Changing ‘gut feelings’ about food: An evaluative conditioning effect on implicit food evaluations and food choice

Comparing the effects of inhibitory control training and evaluative conditioning for unhealthy food behaviours

Cognitive Bias Modification (CBM) is hypothesised to reduce unhealthy food preference and consumption through the completion of computerised cognitive training tasks. While there is evidence to suggest that two popular CBM paradigms (Inhibitory Control Training (ICT) and Evaluative Conditioning (EC)) can have a positive influence on food-related outcomes, issues (and inconsistencies) related to task standardisation and control group design make it difficult to evaluate their standalone efficacy. In a pre-registered laboratory study using a mixed experimental design, our aim was to directly compare a single session of ICT and EC on implicit preference, explicit choice and ad-libitum food intake, while ensuring appropriate active control groups were utilised for each training type (in addition to a passive control group). The results revealed that there were no significant differences in terms of implicit preferences, ad-libitum food consumption or food choice. These results provide limited evidence to support the use of CBM as a psychological intervention for unhealthy food choice or consumption. Further work is needed to isolate mechanisms of effect for successful training and identify the most effective CBM protocols for implementation in future studies.

Are commonly used lab-based measures of food value and choice predictive of self-reported real-world snacking? An ecological momentary assessment study

OBJECTIVES

While the assessment of actual food intake is essential in the evaluation of behaviour change interventions for weight-loss, it may not always be feasible to collect this information within traditional experimental paradigms. For this reason, measures of food preference (such as measures of food value and choice) are often used as more accessible alternatives. However, the predictive validity of these measures (in relation to subsequent food consumption) has not yet been studied. Our aim was to investigate the extent to which three commonly used measures of preference for snack foods (explicit food value, unhealthy food choice and implicit preference) predicted self-reported real-world snacking occasions.

DESIGN

Ecological Momentary Assessment (EMA) design.

METHOD

Over a seven-day study period, participants (N = 49) completed three daily assessments where they reported their healthy and unhealthy snack food consumption and completed the three measures of preference (explicit food value, unhealthy food choice and implicit preference).

RESULTS

Our findings demonstrated some weak evidence that unhealthy Visual Analogue Scale scores predicted between-subject increases in unhealthy snacking frequency (OR = 1.018 [1.006, 1.030], p = .002). No other preference measures significantly predicted self-reported healthy or unhealthy snacking occasions (ps > .05).

CONCLUSIONS

These findings raise questions in relation to the association between measures of preference and self-reported real-world snack food consumption. Future research should further evaluate the predictive and construct validity of these measures in relation to food behaviours and explore the development of alternative assessment methods within eating behaviour research.

An EEG study on the effect of being overweight on anticipatory and consummatory reward in response to pleasant taste stimuli

Two-thirds of adults in the United Kingdom currently suffer from overweight or obesity, making it one of the biggest contributors to health problems. Within the framework of the incentive sensitisation theory, it has been hypothesised that overweight people experience heightened reward anticipation when encountering cues that signal food, such as pictures and smells of food, but that they experience less reward from consuming food compared to normal-weight people. There is, however, little evidence for this prediction. Few studies test both anticipation and consumption in the same study, and even fewer with electroencephalography (EEG). This study sought to address this gap in the literature by measuring scalp activity when overweight and normal-weight people encountered cues signalling the imminent arrival of pleasant and neutral taste stimuli, and when they received these stimuli. The behavioural data showed that there was a smaller difference in valence ratings between the pleasant and neutral taste in the overweight than normal-weight group, in accordance with our hypothesis. However, contrary to our hypothesis, the groups did not differ in their electrophysiological response to taste stimuli. Instead, there was a reduction in N1 amplitude to both taste and picture cues in overweight relative to normal-weight participants. This suggests that reduced attention to cues may be a crucial factor in risk of overweight.

The role of associative learning in healthy and sustainable food evaluations: An event-related potential study

Individuals in industrialized societies frequently include processed foods in their diet. However, overconsumption of heavily processed foods leads to imbalanced calorie intakes as well as negative health consequences and environmental impacts. In the present study, normal-weight healthy individuals were recruited in order to test whether associative learning (Evaluative Conditioning, EC) could strengthen the association between food-types (minimally processed and heavily processed foods) and concepts (e.g., healthiness), and whether these changes would be reflected at the implicit associations, at the explicit ratings and in behavioral choices. A Semantic Congruency task (SC) during electroencephalography recordings was used to examine the neural signature of newly acquired associations between foods and concepts. The accuracy after EC towards minimally processed food (MP-food) in the SC task significantly increased, indicating strengthened associations between MP-food and the concept of healthiness through EC. At the neural level, a more negative amplitude of the N400 waveform, which reflects semantic incongruency, was shown in response to MP-foods paired with the concept of unhealthiness in proximity of the dorsal lateral prefrontal cortex (DLPFC). This implied the possible role of the left DLPFC in changing food representations by integrating stimuli's features with existing food-relevant information. Finally, the N400 effect was modulated by individuals' attentional impulsivity as well as restrained eating behavior.

