自闭症谱系障碍儿童对环境图片威胁知觉的眼动研究

An Eye Movements Study on the Perception of Threat through the Environment-picture Task among Children with Autism Spectrum Disorders

以30名自闭症谱系障碍(ASD)儿童为被试,通过环境图片视觉搜索方式,借助Tobii X120眼动仪记录被试的注视时间和注视次数探讨ASD儿童威胁知觉的特点。结果发现:(1)相比于非威胁目标,ASD儿童对威胁目标对象存在知觉优势,其威胁知觉受刺激类型及矩阵大小的影响。(2)ASD儿童对于全威胁刺激(蛇)的负性图片存在注意固着现象,表现在对全威胁刺激环境图片的注视时间显著增加。(3)眼动技术能够有效地应用于部分ASD儿童的威胁知觉研究。

Threat perception is the mental process in which an individual assesses whether the environment poses any danger or negative stimuli, and whether the individual adopts a certain cognitive or behavioral strategy to cope with possible stresses. Rapid search and perception of threat and reasonable response is a crucial part in children＇s social development, and especially a core premise of their life quality. Existing studies based upon normal subjects have shown that people tend to have selective attention towards emotional threat when processing environment cues with neutral, positive or uncertain valence. However, in view of the physical and mental abilities of individuals with autism spectrum disorders （ASD）, researchers are interested in issues such as whether these individuals have the same threat perception as normal subjects and how to effectively study ASD children＇s threat perception. Therefore, the study mainly focuses on three aspects ： first, whether ASD children have any advantages in perceiving threat in the task; second, how the types of stimulating sources relate to the size of matrix, and whether the two affect the eye movements when ASD children perceive threat; third whether the total fixation duration （ TFD ） and the fixation count （ FC ） on the pictures in all - threatening environment are longer/more than those on pictures in an all -threatening negative environment. In the study, 30 ASD children （28 boys and 2 girls） were chosen as the subjects. Snakes and flower pictures represent the threat- ening stimuli and non - threatening stimuli. All the stimulating pictures consisted of a matrix of four or nine small pictures arranged in a 2 by 2 matrix and a 3 by 3 matrix. Half the matrices were composed of small identical pictures. The other half of the matrices had one small picture that was a target and a different valence picture from other distracter pictures. Subjects were tested individually in a quiet room and were seated approximately 64cm from the computer screen. They were asked to find out the target small picture using the com- puter mouse, and their eye movements were recorded with a Tobii X 120 Eye Tracker. The study revealed that （ 1 ） ASD children had advantages in threat perception, and their threat perception was affected by types of stimulating sources and the size of matrix, especially in the small size matrix of environment - picture task. （2） ASD children had fixed attention towards all - threatening negative environment picture （snake）. In the small size matrix task, ASD children had longer fixation duration in the all - threatening negative environment pictures than in other environment pictures. （ 3 ） Eye - tracker technology made up for the defects in behavioral materials and low ecological validity in traditional studies. The study has arrived at the following conclusions ： firstly, ASD children display a threat superiority effect in the environment - picture task, compared to the non -threat targets; secondly, ASD children have fixed attention towards all -threatening negative environment pictures; finally, eye - tracker technology can be effectively applied to the study of perception of threat in children with ASD, which can provide moire important reference material to further research.