Nutritional Information Research: a Review of the Issues

Eve M. Caudill, University of Illinois, Urbana-Champaign
[ to cite ]:
Eve M. Caudill (1994) ,"Nutritional Information Research: a Review of the Issues", in NA - Advances in Consumer Research Volume 21, eds. Chris T. Allen and Deborah Roedder John, Provo, UT : Association for Consumer Research, Pages: 213-217.

Advances in Consumer Research Volume 21, 1994      Pages 213-217

NUTRITIONAL INFORMATION RESEARCH: A REVIEW OF THE ISSUES

Eve M. Caudill, University of Illinois, Urbana-Champaign

Similar information disseminated to consumers is often perceived differently, depending on the characteristics of the consumer, the characteristics of the product, and the characteristics of the information itself. For example, previous research indicates that consumers' food purchasing attitudes and behavior are affected by how nutritional information is provided and what information is provided, as well as the individual differences among consumers.

Nutritional information research has traditionally been guided by public policy concerns. Much of the early public policy concerns involved increasing consumers' awareness of the relationship between diet and health. As consumers' interest in health and diet issues began to increase, their interest in the nutritional value of food products increased (Ippolito and Mathios 1991), and researchers turned their attention to the more complex issues involved in consumer acquisition and utilization of the information. (See Table 1).

NUTRITIONAL INFORMATION RESEARCH

Research on nutritional information primarily has involved two general themes: information provision and information acquisition and utilization. This review discusses the research in the context of both these themes, though an underlying goal of most previous research has been to enhance consumers' utilization of nutritional information. Although the utilization construct can be considered from two perspectives, cognitive and behavioral (Bettman 1975), much of the research has focused on cognitive issues, partly because behavioral issues are more complex and difficult to study.

Information Provision

Four areas relevant to information provision will be reviewed: informational aids, information type and format design, information channel, and information viability.

Informational Aids. One concern with nutritional information provision programs has been that consumers do not access nutrition information because of its high processing costs. Researchers have examined, through both field and experimental research, the effect of providing information designed to lower consumers' processing costs. Several field experiments, conducted at point-of-purchase locations, focused primarily on changing purchasing behavior by providing additional or simplified external information (Russo et al. 1986; Muller 1985; Levy et al. 1985; Winett et al. 1991; Patterson et al. 1992).

Russo et al. and Muller conducted similar type supermarket studies; both provided nutritional information on poster boards intended to assist in comparisons across products and nutrients. Russo et al. measured the effect of providing different information matrices ranging from a complete listing of nine nutrients to a summarized nutritional index. Muller measured the effect of several variables including brand name, nutrient importance, and number and order of nutrients. Both studies found that the provision of information per se was the primary factor in behavior change; Russo et al., however, obtained this result only when using a negative nutrient. Davis-Chervin et al. (1985) found similar, though more moderate, results in their information provision program utilizing a cafeteria point-of-choice location.

Levy et al.'s (1985) two year study used shelf markers, which provided simplified and abbreviated brand-specific nutritional information for a variety of different products throughout a number of stores. While this intervention program was able to obtain an overall positive effect on purchasing behavior, a similar study by Patterson et al. (1992), also based in Washington, D.C. and Baltimore supermarkets, was not so successful. Their program showed a modest, to occasionally negative, impact on purchasing behavior. The complexity involved in conducting this type of field study, as well as the potential for an already heightened consumer awareness from previous studies, were suggested as possible reasons for these results.

Finally, Winett et al.'s (1991) mode of information deliverance deviated from previous intervention programs. A computer was used, which interacted with consumers and provided them with feedback concerning their intended purchases. These researchers obtained modest increases in lower-fat food purchases but no changes in higher-fiber purchases.

Overall, these studies indicate that information aids can have a positive, although limited, effect on behavioral change. Design problems can have a major effect on the outcomes of these studies. For example, there is difficulty involved in assessing the comparability of the control and intervention groups. This lack of comparability may be the result of demographic or socioeconomic differences between point-of-purchase locations. Thus, sales response variance could be the result of differences in consumers' ability to process the information or purchase the products.

