限制性饮食者对体形信息注意偏向研究

发布时间：2018-09-10 07:41

【摘要】：限制性饮食者（restricted eater）是指长期进行饮食限制以达到控制体重或者减轻体重目的的慢性节食者，与临床症状（如神经性厌食，神经性贪食）相比，限制性饮食者在人群中所占比例更大。限制性饮食者和节食者是两个关系密切容易等同的两个概念，而他们既有相似之处也存在着内在区别。限制性饮食被认为能预测饮食失调的发生，并且能够预测其强度。参照对负面身体自我者、饮食失调者等的研究发现，无论是身体意象障碍者和饮食障碍患者等临床被试，还是限制性饮食者、高瘦身倾向个体等非临床被试，他们在加工身体、身材或食物信息时存在注意偏向，表现出对这类信息的高度敏感，并把这种注意偏向解释为对信息的注意警惕或注意敏感，但也有研究发现，注意偏向还可能是由注意的脱离困难引起的；而且又有研究发现，注意偏向还存在另一种成分一注意回避。也就是说，注意偏向的机制可能存在以下三种成分：注意警惕、注意脱离困难和注意回避。限制性饮食者和非限制饮食者在饮食失调发生的早期，对体重体形信息是否存在认知资源分配上的差异，存在差异又表现在那些方面，是仅对超重图片存在注意偏向还是对和体形体重相关的图片都存在注意偏向？存在注意偏向的话，又表现在哪些成分上，是开始的注意警觉还是注意回避？所以，本研究采用体形体重相关的信息作为刺激材料，采用点探测范式，考察不同时程上，注意偏向成分的变化，发现限制性饮食者在体形信息呈现最初（200ms），相比于中性图片，注意更容易朝向胖图和瘦图，从注意脱离指标分析，在一段时间内，认知活动也是朝向体形图片，而在随后的注意中（500ms），却表现出对体形相关图片的注意回避。非限制性饮食者，虽然也存在对体形线索早期的注意警觉，不同的是，仅在胖图上，非限制性饮食者表现出了注意回避。在后期（500ms）的注意偏向中，非限制性饮食者表现出对体形图片的注意脱离困难。当区分限制性饮食者为两类亚型（成功者和失败者）之后，注意成分变得复杂。成功者在注意的最初阶段（200ms）表现出对体形胖瘦图上早期的注意朝向以及认知活动的脱离困难，分析表明，成功者更多的在早期将注意朝向瘦图，对胖图有一定程度上的脱离困难，对胖瘦两种体形图片在注意回避上无显著差异，而在后期（500ms）的注意成分中，对体形图片的都表现出注意回避，且更多的回避瘦图片。失败者在注意早期（200ms）更多的表现出对瘦图片的注意朝向和脱离困难，，对胖图片有注意回避的趋势，而随后（500ms）的注意中失败者对胖图片存在明显的注意回避而对瘦图片给予更多的认知加工表现出注意脱离困难。结合眼动技术能够更好的记录成分的转变，眼动实验发现限制性饮食者对胖身体图片注意偏向的时间进程模式为：早期的注意定向偏向、早期的注意探测加速以及持续到晚期的注意维持，未发现行为实验中的注意回避；对瘦图片一样存在早期注意朝向、探测加速和后期的注意维持；非限制性饮食者对比中性图片对体形图片也存在注意定向偏向，但是对胖图片的注意偏向与中性图片差异并不显著。综合以上研究，限制性饮食者对体形图片存在注意偏向，且对胖瘦图片都表现出警觉——维持，而非限制性饮食者仅表现出对瘦图片的警觉—维持，而对胖图片采取警觉——回避模式，这也许可以解释限制性饮食者出现身体意向障碍进而出现饮食失调的原因。
[Abstract]:Restricted eaters are chronic dieters who have a long-term dietary restriction to achieve weight control or weight loss. Restricted eaters account for a larger proportion of the population than clinical symptoms (such as anorexia nervosa or gluttony nervosa). Restricted eaters and dieters are closely related and easy to eat. Restricted diet is believed to predict the occurrence and intensity of eating disorders. Reference to studies on negative body selves, eating disorders, and other clinical subjects, including people with body image disorders and patients with eating disorders, or restrictions. Non-clinical subjects, such as those with a high lean tendency, exhibit a high degree of attention bias in processing body, body shape or food information, and interpret this attention bias as attention alertness or attention sensitivity to information. However, some studies have found that attention bias may also be caused by attention breaking away from difficulty. Difficult to cause; and studies have found that attention bias has another component, attention avoidance. In other words, the mechanism of attention bias may exist in the following three components: attention alert, attention out of difficulty and attention avoidance. Are there differences in the allocation of cognitive resources, and the differences are shown in those aspects: attention bias only for overweight pictures or attention bias only for pictures related to body weight? If there is attention bias, what are the components of attention bias, which is the initial attention alertness or attention avoidance? Body weight-related information was used as stimulus materials and point-detection paradigm was used to investigate the changes of attentional bias components in different time-course. It was found that the restrictive dieters presented the initial body shape information (200ms). Compared with the neutral pictures, attention was more likely to be directed towards fat and thin pictures. From the analysis of attentional disengagement index, cognitive activities were also observed during a period of time. Non-restrictive dieters showed attentional avoidance of body-related pictures during subsequent attention (500ms). Although early attention to body clues was also observed in non-restrictive dieters, the difference was that only on fat pictures, non-restrictive dieters showed attentional avoidance. Dieters showed difficulty in detaching attention from body image. When restrictive dieters were divided into two subtypes (successful and unsuccessful), attention components became complex. Successful people showed early attention orientation and difficulty in detaching cognitive activity from body image at the initial stage of attention (200 ms). The analysis showed that successful people had difficulty in detaching attention from body image. More attention was paid to lean pictures in the early stage, and more attention was paid to lean pictures. Losers showed more attention avoidance in the early stage of attention (200ms). Attention orientation and detachment difficulty were found in thin pictures, and attentional avoidance tended to be found in fat pictures. Later (500 ms) attention failure showed significant attentional avoidance to fat pictures and showed attentional detachment difficulty in giving more cognitive processing to thin pictures. The temporal patterns of attention bias to fat body pictures in current restrictive dieters are: early attention orientation bias, early attention bias.
There was no attentional avoidance in the behavioral experiment; there were early attentional orientation, detection acceleration and late attentional maintenance in the thin pictures; there was attentional orientation bias in the non-restrictive diet compared with the neutral pictures, but there was attentional bias and neutrality in the fat pictures. The difference is not significant.
Overall, restrictive dieters showed a bias toward body image, and showed vigilance to fat and thin pictures - maintenance, while non-restrictive dieters showed only vigilance to thin pictures - maintenance, and vigilance to fat pictures - avoidance pattern, which may explain restrictive dieters'physical intention disorder progression. And the cause of eating disorders.
【学位授予单位】：鲁东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：B842

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