Pain Influences The Cognition Of Food Preferences

Pain has evolutionary significance to humans,whereby the behaviors evoked by pain are critical for human survival.Food also plays an indispensable role in human survival and development,but the effect of pain on food preference and its neural mechanism are still unknown.Therefore,the current study will explore the relationship between pain and food preference from different perspectives.All stimulus materials used in the three studies were homemade and evaluated,including low-calorie and non-spicy food,low-calorie and spicy food,high-calorie and non-spicy food,as well as high-calorie and spicy food pictures.In the Study 1,the effects of pain on food preference were investigated from the behavioural level.2(treatment: painful,control)× 2(food energy: low calorie,high calorie)× 2(food pungency: non-spicy,spicy)was used as the three-factor experimental design.Thirty participants(15 females)were asked to complete the task which required them to judge whether like the food in the four categories of pictures or not,their preference and emotional reactions to the food in the picture,as well as subjective preference ratings to actual foods in different treatments.In the Study 2,the effects of pain on the preferential processing of food cues were investigated from the neural response level by adopting event-related potentials(ERP)technique.2(treatment: painful,control)× 2(food energy: low calorie,high calorie)× 2(food pungency: non-spicy,spicy)was used as the threefactor experimental design.Thirty participants(15 females)were asked to complete the task which required them to judge whether like the food in the four categories of pictures or not in different treatments.In the study 3,the gender difference in the effects of pain on food preference was investigated by ERP technique on the basis of the Study 2.2(treatment: painful,control)× 2(food energy: low calorie,high calorie)× 2(food pungency: non-spicy,spicy)× 2(gender: male,female)was used as the four-factor experimental design.Forty participants(20females)were asked to complete the same task in the Study 2.The main results of the study are as following:The study 1 showed that participants’ subjective preference ratings to actual low-calorie and non-spicy foods in the painful treatment were significantly higher than in the control treatment,but this differentiation was absent in subjective preference ratings to other three categories of actual foods,suggesting that pain increases individuals’ preference for lowcalorie and non-spicy foods.The study 2 indicated that compared with the control treatment,P3 and LPP amplitudes over the parietal-occipital region evoked by low-calorie and non-spicy food pictures were significantly larger in the painful treatment,but these differentiations were absent in other three categories of food pictures,suggesting that pain may inhibit individuals’ preferential processing of high-calorie food cues,and meanwhile activate the preferential processing of non-spicy food cues.That is to say,pain increases individuals’ preference for low-calorie and non-spicy foods.The study 3 declared that compared with males,N1 amplitudes over the frontal region of females evoked by low-calorie and non-spicy food pictures were significantly larger in the painful treatment,suggesting that pain may enhance females’ preferences for low-calorie and non-spicy food by redirecting their early attention to low-calorie and non-spicy food cues,but this effect may be not evident in males,suggesting that there is gender difference in the effect of pain on preference for low-calorie and non-spicy foods.In summary,pain can influence individuals’ preference for low-calorie and non-spicy foods.At the level of behavioral responses,pain increased individuals’ subjective preference ratings to actual low-calorie and non-spicy foods,as well as at the level of neural responses,pain inhibited individuals’ preferential processing of high-calorie food cues,and meanwhile activated their preferential processing of non-spicy food cues,which indicates that people may prefer low-calorie and non-spicy foods when they in pain than in the absence of pain,and this effect is more pronounced in females than males.These findings could help us understand how individuals process food cues in painful condition and its gender difference,as well as provide some educational implications for the diet interventions of college students and patients with chronic pain when experiencing pain and the obesity interventions of obese people.The current study not only conducted an empirical study on a phenomenon in daily life,but also provided educational implications for different populations.