On the influence of Libet clock parameters on intentional binding and intention timing

The Libet clock method for subjective timing of events is a widely used implicit
agency and intention timing measure. However, to date, it has been unclear how the
properties of the Libet clock stimulus, as well as the participant instructions, affect these two
cognitive phenomena and, by extension, the comparability of results across the volition
literature. This is something this PhD thesis assessed for the very first time.

In a series of experiments, I first investigated how manipulations of the Libet clock
influenced intentional binding, a paradigm based on the Libet clock that provides an implicit
measure of sense of agency. I found that certain manipulations of the clock, namely the
rotation speed and radius, significantly impact on binding. I then moved beyond the clock
stimulus per se and found that manipulations of Libet-style action initiation instructions
influence binding. Finally, I turned the lens on intention timing itself, something the Libet
clock was originally designed to measure. I found that manipulations of the Libet clock speed
and number of clock markings have a significant effect on intention timing judgments.

These findings are discussed in the context of their practical implications for the interstudy
variability in results in volition research, and of their theoretical implications for theories
of sense of agency and intention timing.