Perceivers vary in their capacity to benefit from feedback in learning to perceive length by dynamic touch

Abstract

Earlier ecologically motivated studies have revealed substantial individual differences in perceptual learning: Individuals varied in their ability to attune to a specifying variable. A possible source of these individual differences is between-subjects variation in the capacity to benefit from feedback. Although this hypothesis was postulated by Withagen & van Wermeskerken (2009), their experiment could not exclude other factors that might be involved. The aim of the present experiment was to provide a more critical test of their hypothesis. To this end, we trained two groups of participants in length perception by dynamic touch in two different learning environments. In one environment, it was easier for a perceiver to separate the perceptual noise from the error that resulted from the detection of a nonspecifying variable. This separation was more difficult to make in the other learning environment. All of the participants responded to the feedback in the easy environment, but not all of them did in the difficult environment. This indicates that individuals indeed differ in their capacities to benefit from feedback. The implications of these results for recent debates on individual differences are discussed.

Transfer of attunement in length perception by dynamic touch

“…Although with the right hand none of the participants continued to rely on the variable, they detected in the pretest only five participants (Participants 1, 4, 5, 11, and 12) learned to detect a specifying variable with this hand. This is in line with earlier studies on length perception with the right hand that showed that participants vary in their ability to learn to detect specifying variables (Menger & Withagen, 2009 ; Rop & Withagen, 2014 ; Withagen & van Wermeskerken, 2009 ). Moreover, the present study demonstrated that participants also vary in the type of transfer.…”

“…Because individuals have been found to vary in their perceptual learning capacities (Menger & Withagen, 2009 ; Rop & Withagen, 2014 ; Withagen & Caljouw, 2011 ; Withagen & van Wermeskerken, 2009 ), we analyzed the learning trajectories of each individual participant as well. To test whether an individual relied on a specifying variable or a nonspecifying variable, we compared for each participant in each test phase the correlation of perceived length and actual length with the correlation of perceived length and the most highly correlated nonspecifying variable, using Williams’ t-statistic (May & Hittner, 1997 ; Williams, 1959 ).…”

“…Second, the low correlations between actual length and I 1 and M , imply that they are poor variables to use for length judgments and therefore will yield clearly detectable errors in the feedback. This increases the chance that a change in variable usage will occur (Jacobs, Runeson, & Michaels, 2001 ; Michaels et al, 2008 ; Rop & Withagen, 2014 ).…”

“…During the past decade, individual differences in dynamic touch have been studied extensively (Arzamarski et al, 2010 ; Michaels et al, 2008 ; Stephen et al, 2010 ; Withagen & Caljouw, 2011 ; Withagen & Michaels, 2005 ). Using a relatively large sample size, Withagen and van Wermeskerken ( 2009 ), for example, observed that participants vary in how they respond to feedback and suggested that perceivers vary in their perceptual learning capacities (Menger & Withagen, 2009 ; Rop & Withagen, 2014 ).…”

“…Hence, if perceivers initially detect, say I 1 , and then learn to detect a specifying variable, their perception of length improves—i.e., rods that are of equal length can first be perceived as being different in length, but when a specifying variable is attuned to, the rods are perceived as being of the same length. Perceivers have been found to be capable of learning to rely on a specifying mechanical variable (Menger & Withagen, 2009 ; Michaels et al, 2008 ; Withagen & Michaels, 2005 ), although large individual differences in this capability have been reported (Rop & Withagen, 2014 ; Withagen & Caljouw, 2011 ; Withagen & van Wermeskerken, 2009 ).…”