Effect of False Information on Responses in a Signal-Detection Task

Abstract

In a 2-alternative, temporal, forced-choice signal-detection task, observers received degrees of correct information as to the interval in which the signal had occurred. Groups π(100), π(75), and π(50) received correct feedback following every trial in the proportions 1.00, 0.75, and 0.50, respectively. Group π(0) received no information on any trial. 18 observers were run for 400 trials under each combination of 2 E/N0's and the 4 information conditions. Results were (a) detection rate was greatest for π(100) and π(0) within both E/N0's; but (b) rate of Group π(100)>π(0) for low E/N0 and π(0)>π(100) for high E/N0, in agreement with an earlier result obtained in a Yes-No experiment. Are S1EjAk states on trial n independent of S1EjAk states on trial n−1 (where i, j, k=1, 2 and Si=stimulus interval, Ej=experimenter feedback to observer, Ak=response of observer)? That is, are transition probabilities stationary? For both E/N0's: (1) all states for π(0) were stationary; (2) a single state (S2E2Ak) was nonstationary for π(100) groups; (3) half the states (all S2) were nonstationary for π(75); while (4) more than half of the states (S1 and S2 randomly) were stationary for the π(50) groups. (7) First-order sequential effects clearly were strongest under feedback. (8) Detection rates were higher and false-alarm rates lower on trials following EjAk agreements (i.e., j=k) than on disagreement trials (j≠k).