The readiness potential reflects intentional binding

Abstract

When a voluntary action is causally linked with a sensory outcome, the action and its consequent effect are perceived as being closer together in time. This effect is called intentional binding. Although many experiments were conducted on this phenomenon, the underlying neural mechanisms are not well understood. While intentional binding is specific to voluntary action, we presumed that preconscious brain activity (the readiness potential, RP), which occurs before an action is made, might play an important role in this binding effect. In this study, the brain dynamics were recorded with electroencephalography (EEG) and analyzed in single-trials in order to estimate whether intentional binding is correlated with the early neural processes. Moreover, we were interested in different behavioral performance between meditators and non-meditators since meditators are expected to be able to keep attention more consistently on a task. Thus, we performed the intentional binding paradigm with 20 mindfulness meditators and compared them to matched controls. Although, we did not observe a group effect on either behavioral data or EEG recordings, we found that self-initiated movements following ongoing negative deflections of slow cortical potentials (SCPs) result in a stronger binding effect compared to positive potentials, especially regarding the perceived time of the consequent effect. Our results provide the first direct evidence that the early neural activity within the range of SCPs affects perceived time of a sensory outcome that is caused by intentional action.

Illusory Temporal Binding in Meditators

“…Finally, activity in the pre-supplementary motor area (preSMA) reflects motor intentions (Lau Rogers Haggard and Passingham 2004). The disruption of activity in the preSMA by repetitive trans-cranial magnetic stimulation (rTMS) has been found to lead to a reduction in outcome binding (Moore et al 2010) and the amplitude of the early readiness potential in the preSMA (associated with motor preparation) has been found to positively correlate with outcome binding (Jo et al 2014). …”

“…Jo et al (2014) reported a non-significant difference in intentional binding between mindfulness meditators and age-matched controls. However, Bayes factors can be employed to test evidence for the null hypothesis (Dienes 2014; Wagenmakers et al in press; Dienes 2016), and in fact a meta-analysis of the results of the two studies provides sensitive evidence for an increase in overall binding and outcome binding (see Supplementary materials).…”

“…Jo et al (2014), the one previous study that has addressed the question of intentional binding in meditators, found no significant difference between meditators and non-meditators in intentional binding. However, a non-significant result does not in itself mean there is no effect.…”

“…These considerations can be used to make different predictions. On the one hand, meditators may be more accurate in their timing estimates due to improvements in metacognition and attention resulting from mindfulness practice (Jo et al 2014). On the other hand, the ability to develop accurate prior expectations concerning the outcome of intentions, and to consistently and reliably use those expectations, could lead to perception of the tone as occurring early.…”

“…If mindfulness increases the relative precision afforded to action timing judgements, then the meditation group should show decreased action binding and increased outcome binding due to improved metacognitive access to motor intentions resulting from a history of sustained attention to intentions and actions. Alternatively, if meditators are more accurate in their timing estimates as a result of improved attentional abilities generally, their reported judgements should be more veridical and they should show less binding of any sort (Jo Hinterberger and Schmidt 2014). …”