THE EFFECTS OF AGEING ON CONTROLLED ATTENTION IN STROOP AND NEGATIVE PRIMING TASKS Julia Mayas, Manuel Sebastián, Francisco Muñoz & Soledad Ballesteros* Department of Basic Psychology II, Universidad Nacional de Educación a Distancia, Madrid, Spain Introduction: The current study examined the effect of aging on context facilitation and conflict processing by comparing the performance of 18 younger and 18 older healthy adults in Stroop color-word and Negative Priming (NP) tasks. The aim of the present study was to test the hypothesis that aging affects executive or controlled inhibition to a greater extent than automatic inhibition.The Stroop effect refers to the observation that people are slower to name the ink color of incongruent color words [1] The NP paradigm is used to study the capacity of the attentional system to inhibit information that is not relevant for the task being performed [2].This is done by measuring the effect on subject’s performance of previously inhibited information that is now relevant (i.e., a previous distracter is now used as target stimulus). It is widely assumed that negative priming is a result of the selection that occurs in the first display. This type of task has been traditionaly considered as a measure of automatic processes in opposite to the controlled attention processes required for the stroop effect. Methods  Participants N= 18 x 2  Material: 4 basic colour words were used as stimuli (red, green, blue and yellow). Each word was displayed in any of the four different ink colours (red-green-blue or yellow). The experiment was performed on a Toshiba M 40-285 laptop with a 15.4” color monitor and a Centrino processor.. E-Prime programming software was used to create the experiment, display stimuli, control timing, and log participants’ responses through a keyboard.  Procedure: Participants sat at about 50 cm in front of the computer screen. A trial started with a black fixation cross displayed at the centre of the computer screen, over a light grey background. After 1000 msec, one of the 4 colour words was presented at the centre of the screen. The stimuli were pseudo randomly presented so that neither the same colour nor the same words were presented on two consecutive trials. Participants were instructed to name the colour of the stimulus, while ignoring the word. The stimulus was present until participant’s response was emitted. The experimenter recorded the response given, for measuring accuracy. The experiment consisted of a block of practice trials and 5 blocks of 48 experimental trials each. In total 240 trials per participant. Design and results: Stroop effect: responses were coded as a function of the congruency between the colour in which the stimulus was displayed and the colour word being presented. - Congruent trials: the colour of the word was the same that the ink colour . - Incongruent trials: the stimulus was presented in a colour different from the one the word designated. The design consisted in a within-participant factors: NCongruency (Congruent or Incongruent). NP effect: responses were coded as a function of the relationship between the colour of the current target word and the color ink presented in the previous trial (distractor). -Ignored Repetition trials were those in which the words of the preceding trial were the same that the colour of the current stimulus. -Control trials were those in which both the target (colour) and the distractor dimension (word) were different from the target and distractor of the previous trial. The design had one within-participant factor: Repetition (Ignored Repetition, Control). Analysis of Stroop effect: A 2 (group) X 2 (N-Congruency) × 2 (N-1 Congruency) repeated measures ANOVA was performed on the mean RTs of all the experimental conditions. The group was manipulated between subjects. The analysis showed a highly significant Stroop effect, as revealed by the main effect of N-Congruency. This effect was showed by faster RT (799.14 ms) in the N- Congruent condition compared with RT in the Incongruent condition (936.32 ms). The between subject group was also significance with slower responses for the older group (941.52 ms) compared with the younger group (793.94 ms). A two-way interaction NCongruency x group was also significance, for older participants the Stroop effect was larger (186 and 89.1 ms for older and young adults, respectively) Analysis of the NP effect: A repeated measures ANOVA was performed with Repetition (Control, Ignored Repetition) as the single factor that resulted significance, The NP effect was observed in both groups: RT was 20 and 26 ms slower (young and older participants, respectively) in the Ignored Repetition than in the Control condition. The no interaction between NP and group revealed that both group showed similar NP effect. Conclusions: One of the major accounts of cognitive aging states that age effects are related to a deficiency of inhibitory mechanisms (Hasher & Zacks, 1988). [3] The present results showed age-related differences in the Stroop task in which older adults performed significantly worse than the younger group. In contrast, performance in the negative priming task did not differ between groups as young and older adult performed similarly. These results suggest that not all the inhibitory mechanisms are impaired in aging. Following the distinction that we took from Nigg [4] between executive and automatic inhibition, we found a greater susceptibility of executive (controlled) inhibition to aging but not in automatic inhibition. References: [1] MacLeod, C. M. (1991). Half a century of research on the Stroop effect: An integrative review. Psychological Bulletin, 109, 163-203. [2] Tipper ( 2001)Does negative priming reflect inhibitory mechanisms? A review and integration of conflicting views. Quaterly Journal of Experimental Psychology, 54, 321-343. [3] Hasher, L., & Zacks, R. T. (1988). Working memory, comprehension, and aging: A review and a new view. In G. H. Bower (Ed. ), The psychology of learning and motivation, 22 (pp. 193-225). Orlando, FL: Academic Press. [4] Nigg, J. T. (2000). On inhibition/disinhibition in developmental psychopathology: Views from cognitive and personality psychology and a working inhibition taxonomy. Psychological Bulletin, 126, 200-246. Figure 1. Mean RTs ( ms) for the 2 Groups in the STROOP- NP Experiment. + + RED YELLOW YOUNG ADULTS OLDER ADULTS YEARS 30.46 (3.9) 75 (7.2) EDUCATION 18 (4.5) 12 (4.1) MMST 30 29.4 (0.68)