Special Session Summary Weight and Height and Shape and Size: When Do Peripheral Cues Drive Evaluation and Consumption?

Brian Wansink, University of Illinois at Urbana-Champaign
Koert van Ittersum, University of Illinois at Urbana-Champaign
[ to cite ]:
Brian Wansink and Koert van Ittersum (2003) ,"Special Session Summary Weight and Height and Shape and Size: When Do Peripheral Cues Drive Evaluation and Consumption?", in NA - Advances in Consumer Research Volume 30, eds. Punam Anand Keller and Dennis W. Rook, Valdosta, GA : Association for Consumer Research, Pages: 363-365.

Advances in Consumer Research Volume 30, 2003     Pages 363-365

SPECIAL SESSION SUMMARY

WEIGHT AND HEIGHT AND SHAPE AND SIZE: WHEN DO PERIPHERAL CUES DRIVE EVALUATION AND CONSUMPTION?

Brian Wansink, University of Illinois at Urbana-Champaign

Koert van Ittersum, University of Illinois at Urbana-Champaign

INTRODUCTION

A wide variety of factors influence purchase and consumption behavior. In this special topic session, however, we focus on how those less salient factors such as weight, height, shape, and size influence evaluation and consumption. Even if they are of little diagnostic or rational value (Rao and Monroe 1988), these peripheral cues may influence behavior because they offer cognitive shortcuts. For instance, weight may be used as an indicator of quality, and large product sizes may be perceived as "good deals." Besides providing consumers with cognitive shortcuts, peripheral cues also may influence evaluation and consumption by causing visual illusions that subsequently and unknowingly bias judgment and behavior (Chandon and Wansink 2002). In this session, we examine the use of peripheral cues as cognitive shortcuts, as well as the effect of two peripheral-cues induced, and well-known illusions on purchase and consumption volumes: the vertical-horizontal illusion and the size-contrast illusion.

BACKGROUND AND OBJECTIVES

Research on the effect of peripheral cues, such as the weight, height, shape and size of products, on evaluation and consumption is limited. Nevertheless, different studies suggest that peripheral cues may have a substantial influence on judgment and behavior. Raghubir and Krishna (1999) show that people believe taller glasses to contain more than shorter glasses. Raghubir and Krishna further show that as result of the misperception that tall glasses contain more than shorter glasses with the exact same capacity, people consume more when drinking from tall glasses, but also that they are less satisfied with drinking from tall glasses (i.e., dissatisfaction). Krider, Ragubir and Krishna (2001) show that people believe that circular tubs of butter contain less than rectangular butter tubs, which in turn causes them to take more tubs when confronted with circular tubs of butter, versus rectangular ones. Moving beyond perceptions of volume, we also know that package sizes can influence consumption volume (Folkes, Martin and Gupta 1993; Wansink 1996). Taken together, these studies strongly suggest that peripheral cues, such as the shape and size of serving containers unknowingly influence evaluation and consumption.

The objective of this session is twofold. First, we aim at increasing the awareness of the potential effect of peripheral cues such as weight, height, shape and size on evaluation and consumption behavior. Second, we want to increase the understanding of how these peripheral cues influence judgment and behavior. Being aware of and understanding the effects of these peripheral cues is important for academics, marketers, policy makers, health professionals, product designers, and consumers who are concerned with controlling purchase and consumption (Wynder, Winter, and Cohen 1997). First, our insights on the effect of peripheral cues on judgment and behavior need to be acknowledged in sensory, nutritional and for instance calorie studies. The size and shape of the plates or glasses used in these studies may influence judgment such that they affect final research outcomes and conclusions. People in the hospitality industry may use our insights to decrease costs (via serving size) without decreasing satisfaction, policy makers can use the insights to decrease waste (Wansink, Painter, and van Ittersum 2001). Health, dietetics, and consumers themselves, in turn, can use the insights obtained to decrease overconsumption (Painter, Wansink, and Hieggelke 2002). Further, for product designers, a better understanding of the effect of peripheral cues allows them to develop and design better and more 'efficient’ products (e.g., products that are evaluated more favorable or simply are more profitableBAless for more").

