Keeping track of who said what: Performance on a modified auditory n-back task with young and older adults.

Gary R Kidd,Larry E Humes

doi:10.3389/fpsyg.2015.00987

Abstract

A modified auditory n-back task was used to examine the ability of young and older listeners to remember the content of spoken messages presented from different locations. The messages were sentences from the Coordinative Response Measure (CRM) corpus, and the task was to judge whether a target word on the current trial was the same as in the most recent presentation from the same location (left, center, or right). The number of trials between comparison items (the number back) was varied while keeping the number of items to be held in memory (the number of locations) constant. Three levels of stimulus uncertainty were evaluated. Low- and high-uncertainty conditions were created by holding the talker (voice) and nontarget words constant, or varying them unpredictably across trials. In a medium-uncertainty condition, each location was associated with a specific talker, thus increasing predictability and ecological validity. Older listeners performed slightly worse than younger listeners, but there was no significant difference in response times (RT) for the two groups. An effect of the number back (n) was seen for both PC and RT; PC decreased steadily with n, while RT was fairly constant after a significant increase from n = 1 to n = 2. Apart from the lower PC for the older group, there was no effect involving age for either PC or RT. There was an effect of target word location (faster RTs with a late-occurring target) and an effect of uncertainty (faster RTs with a constant talker-location mapping, relative to the high-uncertainty condition). A similar pattern of performance was observed with a group of elderly hearing-impaired listeners (with and without shaping to ensure audibility), but RTs were substantially slower and the effect of uncertainty was absent. Apart from the observed overall slowing of RTs, these results provide little evidence for an effect of age-related changes in cognitive abilities on this task.

Highlights

Many people have difficulty participating in conversations when listening conditions are not ideal
The slow mean response time for this older group was partly due to one listener whose average RT was about 2.6 standard deviations above the group mean. (This subject was retained because performance was above chance and response times showed systematic variation with conditions.) even without this subject, mean performance was still
This study used a modified auditory n-back task with multiple talkers and locations to approximate the demands of a sequential multitalker conversation

Summary

Introduction

Many people have difficulty participating in conversations when listening conditions are not ideal. Speaking with one person face-to-face in a quiet environment is considerably easier than conversing with a group in a noisy restaurant, and the difficulty tends to be greater for older listeners, especially those with hearing loss (Humes, 2002; Humes and Dubno, 2010). Often confounded with background noise, is the presence of multiple talkers participating in a group conversation. Such conversations often take place in noisy environments with the participants talking over each other; but even in a quiet environment with polite turn taking, this can be a challenging listening situation for some listeners. Listening to each new contribution to a conversation while remembering earlier remarks from other talkers and correctly attributing those remarks to the different participants places demands on cognitive abilities that tend to decline with age

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Discussion

Conclusion