Fig. (2) UCS expectancy and unconditioned SCR. a) Learning-related differences in UCS expectancy. UCS expectancy on Early and Late test trials was higher during CS+UCS and CS−UCS trials vs. UCS alone trials. b) Learning-related changes in unconditioned SCR expression were also observed. During Early test trials unconditioned SCRs were diminished on CS+UCS and CS−UCS trials compared to UCS alone trials. No differences were observed between CS+UCS and CS−UCS trials. During Late test trials no differences were observed between CS+UCS, CS−UCS, or UCS alone trials.