All I Need Is Two: The Clinical Potential of Adding Evaluative Pairing Procedures to Cognitive Behavioral Therapy for Changing Self-, Body- and Food-Related Evaluations

Pairing procedures are among the most frequently used paradigms for modifying evaluations of target stimuli related to oneself, an object, or a specific situation due to their repeated pairing with evaluative sources, such as positive or negative images or words. Because altered patterns of evaluations can be linked to the emergence and maintenance of disordered cognitions and behaviors, it has been suggested that pairing procedures may provide a simple yet effective means of complementing more complex intervention approaches, such as cognitive behavioral therapy (CBT). Here, we summarize recent studies that explored the clinical potential of pairing procedures for improving self-esteem, body satisfaction, and food and consumption preferences. While no study has yet combined pairing procedures with CBT, there are several successful examples of pairing procedures in clinically relevant domains and clinical populations. We discuss potential sources of heterogeneity among findings, provide methodological recommendations, and conclude that pairing procedures may bear clinical potential as an add-on to classical psychotherapy.

Carrots for the donkey: Influence of evaluative conditioning and training on self-paced exercise intensity and delay discounting of exercise in healthy adults

To choose exercise over alternative behaviours, subjective reward evaluation of the potential choices is a principal step in decision making. However, the selection of exercise intensity might integrate acute visceral responses (i.e. pleasant or unpleasant feelings) and motives related to goals (i.e. enjoyment, competition, health). To understand the factors determining the selection of exercise in its intensity and evaluation as a modality, we conducted a study combining exercise training and evaluative conditioning. Evaluative conditioning was performed by using a novel technique using a primary reinforcer (sweetness) as the unconditioned stimulus and physical strain i.e. heart rate elevation as the conditioned stimulus during interval training, using a randomized control design (N = 58). Pre, post-three weeks interval training w/o conditioning, and after 4 weeks follow-up, participants were tested on self-paced speed selection on treadmill measuring heart rate, subjective pleasantness, and effort levels, as well as delay-discounting of exercise and food rewards. Results revealed that the selection of exercise intensity was significantly increased by adaptation to training and evaluative conditioning, revealing the importance of visceral factors as well as learned expected rewards. Delay discounting rates of self-paced exercise were transiently reduced by training but not affected by evaluative conditioning. In conclusion, exercise decisions are suggested to separate the decision-making process into a modality-specific cognitive evaluation of exercise, and an exercise intensity selection based on acute visceral experience integrating effort, pleasantness, and learned rewards.

Shaping Healthy Eating Habits in Children With Persuasive Strategies: Toward a Typology

There is an abundance of evidence that the presentation of unhealthy foods (UHFs) in different media has the power to shape eating habits in children. Compared to this rich body of work with regard to the effects of UHF presentations, studies testing the effects of healthy foods (HFs) are less conclusive. In particular, while the persuasive mechanisms behind HF presentations are well-understood, we lack insights about the role of messages factors, that is, how are (and should) HFs (be) presented in order to foster healthy eating habits in children. This paper tackles this research gap by suggesting the Persuasive Strategies Presenting Healthy Foods to Children (PSPHF) typology, classified along three pillars: (a) composition-related characteristics, (b) source-related characteristics, and (c) information-related characteristics. Against the background of the PSPHF typology, we review the available empirical evidence, outline pressing research gaps, and discuss implications for researchers, health promoters, and program planers.

Exploring Strategies to Optimise the Impact of Food-Specific Inhibition Training on Children's Food Choices

Food-specific inhibition training (FSIT) is a computerised task requiring response inhibition to energy-dense foods within a reaction-time game. Previous work indicates that FSIT can increase the number of healthy foods (relative to energy-dense foods) children choose, and decrease calories consumed from sweets and chocolate. Across two studies, we explored the impact of FSIT variations (e.g., different response signals, different delivery modes) on children's food choices within a time-limited hypothetical food-choice task. In Study 1, we varied the FSIT Go/No-Go signals to be emotive (happy vs. sad faces) or neutral (green vs. red signs). One-hundred-and-fifty-seven children were randomly allocated to emotive-FSIT, neutral-FSIT, or a non-food control task. Children participated in groups of 4-15. No significant FSIT effects were observed on food choices (all values of p > 0.160). Healthy-food choices decreased over time regardless of condition (p < 0.050). The non-significant effects could be explained by lower accuracy on energy-dense No-Go trials than in previous studies, possibly due to distraction in the group-testing environment. In Study 2, we compared computer-based FSIT (using emotive signals) and app-based FSIT (using neutral signals) against a non-food control with a different sample of 206 children, but this time children worked one-on-one with the experimenter. Children's accuracy on energy-dense No-Go trials was higher in this study. Children in the FSIT-computer group chose significantly more healthy foods at post-training (M = 2.78, SE = 0.16) compared to the control group (M = 2.02, SE = 0.16, p = 0.001). The FSIT-app group did not differ from either of the other two groups (M = 2.42, SE = 0.16, both comparisons p > 0.050). Healthy choices decreased over time in the control group (p = 0.001) but did not change in the two FSIT groups (both p > 0.300) supporting previous evidence that FSIT may have a beneficial effect on children's food choices. Ensuring that children perform FSIT with high accuracy (e.g., by using FSIT in quiet environments and avoiding group-testing) may be important for impacts on food choices though. Future research should continue to explore methods of optimising FSIT as a healthy-eating intervention for children.

