Validation of the Directional Command Flanker Task

Flanker tasks are among the most popular paradigms for studying conflict resolution, particularly the intuitive “arrows” flanker task. To date, there is no auditory equivalent of this task, potentially due to the risk of perceptual masking. Using the strategy of reducing masking through vocal differences between the two competing talkers, the present study explores the validity of a speech-based flanker task with co-located talkers. One hundred and forty two healthy young participants (aged 18 – 24) participated in three auditory flanker tasks using naturally-produced speech with increasing spectral separation. Stimuli were the command words ‘left’ and ‘right,’ as well as two neutral flankers designed to impose masking effects, one containing only acoustic-phonetic information, and another containing lexical information. On each trial, the target and flanker the target and flanker words were heard concurrently, with participants responding to the direction spoken by the target talker. Classic conflict effects were observed to the incongruent flanker which could not be attributed to masking. As expected, both masking and conflict effects were attenuated by spectral separation. A final experiment with 62 healthy adults (aged 18 – 59) compared the test-retest reliability and distributional properties of this directional command flanker task with the arrows flanker task. The auditory task demonstrated very similar test-retest reliability and evolution of conflict effects over time to the visual task. This pattern of results indicates that the directional command flanker task is highly similar to the arrows flanker task and can be used to quantify inhibitory control in the auditory modality.