We investigated the perceived frequency elicited by two vibrating probes on the skin. Participants ni¾ź=i¾ź11 compared two probes vibrating in counter-phase 25i¾źHz, with comparison stimuli of in-phase vibration 18---54i¾źHz. They indicated which had the higher perceived frequency. Skin sites on the palm glabrous and arm hairy were tested with a range of probe separations 1---16i¾źcm and amplitudes 10---120i¾źµm. Perceived frequency increased with decreasing separation of the probes F1,10i¾ź=i¾ź182.8, pi¾ź<i¾ź0.001. The two skin sites did not significantly differ F1,10i¾ź=i¾ź3.6, pi¾ź=i¾ź0.087. Perceived frequency was only minimally affected by amplitude changes between 40 and 120i¾źμm F2,20i¾ź=i¾ź6.4, pi¾ź=i¾ź0.007, $$ \eta_{G}^{2} = 0.06 $$. Both phase and spatial separation strongly influence vibrotactile interaction between two skin locations in a manner largely independent of changes in amplitude, and of skin type.
['Sarah McIntyre', 'Ingvars Birznieks', 'Robin Andersson', 'Gabriel Dicander', 'Paul P. Breen', 'Richard M. Vickery']
Temporal Integration of Tactile Inputs from Multiple Sites