Competing speech perception in older and younger adults: behavioral and eye-movement evidence

Abstract

Objectives: The purpose of this study was to examine eye-movement patterns in older and younger adults to identify differences in how they respond to both to-be-attended and to-be-ignored speech.

Design: The study described in this article used an eye-tracking paradigm to provide insight into the factors underlying competing speech understanding in older (n = 23) and younger (n = 22) listeners. Participants attended to a sentence presented in one ear and were instructed to click on a visually displayed word that was heard in that ear while their eye movements were monitored. A foil word also was shown on the screen. Either no sound, steady state noise, or competing speech was presented to the other ear.

Results: Comparisons between younger and older listeners on all three types of indicators measured in this study (percent correct, response time, and eye movement patterns) demonstrated that older adults were more greatly affected by competing speech than were younger adults. Differences between the groups could not be attributed to the presence of hearing loss in the older participants, as performance for all subjects was at ceiling in quiet and none of the performance metrics was significantly associated with degree of hearing loss.

Conclusions: Results of this study support the idea that age-related changes other than lack of audibility or susceptibility to energetic masking negatively affect the ability to understand speech in the presence of a competing message.

Figure 1

Composite audiogram for the older subjects in the present study. The dotted lines represent the range of pure-tone thresholds.

Figure 2

Mean word identification accuracy for each condition. Error bars represent the standard error.

Figure. 3

Mean response time (in msec) for correct trials. Error bars represent the standard error.

Figure 4

Fixation proportion over time to target and foil words, by age group. Individual panels display data in the four experimental conditions.

Figure 5

Probability of fixating on the foil word at any time between onset of the to-be-attended word and the subject's response. Error bars represent the standard error.

Figure 6

Total time fixating on the foil (in msec). Error bars represent the standard error.

Figure 7

Latency between the onset of the to-be-attended word and the first fixation on that word (in msec). Error bars represent the standard error.