The Impact of Target Base Rate on Training and Transfer of Learning in Airline Luggage Screening: An Examination of Three Base Rate Scenarios

Summary We examined the extent to which transfer of training is impacted by target probability and physical similarity of training and transfer stimuli. Participants performed a luggage screening task where they trained on three base rates of weapon presence as follows: 100%, 50% and 20%; at transfer, participants detected the same weapons (Study 1) or novel weapons (Studies 2 and 3) at a base rate of 20%. In Study 3, we modified training such that all participants observed the same absolute number of weapons (n = 100) across base rate conditions. In Study 1, different base rates did not significantly impact transfer. In Study 2, 100% base rates helped hit rates at transfer but increased false alarms via liberal shifts in decision criteria and slowed detection times. Study 3 revealed no effect of base rates on transfer hit rates; however, training on 100% base rates still led to liberal responding and inflated false alarms. Copyright © 2013 John Wiley & Sons, Ltd.