An alternative test of the adams-creamer decay hypothesis in timing motor responses

Ss were randomly assigned to either a vestibular proprioception (VP) group (N = 30) or a no vestibular proprioception (NVP) group (N = 30). The VP group was tested while supine on a table rotated 60 deg. in the vertical plane and, at the cessation of rotation, Ss estimated a 2-sec. interval. Procedures were identical for the NVP group with the exception that they received no body rotation. All Ss received 40 trials and knowledge of results was given during a 20-sec. intertrial interval. The VP group had significantly smaller mean absolute and algebraic error scores than the NVP group. The difference between the mean variable error scores of the two groups was not significant. Results supported the Adams-Creamer decay hypothesis in terms of absolute error scores and algebraic error scores, but did not support the hypothesis in terms of variable error scores.