Madec, S. 1, 2 , Arnaud, R. 1, 2 & Jonathan, G. 1, 2
1 CNRS, France
2 Laboratoire de Psychologie Cognitive, Aix-Marseille University, Marseille, France
How long does it take to identify a simple visual symbol like a letter? We address this general issue by measuring letter identification times for five participants (1) in a naming/delayed naming task and (2) in a perceptual identification task. To obtain an index of letter identification times from the first task, we subtract delayed naming times (indexing voice-key constraints and output processes) from naming times. We found that the resulting mean letter identification times were strongly correlated between participants and within each task. However, the correlation between mean response times per letter across tasks were surprisingly quite low (r[24] = .24) and while letter frequency was correlated with the first task (r[24]=-.49), this was not the case for the second task (r[24]=.07). These results suggest that different task-dependent cognitive processes are involved in each of these experimental paradigms and that there are no task-independent ways of measuring identification times. Simulations done with a simple interactive activation model of letter processing indicate that, in the naming/delayed naming task, lateral inhibition connections at the letter level plays a major role while feedback connections are more important in the perceptual identification task.