Holcombe:TactileMotion

SUPA Sydney University Perception and Action Lab Primer editing help refcard

• Has anyone measured pure stretch adaptation? Makes a MAE?
• Our effect is orientation selective?
• someone found lack of correlation between pressure thresholds and motion (displacement) thresholds
• Konkle et al. could be multimodal integration during test rather than transfer. Or criterion shift when dunno motion, just go with other modality

Dark after light weird reversals when close eyes

• look in mirror whole time before close eyes, so opposite motion.
• look at periscope or double mirror whole time so doesn't correspond
• stimulus transients trigger the reversals?
• can't fool stretch receptors? is reason why motion corret at begining. Or rather, because wider range of spatiotemporal freqs

These notes refer to results by Tanja Seizova-Cajic and Sarah McIntyre Alex Holcombe . Contact Sarah for information about citing

Literature

Jacono M, Gori M, Sciutti A, Sandini G, Burr D, 2008, "Perception of acceleration and deceleration in visual, tactile and visuo-tactile stimuli" Perception 37 ECVP Abstract Supplement, page 49

Perception of acceleration and deceleration in visual, tactile and visuo-tactile stimuli

M Jacono, M Gori, A Sciutti, G Sandini, D Burr

Psychophysical literature suggests that the human visual system is more sensitive to speed than acceleration (the temporal derivative of velocity). However few studies consider tactile perception of acceleration and none of them analyzes the visual - tactile modality. Here we investigated visual, tactile and bimodal perception of acceleration/deceleration by measuring speed discrimination over a wide range of transient speeds (from 6.8 to 454 cm s-1). The stimuli were physical wheels etched with sinewave profile. They could be seen, felt or concurrently seen and felt. Subjects were presented sequentially with the standard stimulus, characterized by a fixed final velocity and variable accelerations and with the comparison test, which reached different final velocities with maximal acceleration. Subjects had to evaluate in 2AFC protocol which interval contained the faster movement, using only visual, only tactile or bimodal information. We found similar PSEs among visual, tactile, and bimodal tasks considering all the different accelerations. Moreover we investigated the difference between deceleration and acceleration and the integration of bimodal signals characterized by opposite direction of motion.

Gori M, Mazzilli G, Sandini G, Burr D, 2008, "A characteristic 'dipper function' for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities" Perception 37 ECVP Abstract Supplement, page 6 A characteristic 'dipper function' for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities

M Gori, G Mazzilli, G Sandini, D Burr

We measure bimodal and unimodal visual and tactile velocity discrimination thresholds over a wide range of base velocities and spatial frequencies. The stimuli were two physical wheels etched with a sinewave profile that was both seen and felt, allowing for the simultaneous presentation of visual and haptic velocities, either congruent or in conflict. Stimuli were presented in two separate intervals and subjects reported the faster motion in 2AFC using visual, tactile or bimodal information. We found an improvement in the bimodal thresholds well predicted by the maximum likelihood estimation model and not specific for direction. Interestingly, both bimodal and unimodal thresholds showed a characteristic 'dipper function', with the minimum at a given 'pedestal duration'. The 'dip' occurred over the same velocity range at all spatial frequencies and conditions. Most interestingly, a tactile pedestal facilitated a visual test and vice versa, indicating facilitation between modalities and suggesting that the thresholding of these signals occurs at high levels after crossmodal integration.