Comparing implementation intention interventions in relation to young adults’ intake of fruit and vegetables

This study tests whether the effectiveness of implementation intention-based interventions to increase fruit and vegetable intake in a young adult population can be enhanced using additional pre-intervention instructions and alternative formats; namely, an ‘if-then’ implementation intention versus a more general, ‘global’ plan that does not explicitly link a situational cue with a goal-directed response. Participants (N?=?557) completed pre-test measures of planning, motivation and behaviour with respect to increasing their fruit and vegetable intake before being randomised to a 3 (intervention format: control vs. ‘if-then’ vs. ‘global’ implementation intentions)?×?2 (pre-intervention instruction vs. no pre-intervention instruction) between-participants design. Results revealed a significant intervention format by time interaction, such that intake significantly increased by 0.50 portions in the if-then format condition compared with 0.31 in the global format and 0.01 in the control condition. These results suggest that ‘if-then’ manipulations are superior in promoting behaviour change in an applied setting. The use of pre-intervention instructions had no additional effect on behaviour, providing evidence for the efficacy of implementation intentions even when experimenter demand is reduced. Evidence is also presented to suggest that reported increases in intake are not related to demand characteristics.     

Evidence for Discontinuity Patterns Across the Stages of Change: A Role for Attitudinal Ambivalence

Cross-sectional analyses of the transtheoretical ("stages of change") model (TTM) can provide valuable information concerning the variables that are likely to shift individuals from one stage to the next. The present study was designed to investigate the roles of theory of planned behaviour (TPB) variables and attitudinal ambivalence across the stages of change. Two samples derived from the general population completed measures of stage, TPB and attitudinal ambivalence with respect to consuming a low-fat diet (n = 148) and eating five portions of fruit and vegetables per day (n = 151). Consistent with previous research, the present study found linear increases in TPB variables across the stages of change. However, as predicted, attitudinal ambivalence showed discontinuity patterns, displaying a quadratic relationship with the stages of change, such that least ambivalence was experienced in the precontemplation and maintenance stages. Discussion of the findings focuses on implications for the development of theory-driven interventions.     

Testing compensatory health beliefs in a UK population

Compensatory health beliefs, beliefs that healthy behaviours can compensate or neutralise unhealthy behaviours, have been proposed as one way of understanding why people engage in health-risk behaviours (Knäuper, B., Rabiau, M., Cohen, O., & Patriciu, N. (2004). Compensatory health beliefs scale development and psychometric properties. Psychology and Health, 19, 607–624). However, measuring compensatory health beliefs has proved a challenge, with several recent studies being unable to replicate the psychometric properties of Knäuper et al.'s (2004) scales. The aims of this study were to: (1) test the factor structure of the compensatory health beliefs scale in the UK, (2) examine the predictive validity of the scale by testing the relationships between compensatory health beliefs and health behaviours over a six-month time interval and (3) assess the 6-month test–retest reliability of the scale. A total of 393 participants completed measures of compensatory health beliefs and health behaviours at two time points separated by six months. The findings were potentially problematic for research into compensatory health beliefs: the factor structure was not confirmed, there was little evidence of predictive validity, and test–retest reliability was poor. Further research is required to understand the operation of compensatory health beliefs and to develop the measurement of compensatory health beliefs.     

Perceptions of source efficacy and persuasion: Multiple mechanisms for source effects on attitudes

When communicators are perceived as likely to bring proposed outcomes to fruition, they have source efficacy. Although perceptions of source efficacy are common in persuasion settings, this construct has received little direct research attention. The present research explored how source efficacy may impact persuasion in different ways at different levels of motivation to process messages. Across three experiments, participants encountered message arguments of varying quality from a source manipulated to be relatively efficacious or inefficacious. When motivation to process the message was low, source efficacy served as a peripheral cue (Experiment 1). When motivation was high, efficacy information learned before the message biased processing of ambiguous messages (Experiment 2), but source efficacy learned after the message affected the amount of confidence people had in their message‐related thoughts (Experiment 3). These effects of source efficacy were distinct from effects of perceived source expertise/credibility. Copyright © 2011 John Wiley & Sons, Ltd.     

