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.