Understanding the complex relationship humans have with food goes beyond simple nutritional needs; it delves into the realm of attitudes and behaviors that significantly impact eating habits. For individuals practicing restrained eating, these attitudes can be particularly influential. This article explores the methodologies used in a recent study to investigate the intricate impact of implicit food attitudes on eating behaviors, particularly among women who consciously restrain their eating habits to manage their weight. This study, focusing on implicit associations and inhibitory control, offers valuable insights into the psychological underpinnings of our relationship with food.
The research meticulously designed experiments to dissect how our subconscious attitudes toward food can influence eating behaviors. By employing a cohort of 91 female participants identified as restrained eaters, the study leveraged psychological tools like the Implicit Association Test (IAT) and the Food Stop-Signal Task (F-SST) to uncover these hidden biases. The demographic and clinical characteristics of the participants were carefully documented, ensuring a robust understanding of the sample group. These participants, drawn from a university undergraduate population, were screened for restrained eating tendencies using the Restrained Eating subscale of the Dutch Eating Behavior Questionnaire (DEBQ-R). This rigorous screening process ensured that all participants included in the final analysis exhibited a clear pattern of restrained eating, a crucial factor for the study’s focus. Ultimately, after accounting for outliers in reaction time and accuracy, the study focused on a final sample of 78 female participants, randomly divided into three experimental groups: flexible inhibition, food-response, and food-inhibition.
The study’s procedure was ethically approved and pre-registered, adhering to strict APA ethical standards to ensure participant safety and data integrity. Participants were asked to abstain from eating for an hour before the experiment to standardize hunger levels across the sample, minimizing potential confounding variables related to immediate hunger. To maintain the integrity of the study and ensure participants’ naivety regarding its true purpose—investigating the impact of attitudes towards food—, the experiment was cleverly presented as two separate, unrelated studies. Initially, participants completed a demographic questionnaire and rated their hunger and food-related anxiety levels using a visual analog scale (VAS). This was followed by the first Implicit Association Test (IAT). After the first IAT, participants were informed of a mandatory 20-minute wait before continuing, during which they were offered the chance to participate in a “second” study. All participants opted into this “second” study, which was, in fact, the next phase of the experiment. Here, they were randomly assigned to one of the three experimental groups and completed the food stop-signal task (F-SST) tailored to their group. Following the F-SST, a bogus taste test was administered to measure actual food consumption, followed again by VAS questionnaires assessing hunger and food-related anxiety. Participants were then told they would resume the “original” study, completing the second IAT. Finally, they filled out the comprehensive DEBQ and the Depression Anxiety Stress Scales-21 (DASS-21). This carefully orchestrated procedure ensured that the manipulation of food associations through the F-SST, designed to subtly influence attitudes towards food, occurred between the two administrations of the IAT, allowing for the measurement of any shifts in implicit attitudes.
The core of the study relied on two primary measures: the Implicit Association Test (IAT) and the Food Stop-Signal Task (F-SST). The IAT is a cornerstone tool in psychological research designed to measure automatic, or implicit, associations people hold between concepts. In this study, the IAT was adapted to explore implicit attitudes towards food, specifically high-calorie versus low-calorie foods and their association with pleasant or unpleasant words. Participants were tasked with classifying stimuli—either images of food or words—into predefined categories as quickly and accurately as possible. The speed at which participants associate different categories reveals the strength of their implicit biases. The IAT used in this study involved classifying food images (high and low-calorie) and words (pleasant and unpleasant). The test was structured into seven blocks. Practice blocks helped participants familiarize themselves with the task, while critical target blocks measured reaction times when high-calorie foods were paired with pleasant words versus when they were paired with unpleasant words. Faster reaction times when high-calorie foods are paired with pleasant words indicate a more positive implicit attitude towards high-calorie food.
Complementing the IAT, the Food Stop-Signal Task (F-SST) was employed to assess inhibitory control in relation to food stimuli and to experimentally manipulate the association between food and inhibition. Participants were instructed to respond to images appearing on screen – pressing one key for food items and another for non-food items. Crucially, in 25% of trials, a ‘stop-signal’ appeared, instructing participants to withhold their response. The time between the food image (go-signal) and the stop-signal (stop-signal delay or SSD) was dynamically adjusted; becoming shorter after successful inhibitions and longer after failures, thereby precisely measuring individual inhibitory control. The study innovatively manipulated the proportion of food-related stop-signal trials across the three experimental groups to influence attitudes towards food through associative learning. The ‘flexible inhibition’ group experienced an equal distribution of food and non-food stop-signals, creating a balanced association. The ‘food-response’ group had only non-food stop-signals, associating food with the ‘go’ response and non-food with ‘stop’. Conversely, the ‘food-inhibition’ group encountered only food stop-signals, associating food with inhibition. These manipulations were designed to test how altering the learned associations between food and inhibition would impact implicit food attitudes and subsequent eating behavior.
Beyond these implicit measures, the study also incorporated explicit measures of eating behavior and psychological state. The bogus taste test was utilized to directly measure food consumption. Participants were provided with bowls of palatable snacks and asked to taste and rate them, with the total amount consumed secretly recorded as a measure of their actual food intake. To assess broader eating behaviors and emotional states, participants completed the Dutch Eating Behavior Questionnaire (DEBQ) and the Depression Anxiety Stress Scales-21 (DASS-21). The DEBQ provided insights into restrained, emotional, and external eating behaviors, while the DASS-21 measured levels of depression, anxiety, and stress. These questionnaires provided valuable context and helped to understand the relationship between implicit attitudes towards food, explicit eating behaviors, and emotional well-being.
In conclusion, this study meticulously employed a range of psychological methodologies to investigate the nuanced impact of attitudes towards food, particularly implicit attitudes, on eating behaviors in restrained eaters. By combining implicit and explicit measures, and by experimentally manipulating the association between food and inhibition, this research provides a robust framework for understanding the complex interplay between our subconscious biases, cognitive control, and eating habits. The findings from this study are poised to contribute significantly to the field, offering potential avenues for interventions aimed at fostering healthier relationships with food, particularly for individuals struggling with restrained eating and related eating disorders.