Testing multiple means of self-affirmation

The effects of self-affirmation manipulations are not yet well understood because several different affirmation manipulations have been tested using multiple dependent variables. The aim of the present research was to establish whether global self-feelings and self-esteem, or interpersonal positive feelings are affected by affirming the self. Experiment 1 showed that completing a kindness questionnaire led to adolescent girls reporting more positive interpersonal feelings, but no greater self-feelings or self-esteem than completing an opinions (control) questionnaire. Experiment 2 showed again that self-affirmation did not affect self-esteem, and that there were few differences between writing an essay about a cherished value, writing an essay about kindness, or completing a questionnaire about kindness in boosting positive interpersonal feelings. The findings are discussed in relation to self-affirmation theory and the possible practical implications of self-affirmation for aiding the delivery of social and health messages.     

Evaluation of Potential Kidney Donors with the Personality Assessment Inventory: Normative Data for a Unique Population

Many transplant centers require personality assessment and/or psychiatric clearance prior to allowing an individual to donate a kidney. This is a unique cohort for personality assessment, and there is no normative information available for this population on standardized self-report measures such as the Personality Assessment Inventory (PAI). We evaluated a prospective sample of 434 kidney donor candidates with development of normative T-scores relevant to this specific comparison group. Compared to the original normative group from the PAI manual, potential kidney donors are 5–7 T-score points above the mean on PIM, RXR, DOM, and WRM and 4–6 points below the mean on the majority of the remaining scales. Raw score/T score conversion tables are provided. The normative data provided here is meant to supplement the original normative information and aid psychologists in evaluation of this unique medical population.     

Test of a brief theory of planned behaviour‐based intervention to promote adolescent safe sex intentions

The present study tested a brief (303 word) intervention designed to change attitude, subjective norm, and perceived behavioural control regarding a safe sex behaviour in a sample of 16‐ to 18‐year‐olds. Participants (N = 288) were randomized to receive either an experimental intervention or a control (knowledge only) intervention and completed measures of their reactions to the stimuli as well as pre‐ and post‐test measures of theory of planned behaviour variables. The experimental intervention significantly increased message processing (mean between‐group difference = 0.73, 95% CI = 0.40, 1.06; Cohen's d = .52), message acceptance (mean between‐group difference = 0.82, 95% CI = 0.57, 1.07; Cohen's d = .77), subjective norm (adjusted Mean between‐group difference = 0.54, 95% CI = 0.26, 0.81; Cohen's d = .37; mean within‐group difference for intervention condition = 0.59, 95% CI = 0.36, 0.81; Cohen's d = .38) and intention (adjusted Mean between‐group difference = 0.27, 95% CI = 0.02, 0.53; Cohen's d = .20; mean within‐group difference for intervention condition = 0.54, 95% CI = 0.33, 0.75; Cohen's d = .31), but not attitude or perceived behavioural control. The effects of the experimental intervention on intention were mediated solely through subjective norm. The present findings: (a) compare favourably in terms of the effect sizes reported in previous research in this area (mean Cohen's d for within‐group difference for intervention conditions = .009 and .09, for norms and intention, respectively, see Albarracín et al. (2003) ), (b) imply that subjective norms are causally related to intentions, and (c) suggest that interventions designed to change subjective norms (as opposed to communication of risks and fear appeals) might ultimately be effective in changing behaviour.     

From attitudes to behaviour: Basic and applied research on the theory of planned behaviour

The present article traces the development of the theory of planned behaviour, from early research on the attitude-behaviour relationship through the theory of reasoned action. In particular, it is argued that a perceived lack of correspondence between attitude and behaviour led to examination of variables that either moderated (e.g., attitude strength, measurement correspondence) or mediated (behavioural intention) the relationship between attitudes and behaviour. Several meta-analytic reviews provide strong empirical support for the theory of planned behaviour, yet several applied and basic issues need to be resolved. The six papers that make up the remainder of this special issue address several of these issues.     

Predicting uptake of housing services: The role of self-categorization in the theory of planned behaviour

The theory of planned behaviour (TPB) and self-categorization theory (SCT) were used to predict homeless people’s (n = 80) uptake of housing support services. Homeless people’s uptake behaviour was measured one year after a TPB/SCT-based interview schedule was administered. Congruent with previous research, TPB variables were influential predictors of both intention and behaviour. However, the addition of self-categorization variables, such as friendship group norms and identification as a housing support service user, significantly increased the rate prediction for both intention and behaviour, respectively. The implications of the research are firstly, that social cognition models are useful for understanding uptake of housing support services; and secondly, the addition of self-categorization variables aids in exploring the central role that social norms play in understanding the uptake of these services. These findings are discussed in terms of their impact on theory and practice.