A study on cognitive experience in response to vibrational stimuli of various frequencies at different intensities

The present study aimed to evaluate the cognitive experience associated with frequency and intensity by presenting subjects with vibrational stimuli of eight frequencies (10, 50, 100, 150, 200, 225, 250, and 300 Hz) and three intensities (Level 1: 0.25 G, Level 2: 0.38 G, Level 3: 1.3 G). The study participants were right-handed healthy adults (13 male subjects aged 23.2 years ± 0.8 and 7 female subjects aged 22.3 years ± 1.5) with normal cognitive function. The trials consisted of a stimulation phase (0.1 s) and a rest phase (6 s). After all types of stimuli were presented over five trials, a subjective evaluation was completed. As a result, the cognitive characteristic 'weak' was associated with the low frequency band of all intensity levels, while 'strong' was associated with an increase in vibration frequency and intensity. In addition to 'weak' and 'strong', the characteristic 'vibrating' was associated with frequencies above 100 Hz for all intensities. There were differences in cognitive experience, such as 'thick', 'blunt', and 'heavy,' between 100 and 150 Hz based on the level of intensity. In high frequency vibrations, between 200 and 300 Hz, the main characteristics changed to 'fast', 'shallow', and 'light' according to the intensity level. In this study, it was possible to derive cognitive experiences describing weight, unevenness, and thickness at specific intensities and frequencies in addition to the characteristics 'weak' and 'strong', which are typically associated with stimulus strength and frequency. If more diverse tactile properties can be derived through more detailed manipulations of stimulus intensity and frequency, complex linguistic information can then be associated with direct touch.