RESULTS AND CONCLUSIONS

To gain a better understanding of the effect of peripheral cues on evaluation and behavior, in this special topic session, three papers, testing the effect of different peripheral cues are presented.

The first paper by Swain demonstrates how consumers use peripheral cues as cognitive shortcuts by examining how "weight" influences product preference depending on whether a consumer holds the product (i.e. haptic weight information) or is merely provided with verbal weight information. In the second paper, Yang and Raghubir focus on the peripheral cue "height," and explain that the vertical-horizontal illusion caused by the elongation of beer bottles influences purchase quantities. The third paper by Wansink and Van Ittersum shows that the vertical-horizontal illusion explains why elongation positively influences the actual volume poured, but negatively affects perceived volumes poured.

The overall conclusion of the three studies is that peripheral cues have a substantial influence on evaluation and behavior. Second, people are generally unaware of the fact that and how their judgment and behavior is influenced by peripheral cues. Though the effect of peripheral cues decreases when the involvement in the judgment task is increased, the effect never is entirely eliminated.

 

WEIGHING YOUR OPTIONS: THE EFFECT OF PRODUCT WEIGHT ON PREFERENCE

Scott D. Swain, University of South Carolina

The present research examines the effect of the product weight on preference. Significant differences are demonstrated between preferences based on verbal weight information (i.e. labels indicating product weight) and those based on haptic weight information (i.e. weight perceived via active touch). The results suggest that modern cultural, technological, and industrial design ethos espousing the virtues of dematerialization and efficient structures may not resonate with consumers’ intuitions about product dimensions.

In Study 1, participants viewed six visually indistinct pairs of products: cameras, push-button lights, outdoor floodlights, mini coffee grinders, food portion scales, and travel alarm clocks. Labels underneath each option indicated relative product weights (heavier or lighter). Consistent with a consumption imagery explanation, a significant percentage of participants preferred heavier outdoor floodlights, mini coffee grinders, and food portion scales (heaviness implies more power, stability) but lighter cameras, push-button lights, and travel alarm clocks (heaviness implies more burden). These results were replicated when the verbal labels heavier and lighter were replaced with ecologically conservative numerical differences (e.g. 5.5 oz. vs. 7.5 oz for cameras).

In Study 2, participants viewed and lifted the products used in Study 1. Objective weight differences were manipulated to be small but noticeable (as determined through pretests). Heavier options were clearly preferred in all product categories including those where lighter options were preferred in the absence of haptic weight perception (i.e. cameras, travel alarm clocks, and push-button lights). Cognitive response data is consistent with the notion that consumers have an intuitive, positive response to heavier products that is driven more by the feel of weight than by specific beliefs about how weight translates into quality.

To establish more confidence these results, Study 3 used a new product class (headphones) where heaviness is clearly a consumption liability (confirmed in a pretest similar to Study 1) and where the options were visually distinct (different graphics, same shape and volume). Additionally, weight was varied at three levels: 1) 4.5 oz. vs. 4.5 oz., 2) 4.5 oz. vs. 6.0 oz., or 3) 4.5 oz. vs. 8.0 oz. Consistent with the first two studies, participants preferred heavier headphones during holding and lighter headphones during viewing.

Study 4 was similar to Study 1 except that participants were instructed to focus on the products physical properties (consider how the product works and why one brand might be heavier than another and consider the materials, parts, and the way things are made). Despite this attempt to force participants to associate product weight with the product and not with consumption consequences, the same pattern of preference revealed in Study 1 emerged.

Study 5 was similar to Study 2 except participants were instructed to mentally imagine using the product and were asked to imagine how satisfied they would be with the product in these scenarios. However, explicit instructions to engage in consumption imagery did not alter consumers preference for heavy options across all six categories.

Study 6 was similar to the lifting portion of Study 3 except that the brand names of the headphones were revealed (Sony and Maxell). Pretests revealed that Sony was perceived to be significantly higher in perceived quality than Maxell. Although Sony was preferred to Maxell in all weight conditions, it was preferred less so when it was lighter.

