Figure 3: Mean number of errors (± SEM) made before reaching criterion in the concurrent discrimination performance for animals with neonatal lesions (Neo-C and Neo-A-ibo) and for animals with adult-onset lesions (Adult-C and Adult-Aibo; data are from Machado and Bachevalier, 2009) that had learned the task for the first time at the age of approximately 4 years. Criterion was set at 90% correct or better over 5 consecutive days.