Effects of priming thoughts about control on anxiety and food intake as moderated by dietary restraint

Does inhibitory control spill over to eating behaviors? Two preregistered studies of inhibitory spillover effects on food intake and reactions to food stimuli

Overweight and obesity are worldwide conditions associated with detrimental medical and psychosocial outcomes. As inhibitory control deficits are thought to contribute to weight gain, they are a worthwhile target for new approaches. Previous research has shown that the execution of inhibitory control in one domain leads to a concurrent increase of inhibitory control in another domain, an effect denoted as inhibitory spillover effect (ISE). Therefore, we assumed that exertion of inhibitory control in a food-unrelated domain in overweight and normal weight individuals will decrease food intake in a simultaneous bogus taste test (BTT; study 1) as well as increase food-specific response inhibition ability in a stop signal task (SST; study 2). We assumed stronger effects in overweight individuals. In both studies ISE was induced via cognitive priming and compared to a neutral condition in a group of overweight (OW: n = 46 for study 1, n = 46 for study 2) and normal weight (NW: n = 46 for study 1, n = 46 for study 2) individuals. In the ISE condition with an inhibitory control priming task, participants had to learn and retain control-related words while simultaneously performing a BTT (study 1) or SST (study 2). In the neutral condition, participants followed the same protocol, albeit memorizing neutral (i.e., control-unrelated) words. There was no significant interaction of weight group × cognitive priming condition neither regarding food intake (study 1) nor regarding food-related response inhibition (study 2). Cognitive priming, as implemented in the present studies, does not instigate an ISE strong enough to improve inhibitory control during food intake or food-related response inhibition. Relevant practical and theoretical aspects as well as implications for future research on the ISE are discussed.

The effect of item placement on snack food choices from physical and online menus

Previous attempts to promote healthy eating using explicit techniques have not been consistently successful. We therefore investigated an implicit strategy (item placement techniques) to encourage healthy food choices in the context of snack menus. Two experimental studies compared presentation of healthy items in the top, middle, and bottom sections of a snack menu. Study 1 compared these presentations in a physical paper-based menu, while Study 2 used an online menu. Menus consisted of 8 unhealthy and 4 healthy items, arranged in three rows of four in Study 1, and one column of 12 in Study 2. In each study, participants selected one food item from one of the three experimental menus, before completing the Revised Restraint Scale (to determine dietary restraint status). In Study 1 (n = 172), item placement condition did not predict healthiness of food choice. In Study 2 (n = 182), healthy items were most popular from the first section of the menu, in comparison to the middle or last sections. Dietary restraint did not moderate the effect of item placement condition on food choice. In line with nudging principles, our results suggest that item placement techniques could be a potentially powerful tool in promoting healthy choices from online snack menus.

Does measuring body weight impact subsequent response to eating behavior questions?

OBJECTIVES

If being weighed impacts perceptions of eating behavior, it is important that the order of questionnaires and weighing be considered in research and practice. A quasi-experimental study was performed to examine whether being weighed immediately prior to completing a questionnaire affects responses to eating behavior questions. It was hypothesized that being weighed would serve as a priming stimulus and increase measures of dietary restraint, disinhibition, and hunger.

METHODS

Trained researchers collected a sample of volunteers (n = 355) in 8 locations in the United States on two Saturdays in the summer of 2011. Half of the participants were weighed immediately prior to completing the Three Factor Eating Questionnaire (TFEQ), with the remaining half weighed immediately after TFEQ completion.

RESULTS

A priori hypotheses were not supported despite replicating known relationships between weight, dietary restraint and disinhibition. Results indicated that being weighed first produced a difference in differences on disinhibition scores between low restraint score (95% CI = 4.65-6.02) and high restraint score (95% CI = 6.11-7.57) compared to being weighed after questionnaire completion (p = 0.003). However, this relationship was not significant when modeling restraint as a continuous variable, questioning the use of dichotomization.

CONCLUSIONS

Being weighed is unlikely to be a strong enough prime to significantly change scores on eating behavior questionnaires for everyone, but may allow differences in restraint status to become more evident. Researchers assessing dietary restraint should be wary of the possibility of producing different results when treating restraint as continuous or dichotomous, which could lead to different interpretations.

The effects of acute aerobic activity on cognition and cross-domain transfer to eating behavior

Prior studies have demonstrated that a single session of aerobic exercise can enhance cognitive functioning; specifically, the inhibition facet of executive function (EF). Additionally, previous research has demonstrated that inhibitory abilities are essential for effective dietary self-control. However, it is currently unknown whether exercise induced enhancements in EF also facilitate self-control in the dietary domain. The present study sought to determine whether a single session of aerobic exercise enhances EF, and whether there is a transfer effect to dietary self-control. Thirty four undergraduate students were randomly assigned to one of three exercise conditions: (1) minimal exercise; (2) moderate intensity exercise (30% heart rate reserve); (3) vigorous intensity exercise (50% heart rate reserve). After the exercise bout, participants completed three standardized EF tasks followed by a bogus taste test for three appetitive snack foods (milk chocolate and potato chips) and two control foods (dark chocolate and crackers). The amount of food consumed during the taste test was covertly measured. The results revealed a significant main effect of treatment condition on the Stroop task performance, but not Go-NoGo (GNG) and Stop Signal task performance. Findings with respect to food consumption revealed that EF moderated the treatment effect, such that those with larger exercise effects on Stroop performance in the moderate intensity exercise condition consumed more control foods (but not less appetitive foods). These findings support the contention that a single bout of aerobic exercise enhances EF, and may have transfer effects to the dietary domain, but that such effects may be indirect in nature.

