Body-scaled transitions in human grip configurations.

This article reports two experiments that were set up to examine the preferred human grip configuration used to displace cubes that varied in length (Lc), mass (Mc), and density (ML3). In particular, the authors sought to provide a more precise test of a dimensional relation between the object and the hand that had previously been shown to predict the grip configuration used to transport an object from one location to another. The experiments examined 2 grip transitions (from 3 digits to 4 digits and from 1 hand to 2 hands) within 2 sets of object conditions. In Experiment 1, cubes with a low density and a small increment in size (1 mm) were used, whereas in Experiment 2, cubes with 2 fixed sizes and small increments in mass were used. The results showed that the body-scaled equation K = logLc + (logMc/a + bMh + cLh), where Mh and Lh are the anthropometric measures of the hand mass and length and a, b, and c are empirical constants, is the body-scaled information that predicts the grip configurations used to displace objects.