Knowledge of Results After Good Trials Enhances Learning in Older Adults

In recent years, some researchers have examined motor learning in older adults (e.g., Carnahan, Vandervoort, & Swanson, 1996; Daselaar, Rombouts, Veltman, Raaijmakers, & Jonker, 2003); Smith et al., 2005; Wishart & Lee, 1997). Some of these studies have specifically looked at the effectiveness of different manipulations of extrinsic feedback, or knowledge of results (KR). While in young adults decreasing the “usefulness” of feedback often enhances learning (for reviews, see Schmidt, 1991; Swinnen, 1996; Wulf & Shea, 2004), this evidence appears to be somewhat mixed for older adults. While some studies found similar effects of different KR manipulations for younger and older adults (e.g., Carnahan et al., 1996; Swanson & Lee, 1992), others did not find unqualified benefits of making KR more difficult to use for learning in older adults (e.g., Behrman, Vander Linden, & Cauraugh, 1992; Wishart & Lee, 1997; Wishart, Lee, Cunningham, & Murdoch, 2002). In the study by Carnahan et al. (1996), for example, older adults (average age: 75.0 years) practiced a computer-keypressing task with a specified goal time. KR was provided either in a summary format, where KR about each trial was provided only after the completion of a given block of trials, or after every single trial. Similar to what studies with younger adults have shown (e.g., Gable, Shea, & Wright, 1991; Schmidt, Young, Swinnen, & Shapiro, 1989; Schmidt, Lange, & Young, 1990; Yao, Fischman, & Wang, 1994), summary KR resulted in more effective retention performance than did KR provided after every trial. In contrast, other studies did not find learning advantages of more “difficult” KR manipulations, such as reduced KR frequencies, for motor skill learning in older adults (e.g., Behrman et al., 1992; Wishart & Lee, 1997; Wishart, Lee, Cunningham, & Murdoch, 2002). Behrman et al. (1992) used a task that required participants (average age: 69 years) to reproduce a force-time curve, presented on an oscilloscope, by modulating isometric force production of their right elbow extensors. Similar to what Vander Linden, Cauraugh, and Greene (1993) found for young adults using a similar task, concurrent knowledge of performance (KP) was not beneficial to learning, compared to terminal KP (100% or 50%). However, the 50% KP condition did not result in more effective learning than the 100% condition, contrary to Vander Linden et al.’s (1993) findings. Furthermore, Wishart and Lee (1997) did not find differential learning effects as a function of different KR frequencies (100% versus 67%) for older adults (average age: 66.2 years) on a task that required participants to produce a continuous movement comprising three distinct spatial segments with specific timing requirements (although no KR frequency effects were found for younger participants [average age: 19.8 years] either). In the Wishart et al. (2002) study, younger (19–27 years) and older (65–70 years) participants practiced a bimanual coordination task under concurrent or reduced feedback conditions. Older participants not only performed generally less effectively than younger participants, but they also benefited more from concurrent feedback relative to terminal feedback. Finally, in Van Dijk and Hermens’ study (2006), younger adults (20–35 years) were able to utilize myofeedback (i.e., display of electromyographic signal) in a task requiring them to lower trapezius muscle activity, whereas older adults (55–70 years) were not. Knowledge of Results After Good Trials Enhances Learning in Older Adults