Long-term memory for concepts by squirrel monkeys

Abstract

Memory for concepts learned previously in three separate experiments was assessed: (1) oddity and dimension-abstracted oddity after a 2.33-year interval, (2) conditional discrimination with conceptual simultaneous and successive cues after a 1.33-year interval, and (3) numerous-ness discrimination involving 2 versus 7 “dots” after a 5-year interval. The strongest evidence for LTM was seen in the monkey retested on the 2 versus 7 dots problem on which he responded correctly on 80% of the first 40 trials. He also met criterion (36 of 40 correct) in 80 trials compared with 300 for his earlier training and with 240 and 360 trials for two monkeys being trained for the first time. There was also evidence that some other monkeys showed significant retention on some oddity and DAO tasks, but the evidence was less clear that a third set of monkeys had shown significant retention for the conditional discrimination task. Discussion considers the confounding of retention measures with the possibility for learning in LTM tasks as well as the need for more information on animals’ LTM for concepts. © 1984, Psychonomic Society, Inc.. All rights reserved.