Brain identification times of letters
Résumé
In the present study, 125 letter-naming response times were recorded for each of the 26 uppercase letters of the alphabet and for 6 participants. The same participants also produced 100 delayed naming times for each letter. They finally participated in an event-related potential (ERP) study, in which individual-letter ERPs were obtained by recording 100 trials per letter and per participant. We first computed a simple linear regression between naming and delayed naming latencies that led to an r2 of .79, indicating that a huge amount of the letter-naming variance is produced by output processes. Second, residuals of the regression were used as variance reflecting letter identification processes and were correlated with the individual- letter ERP variance from 0 up to 200 msec after stimulus onset. Significant repeated correlations were observed from 160 to 180 msec after stimulus onset, suggesting that brain letter identification processes take place within this time window.