Several experimental studies indicate that increased cognitive utilization can also result from the use of informational aids. Moorman (1990) combined consequence information (i.e., arousing or emotionally activating information) and reference information (the percentage of nutrient recommended daily allowance), which she embedded into nutritional messages on a package label. Her findings suggest that messages containing consequence information followed by reference information maximize consumer comprehension. Cole and Gaeth (1990) combined a perceptual aid (i.e., additional information on the importance of a nutrient) with cognitive style and age. Their research found the provision of additional information increased consumers' nutrition accuracy ratings, particularly for older consumers. Finally, Viswanathan (1992) provided subjects with summary information which described the nutrient makeup of two products across all available brands. He hypothesized, and in general found, that this type of summary information increased respondents' usage of nutritional information and resulted in increased judgments of product healthiness.

In summary, research has examined the effect of providing informational aids on both the behavior and the cognitive utilization of nutritional information. Because of difficulties in measuring both perspectives simultaneously, researchers have focused on either one or the other. Thus, this research includes two assumptions: 1) consumers will be aware and motivated to read the information when they shop, and 2) consumers will then use the information in their purchasing decisions. Additional research is necessary to assess these assumed linkages between awareness, motivation, and use. Unfortunately, as indicated by previous studies, data are difficult to collect.

Information Type and Format Design. The previous discussion suggests that providing nutritional information per se may not be enough to increase consumers' use of that information. The information used in the format and how the format is designed can also affect these decisions. Research indicates that consumers respond more to information on negative nutrients (e.g., sugar) than to positive nutrients (e.g., vitamins) (Russo et al. 1986; Moorman 1990; Heimbach 1981; Levy et al. 1985; Levy et al. 1991). For example, Heimbach found that over half the consumers surveyed reported using nutritional information to avoid consumption of negative nutrients; sugar raised the most concern. Russo et al. (1986) were able to affect purchasing behaviors when information on sugar was provided.

TABLE 1

Researchers have found mixed results regarding format complexity. Two studies found consumers preferred the more complex (and complete) information (Asam and Bucklin 1973; Russo et al. 1986), and two studies found that consumers did not respond to more complex information (Muller 1985; Brucks et al. 1984). Scammon examined complexity as a function of adjectival (i.e., preprocessed or simplified) versus numeric (i.e., unprocessed) information and found increased nutritiousness evaluations with the less complex adjectival information. Levy et al. (1991) also found consumers preferred adjectival information; although it did not perform as well as numeric information in nutrition label performance tests.

These mixed findings may be the result of complexity being confounded with amount of information. When researchers provide more complete, complex information, they also increase the information load. Thus, consumers may perceive "more to be better" in their evaluations of nutritiousness, but may find the information too complex to process and use in a purchase decision.

Finally, the order of nutrients can impact the acquisition and use of nutritional information (Muller 1985; Geiger et al. 1991; Levy et al. 1992). Muller ordered nutrients in terms of importance, from most to least, or vice versa, while Geiger et al. and Levy et al. grouped nutrients in terms of whether consumers should include or delete them from their diet. Muller found no nutrient order effect. Levy et al. found consumers rated the grouping format least preferable, calling it "preachy"; while research by Geiger et al. found consumers rated the grouping format useful. Implicit in this research are consumers' perceptions of nutrient importance. For example, Muller's use of relatively unimportant, or unknown nutrients (e.g., phosphorus), may have contributed to his inability to find an individual nutrient effect on purchasing behavior.

Format design has been of particular concern for food regulators (Levy et al. 1992a; Levy et al. 1992b; Levy et al. 1991; Geiger et al. 1991). The Levy et al. studies measured consumers' response to a variety of different formats, which were designed in conjunction with extensive input from external sources (e.g., consumer groups, public hearings). The purpose of their research was to help develop and revise a format most acceptable to consumers in terms of comprehensibility and communication effectiveness. Interestingly, Levy et al.'s 1992 research study found that the label consumers preferred and the label on which consumers successfully performed label use tests were different. This difference suggests the difficulty in designing a format which increases both consumers' motivation to acquire the information and their ability to use the information.

Rather than using predesigned labeling formats, Geiger et al. used consumer input to develop an "ideal" nutrition label. "Ideal" was determined in terms of consumers' perceptions of label usefulness. Contrary to findings by Levy et al. (1991; 1992), Geiger et al. found that consumers preferred a bar graph format.

These studies suggest that the nutrients used in research, the order in which they are placed, and consumers' perceptions of the importance of the nutrients can differentially change consumers' use of the information. We need to be aware of these factors when we design future research programs to change consumers' purchasing behavior (see Russo and Leclerc [1991]) for a discussion on the characteristics that differentiate successful programs from unsuccessful programs). Furthermore, consumers' preference for a particular label format may not necessarily indicate their ability to process and use that information in purchasing decisions.

