant results, it does provide some implications for public health campaigns. A moderate difference in mean scores was found between the descriptive norm and positive affect condition, and the injunctive norm and negative affect condition. This study gives some indication that when it comes to eating behavior,
specifically food choice, individuals prefer to exert as little energy as possible in their
decision-making, and provides support for the Theory of Planned behavior, which highlights the importance of social acceptability of behaviors and emphasizes how approval from those around us, within our social network, can impact behavioral intentions (Ajzen, 2012). Even though the results are not significant, both types of informational social norms tested in this study were found to have a positive impact on participants’ food choice intentions, showing that social influence is extremely prevalent in eating behavior, as has been found with other similar health behaviors, such as physical exercise.
The difference in behavioral intentions for the descriptive norm and positive affect condition, and the injunctive norm and negative affect can also be explained by the Elaboration
Likelihood Model, which explains the differences in processing that can occur (Monahan, 1995). Descriptive norms and positive affect are both known to serve as heuristic cues when it comes to decision-making, and require less in-depth processing from the individual. Therefore, the behavioral intention scores for this condition could be higher because this condition did not require participants to spend as much time deciding if adopting such a behavior will be good for them. The scores for the injunctive norm and negative affect
condition were lower, possibly because it required participants to evaluate their current eating behavior more in depth. The findings of this study can attest to the findings of the study by Zajonc (1980), which found that the immediate, automatic feelings/emotions experienced when exposed to an affective appeal guide an individuals evaluation of that behavior, ultimately influencing the decision making process. Therefore, the findings of the injunctive norm and negative affect condition could indicate that participants felt an immediate bad feeling when exposed to the negative appeal, which stated that you will feel miserable if you do not eat your daily serving and in turn did not spend as much time processing the injunctive norm message. Therefore, this study recommends that health campaigns should continue to make use of such descriptive norm strategies but should also consider the addition of positive affect, as the combination was found to produce slightly greater behavioral intentions than a descriptive norm message only.
Limitations
This study has several limitations. First, the results show that the manipulation check was not successful. This could be because the manipulation check was not strong enough and did not exhibit a realistic health campaign situation. The design stimuli used in this study were
created by the researcher and perhaps did not resemble the appearance of a real-life health campaign accurately enough to produce significant results. In addition, the informational social norm messages and affective appeals used in the design stimuli were possibly not strong enough to elicit a feeling of social influence or positive or negative emotion. Therefore, future research would benefit from creating visual stimuli that more closely resemble real life health campaigns and present the messages and affect appeals in a more realistic way. The second limitation to this study is that the internal validity of this study was compromised because of an absence of tighter controls that would have been achievable in a laboratory setting. This allowed participants to complete the study in a location that was convenient to them, therefore allowing them to give self-reported answers that may not be an accurate reflection of their fruits and vegetables intake prior to exposure, or whether they were in fact socially influenced. Future research should focus on creating stronger
manipulations, as a difference between behavioral intention scores was found for the advertisement which combined a descriptive norm message with a positive affective appeal compared to the advertisement which combined an injunctive norm message with a negative appeal. It should be noted however that past research, which is focused on informational social norms have found different norms to be more successful with different health behaviors. For example, several anti-alcohol campaigns have been found to have more success when a descriptive norm approach is used, whereas several anti-smoking campaigns have been found to be more successful when an injunctive norm approach is used (Rimal et al., 2005). As eating behavior has been found to be heavily socially influenced, it is not surprising that both the descriptive norm, and the injunctive norm were found to positively influence behavioral intentions.
While this study did not provide significant results, this study can provide some insight into developing successful health campaigns aimed at targeting obesity levels around the world. The findings of this study attest to the prevalence that social influence has within this health behavior, and can offer some insight into further developing health campaigns. The addition of a positive affective appeal can be used to promote the good feelings or emotions that can be experienced when eating healthy simply by telling the individual to eat fruits and
vegetables because it tastes good, not because it is what has to be done to be healthy. A positive affective appeal perhaps shed some light on the idea that eating fruits and vegetables does not have to be a chore but rather an enjoyable experience. This study is meant to be a step in that direction.
References
Ajzen, I. (2012). Martin Fishbein's Legacy: The Reasoned Action Approach. The Annals of
the American Academy of Political and Social Science, 640, 11-27.
Berger, J., & Rand, L. (2008). Shifting Signals to Help Health: Using Identity Signaling to Reduce Risky Health Behaviors. Journal of Consumer Research, 35(3), 509-518. Berger, J., & Heath, C. (2008). Who Drives Divergence? Identity Signaling, Outgroup
Dissimilarity, and the Abandonment of Cultural Tastes. Journal of Personality and
Social Psychology, 95(3), 593-607.
Blanchard, C., Fisher, J., Sparling, P., Nehl, E., Rhodes, R., Courneya, K., et al. (2008). Ethnicity and the theory of planned behavior in an exercise context: A mediation and moderation perspective in college students. Psychology of Sport and Exercise, 9, 527-545.
Burger, J. M., Bell, H., Harvey, K., Johnson, J., Stewart, C., Dorian, K., et al. (2010). Nutritious or delicious? The effect of descriptive norm information on food choice.
Journal of Social and Clinical Psychology, 29(2), 228-242.
Conner, M., Rhodes, R. E., Morris, B., McEachan, R., & Lawton, R. (2011). Changing exercise through targeting affective or cognitive attitudes. Pyschology & Health,
26(2), 133-149.
Croker, H., Whitaker, K., Cooke, L., & Wardle, J. (2009). Do social norms affect intended food choice?. Preventive Medicine, 49, 190-193.
