INHIBITORY PROCESSES IN YOUNG AND OLDER ADULTS IN A PICTURE WORD TASK

The present study examines changes in healthy young and healthy older adults in the ability to inhibit partially activated information in a picture/word interference paradigm. On each trial, subjects received a cue (i.e., the word PICTURE or WORD) indicating which of two stimuli the subject should attend to in an upcoming picture/word display. The display always contained a superimposed picture and word (e.g., a pict ure of a DEER with the word TEA printed on it). Following display offs et, and depending upon the initial precue, either a test picture (e.g. , KETTLE) or a test word (e.g., MOOSE) was presented. The subject's ta sk was to determine as quickly and as accurately as possible whether t he test stimulus was related to the cued dimension of the earlier pict ure/word display. The speed to reject an unrelated test item (e.g., pi cture of a KETTLE when the precue was PICTURE) that was related to the ignored dimension of the picture/word display (e.g., the word TEA in the picture/word display) was used as an index of the efficiency of th e inhibitory system. The results indicated that older adults had more difficulty than younger adults inhibiting a to-be-ignored word when it was related to a picture test item, but did not have more difficulty inhibiting a to-be-ignored picture when it was related to a word test item. The results indicate that an age-related deficit in the control of interfering information is dependent upon the fluency of the proces sing routes.