Procedure

All trials began with instructions that told participants to rate the subjective cuteness of the presented stimuli. Following a participant’s button press, a mask stimulus consisting of scrambled dots (mean luminance 20.0 cd/m²) and a fixation point in the center of the screen was presented for 3 s. Then, a test stimulus (a face image in an inverted view) was presented at the center of the display for 4 s. Stimulus presentation time (4 s) was determined from the reaction time of the pupil light reflex (Ellis, 1981). Participants rated the cuteness of the face on a 7-point scale (1 = not cute; 7 = very cute) by pressing an assigned key. Participants responded by using a numeric keypad to their right side, but they were not instructed which hand to use. After the key press, the participants could not press the button again to launch the following trial for 3 s. Each participant performed three blocks, which resulted in 60 trials in total. In each block, 20 trials were presented in a random order. This procedure was done in the same way as Kuraguchi and Kanari (submitted), except that the test stimuli were presented upside down.