Effort and Behaviour #1: The Proximity Effect

Læsetid: 8 minutter

The Proximity Effect - A Secret Weapon

By:
Jonas Bjørneskjold
cand.psych, 1st lieutenant
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The psychological impact of distance to an object and the intricacies involved, is referred to as the proximity effect in much of the research literature. In the contexts where it has been researched it is a surprisingly efficacious factor in human choice behaviour. It is also one of the weapons retailers use to make you select one product over another, and a favourite example of such notable behavioural architects as Richard Thaler – see this interview in the Financial Times.

Table of Contents

Research and Applied Interest in Effort and in the Context of Food Behaviour

The adage of ‘making it easy’ is a mainstay in applied behavioural architecture and could be said to be Thaler’s proverb. In the Financial Times interview with Thaler linked to in the introduction, the proximity effect, a bowl of cashews and a running tally on how many cashews Thaler eats is used as running example by the journalist in a gonzo-like manner.

"If you want people to do something, make it easy"

Richard Thaler

Yet, effort is a rather under-researched subject in behavioural science. Intrepid commercial entities do, however, generally not undervalue effort and are dedicated to the ‘make it easy’ adage. The success of amazon’s one-click shopping  (which they literally patented) is a testimony to the concept, even if it relies both on simplifying (i.e. making it obvious and mentally uncumbersome) and actual effort-reduction. One area in which effort has been relatively well researched, though, is in relation to human food-related behaviour and in the shape of distance to the food object.

Since the 1970’s1)Schachter, S. & Friedman, L. N. (1974). The effects of work and cue prominence on eating behaviour. In S. Schachter & J. Rodin (Eds.) (pp. 11-14), Obese Humans and Rats. Erlbaum Associates.15)Singh & Sikes (1974). Role of past Experience on food-motivated behavior of obese humans. Journal of Comparative and Physiological Psychology, 86(3), 503-508. , the effort it takes to attain food items has been a factor considered in research on human food-related behaviour. Both in earlier studies and in modern times, the research has focused on how to impact food selection (e.g. picking and buying food in a cafeteria) and food consumption (i.e. the act of actually eating said food after it has been acquired) in humans in order to help them select and consume a larger quantity of healthier foods instead of unhealthier food. The persistent problem of undereating amongst deployed soldiers who live off rations 2)Popper, R., Hirsh, E., Lesher, L., Engell, D., Jezier, B., & Bell, B. (1987). Field evaluation of improved MRE, MRE VII, AND MRE IV. United States Army Natick Research, Development and Engineering Center.3)Kramer, F. M. & Hirsch E.S. (1993). Situational influences on foot intake. In Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations, has also spawned interest of the US military complex into the issue and spawned lines of research related to the impact palatability and effort required in preparing food. This is not a line of research that will be covered here, but it does represent a reminder of other factors to be mindful of if one intends to understand human food-related behaviour outside the contexts of labs, cafeterias and supermarkets and the food selection-focused research we have to base our knowledge on.

Already in 19764)Levitz, L. (1976). The susceptibility of human feeding behavior to external controls (pp. 53- 60). In G. A. Bray (Ed.), Obesity in Perspective. US Government Printing Office. and 1980 5)Meyers, A. S., Stunkard, A. J. & Coll, M. (1980). Food accessibility and food choice. A test of Schacter’s externality hypothesis. Archives of General Psychiatry, 37, 1133- 1135. two studies found that simply rearranging where food items were located or how accessible they were to customers in a hospital cafeteria (e.g. closing the lid on an ice cream cooler rather than leaving it open) led to decreases in selection (and, indirectly, consumption) of the snack items, cakes and ice cream which were made more cumbersome to acquire.

In more recent studies in the last 25 years, distance has become a favoured operationalization of effort in studies on food behaviour. Across lab studies 6)Engell, D., Kramer, M., Malafi, T., Salomon, M., & Lesher, L. (1996). Effects of effort and social modeling on drinking in humans. Appetite, 26, 129-138.7)Meiselman, H. L., Hedderley, D., Staddon, S. L., Pireson, B. J., & Symonds, C. R. (1994). Effect of effort on meal selection and meal acceptability in a student cafeteria. Appetite, 23, 43-55.8)Privitera, G. J. & Creary, H. E. (2012). Proximity and visibility of fruits and vegetables influence intake in a kitchen setting among college students. Environment and Behavior, 45(7), 876-886.9)Maas, J., de Ridder, D. T. D., de Vet, E. & de Wit, J. B. F. (2011). Do distant foods decrease an intake? The effect of food accessibility on consumption. Psychology & Health, 27, 69-73.10)Hunter, J. A., Hollands, G. J., Couturier, D. & Marteau, T. M. (2018). Effect of snack-food proximity on intake in general population samples with higher and lower cognitive resource. Appetite, 121, 337-347. and real-world studies 11)Painter, J. E., Wansink, B. & Hieggelke, J. B. (2002). How visibility and convenience influence candy consumption. Appetite, 38(3), 237-238.12)Wansink, B., Painter, J. E. & Lee, Y. (2006). The office candy dish: Proximity’s influence on estimated and actual consumption. International Journal of Obesity, 30, 871-875.13)Rozin, P., Scott, S. E., Dingley, M., Urbanek, J. K. & Jiang, H. (2011). Nudge to nobesity I: Minor changes in accessibility decrease food intake. Judgment and Decision Making, 6(4), 323-333.14)Hanks, A.S., Just, D. R., Smith, L. E., Wansink, B. (2012). Healthy convenience: nudging students toward healthier choices in the lunchroom. Journal of Public Health, 34(3), 370-376. manipulation of distance to food items has been shown to be an effectual way of altering the likelihood of people selecting those items and subsequently consuming them.

