1. Poster Title
Firstname Lastname1, William Hedgcock2
Introduction or Abstract Results Conclusions
References
Acknowledgements
1 Tippie College of Business, University of Iowa, 2 Department of Marketing, University of Iowa
Objectives
Insert introduction or abstract text here. Please keep general
text to a minimum of 36pt.
University of Iowa Neuromarketing // William Hedgcock // W270 PBB // william-hedgcock@uiowa.edu
Physiological Indicators of Projection Bias
Ben Olson1, William Hedgcock2
Introduction Study Design Conclusions
References
Acknowledgements
1 Tippie College of Business, University of Iowa, 2 Department of Marketing, University of Iowa
Goals and Measurements
• Standard economic theory assumes that when making
important decisions, individuals are able to accurately
estimate future benefits and costs, enabling them to make
decisions that maximize intertemporal (over time) utility.
• Evidence from experiments, however, shows that people
make systematic errors in decision making when the
results of a choice are separated from the choice itself over
time.
• Specifically, people exaggerate the extent to which future
tastes will resemble their current tastes.
• This projection bias leads to hungry consumers buying too
much food when grocery shopping – they think they’ll be
just as hungry one week later when they eat dinner as they
are now1.
• Appetite also has effects on snacking. When making snack
choices for a time one week in the future, hungry office
workers chose more unhealthy snacks than satiated
colleagues. One week later, if the hungry subjects were
then satiated at the snack time, they reversed their choice
and consumed healthy snacks instead2.
University of Iowa Neuromarketing // William Hedgcock // W270 PBB // william-hedgcock@uiowa.edu
• I seek to observe projection bias in a lab setting when
subjects are bidding on five healthy and five unhealthy
snacks to consume in one week’s time.
• I seek to overserve how hunger affects various
physiological responses, including how long it takes
subjects to fixate on images of snacks, pupil dilation while
looking at snack images, how close subjects lean in while
viewing snack images, and how accurately subjects can
perceive their heartbeats (interoceptive awareness)3.
• I am utilizing a Tobii eye-tracker to measure pupil dilation,
time to first fixation, and distance to screen and Biopac
pulse oximeter to gauge heartbeat perception.
• N=21
• Subjects will potentially pay some of their $5 compensation
to consume a snack during the study.
• 5 healthy snacks, 5 unhealthy snacks
• Visit 1: Subjects are asked how much of their $5 they are
willing to pay to consume each snack in one week. Eye-
tracking data and interoception data are collected.
• Visit 2: Subjects give willingness to pay to consume today.
• 11 subjects hungry during visit 1 and satiated during visit 2
(HS); 10 subjects satiated during both visits (SS).
• I apply the BDM procedure to ensure subjects give their
true value for each snack4.
Results
• Hungry subjects bid higher, on average, for all snacks than
satiated subjects during advance choice.
• Hungry subjects, on average, fixate on the largest snack
images faster than satiated subjects.
• Hungry subjects bid higher for healthy snacks, on average,
than satiated subjects during advance choice. The same is
not true for unhealthy snacks.
• Still analyzing data for additional subjects and conducting
analyses for pupil dilation, distance to screen, and
interoceptive awareness
• So far, the results do not display full projection bias
because snack bids between HS and SS groups during the
immediate choice are not significant.
• However, the data show that hunger, on average, causes
people to make different valuations for food when looking
to the future.
• Looking at healthy snacks and hunger results indicates that
grocery stores may be well advised to display healthy
snack options, rather than only candy, in convenient places
for hungry shoppers to purchase.
• Time to first fixation and hunger level results may have
real-world store shelf applications: grocery stores may
consider placing king size packages of snacks in places
close to eye level to attract more gazes from hungry
shoppers.
1. Kanouse, DE. & Nisbett, RE. (1969). Obesity, food deprivation, and supermarket
shopping behavior. Journal of Personality and Social Psychology, 12(4), 289-294.
2. Read, D. & van Leeuwen, B. (1998). Predicting hunger: the effects of appetite and delay
on choice. Organizational behavior and human decision processes, 76(2), 189-205.
3. Schandry, R. (1981). Heart beat perception and emotional experience.
Psychophysiology, 18(4), 483-488.
4. Becker GM, DeGroot MH, & Marschak J (July 1964). Measuring utility by a single-
response sequential method. Behav Sci 9 (3): 226–32.
Support provided by an undergraduate summer Iowa Center
for Research by Undergraduates (ICRU) fellowship
Eye tracking slide: subjects told to find and
stare at the largest snack size.
In advance choice, we see the hungry
subjects significantly bid more for all snacks
compared to satiated subjects.
0
0.2
0.4
0.6
0.8
1
1.2
Advance Choice Immediate Choice
Bids in dollars
Mean Bids for All Snacks
HS
SS