Aging Effects Of Dual Objective Cost In Visual Search

Visual search is a complex cognitive process,which is an important way for people to obtain information from the outside world.The general visual search process requires individuals to find out specific stimuli from a certain stimulus background and has a high purpose.Simultaneous search for one of two target is slower and less accurate than for a single target.Dual-target cost indicates the competition between two kinds of attention resources and the ability to control the distribution of attention.Because of the complexity of individual visual environment,the research of dual objective search is more practical.Similarly,the increase of the number and complexity of background distraction in the process of visual search will also cause interference to the effective visual search of individuals.In this study,we will continue to explore whether dual-target search will have stable processing costs under different perceptual background distractors conditions.The process of visual search continues throughout a person's life,and the visual search ability of the elderly is affected by sensory and cognitive aging.So,do old adults have stronger dual-target cost effects in dual-target search and in a more complex perceptual context? This study will continue to explore the difference of dual-objective cost between old adults and the young adults under different search setsize.Through the use of eye tracking technology to investigate the visual search process of different search types(single target search,dual target search)and search subsets(4,8,12)for young adults and old adults,to explore the difference in search cost between young adults and old adults.In study 1,40 young adults(YA)and 40 old adults(OA)are recruited and Eyelink 1000 Plus eye tracker is used to track the eye movement trajectory.A mixed experimental design of 2(age: young adults,old adults)×3(search subset: 4,8,12)is adopted to explore the differences of eye movement behavior between YA and OA in simple visual search process.The results show that,compared with YA,OA have a longer search time,a higher search error rate,a longer latency of first target saccade,and a longer decision time.There was an interaction between age and search setsize in response time and accuracy,and there was an interaction between age and search setsize in middle(first target saccade latency)and late(decision time)of eye movement index.This indicates that the elderly have more difficulty in the middle and late eye movement processing than the young in the single target search process.In study 2,40 young adults and 40 old adults are recruited,and the eye movement trajectory of the participants is tracked by using Eyelink 1000 Plus eye tracker,2(age: YA vs.OA)×3(set size: 4,8,12)A mixed experimental design to explore the differences in eye movement behavior between YA and OA in the difficult dual-objective visual search process.The results show that compared with YA,OA have longer search time,higher search error rate,longer saccade latency and longer decision time.There is a significant interaction between age and search type in the middle and late stages of search,with older people showing greater cost in dual-target search.Based on the above,the conclusions are as follows:(1)The inhibition and control ability of the elderly were impaired,and they could not suppress irrelevant interference in the visual search process.(2)With the increase of the difficulty of the search task,the elderly showed worse behavior.Older people tend to adopt more conservative visual search strategies because their visual search ability is weaker than that of younger people.(3)Under the specific cue,the elderly still showed weak search efficiency,indicating the impairment of top-down processing in the elderly.