Gert-Jan de Bruijn Amsterdam School of Communication Research University of Amsterdam

1. Exercise and habits
Gert-Jan de Bruijn
Amsterdam School of Communication Research
University of Amsterdam

3. Habits
“We are what we repeatedly do” - Aristotle (384 - 322 BC)
“Most of the time, we do things we do most of the times”
‘A matter of routine, I’ve done it ever since I finished school” - ABBA (The day before you came)
Behaviour you have done repeatedly in stable context
Some researchers provide evidence that habits are goal-actived behaviours

4. Overview
Understanding exercise behaviour and habits: action control research
Understanding exercise behaviour and habits: affective considerations of exercise
Modeling exercise automaticity: two longitudinal studies in undergraduate samples

5. Habits and Exercise Action Control
Action control: translating intentions into behaviour (e.g. Kuhl, 1985, 1992)
Typically, 30%-50% of study samples are not translating their intentions into behaviour
Is this ‘gap’ less pronounced when strong habits have developed?
Apparently so....
Some work with Ryan Rhodes, University of Victoria

6. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 25 3
Intender 6 2
Moderate habit
Nonintender 19 6
Intender 13 25
Strong habit
Nonintender 7 2
Intender 7 28
Rhodes, Matheson, De Bruijn (2010) J Sport Exerc Psychol, 32, 84-98

7. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 89.3% 10.7%
Intender 75% 25%
Moderate habit
Nonintender 76% 24%
Intender 34.2% 65.8%
Strong habit
Nonintender 77.8% 22.2%
Intender 20% 80%
Rhodes, Matheson, De Bruijn (2010) J Sport Exerc Psychol, 32, 84-98

8. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 89.3% 10.7%
Intender 75% 25%
Moderate habit
Nonintender 76% 24%
Intender 34.2% 65.8%
Strong habit
Nonintender 77.8% 22.2%
Intender 20% 80%
Rhodes, Matheson, De Bruijn (2010) J Sport Exerc Psychol, 32, 84-98

9. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 147 2
Intender 34 10
Strong habit
Nonintender 18 0
Intender 70 49
De Bruijn (2011). Psychol Sport Exerc, 12, 106-114

10. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 98.6% 1.4%
Intender 77.3% 22.7%
Strong habit
Nonintender 100% 0%
Intender 58.8% 41.2%
De Bruijn (2011). Psychol Sport Exerc, 12, 106-114

11. Habits and Exercise Action Control
Weak habit Insufficient PA Sufficient PA
Nonintender 98.6% 1.4%
Intender 77.3% 22.7%
Strong habit
Nonintender 100% 0%
Intender 58.8% 41.2%
De Bruijn (2011). Psychol Sport Exerc, 12, 106-114

12. Intermezzo I
Stronger exercise habits minimize the intention-exercise gap
The relationship is still not perfect, even when strong exercise habits exist
Interact the interaction?
Self-regulatory planning strategies have helped before (some work by someone called Falko)

13. Methods
Online study amongst undergraduate students in a social psychology course (n=415)
Baseline assessment: intention - habit strength - action planning
Follow-up (= baseline + two weeks): exercise behaviour (IPAQ)
Baseline items in relation to ‘exercising for at least 60 minutes in the next two weeks’ on 7-point
scales (-3 = totally disagree; +3 = totally agree)
Action planning items (alpha = .94)
I have made detailed plans (i) when, (ii), where, (iii) with whom, and (iv) what kind
Intention items (alpha = .96)
(i) I intend to exercise and (ii) I am sure I will exercise
Habit strength items cf. Verplanken and Orbell (2003): alpha = .95
e.g. exercising is something (i) I do automatically, (ii) I start doing without having to think about
it, (iii) I do without thinking, (iv) I would find hard not do

14. Methods
Analytical plan
Basic descriptives
Stepwise regression analysis
Step 1: Perceived Behavioural Control - Intention
Step 2: Instrumental Attitude - Affective Attitude - Subjective Norms
Step 3: Habit Strength - Planning
Step 4: The three two-way interactions (e.g. planning x intention, habit x planning)
Step 5: Three-way interaction habit x planning x intention
Follow-up analysis
Two-way interaction: slope analysis using Aiken & West (1991) suggestions
Three-way interaction: slope analysis and slope comparison tests using Dawson & Richter
(2006) suggestions

15. Results (2)
Step 1 Step 2 Step 3 Step 4 Step 5
Intention .24** .24** .18* .18* .17*
PBC .34*** .33*** .25** .19* .22**
Step 2 variables
Instrumental attitude .04 .04 .01 .01
Affective attitude .02 -.08 .01 -.01
Subjective norm -.05 -.08 -.06 -.05
Step 3 variables
Habit strength .23** .15* .10
Planning .20** .25** .14*
Step 4 variables
Habit x Planning .13 .14
Habit x Intention .22** .24***
Intention x Planning .20** .25***
Step 5 variables
Habit x Planning x Intention .15**
De Bruijn, Rhodes, & Van Osch (in press). J Behav Med

