Sensitivity of human tactile inspection

Human performance in an inspection task involving the active probing of cracks in metal cylinders with a hand-held probe was measured. Detection probabilities of novice and experienced inspectors were measured for each of a range of crack widths. For both subject groups, detection probability increased with increasing crack width and with decreasing probe-tip diameter. Novice inspectors given one hour of training had detection probabilities comparable to those of experienced inspectors.