Comparative Cognitive Aging And Its Effects On Working Memory And Saccadic Trade-off Strategies In A Visual Search Task

The comparative visual search task is performed by storing elements of a picture in working memory and by making saccades between two pictures.Both of these processes have certain costs,and when costs change due to changes in the reliability of visual information acquisition(e.g.working memory load,task predictability,etc.),individuals will coordinate between working memory and saccades.The visual search ability of the elderly is affected by sensory and cognitive aging.Reduced visual working memory capacity,slower processing speed,and reduced accuracy may prompt older adults to adopt strategies to compensate for reduced visual acuity and cognitive abilities.In this study,by changing the number of elements and distance of elements in images in the comparison visual search task,we explored the eye movement characteristics of the elderly and the young,and how the elderly and the young coordinate working memory and saccades.Eighteen young adults and Eighteen older adults participated in the study.The Eyelink2000 eye tracker is used to record the eye movements of the subjects during the comparison visual search.The mixed experimental design of 2(age group: young people,old people)×3(number of elements: 3,6,9)×3(distance of elements: 1°,1.5°,2°)was adopted.The dependent variables were total fixation time,fixation counts,saccade number and average fixation time.The experimental data were analyzed by repeated measure variance using SPSS25.0.The results of the experiment show that when the number of elements is small,the change of element distance has no significant effect on comparative visual search,while when the number of elements is large,the increase of element distance will increase the difficulty of comparative visual search.Moreover,with the increase of the number of elements and the increase of the distance of elements,the increase of the total fixation time,fixation counts and saccade number of the elderly was significantly more than that of the young.More importantly,when the number of elements was small,the saccades and average fixation time of the old and young people did not change significantly with the increase of the distance between the elements.When the number of elements was high,the number of saccades of the elderly increased significantly and the average fixation time decreased with the increase of the distance between elements,while the number of saccades of the young people increased significantly and the average fixation time did not change significantly.Based on the above research results,it can be found that the influence of element quantity on distance of different elements is significantly different.There was cognitive aging in the task of comparative visual search.And when the cost of working memory increases,older adults show a trade-off between working memory storage and saccades for information,increasing saccades and decreasing working memory,meaning more cautious strategies to compensate for the effects of cognitive aging.