Information Channels. Nutritional information is typically provided to consumers via package labels, advertisements, or point-of-purchase displays. Researchers have debated the benefits of these different channels in disseminating nutritional information. Some researchers defend the use of advertisements as a source of product information, claiming that advertisements have increased consumers' knowledge of the relationship between diet and health (Calfee and Pappalardo 1991; Ippolito and Mathios 1991; Caswell 1992). For example, market share data has shown that the provision of health claims through manufacturer-produced print advertisements has positively influenced consumers' purchasing behavior (Ippolito and Mathios 1991; Levy and Stokes 1987). Others have warned of the possibility of misleading claims, i.e., the more relaxed regulations for advertising may induce food companies to make claims about relatively unimportant nutrients (Silverglade 1991). Researchers have assumed consumers respond equally to information disseminated through different information channels (see Ford et al. 1992). Interestingly, however, the regulatory agencies do not hold advertisements and labels to the same regulatory standards, thus suggesting these two information channels are not the same. In fact, labels have stricter regulatory standards than do advertisements (Silverglade 1991; Serafino 1992). Implicit in the regulatory differences is that consumers respond differently depending on where they obtain their information; however, this differential response has not been systematically researched.

Usefulness of Providing Information. Much of the earlier research looked at the usefulness of providing nutritional information. Usefulness comes from a more public policy perspective, which is concerned with the necessity of providing this information, that is, do the consumers really need it, and do they really use it in their purchasing decisions. Researchers found that although consumers responded positively to receiving nutritional information (Daly 1976), only certain segments of the population either had the ability (e.g., in terms of education, nutritional concern, or prior knowledge) (Lenahan et al. 1973; Vandenberg 1978) or the motivation to acquire the information (Jacoby et al. 1977).

In summary, research on information provision has found that consumers want nutritional information but whether they use this information is still in question. Research has found that consumers prefer more information, yet we are not sure if consumers actually use all this information or if they just feel more confident when more information is provided. Much of the research has emphasized cognitive utilization (e.g., evaluation of nutritiousness) with less research conducted on the issues of why consumers acquire nutritional information and, then, whether the information is used in purchasing decisions. If our ultimate goal, however, is to change consumers' purchasing behaviors we need to increase our understanding of the link between cognitive utilization and behavioral utilization.

Acquisition and Utilization

Information first has to be acquired for consumers to participate in evaluative or purchase behaviors. Of importance, then, is the issue of motivation. Motivation can be defined as consumers' goal-directed arousal to engage in particular behaviors (see Moorman 1993). Thus, once aware of the information, consumers need to be motivated to acquire the information to form an attitude necessary to change a behavior (Russo et al. 1986).

Motivation and Ability. Moorman's (1990) research suggests that consequence information increases motivation, regardless of consumer differences. In addition, both the lowering of processing costs and the increasing of benefits have been suggested as motivating factors in consumers' use of information (Russo et al. 1986; Russo and Leclerc 1991). Motivation can also be affected by perceptions of nutrient importance.

Deterrents to motivation also exist, including complexity of information, and consumer confusion and disinterest. As previously discussed, a number of research studies have been concerned with the complexity of nutritional information and have sought to reduce this complexity and hence the information processing costs.

Consumer confusion can be attributed to several conditions. The first condition is external to the consumer and is a function of the current state of nutritional information regulation (Caswell 1992; Silverglade 1991). A lack of uniformity in regulatory standards exists between advertisements and labels as well as between some product categories (Caswell 1992). And because products do not all exist under the same regulatory jurisdiction i.e., the USDA regulates meat and poultry products and the FDA regulates packaged food products, the potential exists for different products to exhibit different nutritional profiles.

Confusion can also result from consumers' inability to process nutritional information (Brucks et al. 1984; Moorman 1990; Daly 1976). Consumers' ability, or lack of ability, can change, though, depending on the individual (Moorman 1990, 1993; Levy et al. 1991, 1992; Cole and Gaeth 1990), the product (Brucks et al. 1984), or consumers' perceptions of the nutrient (Muller 1985). Although research on individual differences in the context of nutritional information use has been limited, a number of research studies have included the caveat that these differences have the potential to affect their findings (Ippolito and Mathios 1991; Calfee and Pappalardo 1991; Daly 1976; Jacoby et al. 1977; Heimbach 1981; Vandenberg 1978). There has been no systematic research, however, following up on this concern.