Friends are not to be eaten: Children are reluctant to eat cookies that share physical and psychological human features due to their desire to relate to the food

Children's food marketers very often use anthropomorphism in advertising as if it is an effective technique aimed at increasing food consumption. However, the evidence supporting this effect is mixed. In this research, we propose that while a food product's humanlike appearance (physical anthropomorphism) may increase consumption, attribution of mental states and emotions (psychological anthropomorphism) to a physically anthropomorphized food product discourages consumption because it facilitates the formation of a social-like relationship with the food. In two studies, we tested this prediction on samples of children. Preschoolers (N = 91 and N = 97) were randomly assigned to one of three conditions in which they were presented with a cookie that was both physically and psychologically anthropomorphized, physically anthropomorphized only, or not anthropomorphized. In two studies, we observed whether children left alone with the cookie would consume it and how quickly it would happen. Additionally, in Study 2, we asked children about their desire to relate to the cookie. The results confirmed that physical anthropomorphism accompanied by psychological anthropomorphism considerably reduced consumption of the cookies compared to both mere physical anthropomorphism and non-anthropomorphism. Moreover, the reduced appetite for cookies that were physically and psychologically anthropomorphized was mediated by the desire to relate to them. We discuss the implications of these results.

Examining cognitive bias modification interventions for reducing food value and choice: Two pre-registered, online studies

There is considerable interest in Cognitive Bias Modification (CBM) as a potential treatment for overweight/obesity. Inhibitory Control Training (ICT: also known as motor response training) and Evaluative Conditioning (EC) are two popular paradigms which rely on associatively learned responses (unhealthy food - > inhibition, or unhealthy food- > negative stimulus, respectively) through repeated cue-response contingencies. Both ICT and EC have demonstrated some effectiveness for reducing food intake, value and/or choice, when administered in the laboratory and online. However, studies have been criticised for inconsistencies in design (e.g. use of inadequate control groups) which makes it difficult to draw robust conclusions. In two pre-registered, online studies our aim was to examine active ICT (study 1: N = 170) and EC (study 2: N = 300) in multiple groups where the cue- > response contingencies were systematically varied (100%, 75%, 50%, 25%), before examining food-cue valuations and hypothetical food choice. In both studies varying the cue- > response contingencies did not lead to significant changes in food-cue devaluation following training. ICT did not substantially influence hypothetical food choice, whereas there was weak evidence that EC reduced choice for unhealthy foods, compared to a control group with 50% cue-response contingencies. Taken together both studies provide limited evidence for online CBM as a viable psychological treatment - at least through the mechanism of food-cue devaluation or changes in healthy and unhealthy food choice. Future research is needed to investigate the factors that contribute towards successful CBM training to critically evaluate the potential for these strategies within interventions.

A Systematic Review Of Implicit Attitudes And Their Neural Correlates In Eating Behaviour

An increasing number of studies suggests that implicit attitudes toward food and body shape predict eating behaviour and characterize patients with eating disorders (EDs). However, literature has not been previously analysed, thus differences between patients with EDs and healthy controls and the level of automaticity of the processes involved in implicit attitudes are still matters of debate. The present systematic review aimed to synthetize current evidence from papers investigating implicit attitudes towards food and body in healthy and EDs populations. PubMed, EMBASE (Ovid), PsycINFO, Web of Science and Scopus were systematically screened and 183 studies using different indirect paradigms were included in the qualitative analysis. The majority of studies reported negative attitudes towards overweight/obese body images in healthy and EDs samples and weight bias as a diffuse stereotypical evaluation. Implicit food attitudes are consistently reported as valid predictors of eating behaviour. Few studies on the neurobiological correlates showed neurostimulation effects on implicit attitudes, but the automaticity at brain level of implicit evaluations remains an open area of research. In conclusion, implicit attitudes are relevant measures of eating behaviour in healthy and clinical settings, although evidence about their neural correlates is limited.

Neurophysiological Effects Associated With Subliminal Conditioning of Appetite Motivations

When attempting to encourage eating, explicitly providing statements like "eating is pleasant" may produce little effect. This may be due to subjective, negatively-valenced narratives evoked by perception of the verb "eating" (e.g., eating →fat →lonely), overriding any explicitly provided eating-pleasant valence information. In our study, we presented eating-related verbs under subliminal visual conditions to mitigate the onset of eating-associated deliberation. Verbs were linked with neutral or positively valenced terms across independent blocks. Modulations of event-related magnetoencephalographic (MEG) components and parietal activations in the alpha range (8-12 Hz) illustrated a significant effect of valence during pre-lexical time windows. We found significantly greater saliva production and declarations of increasing hunger after eating-related verbs were linked with positive terms. Orally reported preferences did not vary between conditions.