US duration and local trial spacing affect autoshaped responding

摘要: The acquisition and maintenance of signal-directed pecking was examined in week-old Leg-Horn chicks responding to a keylight stimulus paired with heat. In contrast previous studies using pigeons food as the US, both speed asymptotic level keypecking were direct function US duration. Experiment 2 within-subject design isolate effects trial spacing on performance during immediate from following fixed length. These comparisons revealed significant effect intertriai interval (ITI), less after shorter intervals. different temporal apparent trial, but not trial. local ITI better predicted by recent autoshaping model based relative waiting time (Jenkins, Barnes, & Barrera, 1981) than expectancy (Gibbons Balsam, 1981). However, neither A reexamination US-duration literature suggested that diversity findings is consistent assumption conditioned an inverted U-shaped