16. Simple slope analysis
Planning x intention interaction
Low exercise planning: intention - exercise beta = .27***
Medium exercise planning: intention - exercise beta = .43***
High exercise planning: intention - exercise beta = .63***
Habit x intention interaction
Low exercise habit: intention - exercise beta = .16*
Medium exercise habit: intention - exercise beta = .42***
High exercise habit: intention - exercise beta = .62***

17. Simple slope analysis: planning x habit x intention
Exercise behaviour
(1) High Planning, High Habit
(2) High Planning, Low Habit
(3) Low Planning, High Habit
(4) Low Planning, Low Habit
Low Intention High Intention
Low planning, low habit: Intention-exercise beta = -.08 (ns) Low planning, high habit: Intention-exercise beta = .25*
High planning, low habit: Intention-exercise beta = .17 (ns) High planning, high habit: Intention-exercise beta = .74***
De Bruijn, Rhodes, & Van Osch (in press). J Behav Med

18. Planning x habit x intention: follow-up tests of slope differences
High planning, high habit (beta = .74)
High planning, low habit (beta=.17): t(413) = 5.204***
Low planning, high habit (beta=.25): t(413) = 4.318***
Low planning, low habit (beta=-.08): t(413) = 5.794***
High planning, low habit (beta = .17)
Low planning, high habit (beta=.25): t(413) = .-.428 (ns)
Low planning, low habit (beta= -.08): t(413) = 2.593**
Low planning, high habit (beta = .25)
Low planning, low habit (beta=-.08): t(413) = 3.754***
De Bruijn, Rhodes, & Van Osch (in press). J Behav Med

19. Intermezzo II
Strong exercise habits minimize the intention-exercise gap
Strong habits in combination with strong action plans minimize this gap even further
One potential problem: we tend to ask people all sort of things before they exercise
How to people think about exercise, after they have done their exercise?
Study on Habits, Exercise, Pre-exercise affect, and Post-exercise affective responses
Why study affective responses?

20. Affect and Exercise
Judgments about the overall pleasure/enjoyability of exercise behaviour
Meta-analysed r between PA and affect is .42 (95%CI .37-.46) (Rhodes et al., 2009)
Affect influences exercise behaviour directly (e.g. unmediated by intentions), similar to habit
Usually a strong correlation between affective attitudes and habits (r between .40 and .66)
Main question: how do strong habitual exercisers react to insufficient exercise?
Study done in collaboration with Professor Bob Grove (University of Western Australia)

21. Affect and Exercise
288 participants (M = 21.3 years, SD = 2.96, 73.3% females)
Baseline data (-3=totally disagree; +3 = totally agree)
SRHI towards sufficient exercise behaviour
Affective attitude towards sufficient exercise behaviour in the next 2 weeks
Enjoyable - Pleasant - Relaxing
I intend to / I am sure I will engage in sufficient exercise in the next 2 weeks
Follow-up data (= baseline + 2 weeks)
Exercise behaviour in the previous two weeks (relevant items from IPAQ)
Post-exercise affective attitudes (enjoyable - pleasant - relaxing)
Engaging in the amount of exercise in the past two weeks, was for me...

22. Affect and Exercise: Methods
Three exercise habit strength groups
Weak habits: habit strength score <= -2 (n = 53)
Moderate habits: habit strength score between -2 and +2 (n = 197)
Strong habits: habit strength score >= +2 (n = 38)
Two exercise groups
Insufficient exercise: did not meet the exercise norm (n = 227)
Sufficient exercise: did meet the exercise norm (n = 61)
2 (norm) x 3 (habit strenght) analysis of variance, with intention as covariate

23. Affect and Exercise: Results
Low Habit Moderate Habit Strong Habit
3
2,59
2
1,61
1
0,21
0
-1
Post-Exercise Affect
F(2,282) = 35.55, p < .001, η2 = .20

24. Affect and Exercise: Results
Insufficient Exercise Sufficient Exercise
3
2,16
2
1,51
1
0
-1
Pre-Exercise Affect
F(2,283) = 3.96, p = .0122, η2 = .02

25. Affect and Exercise: Results
Low Habit Moderate Habit Strong Habit Moderate Habit Strong Habit
Do not meet norm Meet norm
3 2,75
2,42
2 1,9
1,53
1
0,21
0
-1
Pre-Exercise Affect
F(1, 283) = 0.01, p = .942, η2 = .00

26. Affect and Exercise: Pre-exercise Affect
People who have a more enjoyable outlook on future exercise behaviour...
...exercise more.
Not particularly novel
This effect does not depend on exercise habit strength
Perhaps somewhat novel
What happens with post-exercise affect?