 

CAN BOTTLES SPEAK VOLUMES? THE EFFECT OF PACKAGE SHAPE ON HOW MUCH TO BUY

Sha Yang, University of California

Priya Raghubir, University of California at Berkeley

This paper examines the effect of package shape on purchase quantity. Drawing from the literature on volume perception, we show that even when volume information is accessible on package labels, elongated containers are perceived to contain more than less elongated containers of equal volume. In the context of the product category, beer, this translates into bottles being perceived to contain more than cans. Three moderators are examined: product category experience, desired consumption level, and product consumption context. The paper contributes to the literature on volume perceptions, by demonstrating that higher experience with the product category, higher levels of desired consumption, and contexts where purchase quantity anchors are salient, moderate the effects of package shape.

The primary contribution of the paper to marketing is to demonstrate the consequences of differences in perceived volume on purchase quantity. The bias in volume perception translates into fewer bottles versus cans being purchased (controlling for other variables such as price, promotions etc.). The thesis of the paper is to demonstrate that the number of units purchased is contingent on the shape of a container, holding constant actual volume and price of the container. Studies using a range of methodologies, samples, and types of analysis, systematically test predictions of the consequences of this bias in volume perception on purchase quantity.

A pre-test replicates the elongation effect in volume perceptions (cf. Raghubir and Krishna 1999) in the context of differentially elongated bottles of beer. The pretest controls for package material (glass), and shows that the effects hold even when package label information is available to consumers to make a judgment. The remaining studies examine differences in bottles versus cans, where the former is more elongated than the latter. Study 1 experimentally demonstrates that beer bottles are perceived to contain more than beer cans, even in the presence of volume information on the package label. The moderating role of experience in attenuating this bias in volume perceptions is shown.

In Study 2, we analyze scanner panel data for light beer purchase, and show that beer bottles generate a lower purchase quantity as compared to beer cans. The average number of cans purchased per purchase occasion is 63.66% higher (15.99) than the average number of bottles purchased (9.77). Results hold while statistically controlling for differences in price, package size availability, and differential weight of bottles and cans. Heterogeneity in the sample is leveraged to examine the attenuating effect of the moderating factor of experience on purchase quantity decisions.

In Study 3, we report the results of a virtual shopping survey. These results replicate and extend the findings of Studies 1 and 2. The package shape bias (lower purchase quantity for bottles versus cans) replicates, but is found to be moderated by product category experience.

The theoretical contributions of this paper are to (i) demonstrate the effect of package shape on the purchase quantity decision; (ii) identify product category experience as a moderator of the effect of elongation on volume perceptions; (iii) identify consumption motivation, and product context, as moderators of the link between volume perceptions and purchase quantity.

 

THE INFLUENCE OF PERIPHERAL CUES ON CONSUMPTION VOLUME

Brian Wansink, University of Illinois at Urbana-Champaign

Koert van Ittersum, University of Illinois at Urbana-Champaign

When people serve themselves, how does the shape and size of bowls, plates, and glasses influence how much they consume and how much they believe they consume?

Along with being of interest to researchers, this issue is relevant to health professionals and to those on restricted diets (Wynder et al. 1997). We consume the vast majority of our food from bowls and plates, yet there is little evidence of how the size and shape of serving containers influence consumption volume when people are serving themselves in a single-serving context.

There is good reason to believe that the size and shape of serving containers bias consumption. Careful studies have shown that the size and shape of containers bias perceptions of capacity. Studies on volume perceptions show that people believe taller glasses to contain more than shorter glasses (Raghubir and Krishna 1999), and that circular tubs of butter contain less than rectangular butter tubs (Krider, Raghubir, and Krishna 2001). These biases may, in turn, influence the serving behavior and consumption volume of people. Moving beyond perceptions of volume, we also know that package sizes can influence consumption volume (Folkes, Martin and Gupta 1993; Wansink 1996). Taken together, these studies suggest that contextual stimuli, such as the shape and size of serving containers may unknowingly influence consumption volume.

