Table 2.

Learning-Set performance summary by individual.

	Accuracy (percent selection of the correct stimulus)			Response time (seconds to move the cursor to a stimulus)

Monkey	PM blocks	Non-PM blocks	independent samples t-test	PM blocks	Non-PM blocks	independent samples t-test
Chewie	76.19	87.09	t(66) = −1.980, p = .052^u	2.08	2.04	t(1101) = .349, p = .727
Gale	75.00	93.98	t(3) = −.759, p = .503^u	1.71	1.56	t(808) = .742, p = .458
Han	83.93	89.78	t(59) = −1.193, p = .238^u	1.81	1.93	t(176) = −1.760, p = .08^u
Hank	86.29	83.30	t(652) = .924, p = .356	2.09	2.35	t(407) = −3.889, p < .001^u
Lou	89.66	89.06	t(842) = .141, p = .888	1.98	2.07	t(94) = −1.266, p = .209^u
Luke	98.48	97.50	t(704) = .496, p = .620	1.73	1.54	t(699) = 2.412, p = .016
Murph	92.50	94.18	t(327) = −.400, p = .689	2.37	2.22	t(319) = 1.226, p = .221
Obi	95.19	96.46	t(1119) = −.656, p = .512	1.64	1.84	t(184) = 3.521, p = .001^u

Drella	N/A	N/A	N/A	N/A	N/A	N/A
Gabe	N/A	N/A	N/A	N/A	N/A	N/A
Griffin	94.12	90.77	t(62) = 1.346, p = .183^u	2.03	2.07	t(475) = −.104, p = .917
Liam	89.13	94.26	t(49) = −1.421, p = .161^u	1.58	2.08	t(151) = −5.975, p < .001^u
Lily	77.78	80.1	t(30) = −1.385, p = .176^u	1.74	2.45	t(158) = −8.821, p < .001^u
Logan	96.61	98.38	t(675) = −.831, p = .406	1.92	1.99	t(669) = −.508, p = .611
Nala	81.36	88.89	t(66) = −2.161, p = .034^u	1.64	1.99	t(117) = −5.306, p < .001^u
Wren	94.16	92.62	t(35) = −1.386, p = .122^u	1.76	2	t(71) = −2.665, p = .010^u

Note: Plain-text names are rhesus monkeys and italicized names are capuchin monkeys. Two capuchin monkeys (Drella and Gabe) failed to reach criterion on the first level of the task and were therefore removed from the study. Note that only the t-values shown in bold were significant in the predicted direction (six others were significant in the opposite direction). A superscript “u” next to an independent samples t result indicates that the unequal variances version of the test was required.