In visual and auditory (basic-perceptual) paradigms, degradation of stimuli is common. In vision, there are blurring or contrast change available; in audition there are, e.g., high and low pass filters. Does anyone know if there are paradigms available that allow to degrade haptic stimuli? In the sense that these degradations make the task harder or easier?
As far as I know this degradation would also depend in which scenario you are considering. For example, you could have only unidirectional haptic stimuli (such as simple haptic feedback when you touch your mobile) or bidirectional haptic interaction (where you have position/velocity signal flowing from the operator side and visual/acoustic/force signal flowing from the teleoperator side) which is usually applied in telemanipulation frameworks.
In both cases, I would say that transmission/displaying delay for haptic stimuli is a form of degradation that you could consider. It can be quite critical if you have the second scenario (that I mention is the previous paragraph) in mind since depending on the amount of delay you could even bring the system to unstable behavior.
If you are considering real-time transmission of haptic signals you could also look into packet losses especially if there is data reduction/compression involved. The artifacts that users might perceive highly depend on the prediction approach you employ to cover for the "dropped" samples.
Another aspect that you might want to have a look is the perceptual deadband for haptic signals (which has been often used to aid in the data reduction). You can look for Weber's law for more details but the basic idea is that the human haptic perception is limited and rather relative to the stimulus that is being currently displayed to them. So, we have a larger tolerance to intensity changes if a strong stimulus is being applied, and a lower tolerance if the stimulus is weaker. That means that you could play with the degradation in the signal according to the stimulus intensity and see how that affects task performance.
I hope that helps you a bit. If you have further questions or details that you are willing to disclose so I have a more concrete answer to you, let me me know.
I'm not sure that I understand the question. Are you planning on using a haptic input that can be degraded? And for what purpose? Haptic input is more that touch.
transmission/displaying delay and deadband are really problems. Could these be the main reason for being used with virtual reality applications which restrict them mainly to training activities?
I'm guessing a bit at what your after but based on the examples you give I cant see why you might not use the same approaches as one uses in vision and audition assuming your talking about touch. If so you could use a tactile stimulator consisting of a matrix of piezoelectric actuators. One such device I've seen described is the STReSS2 distributed tactile stimulator (see: http://www.cim.mcgill.ca/~haptic/pub/QW-ET-AL-CHI-06.pdf)
In this case it should be possible to vary the signal to noise ratio to manipulate difficulty. For example if the target is a moving stimulus across the fingertip one could vary the difficulty of detection by varying the number of actuators giving a consistent motion signal to the number out of sych with the motion target.
Haptics is essentially multimodal. It is subserved by a vast range of receptors. And depending on spatial and temporal scale this or that modality can dominate. Compare estimating haptically the shape of an elephant and of portrait on a coin. These two cannot be based on the same type of input.
I agree with the suggestion of David Cottrell. I think that the device he's talking about is the only currently existing commercial solution with such a wide range of possible applications. Yet, it only works for finger-sized object. If you are interested in the perception of large shapes, it's better to consider using existing haptic devices.
If you interested in a perception of texture and small shape details (asperities) a cheap solution would be to attenuate paccinians by applying constant vibration to the sensing part. It masks significant amount of information and your fingers feel half-numb.
This is more about stimuli than paradigms, but you should look at the work of Flip Phillips at Skidmore College. In this paper:
http://www.academia.edu/2819842/Creating_noisy_stimuli
he discusses noisy "degraded" stimuli, and in later work generalizes this to Gibson-like "fee lies" and compares visual and haptic discrimination.
- Badges
- Science topic
- Similar topics
- Psychology