27. Affect and Exercise: Results
Low Habit Moderate Habit Strong Habit Moderate Habit Strong Habit
Do not meet norm Meet norm
3 2,86
2
1,51 1,52
1,11
1
0
-0,03
-1
Post-Exercise Affect
F(1, 283) = 6.45, p = .016, η2 = . 03

28. Affect and Exercise: Results
Low Habit Moderate Habit Strong Habit Moderate Habit Strong Habit
Do not meet norm Meet norm
3
2
1,52
1,11
1
0
-1
Post-Exercise Affect
Mean difference = 0.41, p = .354

29. Affect and Exercise: Results
Low Habit Moderate Habit Strong Habit
Moderate Habit Strong Habit
Do not meet norm Meet norm
3 2,86
2
1,51
1
0
-1
Post-Exercise Affect
Mean difference = 1.35, p < .001

30. Affect and Exercise: Post-exercise Affect
People who do not exercise in line with their habits, feel bad about their performance
This effect is most pronounced in those who have strong exercise habits
Use anticipated regret in exercise interventions?

31. Intermezzo III
Strong exercise habits minimize the intention-exercise gap
Strong habits in combination with strong action plans minimize this gap even further
People with strong habits have strong (negative) affective responses to insufficient exercise
Perhaps we can conclude that exercise habits are relevant for exercise behaviour
Then what predicts exercise habits? Two studies on exercise automaticity

32. Antecedents of exercise automaticity (study 1)
Undergraduate students (66.6% female, mean age = 21.24 (SD = 2.82)
Baseline data
Intention towards sufficient exercise behaviour in the next two weeks
Perceived Behavioural Control towards sufficient exercise behaviour
Affective and Cognitive attitude towards sufficient exercise behaviour
Planning items when - where- what type of exercise behaviour
Follow-up data (baseline + 2 weeks)
Habit strength towards exercise behaviour
Stepwise regression analyses: follow-up habits as dependent variable
Step 1: main effects
Step 2: interaction effects

33. Antecedents of exercise automaticity (study 1)
Step 1: significant T0 predictors of T1 exercise automaticity
Affective attitude: B = .14
PBC: B = .43
Planning when: B = .18
Planning where: B = .18
Exercise behaviour: B = .22
Step 2: significant T0 interactions of T1 exercise automaticity
PBC * Planning when: B=.24

34. Antecedents of exercise automaticity (study 1)
Simple Slope analyses
Low PBC: Planning When - Automaticity relationship is B = .20, p = .001
Mean PBC: Planning When - Automaticity relationship is B = .11, p = .012
High PBC: Planning When - Automaticity relationship is B = .06, p = .274

35. Antecedents of exercise automaticity (study 1)
What predicts increases in exercise automaticity?
You should exercise more
You should enjoy it more
You should feel confident about exercising
You should plan when and where to exercise
When you have low self-efficacy, you need to plan when
When you have high self-efficacy, you do not need to plan when

36. Antecedents of exercise automaticity (study 2)
Three wave study in undergraduate students (n = 288)
Time 0: intention - action planning - habit - exercise behaviour
Time 1: intention - action planning - habit - exercise behaviour
Time 2: habit - exercise behaviour
Structural Equation Models were constructed in AMOS 7.0
Test significance of all paths
Test mediation of T1 variables on T0 - T2 relationships

37. Exercise Intention Habit Planning
Exercise Intention Habit Planning
Exercise Habit
Model fit: χ = 46.86 (9), p < .001, NFI=.98, CFI=.98, RMSEA=.09, AIC=158.86

38. Exercise Intention Habit Planning
Exercise Intention Habit Planning
Exercise Habit
Final model fit: χ = 19.45 (15), p = .149, NFI=1.00, CFI=1.00, RMSEA=.02, AIC=119.46

39. Antecedents of exercise automaticity (study 2)
Exercise T0 predicts exercise T1 (b=.60), intention t1 (b=.14) and habit T1 (b=.19)
Intention T0 predicts intention 1 (b=.49)
Planning T0 predicts Planning T1 (b=.62), exercise T1 (b=.15), and intention T1 (b=.11)
Habit T0 predicts Planning T1 (b=.19), exercise T1 (b=.15), Habit T1 (b=.58), intention T1 (b=.19)
Habit T0 also predicts Habit T2 (b=.45)
Exercise T1 predicts exercise T2 (b=.66)
Habit T1 predicts Habit T2 (b=.45) and Exercise T2 (b=.10)
Intention T1 predicts Habit T2 (b=.16) and Exercise T2 (b=.11)

40. Relevant references
De Bruijn GJ, Rhodes Re, Van Osch L (in press). Does action planning moderate the intention-habit
interaction int the exercise domain? A three-way interaction analysis investigation. J Behav Med
De Bruijn GJ (2011). Exercise habit strength, planning and the theory of planned behaviour: an
action control approach. Psychol Sport Exerc, 12, 106-14
Gardner B, De Bruijn GJ, Lally P (2011). A systematic review and meta-analysis of applications of
the self-report habit index to nutrition and physical activity behaviors. Ann Behav Med, 42, 174-187.
Rhodes RE, De Bruijn GJ, Matheson D (2010). Habit in the physical activity domain: Integration with
intention temporal stability and action control. J Sport Exerc Psychol, 32, 84-98
De Bruijn GJ, Keer M, Conner M, Rhodes, RE (in press). Using implicit associations to understand
fruit consumption behaviour and habit strength relationship. J Health Psychol