Table 3.

Mean amplitudes (μV, standard errors of the mean in parentheses) and their significant difference from 0 μV of the Nd and Pd effects of visual attention on ERPs to written letters at different time windows from appearance of letter.

	Phonological tasks	Non-phonological tasks
150–200 msa	−0.9 (0.3)***	−0.6 (0.1)***
200–250 msa	−0.8 (0.4)*	ns
250–300 msa	ns	ns
300–400 msa	−0.6 (0.2)**	ns
400–500 msa	−0.8 (0.2)**	ns
500–600 msa	ns	ns

The amplitudes were measured from collapsed O1/O2 difference waveforms (see Figure 6) obtained by subtracting ERPs to the visual standard stimuli during the A_P tasks from ERPs to the visual standard stimuli during the V_P task and by subtracting ERPs to the visual standard stimuli during the A_NP tasks from ERPs to the visual standard stimuli during the V_NP task.

^aSignificance from one-sided t-tests Bonferroni corrected for t-tests at 3 latency windows.

^***p < 0.001,

^**p < 0.01,

^*p < 0.05, ns, non-significant. Time windows written in bold font were analyzed further with ANOVAs.