Three experiments investigated the size and sources of age-related changes in visual imitation. In Experiment 1, young and older adults viewed sequences of quasi-random movements and then reproduced from memory what they had seen. As expected, older adults made more errors in imitation than their younger counterparts. However, older adults seemed to supplement their memory by exploiting an abstracted representation (gist) of a sequence. Experiments 2 and 3 apportioned the observed age-related changes in imitation performance among several possible causes. Experiment 2 showed that changes in precision of visual perception and motor control together accounted for only a small fraction of age-related changes in imitation quality; Experiment 3 showed that the bulk of the age-related changes arose from the older participants' reduced ability to accommodate for increases in memory load, likely caused by diminished ability to encode or retain detailed information about movement sequences. Guided by these results, strategies are proposed for enhancing older adults' imitation learning. Keywordsaging; imitation; gist; motor skill; memory What do tying shoelaces, hitting a golf ball, and square dancing have in common? Each can be learned by imitation, which is a major way that people of all ages acquire and master important skills. Imitation has been widely studied in infants (Elsner, 2007) and young children (Lepage & Théoret, 2007), but almost no attention has been given to the imitation ability of older adults (but see Celnik et al., 2006;Leonard & Tremblay, 2007). This lack of attention is noteworthy because imitation learning is especially important for older adults. For example, imitation learning makes it possible to maximize the physical and cognitive benefits of participation in exercise, dance, and sports activities (Lautenschlager & Almeida, 2006;Studenski et al., 2006). Additionally, imitation is key for mastering everyday tasks that are essential to the maintenance of older adults' healthy independent lifestyle (Czaja et al., 2006).We anticipate that imitation ability changes with age. After all, successful imitation of seen actions requires the cooperation of several processes that change with age. In particular, age- Betts, Sekuler, & Bennett, 2007;Billino, Bremmer, & Gegenfurtner, 2008;Snowden & Kavanagh, 2006), motor control and motor imagery (Christou & Carlton, 2001;Smiley-Oyen, Lowry, & Kerr, 2007), and working memory (Craik & Salthouse, 1992;Gomez-Perez & Ostrosky-Solis, 2006;Peelle & Wingfield, 2005;Salthouse & Coon, 1993;Small, 2001;Verhaeghen, Marcoen, & Goossens, 1993), each of which is essential for successful imitation. We devised tasks that made it possible to characterize each component process's contribution to imitation's overall quality.Most of our experiments ask participants to view and then reproduce from memory a sequence of quasi-random, linked movements (Sekuler, Siddiqui, Goyal, & Rajan, 2003). Each sequence is enacted by a disk that moves across a computer screen while leavi...

Over repeated viewings of motion along a quasi-random path, ability to reproduce that path from memory improves. To assess the role of expectations and sequence context on such learning, subjects eye movements were measured while trajectories were viewed for subsequent reproduction. As a sequence of motions was repeated, subjects' eye movements became anticipatory, leading the stimulus' motions. To investigate how prediction errors affected eye movements and imitation learning, we injected an occasional deviant motion into a well-learned stimulus sequence, violating subjects' expectation about the motion that would be seen. This unexpected direction of motion in the stimulus sequence did not impair reproduction of the sequence. The externally induced prediction errors promoted one-shot learning: During the very next stimulus presentation, their eye movements showed that subjects now expected the new sequence item to reappear. A second experiment showed that an associative mismatch can facilitate accurate reproduction of an unexpected stimulus. After a deviant sequence item was presented, imitation accuracy for sequences that contained the deviant direction of motion was reduced relative to sequences that restored the original direction of motions. These findings demonstrate that in the context of a familiar sequence, unexpected events can play an important role in learning the sequence.

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