Human cognitive function and the obesogenic environment

Evidence is accumulating which suggests that, in addition to leading to unprecedented rates of obesity, the current food environment is contributing to the development of cognitive impairment and dementia. Recent experimental research indicates that many of the cognitive deficits associated with obesity involve fundamental inhibitory processes that have important roles in the control of food intake, implicating these cognitive impairments as a risk factor for weight gain. Here, we review experiments that link obesity with deficits in memory, attentional, and behavioral control and contemplate how these deficits may predispose individuals to overeat. Specifically, we discuss how deficits in inhibitory control may reduce one's ability to resist eating when confronted with the variety of foods and food cues that are ubiquitous in today's environment. Special attention is given to the importance of memory inhibition to the control of eating and appetitive behavior, and the role of the hippocampus in this process. We also discuss the potential etiology of both obesity and obesity-related cognitive impairment, highlighting non-human animal research which links both of these effects to the consumption of the modern "Western" diet that is high in saturated fats and simple carbohydrates. We conclude that part of what makes the current food environment "obesogenic" is the increased presence of food cues and the increased consumption of a diet which compromises our ability to resist those cues. Improving control over food-related cognitive processing may be useful not only for combating the obesity epidemic but also for minimizing the risk of serious cognitive disorder later in life.

Not intending but somewhat willing: the influence of visual primes on risky sex decisions

OBJECTIVES

This article investigates a potential mechanism underlying the 'sexually conservative puzzle' (the scenario where people reporting little to no casual sex intentions nevertheless go on to engage in casual sex).

METHODS

In two experiments, we tested whether people reporting no behavioural intentions (BI) for casual sex were nevertheless more responsive to risk-conducive cues, when compared to those with some BI. Responsiveness to cues was assessed in terms of increases in behavioural willingness (BW) for casual sex.

RESULTS

In Study 1, subliminal priming of sexual images (vs. control images) increased the casual sex BW of male undergraduates, but only among those who had previously reported no BI for casual sex in a baseline survey. In Study 2, these results were replicated using supraliminal priming with a more diverse online sample; effects were not moderated by age, education, or relationship status.

CONCLUSIONS

Overall, these findings suggest that although sexually conservative people often do not plan on having sex (i.e., they have no BI), for some, their reactive, context-sensitive decision-making (i.e., their BW) can be swayed in the presence of risk-conducive cues.

STATEMENT OF CONTRIBUTION

What is already known on this subject? The sexually conservative puzzle occurs when those with low casual sex intentions go on to have casual sex. When experience for a health-risk behaviour is low, behavioural willingness (BW) tends to predict better than behavioural intentions (BI). Risk-inductive cues can increase risk cognitions and behaviour, but there are important individual differences. What does this study add? Among men with low BI for casual sex at baseline, sexual primes increased casual sex BW. It appears that more sexually conservative men are more swayed by sexual cues. Results highlight an interesting and rather unsuspected group of at-risk individuals.

The power of social influence over food intake: examining the effects of attentional bias and impulsivity

Numerous studies have shown that people adjust their intake directly to that of their eating companions. A potential explanation for this modelling effect is that the eating behaviour of others operates as an external eating cue that stimulates food intake. The present study explored whether this cue-reactive mechanism can account for modelling effects on intake. It was investigated whether attentional bias towards dynamic eating cues and impulsivity would influence the degree of modelling. Participants completed one individual session and one session in which an experimental confederate accompanied them. In the first session, eye movements were recorded as an index of attentional bias to dynamic eating cues. In addition, self-reported impulsivity and response inhibition were assessed. The second session employed a between-participants design with three experimental conditions in which participants were exposed to a same-sex confederate instructed to eat nothing, a low or a large amount of M&Ms. A total of eighty-five young women participated. The participants' self-reported impulsivity determined the occurrence of modelling; only low-impulsive women adjusted their intake to that of their eating companion. Attention towards eating cues and response inhibition, however, did not moderate modelling of food intake. The present study suggests that cue-reactive mechanisms may not underlie modelling of food intake. Instead, the results emphasise the importance of social norms in explaining modelling effects, whereas it is suggested that the degree of impulsivity may play a role in whether or not women adhere to the intake norms set by their eating companion.

The influence of trait and induced state impulsivity on food intake in normal-weight healthy women

Previous research has linked overeating and overweight/obesity to impulsivity. To find out whether impulsivity causes overeating and hence overweight and obesity, we attempted to prime the concept of impulsivity in healthy participants. In a within-subjects design one sample participated in two conditions. In both conditions participants did a priming task that either hinted subtly at the concept of impulsivity or that was neutral in content. Each time the priming task was followed by a bogus taste test. Trait impulsivity was measured by means of a behavioural task and self-report. Firstly, we hypothesized that participants would eat more during the taste test after they had been primed with the concept "impulsivity" compared to after the control session. Secondly, we expected that a more impulsive personality would predict a heightened food intake. Thirdly, we expected that impulsivity would predict food intake better than restraint. The results showed that both the self-report measure of impulsivity and the behavioural task predicted food intake. Restraint did not significantly predict food intake. Primed impulsivity did not increase food intake, possibly because the priming effect did not last long enough.

How impulsiveness and variety influence food intake in a sample of healthy women

This study investigates to what extent an impulsive personality, a varied food environment and their interaction influence food intake. We also investigated whether high-impulsives would exhibit more "eating disordered" thoughts and behaviours. Forty-five low-impulsives and forty-one high-impulsives did a bogus taste test with varied or monotonous food. As expected, high impulsives had a higher food intake compared to low impulsives. Moreover, high-impulsives reported significantly more "eating disordered" thoughts and behaviours than low-impulsives. Neither a main effect of variety nor an interaction between variety and impulsivity were found.