Gloves or clothing significantly raise the threshold
Aliases: interposed-layer tactile attenuation · haptic glove design
What it is
The bare fingertip's tactile threshold is very low, but once contact goes through a glove, clothing, or other material, the threshold rises significantly — the same stimulus that a bare hand easily detects may go entirely unnoticed through a layer of material. How much the threshold rises depends heavily on the material itself: a thin latex glove may have little effect, while a thick winter glove can raise the threshold by more than an order of magnitude. This entry covers the added variable of "contact through material," a different source of interference from changes in the skin's own temperature or condition (covered in the companion entry).
Why it happens
A material layer acts in two ways. First, mechanical attenuation: the material has some thickness and stiffness, so an external force must first deform the material before it is transmitted to the skin, and part of the force is absorbed by the material's elasticity and damping during that deformation — the force actually reaching the receptor is smaller than the force applied. Second, contact-area change: contact through material often spreads pressure that would otherwise be concentrated at one point over a larger area, lowering pressure per unit area and further raising the effective threshold. Thick, soft materials compound both effects, producing the most attenuation; thin, stiff materials (such as the conductive coating on some touchscreen-compatible gloves) attenuate less.
Studying it
Verification uses controlled comparison measurement: the same participants' thresholds are measured bare-handed and through different materials (gloves or fabric of varying thickness and composition), comparing the size of the difference. Engineering work often pairs this with spectral analysis — measuring a material's attenuation curve across vibration frequencies (attenuation of high-frequency vibration through a material is usually more pronounced than attenuation of static pressure) — to inform drive-parameter design for haptic devices meant to work through gloves.
Where it stops holding
The amount of material attenuation is highly frequency-dependent: the same glove may attenuate low-frequency (tens of Hz) vibration far less than high-frequency (several hundred Hz) vibration, so "threshold rises through a glove" is not a single coefficient — it must be discussed alongside the specific drive frequency. A material's attenuation properties can also change with use (glove wear, material ageing), so a factory-measured attenuation figure may not represent the actual state after prolonged use.
Applying it
- For scenarios requiring gloved operation (industrial, medical, outdoor, VR haptic gloves), design haptic feedback drive force/amplitude around "the threshold measured through the target glove material," not the bare-hand threshold — this usually means multiplying the drive energy several times over.
- Prefer driving at a frequency band the material attenuates less: if a glove attenuates one band much less than others, encode the key feedback signal in that band rather than simply raising overall drive strength uniformly.
- How to check: have users wear the glove or clothing actually used in the target scenario and test whether the designed haptic feedback is reliably perceived, rather than validating the effect only bare-handed and assuming it holds through a glove as well.