[Ken Fabos (OP)]

Goosebumps are often cited as a vestigial response, leftover from raising hackles in our furred ancestors, yet they hold erect hairs that have an easily demonstrated tactile sensory function and extend that sensory capacity to it's furthest distance from the skin. I would argue that goosebumps act to enhance such sensitivity by separating the hair shafts (reducing dampening of small vibrations and movements from hairs that are laid together) and by holding the follicle and hair shaft more firmly, giving better feedback of changes to hair orientation. That this occurs during moments of emotional arousal or fright - when maximum sensory sensitivity is at a premium - seems a bit too good a coincidence. Add to that heightened awareness from the adrenalin response, such tactile sensitivity is enhanced in every way.

I'm surprised and a bit dismayed to find that goosebumps, like the body hair they attach to, are often regarded (even by supposedly well-informed sources) as essentially functionless. I do note that some (but definitely not all) sources do mention the sensory function of hairs, yet I've been unable to find any reference to the role goosebumps play in that.