Frequency and amplitude discrimination along the kinesthetic-cutaneous continuum in the presence of masking stimuli

Abstract

Frequency and amplitude discrimination thresholds along the kinesthetic to cutaneous continuum were evaluated on the left index fingerpad using a multifinger tactual display. Target stimuli were presented either in isolation (no-masker condition) or in the presence of masking stimuli (one- or two-masker conditions). Six reference target signals in the frequency range 2-300 Hz (two each from low-, medium-, and high-frequency regions) and at an amplitude of either 20 or 35 dB sensation levels (SL) were used. In the no-masker condition, the range of frequency Weber fraction was 0.13-0.38 and 0.14-0.28, and the range of amplitude discrimination threshold was 1.82-2.98 dB and 1.65-2.71 dB, at 20 and 35 dB SL, respectively. In the masking conditions, average frequency Weber fractions rose to 0.60 and 0.46, and average amplitude thresholds rose to 3.63 and 3.72 dB, at 20 and 35 dB SL, respectively. In general, thresholds were largest in the two-masker condition and lowest in the no-masker condition. Although the frequency and amplitude thresholds generally increased in the presence of masking stimuli, there was some indication of channel independence for low- and high-frequency target stimuli. The implications of the results for tactual communication of speech are discussed.

Passive and Active Discrimination of Natural Frequency of Virtual Dynamic Systems

“…Previous studies have determined the frequency and period discrimination thresholds (or WF) for low-frequency sinusoidal waveforms on passive fingerpads [20], [24]. However, a human's ability to discriminate the natural frequency of a manually excited dynamic system has not been reported in the literature.…”

“…The vibrotactile and kinesthetic frequency WFs (passive case) varied from 2% to 72%. Variability in the size of WFs was largely due to different experimental conditions, stimulus parameters (frequency and amplitude), and the presence of another stimulus (the masker) along with the target stimulus (see a review in [20]). …”

Controller design and consonantal contrast coding using a multi-finger tactual display

“…The two sensory systems are perceptually independent ͑Bolanowski et Israr et al, 2006͒ and can be utilized simultaneously to improve the transmission of features associated with speech signals. Tan et al ͑1999, 2003͒ formed a set of synthetic waveforms from the two sensory systems and demonstrated that relatively high rates of information could be transmitted through the tactual sense.…”

“…Across the frequency range of dc to 300 Hz, an amplitude of 0 dB sensation level ͑SL͒ ͑decibels above HDT͒ to at least 47 dB SL can be achieved at each frequency, thereby matching the dynamic range of tactual perception ͑Verrillo and Gescheider, 1992͒. Details of the TactuatorII can be found in Israr et al, 2006͑cf. Sec.…”

The design and field observation of a haptic notification system for timing awareness during oral presentations

“…Icons for progress updates, errors, and warnings provide insights for presentation cues [15,44]. Signal perception, usually vibrotactile and on the fingertips, has been examined as a function of intensity [19], duration [44], and tempo and rhythm [12,44]. Information can be expressively conveyed through tactile patterns [5], but at least small numbers of arbitrary mappings can be learned as easily as meaningful ones [11].…”