We first tested whether the participants' length judgments were more closely tied to actual length after feedback.
The participants put their hand or feet through one of the openings in the curtain to make the length judgments.
To find out whether attunement occurred, we tested for each individual participant which mechanical variables constrained the length judgments of each limb in each test phase.
On each side of the rail, there was an armrest in which the forearm was positioned during the length judgments with the hands.
Remarkably, the dots influenced the line length judgments, even though subjects could not report about the groupings when asked (see also Chan & Chua, 2003).
Surprisingly, after training the left foot, this foot did not show improvement in the length judgments, but the other limbs did (Fig. 3).
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.
However, crossing the effects of age and experience, they found that the differences are attributable primarily to experience and not to age itself: Experience in playing a racket sport was more influential on the length judgments than was age.
In addition, the touching of the curtain with the rod provided also some haptic feedback that has proved to be sufficient to improve length judgments by dynamic touch (Stephen & Arzamarski, 2009).
Moreover, we also observed that for some participants, training an effector did not result in an improvement in length judgments with that limb but led to attunement to a specifying variable with one of the other limbs.
However, we found no significant interaction of test x limb, F 3, 42) = 0.99, p > 0.05, indicating that the improvement in the length judgments with the right foot transferred to all the other limbs (Fig. 3).