In summary, a number of variables can affect consumers' motivation and ability to acquire and use nutrient information. Many of these issues have not been systematically researched. For example, researchers have not systematically studied issues related to the consumer such as perceptions of nutrient importance or prior knowledge. In previous studies, lesser known nutrients (e.g., thiamine) have been combined with better known nutrients (e.g., vitamin C), perhaps mitigating consumers' response. In addition, prior knowledge should not suggest importance. For example, Moorman (1990) used nutrients familiar to consumers, though she did not measure perceived importance. Prior knowledge and perceived importance are separate issues; prior knowledge would affect ability, while perceived nutrient importance may impact motivation.

GENERAL DISCUSSION AND FUTURE RESEARCH

As this review has summarized, a majority of the studies directly or indirectly have investigated issues related to the acquisition and utilization of nutritional information. However, two areas of additional research would enhance the research already conducted: 1) the further examination of the connection between acquisition and utilization and behavior, and 2) the role of motivation. Although some studies have looked at purchasing behavior, most of the research has assumed purchase and consumption automatically follow the acquisition and utilization of nutrition information. Because the impetus behind much of nutritional information research involves changing consumer behavior, the need exists to confirm this relationship between information utilization and purchase behavior.

Research on two concepts, consumers' individual differences and consumers' differing perceptions of nutrient importance, may increase our understanding of this purchasing behavior. Research involving individual differences has been limited, and researchers disagree on its importance. For example, Moorman's (1990) research suggests that the utilization of information depends on the goals of the individual. Muller (1985) aggregated consumer response, suggesting the unimportance of individual differences.

Conceptually, consumers can be separated into three broadly defined health classifications: those consumers with an overall positive orientation toward their responsibility for their health; those consumers who are interested in specific and idiosyncratic nutrient/health relationships; and those consumers who are not concerned with health issues and see little or no connection between their diet and their health. This assumption of different "health" segments suggests that research results may differ depending on the makeup of the sample taking part in the study and the interaction of this sample with the dependent measures. For example, some consumers indifferent to health issues may show ability, and perhaps motivation, during a research exercise but may exhibit either neutral or negative purchase intentions. Other consumers may be selectively interested in nutritional information, i.e., they may be interested in information on sodium and high blood pressure and may not be concerned about information on fiber.

The above discussion implies that different consumers may have different meaning structures, thereby affecting their perceptions of nutrient information. Venkatesan (1978) has noted that previous research has focused primarily on "what" information or "what" attributes of food products ought to be provided to consumers; however, little attention has been paid to "why" consumers make their purchasing decisions. Why would consumers purchase a food product based on nutritional attributes? We have our assumptions: they do so because they are concerned with their health or with their children's health or because they are concerned with aging or because we've made the processing of this information easier. But we really don't know why.

Not much has changed in nutrition research in this regard; researchers have made little progress linking consumers' attitudes towards nutritional information and purchase and use behaviors. Fifteen years ago Venkatesan (1978) suggested the need for longitudinal research aimed at looking at consumer consumption patterns and, unfortunately, this type of research has yet to be conducted. Phenomenological interviews conducted over an extended period of time would be one method used to study both consumption patterns and meaning structures. This type of methodology enables the researcher to understand an issue from a first-person perspective (cf. Thompson, Locander and Pollio 1989) and allows for more depth of knowledge by the researcher. Because respondents are not prompted by specific questions from the interviewer but, rather, are encouraged to discuss a topic within a flexible set of boundaries, it is expected that respondents will discuss the issues that are of importance to them. This type of methodology could enable the field of nutritional information to gain not only a more in-depth understanding of what variables are affecting purchasing decisions but also why these variables are salient.

Finally, consumers' motivation to search for and use nutrition formats is an important variable and in need of further research. While the majority of the nutritional information research has focused on lowering consumers' processing costs, through the provision of reference materials and easier-to-understand formats, more research should be focused on how to motivate consumers to first pay attention to and then to process and use nutritional information. Ease of processing will not necessarily increase consumers motivation to process the information. Motivation seems to be the driving force behind consumers seeking further information once their attention is gained, and without motivation other consumer characteristics such as ability, cognitive style, or prior knowledge may not be engaged in purchasing situations.

