Date of Award

January 2019

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Psychology

First Advisor

Adam L. Lawson

Second Advisor

D. Alexander Varakin

Third Advisor

Ronald J. Messerich

Abstract

In the “Libet study” the onset of movement-related brain activity preceded the reported time of the conscious intention to move, suggesting that non-conscious brain processes predetermine voluntary movements (Libet, Gleason, Wright, & Pearl, 1983). While the study’s basic results have been replicated, its validity and assumptions have been questioned. Dominik et al. (2017) provided evidence against the study’s assumption that movement and intention to move are distinct events. In this study, in which researchers did not train participants to distinguish between movement and intention, reports for intention and movement were identical. This differed from the Libet study, in which intention was reported significantly earlier in time than movement. The current study sought to replicate the findings of Dominik et al. Participants (N = 22) were assigned to one of two groups. Both groups performed the same tasks, differing only in order of task completion. In both tasks participants made mouse clicks while tracking time via an analog clock. In one task participants reported the moment they initiated their click. In the other participants reported the moment they intended to click. Crucially, when given instructions for the initial task, they were not told about the existence of the other task. Results showed an interaction of group and task, F (1, 970) = 89.571, p < .001, η_p^2 = .085. The most crucial pairwise comparison, on the initial task, revealed no difference in movement and intention reports. These findings suggest that intention reports in the Libet study may be invalid.

Share

COinS