Presented at the 16 th Annual Meeting of the Society for Personality and Social Psychology Long Beach, CA February, 2015 Background Personality, time-of-day preference, and healthy eating: The mediational role of morning-eveningness Ryan J. Walker 1, Andrew N. Christopher 2, Mareike B. Wieth 2, and Joshua Buchanan 1 1 Miami University 2 Albion College Personality is associated with eating behavior (e.g., Elfhag & Morey, 2008) o Conscientiousness, extraversion, agreeableness, and openness are related to healthy eating behavior o Neuroticism is related to unhealthy eating behavior Personality traits predict time-of-day preference (Adan et al., 2012) o Conscientiousness and agreeableness predict morningness o Neuroticism predicts eveningness o Extraversion and openness are not typically related to time-of-day preference Time-of-day preference also predicts eating behavior (e.g., Schubert & Randler, 2008) o Morning preference is associated with healthy eating behavior o Evening preference is associated with unhealthy eating behavior Modern societies are not set up to accommodate the circadian rhythms of some people, primarily evening people (Roenneberg et al., 2007) o Rising before preferred wake time leads to increased appetite and obesity (Knutson et al., 2007) Hypothesis: time-of-day preference will mediate the relationship between personality and eating behavior 279 participants (M age = 34.08, SD age = 11.45; 54% male) o Average Body Mass Index (BMI) = Costa and McCrae’s (2008) 60-item NEO-FFI-3 o Conscientiousness o Agreeableness o Extraversion o Openness to experience o Neuroticism Horne and Ostberg’s (1976) Morningness-Eveningness Questionnaire (MEQ) o Higher scores = morning preference; lower scores = evening preference o Example: “During the first half hour after having awakened in the morning, how tired do you feel?” The 16-item Three-Factor Eating Questionnaire (Karlsson et al., 2000) o Restrained eating (α =.81)  higher scores indicate healthy eating  Conscious restriction of food intake to control body weight o Emotional eating (α =.92)  higher scores indicate unhealthy eating  Inability to resist emotional cues o Uncontrolled eating (α =.89)  higher scores indicate unhealthy eating  Tendency to eat more than usual due to loss of control over intake Personality predicted eating behavior o Restrained eating  Conscientiousness (r =.06), agreeableness (r = -.02), extraversion (r =.21**), openness (r = -.06), neuroticism (r = -.06) o Emotional eating  Conscientiousness (r = -.32**), agreeableness (r = -.06), extraversion (r = -.16**), openness (r =.00), neuroticism (r = -.40**) o Uncontrolled eating  Conscientiousness (r = -.33**), agreeableness (r = -.20**), extraversion (r = -.15*), openness (r = -.05), neuroticism (r = -.36**) Personality was associated with time-of-day preference o Conscientiousness, r =.23** o Agreeableness, r =.15* o Extraversion, r =.23** o Openness, r =.04 o Neuroticism, r = -.28** Time-of-day preference predicted eating behavior o Restrained eating, r =.18** o Emotional eating, r =.07 o Uncontrolled eating, r = -.21** * p <.05 ** p <.01 Time-of-day preference partially mediated the relationship between personality (i.e., conscientiousness, extraversion, and neuroticism) and eating behavior, primarily uncontrolled eating o Further substantiates the interrelationships between personality, time-of-day preference, and eating behavior What is the mechanism? o Sleep cycle disruptions more common in evening people (Kanerva et al., 2012) o Disruptions negatively impact eating behavior and health (Knutson et al., 2007) Time-of-day preference is the underlying biological mechanism that, in part, drives the relationship between personality and eating behaviors o Future work should directly test mechanism Limitations o We did not examine actual food consumption  The three-factors of eating predict food consumption (de Lauzon et al., 2004) o The unexpected relationship between extraversion and morningness  The NEO-FFI-3 includes the facet of activity, instead of impulsivity, and this facet might drive the relationship between extraversion and morningness (Muro et al., 2009) Future Direction o Does time-of-day preference mediate the relation between personality and other health-related behaviors?  Tobacco use  Excessive alcohol and drug use Conclusion o Time-of-day preference accounts for personality differences in eating behaviors Restrained eating o Time-of-day (ToD) preference mediated the relationship between extraversion and restrained eating (CI [.002,.034]) o Other models were nonsignificant  Indirect effect of conscientiousness, ToD preference, restrained eating was significant (CI [.004,.038])  Indirect effect of neuroticism, ToD preference, restrained eating was significant (CI [-.031,-.004]) Emotional eating models were nonsignificant Uncontrolled eating o ToD preference partially mediated the relationship between conscientiousness and uncontrolled eating (CI [-.043, -.003]) o ToD preference partially mediated the relationship between neuroticism and uncontrolled eating (CI [.001,.037]) o ToD preference partially mediated the relationship between extraversion and uncontrolled eating (CI [-.058, -.008]) o Agreeableness models were nonsignificant o Openness models were nonsignificant Walker, R. J., Christopher, A. N., Wieth, M. B., & Buchanan, J. P. (2015). Personality, time-of-day preference, and healthy eating: The mediational role of morning-eveningness, Personality and Individual Differences, 77, Contact information: Ryan J. Walker: Andrew Christopher: Method Results: Zero-Order Correlations Results: Mediational Analyses Results: Mediational Model Discussion