Table 2.

Population statistics for both animals jointly and separately

	Both animals			Monkey L			Monkey F
	n	%	p	n	%	p	n	%	p
Error	32 of 115	28	<10⁻¹⁴	19 of 69	28	<10⁻⁹	13 of 46	28	<10⁻⁶
Difficulty	38 of 115	33	<10⁻¹⁹	28 of 69	41	<10⁻¹⁸	10 of 46	22	<10⁻⁴
Balanced error	27 of 115	23	<10⁻¹⁰	17 of 69	25	<10⁻⁷	10 of 46	22	<10⁻⁴
Balanced difficulty	31 of 115	27	<10⁻¹⁴	22 of 69	32	<10⁻¹¹	9 of 46	20	<10⁻³
Congruent balanced error and difficulty	13 of 115	10	<10⁻²¹	9 of 69	13	<10⁻¹⁵	4 of 46	9	<10⁻⁶
Interaction of error and difficulty	18 of 115	16	<10⁻¹³	13 of 69	13	<10⁻⁵	5 of 46	11	<10⁻¹

Based on α = 0.05, shown are the number of significant cells (n), the percentage of these cells in the population (percentage), and the probability (p) of observing this number by chance alone (binomial test, p₀ = α for the main effects, p₀ = α²/2 for the conjunction analysis of congruent balanced error and difficulty). Excluding the four vPM cells has no meaningful effect on the population statistics. Two of the vPM cells have a significant balanced error signal, one of them in conjunction with balanced difficulty.