Table II.

Behavioral data

Contradictoriness	Logical operator
	Universal	Particular
Correct responses (%)
Contradictory	98.0 ± 3.2	97.5 ± 1.9
Not contradictory	97.9 ± 2.2	98.5 ± 1.7
Reaction times (log s)
Contradictory	2.74 ± 0.007 (550 ms)	2.69 ± 0.006 (490 ms)
Not contradictory	2.71 ± 0.006 (513 ms)	2.70 ± 0.006 (501 ms)

In each of the four experimental tasks, mean across subjects (±S.D.) of the percentage of correct responses and of the reaction times, i.e. the time between the question mark appearance and the subject response, after logarithmic transformation. In squared parenthesis the exponential inverse transformation of the mean is indicated to give an idea of reaction time dimension (ms).