Building on prior findings of volume perceptions and visual scanning (Piaget 1979), we explain the effect of contextual stimuli on volume perceptions and consumption volumes when people serve themselves. Four questions are examined: 1) How do contextual stimuli influence volume perceptions and consumption volumes when people serve themselves? 2) Why do these influences occur? 3) Are people aware of them? 4) Do these influences result in normative over-consumption or under-consumption?

Field studies are conducted to examine the influence of the shape of serving containers on consumption in natural environments. In Study 1, a controlled field experiment was designed in which people were given either a tall, slender glass or a short, wide glass. Because people perceive the capacity of short, wide glasses to be smaller than tall, slender glasses (Raghubir and Krishna 1999), we expect and find that they pour more (19.9%) into short, wide glasses than into tall, slender glasses with the same holding capacity. Consumers believe they poured more (19.8%) into tall, slender glass than into the short, wide glass. Using a standard target volume and expert pourers (veteran bartenders), Study 2 shows that the bias found in Study 1 represents normative over-consumption for short, wide glasses but not normative under-consumption for tall, slender glasses.

Many want to help control a person’s consumption of a product. Those in the hospitality industry want to decrease costs (via serving size) without decreasing satisfaction. Those in public policy want to decrease waste. Those in health and dietetics fields want to decrease over-consumption. Those on restricted diets want to decrease calories, fat, or sugar intake. While people can be consistently reminded be aware of how much they are using, this burdens their vigilance. Instead, there might be more structural changes that could make this easier for consumers.

The ubiquitous nature of pouring has a wide impact on not only on consumer research but also on sensory studies and nutritional research studies that involve tightly controlled consumption in lab conditions. Of particular interest to intake studies in biochemistry and human nutrition is the conclusion that contextual stimuli lead to over-consumption, and not to under-consumption. Because of the importance of this issue, future research should investigate if this conclusion can be generalized to other serving situations, or whether there are situations where contextual stimuli may lead to under-consumption.

REFERENCES

Chandon, Pierre and Brian Wansink (2002), "Does Stockpiling Accelerate Consumption? A Convenience-Salience Framework of Consumption Stockpiling," Journal of Marketing Research, 39:3 (August), 321-335.

Folkes, Valerie S., Ingrid Martin and Kamal Gupta (1993), When to Say When: Effects of Supply on Usage, Journal of Consumer Research, 20 (December),467-477.

Krider, Robert E., Priya Raghubir and Aradhna Krishna (2001) "Pizzas: p or Square? Psychophysical Biases in Area Comparisons," Marketing Science, 20 (Fall 4), 405-425.

Painter, James E., Brian Wansink, and Julie B. Hieggelke (2002), "How Visibility and Convenience Influence Candy Consumption," Appetite, 38:3 (June), 237-238.

Piaget, Jean (1979), "Correspondences and Transformations," In The Impact of Piagetian Theory: On Education, Philosophy, Psychiatry, and Psychology. F. B. Murray (Ed.) Baltimore: University Park Press.

Raghubir, Priya and Aradna Krishna (1999), "Vital Dimensions in Volume Perception: Can the Eye Fool the Stomach?" Journal of Marketing Research, 36 (August), 313-326.

Rao, Akshay R. and Kent Monroe (1988), "The Moderating Effect of Prior Knowledge on Cue Utilization in Product Evaluations," Journal of Consumer Research, 15 (September), 253-264.

Wansink, Brian (1996), "Can Package Size Accelerate Consumption Volume?" Journal of Marketing, 60 (July), 1-14.

Wansink, Brian, James M. Painter, and Koert van Ittersum, (2001) "Descriptive Menu Labels’ Effect on Sales," Cornell Hotel and Restaurant Administrative Quarterly, 42:6 (December), 68-72.

Wynder, Ernst L., John H. Weisburger, and S.K. Ng (1992), "Nutrition: the Need to Define "Optimal" Intake as a Bias for Public Policy Decisions, American Journal of Public Health, 82, 346-350.

Wynder, Ernst L., Leonard A. Cohen, and Barbara L. Winter (1997), "The Challenges of Assessing Fat Intake in Cancer Research Investigations, Journal of the American Dietetic Association, 97 (Suppliment 7), 5-8.

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