Frequency Modulation Detection Thresholds are Unrelated to Individual Differences in Verbal Memory Capacity.

Purpose: Psychophysical measures of auditory sensitivity are often used to explain speech recognition outcomes. However, interpretation of performance on these tasks assumes that they are insensitive to other factors, such as cognitive ability. Recent studies have cast doubt on this assumption by observing relationships between cognition and performance on psychoacoustic tasks. Here, we examined the relationship between memory tasks and two tasks designed to measure frequency modulation (FM) detection to determine whether FM detection task performance reflects individual differences in memory capacity. Method: To test for a relationship between FM thresholds and memory capacity, young adults with normal hearing (N = 31, ages 19 - 40 years) completed FM detection tasks using two different designs (three alternative forced choice and Yes/No) and memory tasks (auditory digit span and visual free recall). Results: Psychometric functions differed across the two FM detection task designs and individual differences in performance were reliable, but no significant correlations were found between memory capacity and FM thresholds. Conclusions: In young adults with normal hearing encoding of temporal fine structure and memory capacity are distinct constructs. Thus, previously observed associations between psychophysical and cognitive measures may reflect the shared effects of age- or hearing-related declines.