title: Perceived control and intrinsic vs. extrinsic motivation for oral self-care: a full factorial experimental test of theory-based persuasive messages.
abstract: BACKGROUND
  Correlational evidence suggests that perceived control (PC) and intrinsic motivation (IM), key constructs in social cognitive and self-determination theories, may interact to reinforce behavior change.
  
  
  OBJECTIVE
  This proof-of-principle study examines the independent and synergistic effects of interventions to increase PC and IM upon dental flossing frequency.
  
  
  METHODS
  University students (n = 185) were randomized in a 2 × 2 full factorial design to receive two computer-based interventions: one to either increase or decrease PC and another to increase either IM or extrinsic motivation. These constructs were measured immediately post-intervention; flossing behavior was measured 1 week later.
  
  
  RESULTS
  The interventions to increase PC and PC/IM had main and interaction effects on flossing, respectively. The PC/IM interaction effect was mediated by increases in PC and IM.
  
  
  CONCLUSIONS
  Combining interventions to increase PC and IM seems to be a promising avenue of research, which has implications for both theory and intervention development.
authors.affiliation: School of Psychology, University of Aberdeen, Aberdeen, UK.
authors.forename: Liam
authors.initials: L
authors.lastname: Staunton
authors.forename: Paul
authors.initials: P
authors.lastname: Gellert
authors.forename: Keegan
authors.initials: K
authors.lastname: Knittle
authors.forename: Falko F
authors.initials: FF
authors.lastname: Sniehotta
mesh_terms: D000293:Adolescent; D000328:Adult; D001521:Behavior Therapy; D005260:Female; D015438:Health Behavior; D006801:Humans; D007389:Internal-External Control; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009910:Oral Hygiene / Q000523:psychology*; D012648:Self Care / Q000523:psychology*; D020377:Self Efficacy; D016896:Treatment Outcome; D055815:Young Adult