A multi-faceted information provision program may encourage consumer acquisition and use of nutritional information (cf. Russo and Leclerc 1991). Thus, certain types of point-of-purchase signs and advertised health claims may positively motivate consumers to become aware of the nutritional makeup of food products. The provision of packaging labels that are easy to read and comprehend would both encourage attention and facilitate processing. And finally, a concerted effort to bring the information found on labels and in advertising more in sync would create more continuity for consumers and would alleviate some of the confusion generated by varying types of messages.

The type of nutritional information conveyed to consumers is also important. An information message that makes a connection between a nutritional attribute and its health benefit (i.e., a health claim) is more likely to gain consumers' attention than is a lengthy list of ingredients with little relationship to why the consumer should purchase the product. Furthermore, negative nutrients seem to be more motivating to consumers. New labels, required to be on packages by May, 1994, will increase information on negative nutrients, in addition to those previously required (new nutrients for which information is required include calories from fat, saturated fat, cholesterol, sugars, and dietary fiber) (Kurtzweil 1993). Nutrients no longer required are thiamine, riboflavin, and niacin. Also included will be a new dietary reference value called the "Daily Value" which will "help consumers understand the role of individual foods in the context of total daily diet" (p. 13). Finally, health claims will be allowed for six nutrient/disease relationships: calcium and osteoporosis, fat and cancer, saturated fat and cholesterol and coronary heart disease, fiber and cancer and coronary heart disease. The new labels appear to disseminate information in an easily-understood format; however, the amount of information consumers will be confronted with has increased. Whether consumers will be able to assimilate all this information and use it in their purchasing decisions will require further research.

While consumers continue to be interested in the relationship between diet and health in their food purchasing decisions, research has also shown consumers moving away from purchasing based on nutritional attributes (New York Times 1993). Perhaps consumers are becoming disillusioned with the conflicting health information and the bombardment of health related "news" itemsCalthough research is needed to investigate these diverging trends. Therefore, as health care costs escalate and the need for consumers to take a more preventive view of their health care increases, continued research is necessary to find ways to more effectively communicate nutritional information to consumers.

REFERENCES

"Americans Found Retreating From Healthy Eating Habits," New York Times, 16 April 1993, A, 1

Asam, Edward H. and Louis P. Bucklin (1973), "Nutrition Labeling for Canned Goods: A Study of Consumer Response," Journal of Marketing, 37(April), 32-37

Bettman, James R. (1975), "Issues in Designing Consumer Information Environments," Journal of Consumer Research, 2(December), 169-177

Brucks, Merrie, Andrew A. Mitchell, and Richard Staelin (1984), "The Effect of Nutritional Information Disclosures in Advertising: An Information Processing Approach," Journal of Public Policy and Marketing, 3, 1-27

Calfee, John E. and Janis K. Pappalardo (1991), "Public Policy Issues in Health Claims for Foods," Journal of Public Policy & Marketing, 10(Spring), 33-53

Caswell, Julie A. (1992), "Current Information Levels on Food Labels," American Journal of Agricultural Economics, 74(December), 1196-1201

Cole, Catherine A. and Gary J. Gaeth (1990), "Cognitive and Age-Related Differences in the Ability to Use Nutritional Information in a Complex Environment," Journal of Marketing Research, 27 (May), 175-184

Daly, Patricia A. (1976), "The Response of Consumers to Nutrition Labeling," Journal of Consumer Affairs, 10(Winter), 170-178

Davis-Chervin, Doryn, Todd Rogers and Mia Clark (1985), "Influencing Food Selection with Point-of-Choice Nutrition Information," Journal of Nutrition Education, 17(1), 18-22

Ford, Gary T., Manoj Hastak, Anusree Mitra, and Debra J. Ringold (1992), "Effects of the New FDA Rules for Food Labels on Disadvantaged Consumers: Unintended Consequences," Marketing Science Institute Research Competition, American University

Geiger, Constance and Ann G. Gallenson (1992), "Nutrition Labeling: In Search of Clarity," Journal of the American Dietetic Association, 92(October), 1217

Geiger, Constance, Bonita W. Wyse, C.R. Michael Parent, and R. Gaurth Hansen (1991), "Nutrition Labels in Bar Graph Format Deemed Most Useful For Consumer Purchase Decisions Using Adaptive Conjoint Analysis," Journal of the American Dietetic Association, 91(July), 800-815

