Jan gave a talk at the “Action and Time Perception” symposium held in Hildesheim as a part of DGPs. He gave a talk about his research titled “Effect Binding for Undetected Spontaneous Micromovements.” Here, he showed that effect binding may be possible in the absence of voluntary control and may be involved in the awareness of the underlying motor acts. Jan appreciated and enjoyed discussing his finding and other issues related to temporal binding and sense of agency with the symposium organiser Katharina Schwarze and its other participants.

You can read the abstract below:

Microsaccades are small, high-velocity eye movements generated involuntarily during stable fixation. Here, we tested whether human observers are aware of microsaccades and if observers experience effect binding between these miniscule motor acts and their consequences.

In two experiments, we displayed a vertically oriented grating with a rapid temporal phase shift (>60 Hz) that rendered the stimulus invisible during fixation. The grating became briefly visible when it slowed down on the retina, either because the observer generated a microsaccade in the direction of the phase shift (active condition) or when the retinal consequence of a previous microsaccade was replayed (replay condition). In additional control trials, no stimulus was displayed at all.

In Experiment 1, participants reported (1) whether they had perceived the stimulus, (2) believed to have generated an eye movement, and (3) their confidence that the stimulus percept was (or was not) caused by the eye movement. In Experiment 2, a clock face was presented along with the stimulus and participants reported the timing of the grating’s visibility. In both experiments, responses were given in the end of each trial.

Observers’ sensitivity towards microsaccade generation was very low, in particular, when a stimulus was displayed—suggesting that spontaneous microsaccades in fact escape awareness. Temporal adjustments revealed that 7 out of our 10 observers reported stimuli earlier when seen during self-generated compared to replayed microsaccades. We interpret these findings as tentative evidence for effect binding in the absence of voluntary control—or indeed awareness—of the underlying motor acts.