The overall goal of this behavioral experiment is to reduce impulsive preference for food during hypothetical intertemporal choices in women by associating food with errors. Given the present rise of eating disorders, this neuroscientific method she6ds light on the crucial role of self-control during food choice. The main advantage of this technique relies on its easy implementation and instructions by the means of a laptop even in clinical settings.
Begin by escorting the participant into a quiet room and sitting them in front of a computer. Collect their demographics, including gender, age, level of education, fasting hours, height and weight. Next, provide the participant with an 11 point Likert scale to collect their self-ratings about feelings of hunger at that moment.
Present a slide show presentation on the computer to randomly display six food pictures with high appetitive value in the female population, one at a time. While each food image is on the screen, simultaneously ask the participant to self-rate the motivation to consume that food item at the moment by using an 11 point Likert scale. Finally, collect the rating sheet and select the two highest rated food items as stimuli for the error task.
Begin by setting up a modified error task to associate the two preselected food stimuli with two different error rates. Include two conditions in which one predicts a low probability of committing an error or LE, and the other predicts a high probability of committing an error, or HE.Use one of the two preselected food items as the cue for the LE condition, called LEFood, and use the other food item as the cue of the HE condition, called HEFood. Randomly intersperse the same number of trials for both conditions.
Once the task has been designed, bring in the participant. Instruct the participant to respond as quickly as possible via a button press to the go signal, which is when the gray scale food item becomes colored, as well as to refrain from responding when a stop signal occurs, which is indicated by a red circle over the colored image. Additionally, inform the participant about all possible feedback, which can be the words correct, error, or too early.
Finally, administer a few training trials as practice with one of the non-selected foods. Then, have the participant complete the error task. After completing the error task, administer two temporal-discounting tasks and a counterbalanced order across participants one at a time, in which one temporal discounting task measures the subjective value for LEFood and the other measures the subjective value for HEFood.
Instruct the participant to make a choice between two options by imagining receiving the specified amount of reward at the specific time. Ask them to indicate their preference by pressing one of the two buttons. Inform them that these are only hypothetical foods and that there is no time limit to make a choice.
For each trial, present a choice between 40 units of fictive food that can be obtained after a variable delay and a smaller amount of the same food available in the immediate present. Then, for the next trial, if the participant chose the smaller option in the previous trial, show a decreased amount for the smaller option. On the other hand, if the participant chose the larger option in the previous trial, show an increased amount for the smaller option.
Repeat this procedure until the participant has made five choices at each delay condition. Then, have them complete a new series of choices at another delay condition. Finally, after completing the experiment, debrief the participant as to whether they were aware of the error manipulation during the error task, and if they think they chose in a different way during the temporal discounting tasks according to the two different foods.
For the error task, participants showed a significantly higher number of errors during the stop trials in the HE condition compared to stop trials in the LE condition. Furthermore, no significant differences in the number of errors during go trials across HE and LE conditions were detected. The two temporal discounting tasks indicated that the discount rate of the HEFood was significantly smaller than the discount rate of the LEFood as determined by baseline hunger.
To clarify the modulatory effect of baseline hunger on the discount rate for future outcomes, a regression analysis showed a significant association between the hunger level and the discount rate of the HEFood. Once mastered, this technique can be done in about one hour, if it's performed properly. After watching this video, you should have a good understanding of how to decrease food choice in patients, in healthy young adult women, by increasing their self-control.