Heimbach, James T. (1981), "Defining the Problem: The Scope of Consumer Concern with Food Labeling," in Advances in Consumer Research, Vol. 8, ed. Kent B. Monroe, Ann Arbor, MI: Association for Consumer Research, 474-476

Ippolito, Pauline M. and Alan D. Mathios (1991), "Health Claims in Food Marketing: Evidence on Knowledge and Behavior in the Cereal Market," Journal of Public Policy & Marketing, 10(Spring), 15-32

Jacoby, Jacob, Robert Chestnut and W. Silberman (1977), "Consumer Use and Comprehension of Nutrition Information," Journal of Consumer Research, 4(September), 119-128

Kurtzweil, Paula (1993), "Good Reading for Good Eating," FDA Consumer, (Special Report), 7-13

Lenahan, R. J., J. A. Thomas, D. L. Call, and D. I. Padberg (1973), "Consumer Reaction to Nutritional Labels on Food Products," The Journal of Consumer Affairs

Levy, Alan S., Sara B. Fein, and Raymond E. Schucker (1992a), "More Effective Nutrition Label Formats Are Not Necessarily Preferred," Journal of the American Dietetic Association, 92(October), 1230-1234

Levy, Alan S., Sara B. Fein, and Raymond E. Schucker (1992b), "Evaluation of Nutrition Label Formats: FDA Study 2," working paper, Food and Drug Administration, Division of Consumer Studies, Washington, DC,

Levy, Alan S., Sara B. Fein, and Raymond E. Schucker (1991), "Nutrition Labeling Formats: Performance and Preference," Food Technology, (July), 116-121

Levy, Alan S. and Raymond C. Stokes (1987), "Effects of a Health Promotion Advertising Campaign on Sales of Ready-to-Eat Cereals," Public Health Reports, 102(July-August), 398-403

Levy, Alan S., Odonna Mathews, Marilyn Stephenson, Janet E. Tenney, and Raymond E. Schucker (1985), "The Impact of a Nutrition Information Program on Food Purchases," Journal of Public Policy and Marketing, 4, 1-13

Moorman, Christine (1990), "The Effects of Stimulus and Consumer Characteristics on the Utilization of Nutrition Information," Journal of Consumer Research, 17(December), 362-374

Moorman, Christine (1993), "A Model of Consumers' Preventive Health Behaviors: The Role of Health Motivation and Health Ability, Journal of Consumer Research, 20(forthcoming)

Muller, Thomas E. (1985), "Structural Information Factors Which Stimulate the Use of Nutrition Information: A Field Experiment," Journal of Marketing Research, 22(May), 143-157

Patterson et al. (1992), "Evaluation of a Supermarket Intervention," Evaluation Review, 16(October), 464-490

Russo, J. Edward and France Leclerc (1991), "Characteristics of Successful Product Information Programs," Journal of Social Issues, 47(1), 73-92

Russo, Edward J., Richard Staelin, Catherine A. Nolan, Gary J. Russell, Barbara L. Metcalf (1986), "Nutrition Information in the Supermarket," Journal of Consumer Research, 13(June), 48-70

Serafino, James M. (1992), "Developing Standards for Health Claims-The FDA and the FTC," Food and Drug Law Journal, 47(4), 335-353

Scammon, Debra L. (1977), "'Information Load' and Consumers," Journal of Consumer Research, 4(December) 148-155

Silverglade, Bruce A. (1991), "A Comment on 'Public Policy Issues in Health Claims for Foods'," Journal of Public Policy & Marketing, 10(Spring), 54-62

Vandenberg, Robert J. (1978), "Food Label Information: What Consumers Say They Use and What They Actually Use," Advances in Consumer Research, Vol. 5, ed. H. Keith Hunt, Ann Arbor, MI: Association for Consumer Research, 484-487

Venkatesan, M. (1978), "Consumer Behavior and Nutrition: Preventive Health Perspective," Advances in Consumer Research, Vol. 5, ed. H. Keith Hunt, Ann Arbor, MI: Association for Consumer Research, 513-520

Viswanathan, Madhubalan (1992), "The Influence of Reference Information on the Usage of Nutrition Information," Working Paper, Department of Business Administration, University of Illinois, Urbana-Champaign

Winett, Richard A. et al. (1991), "An Experimental Evaluation of a Prototype Public Access Nutrition Information System for Supermarkets," Health Psychology, 10(1), 75-78

----------------------------------------