SCT applied to an intervention

A Computerized Social Cognitive Intervention for Nutrition Behavior: Direct and Mediated Effects on Fat, Fiber, Fruits, and Vegetables, Self-Efficacy, and Outcome Expectations Among Food Shoppers.

Eileen S. Anderson, Richard A. Winett, Janet R. Wojcik, Sheila Winett, and Todd Bowden (2001) in Annals of Behavioral Medicine, 23(2):88-100.
Anderson, ES, Winett, RA, Wojcik, RJ. Social cognitive determinants of nutrition behavior among supermarket food shoppers: a structural equation analysis. Health Psychology 2000, 19(5): 479-486

Purpose of study: Examine the impact of self-administered, computer-based intervention on nutrition behavior, self-efficacy, and outcome expectations among supermarket food shoppers.

Population: Supermarket shoppers (96% female, 92% White, mean annual income of $35,000).

Sample size: 277 total (148 control, 129 intervention).

Study Description: Participants accessed grocery store kiosks for tailored messages about healthy eating and received coupons to purchase healthy food ($8-$12). 15 weekly sessions were offered, and most participants accessed 10 segments.

SCT constructs used: Self efficacy, self-regulation, and outcome expectations. The kiosk provided users with personalized nutrition information, behavioral strategies, and goal-setting activities.

Results: Intervention group demonstrated the following:

  • higher levels of nutrition self-efficacy.
  • more positive physical and social outcome expectations.
  • more frequent attainment of goals for consumption of fat, fiber, fruits and vegetables.

Self-efficacy - Was measured using The Nutrition for a Lifetime System (NLS) Food Beliefs Survey which has a total of 48 items and is comprised of three subscales which assess the following areas in nutrition self-efficacy:

  • Increasing fiber and fruit and vegetables (a = .90)
  • Decreasing fat in snacks (a =.88)
  • Decreasing fat in meals (a =.83)

Participants rated their certainty in performing these behaviors on a 10 point Likert scale ranging from: 1 (very sure I cannot) to 10 (very sure I can).

Outcome expectations - Were measured using a 46 item scale that is comprised of four subscales which assess the following areas pertaining to nutrition:

  • Expected family reactions (a=.88)
  • Expected health outcomes (a=.91)
  • Expected budgetary outcome (a=.84)
  • Expected appetite satisfaction (a=.76)

Participants used a 5-point Likert scale to indicate agreement (1=strongly disagree, 5 = strongly agree).

Individual, Social Environmental, and Physical Environmental Influences on Physical Activity Among Black and White Adults: A Structural Equation Analysis.

Source: Lorna Haughton McNeill, Kathleen W. Wyrwich, Ross C. Brownson, Eddie M. Clark, Matthew W. Kreuter in Annals of Behavioral Medicine, 2006, Vol. 31, No. 1, 36-44.

Purpose of study: To examine direct and indirect effects of individual, social environmental, and physical environmental factors on physical activity.

Population and Sample Size: 910 African-American and White lower and middle-income adults between ages 18 and 64.

Study description: Participants were recruited from waiting rooms in Missouri public health centers. They were asked complete to a self-administered survey assessing their current physical activity level and other SCT constructs surrounding exercise.

SCT constructs examined Self efficacy, motivation, social support, environmental factors (neighborhood quality and access to facilities).

Results: Perceptions of the physical environment had direct effects on physical activity. Self-efficacy was the strongest correlate of physical activity, and a positive dose-response relationship was shown between self-efficacy and intensity of physical activity.

Measurement of SCT constructs:

  • Self-efficacy - 7-item scale to rate confidence level on a 5 point Likert scale from 1 (strongly disagree) to 5 (strongly agree). Good internal consistency reliability (a=.87). Questions regarded being physically active when tired or busy, during bad weather, feeling sick, having sore muscles, and recovering from an injury.
  • Motivation - 18-item scale comprised of 3 subscales regarding physical activity. Participants responded used a 5-point Likert scale. Fair internal consistency reliability (intrinsic motivation α=.92; extrinsic motivation for social pressure a=.52; extrinsic motivation for peer acceptance a=.58). Example statements:
    • I want to be physically active to control my weight.
    • I want to be physically active so that others will find me more attractive.
  • Social environment - 6-item scale measuring emotional and informational support using a 5-point Likert scale. Good internal consistency reliability (emotional a=.77; informational a=.77). Example statements:
    • There are people in my life willing to do physical activity with me.
    • I'd be more physically active if I had more information about it.
  • Physical environment - 7-item scale comprised of 2 subscales measuring availability of physical activity facilities and neighborhood quality on a 4-point Likert scale from 1 (very unsafe/unpleasant) to 4 (very safe/pleasant). Good internal consistency reliability (availability of physical activity facilities a=.68; neighborhood quality a=.79; Example statements ask participants to rank the neighborhood's:
    • criminal activity
    • traffic
    • pleasantness for engaging in physical activity