The Proximity Effect

So, what is the proximity effect? Quite literally, it is the distance from the individual making a choice to the relevant choice object. In the research primarily considered here, it is the distance to various food items. Both absolute distance and relative distance between food items one wants people to choose and the relative distance to food items one wants people not to choose are important.

The effect, as earlier explained, has been measured both on food selection which is the most obvious area of impact – but smart researchers have also considered the impact on actual food consumption in their intervention studies and found there to be important differences in effect. In one lab study [12], it was also considered whether or not those who make the extra effort required to attain further-away snack items engage in compensatory eating. Whilst a retailer might be uninterested in whether or not people use or eat what they buy, in the context of health interventions ultimately aiming to improve the quality of the food people eat – what people actually consume is the true outcome measurement.

Impact of Proximity

In the literature, placing the research object in 40, 70 or 140cm away from subjects have generally been used – with some studies using other elements of effortfulness as well, such where in a buffet an item is located or what utensil is available to take a food item. Notice that these distances are quite trivial and that what matters most seems to be that an item is out of immediate reach – the effect then scales flatly and more or less linearly after that is achieved. We do not yet have meta-analysis of the proximity effect, but the research literature is decidedly one-sided as to its significance as an effect both in the lab and in the real world. In lab studies, quite large effect sizes of proximity are generally seen such as a decrease in snack item consumption upwards of 50% for snacks put just 140cm away from subjects – whilst real-world studies reporting all details generally have found smaller effect sizes for food selection in the range of a 11-18.8% increase in healthy food item selection with food consumption increases (with a similar decrease in unhealthy food consumption) in healthy food as low as 3.6%. As a health intervention, this is not impressive – but in the context of a retailer, consumption is relatively unimportant compared to selection In both real-world studies and lab studies, the effect of distance has been shown to be independent of and larger than visibility – a relatively central element in visual attention and what could be considered a centerpiece in both theoretical and applied behavioural science when it comes to making people buy stuff. Interestingly, in one study subjects were found to consistently underestimate their consumption of inconveniently located candy, and overestimating their consumption of conveniently located candy. This finding is contingent with research16)Kivetz, R. (2003). The Effects of Effort and Intrinsic Motivation on Risky Choice.  Marketing Science, 22 (4), 477-502. on how items that we expend effort for change our perceptions of rewards both before, during and after we expend the effort – which can be summed up to mean that we naturally expect effortful options to be more rewarding and are disappointed if they are not.

"Supermarket chains, and other large entities in the retail space capable of deliberate and large-scale testing, are likely to be masters of utilising the proximity effect"