Dennis, A. (1996). Information exchange and use in small group decision making. Small
Group Research, 27, 532-550.
Deutsch, M., & Gerard, H. B. (1995). A study of normative and informational social influences upon individual judgment. The Journal of Abnormal and Social
Fabrigar, L. R., & Petty, R. E. (1999). The Role of the Affective and Cognitive Bases of Attitudes in Susceptibility to Affectively and Cognitively Based Persuasion.
Personality and Social Psychology Bulletin, 25, 363 - 381.
Frewer, L. J., Howard, C., Hedderley, D., & Shepherd, R. (1997). The Elaboration
Likelihood Model and Communication About Food Risks. Risk Analysis, 17(6), 759-770.
Henningsen, M. L., Henningsen, D. D., Cruz, M. G., & Morrill, J. (2003). Social influence in groups: A comparative application of relational framing theory and the elaboration likelihood model of persuasion. Communication Monographs, 70(3), 175-197. Joshipura, K., Hu, F., Willett, W., Manson, J., Stampfer, M., Rimm, E., et al. (2001). The
effect of fruit and vegetables on risk for coronary heart disease. Annals of Internal
Medicine, 134, 1106-1114.
Kaplan, M. (1989). Task, situational, and personal determinants of influence processes in group decision making. Advances in Group Processes, 6, 87-105.
Lawton, R., Conner, M., & McEachan, R. (2009). Desire or Reason: Predicting Health
Behaviors From Affective and Cognitive Attitudes. Health Psychology, 28(1), 56-65. Reno, R. R., Cialdini, R. B., & Kallgren, C. A. (1993). The Transsituational Influence of
Social Norms. Journal of Personality and Social Psychology, 64(1), 104-112. Rimal, R. N., Lapinski, M. K., Cook, R. J., & Real, K. (2005). Moving Toward a Theory of
Normative Influences: How Perceived Benefits and Similarity Moderate the Impact of Descriptive Norms on Behaviors. Journal of Health Communication, 10, 433-450. Robinson, E., Fleming, A., & Higgs, S. (2013). Prompting Healthier Eating: Testing the Use
of Health and Social Norm Based Messages. Health Psychology, Advance online
publication, 1-9.
Systematic Review and Meta-Analysis of the Effect of Informational Eating Norms on Eating Behavior. Journal of the Academy of Nutrition and Dietetics, 114(3), 414-429.
Roth, D., Herman, C., Polivy, J., & Pliner, P. (2001). Self-presentational conflict in social eating situations: a normative perspective. Appetite, 36, 165-171.
Salmon, S. J., Fennis, B. M., de Ridder, D. T., Adriaanse, M. A., & Vet, E. d. (2014). Health on Impulse: When Low Self-Control Promotes Healthy Food Choices. Health
Psychology, 33(2), 103-109.
Stok, F. M., de Ridder, D. T., Vet, E. d., & de Wit, J. B. (2012). Minority talks: The influence of descriptive social norms on fruit intake. Psychology & Health, 27(8), 956-970.
Appendix A: Design stimuli
Following are the advertisements used for each of the four conditions.
Condition 1: Descriptive informational social norm
Condition 3: Descriptive informational social norm and positive affect
Appendix B: Survey Questions Following are the questions used in the online survey
Demographics
1. What is your gender?
2. What is your country of origin? 3. What is your marital status?
4. What is the highest level of education you have completed? 5. What is your current employment status?
6. How many people live in your household?
Current eating behavior
1. How many pieces of fruits and vegetables did you eat yesterday?
2. On average, how many pieces of fruits and vegetables do you eat per day? 3. In a typical week, how often do you eat fruits and vegetables?
Advertisement questions
Based on the advertisement you just viewed, how much do you agree or disagree with the following statements?
1. I found the ad to be appealing 2. The ad made me feel happy
3. I found the advertisement to be nicely presented 4. The ad made me feel concerned
5. The ad made me want to eat a piece of fruit
Attitude toward eating fruits and vegetables
How much do you agree or disagree with the following statements? 1. Eating fruits and vegetables is very important to me
2. Eating fruits and vegetables is healthy
3. Eating fruits and vegetables is important to stay in shape (energetic, motivated, etc.) 4. Eating fruits and vegetables fulfills my need for nutrients, vitamins, and minerals. 5. Eating fruits and vegetables is enjoyable
Affect questions
For me, eating 5 pieces of fruits and vegetables per would be … 1. Unsatisfying … satisfying
2. Unpleasant … pleasant 3. Unappealing … appealing 4. Not enjoyable … enjoyable
How much do you agree or disagree with the following statements: eating fruits and vegetables makes me feel …
1. Happy 2. Good 3. Sad 4. Miserable
Injunctive norm questions
How much do you agree or disagree with the following statements: I eat fruits and vegetables because …
1. I am supposed to eat it 2. My doctor says I should eat it
3. People who are important to me would approve of me eating it 4. It is part of the recommended diet
5. I plan to eat the recommended daily serving of fruits and vegetables because that is what adults my age should do
Descriptive norm questions
How much do you agree or disagree with the following statements: I eat fruits and vegetables because …
1. People close to me (friends, family, colleagues) eat it 2. It makes me look good in front of others
3. Most adults my age eat it 4. Others like it
5. I plan to eat 5 pieces of fruits and vegetables per day because most adults my age do it
1. How many pieces of fruits and vegetables do you plan on eating over the next 24 hours?
2. How many pieces of fruits and vegetables do you plan on eating over the next 4 weeks?
3. I can see myself eating at least 5 pieces of fruits and vegetables per day on a regular basis.
