Automatic recognition apparatus (100, 700) includes multiple automatic recognition subsystems (102, 104, 106) that are cable of producing estimates of the probability that a subject matches a particular identity, a probability estimate combiner (108) that receives estimates from the multiple automatic recognition subsystems (102, 104, 106) and produces a combined estimate, and a decayer that (111) that decreases the certainty of the combined estimate over time while avoiding changing estimates to values that would suggest strong information contrary to the initial values of the combined estimates.