Validating the Behavioral Economic Choice Paradigm to Assess Food Preferences

Validating the Behavioral Economic Choice
Paradigm to Assess Food Preferences
Reslan ,
Karen K.
Saules ,
and Mark K.
Eastern Michigan University, Department of Psychology 1
Wayne State University, Department of Psychiatry and Behavioral Neurosciences 2
Behavioral economic theory is a useful framework for analyzing
factors influencing choice. Historically, human behavioral economic
research has focused on drug choice. In light of parallels between
eating and addictive behavior, economic choice paradigms may
also be valuable for understanding food-maintained behavior. The
primary objective of this investigation was to validate a human
laboratory model of food-appetitive behavior in healthy individuals.
Female non-smokers of normal BMI (mean + SD = 26.7 + 6.0)
were recruited. To control pre-session food satiation, subjects were
asked to refrain from eating two hours prior to the experiment. Two
independent groups completed either two experimental sessions
conducted over consecutive 30-min intervals (n=17), or one
concurrent food choice session (n=21) conducted over 30 min. Unit
food amount per trial was equated on mass during consecutive
sessions (1 Dove BarTM= 6 Teddy GrahamsTM), and concurrent
sessions (1 Hershey KissTM = 1 Kraft cheese cube).
In each session, subjects could work for units of food on an 11-trial
progressive ratio schedule (FRs = 5, 12, 33, 100, 180, 340, 540,
835, 1220, 1660, 2275). Subjects were told that unit food amount
would be constant, but response requirement (unit price, UP)
would increase on successive trials. Upon completion, subjects
were asked to consume all food earned. Group-percent food
choices across UPs were fit with a standard exponential demand
equation: Y= log(L) * exp(−AX)
Demand for High-Sugar/High-Fat (Dove BarTM) vs. LowSugar/Low-Fat (Teddy GrahamsTM) in Consecutive Choice
During consecutive choice
sessions, demand for the
high-sugar/high-fat food
option was slightly but
significantly more inelastic
than the low-sugar/low-fat
food, Pmax (UP at which
slope of curve equals –1) =
663 vs. 494, F(1,17) = 6.45,
p < .05.
Demand for High-Sugar/High-Fat (Hershey KissTM ) versus LowSugar/High-Fat (Cheese Cube) During Concurrent Choice Sessions
During concurrent choice sessions, overall-sample (n=21) demand for the
high-sugar/high-fat (Hershey KissTM) and low-sugar/high-fat food (cheese
cube) did not significantly differ (Pmax= 449 vs. 388), but there were significant
independent subgroup differences in concurrent food choice.
Restrained vs. Unrestrained Eaters (TFEQ; Stunkard & Messick, 1985)
Demand for the high-sugar/high-fat food was more inelastic for Restrained
(n=12) than Unrestrained eaters (n=9), Pmax= 632 vs. 297, F(1,15) = 27.36, p
< .001 (left panel), whereas for low-sugar/high-fat food the opposite pattern
was observed (more inelastic for Unrestrained than Restrained eaters), Pmax=
278 vs. 711, F(1,15) = 11.91, p < .01 (right panel).
High-BMI (>25) vs. Low-BMI (<25) Subjects
Demand for the high-sugar/high-fat food (left panel) was more inelastic among
subjects with High BMI (n=11) vs. Low-BMI (n=9), Pmax = 586 vs. 351, F(1,16) =
14.71, p < .02. In contrast, demand for the low-sugar/high-fat food (right panel) was
more inelastic for Low- vs. High-BMI subjects, Pmax = 577 vs. 339, F(1,17) = 5.06,p
< .04. Chocolate/cheese choice differences were significant only in High-BMI
High vs. Low-Impulsive Subjects (Food Delay Discounting Task)
Subjects completed a chocolate delay discounting task (1 Hershey KissTM now
vs. 1 bag of 75 chocolates in [5 to 180] min) and were classified from their
discounting rates (k values) as High-Impulsive (n=9) or Low-Impulsive (n=11).
Demand for the high-sugar/high-fat option (left panel) was more elastic for
High- vs. Low-Impulsive subjects, Pmax = 407 vs. 546, F(1,17) = 5.89, p < .05.
Similarly, demand for the low-sugar/high-fat option (right panel) was more
elastic for High- vs. Low-Impulsive subjects, Pmax = 217 vs. 594, F(1,16) =
26.73, p < .0001.
• Demand curves for more palatable food (i.e., high-sugar/high-fat) were
generated in the direction expected
 More demand-inelastic (price-resistant) behavior was evident for highsugar/high-fat food. The relative value of this option depended on the choice
procedure (consecutive vs. concurrent) and the food comparator (low-sugar/lowfat vs. low-sugar/high-fat). Further parametric studies would be useful.
• Significant group differences in food choice were noted for restrained
eaters, high-impulsive, and high-BMI subjects
 Restrained eaters’ chocolate demand was higher than cheese, but the reverse
pattern was observed for Unrestrained eaters. This is consistent with the notion
that attempts to restrict eating may enhance desire for more palatable foods.
 High food-impulsive subjects worked less for both food types, consistent with
desiring smaller, more immediate outcomes.
 High BMI subjects defended consumption of chocolate more, but cheese less,
relative to Low BMI subjects. This is consistent with the idea that obese
individuals prefer sweet foods to maintain energy intake.
• There may be other clinically important individual difference and
psychopharmacological effects on food choice behavior
 The next goal of this programmatic work is to determine the effects of nicotine
and nicotine abstinence on food-appetitive behavior among weight concerned
smokers (who are mostly female).
Supported in part by Joe Young, Sr. Funds (State of Michigan)