Comparison of discrete and continuous auditory detection for real and simulated over-flight signals

Abstract

Many auditory detection tasks employ discrete stimulus samples, presented during well-defined, brief observation intervals at predictable times. However, real-world listening is a continuous process without clearly defined intervals possessing indicators of when to listen and respond. The current study was designed to investigate the differences between a discrete, interval-based method and a continuous, free-response method. Increasing understanding of differences in methodology leads to a model predicting real-world perception from interval-based laboratory detection data. Real and simulated aircraft over-flight signals were presented to human subjects in a continuous, free-response task in which the subjects indicated when they could detect the signal. The same signals were also divided into 1-s audio files, which were presented to the same subjects in different sequences using a single-interval, forced-choice paradigm. The results indicated that the presentation sequence does not have an effect on human performance. Comparison of psychometric function derived from interval-based and free-response data indicated a shift to higher signal-to-noise ratios on approach when no clear response interval is provided, but the same shift was not observed on departure.