Apparatus
Stimuli were presented on an Asus ROG PG278Q monitor (99 Hz, 2560*1440 px, 67.5 cm distance from eye position) in a light- and sound-attenuated room. A chin and forehead rest was used. Psychopy version 2021.2.3 (Peirce et al., 2019) was used to conduct the experiment. Participants’ left eyes were tracked using a video-based Eyelink 1000 tracker (SR research; 1000 Hz). A nine-point calibration and validation of the eye-tracker was performed at the beginning of each block.
Tactile stimulation was delivered using custom-made tappers. A tapper consisted of a cord with a copper coil at the end, in which a small magnet and a pin were embedded. Binary input from the PC could reverse the magnetic field, pushing out the magnet and pin. When applied to the skin, this produced a single brief, non-painful tactile stimulation.