Implementation of the Proximity Effect

Whether intentionally or unintentionally, the proximity effect is a factor in all physical designs. It is also a consideration in the design of virtual environments, and as seen in the placement of items on a menu appears to impact the choice of said items substantially (56%17)Rosenbaum, D. A., Gong, L. & Potts, C. A. (2014). Precastrination: Hastening sub-goal completion at the expense of extra physical effort. Psychological Science, 25 (7), 1487-1496.). The proximity effect, along with the use of concepts such as salience (i.e. how effectively something draws attention amongst other elements within visual perception) and visibility (i.e. how likely elements are to be within visual perception), is already in heavy use in industries that rely heavily on physical design. Supermarket chains, and other similar large entities in the retail space capable of deliberate and large-scale testing, are likely to be masters of utilising the proximity effect (as well as salience and visibility) to make you buy specific goods rather than other goods. Even on the boutique/store level, owners through trial and error often figure out how to improve their sales even if they do not optimise them. My point here, is that possessing a testing ground and intentionally using it to see how customers react to small alterations, is the gold standard of behavioural testing. But there are some takeways to guide that process or which can be implemented if large scale testing and data analysis isn’t something you’re capable of.
  • People prefer reaching for something (even uncomfortably and through exerting more physical effort) over getting up from a chair, walking around an obstacle or anything similar.  A number of studies on physical movement and movement-planning has shown this18)Potts, C. A., Callahan-Flintoft, C. & Rosenbaum, D. A. (2018). How do reaching and walking costs affect movement path selection. Experimental Brain Research, 2(36), 2727-2737..  So anything placed WITHIN each rather than OUTSIDE reach will be disproportionally perceived as less effortful to attain.
  • Partly leading from the last point, where people face is important. People vastly prefer reaching with their preferred hand, meaning that roughly 80% of people will want to use their right hand. When choosing between two items in a store, one item placed to the left and one to the right at the exact same distance and with the exact same attractiveness to the person, people are much more likely to favour the item to the right as they are likely to be right-handed.
  • When items are moved out of reach, how likely people are to choose them scales more or less linearly up until about 2 meters. We do not know how larger distance differences impacts the choice process.
  • Combining proximity, visibility and salience appears to interact to produce choices even more attractive than each individual element would suggest.
  • Remember that putting something you want people to interface with directly in their path so navigating around it takes effort, you make what you want people to do easy by making not doing it harder.

References   [ + ]

1. Schachter, S. & Friedman, L. N. (1974). The effects of work and cue prominence on eating behaviour. In S. Schachter & J. Rodin (Eds.) (pp. 11-14), Obese Humans and Rats. Erlbaum Associates.
2. Popper, R., Hirsh, E., Lesher, L., Engell, D., Jezier, B., & Bell, B. (1987). Field evaluation of improved MRE, MRE VII, AND MRE IV. United States Army Natick Research, Development and Engineering Center.
3. Kramer, F. M. & Hirsch E.S. (1993). Situational influences on foot intake. In Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations
4. Levitz, L. (1976). The susceptibility of human feeding behavior to external controls (pp. 53- 60). In G. A. Bray (Ed.), Obesity in Perspective. US Government Printing Office.
5. Meyers, A. S., Stunkard, A. J. & Coll, M. (1980). Food accessibility and food choice. A test of Schacter’s externality hypothesis. Archives of General Psychiatry, 37, 1133- 1135.
6. Engell, D., Kramer, M., Malafi, T., Salomon, M., & Lesher, L. (1996). Effects of effort and social modeling on drinking in humans. Appetite, 26, 129-138.
7. Meiselman, H. L., Hedderley, D., Staddon, S. L., Pireson, B. J., & Symonds, C. R. (1994). Effect of effort on meal selection and meal acceptability in a student cafeteria. Appetite, 23, 43-55.
8. Privitera, G. J. & Creary, H. E. (2012). Proximity and visibility of fruits and vegetables influence intake in a kitchen setting among college students. Environment and Behavior, 45(7), 876-886.
9. Maas, J., de Ridder, D. T. D., de Vet, E. & de Wit, J. B. F. (2011). Do distant foods decrease an intake? The effect of food accessibility on consumption. Psychology & Health, 27, 69-73.
10. Hunter, J. A., Hollands, G. J., Couturier, D. & Marteau, T. M. (2018). Effect of snack-food proximity on intake in general population samples with higher and lower cognitive resource. Appetite, 121, 337-347.
11. Painter, J. E., Wansink, B. & Hieggelke, J. B. (2002). How visibility and convenience influence candy consumption. Appetite, 38(3), 237-238.
12. Wansink, B., Painter, J. E. & Lee, Y. (2006). The office candy dish: Proximity’s influence on estimated and actual consumption. International Journal of Obesity, 30, 871-875.
13. Rozin, P., Scott, S. E., Dingley, M., Urbanek, J. K. & Jiang, H. (2011). Nudge to nobesity I: Minor changes in accessibility decrease food intake. Judgment and Decision Making, 6(4), 323-333.
14. Hanks, A.S., Just, D. R., Smith, L. E., Wansink, B. (2012). Healthy convenience: nudging students toward healthier choices in the lunchroom. Journal of Public Health, 34(3), 370-376.
15. Singh & Sikes (1974). Role of past Experience on food-motivated behavior of obese humans. Journal of Comparative and Physiological Psychology, 86(3), 503-508.
16. Kivetz, R. (2003). The Effects of Effort and Intrinsic Motivation on Risky Choice.  Marketing Science, 22 (4), 477-502.
17. Rosenbaum, D. A., Gong, L. & Potts, C. A. (2014). Precastrination: Hastening sub-goal completion at the expense of extra physical effort. Psychological Science, 25 (7), 1487-1496.
18. Potts, C. A., Callahan-Flintoft, C. & Rosenbaum, D. A. (2018). How do reaching and walking costs affect movement path selection. Experimental Brain Research, 2(36), 2727-2737.
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