Effect of informational masking on auditory working memory: role of linguistic information in the maskers
Anoop Basavanahalli Jagadeesh ORCID Icon & Ajith Kumar U ORCID Icon
Published online: 26 Jun 2019
Download citation  https://doi.org/10.1080/21695717.2019.1630980 

Select Language​▼
Translator disclaimer
Abstract
Purpose: The current study aimed at observing how informational maskers with varying degrees of linguistic information affect working memory (WM) performance. The linguistic information in the maskers was varied by increasing the number of speakers in the babbles as well as by time-reversal of these babbles.

Method: Backward digit (BD) span was measured on 24 normal-hearing native speakers of Kannada language. BD spans were measured under six background conditions – quiet, 2- and 8-speaker babbles (2SB and 8SB), time-reversed 2- and 8- speaker babbles (2RB and 8RB), and speech spectrum noise. The digits were presented at 75 dB SPL and the SNR was maintained at +5 dB to ensure complete audibility and intelligibility of the target digits. Using an adaptive procedure, BD span was calculated as the average of the last four reversals.

Results: One-way repeated measures ANOVA showed that the 2SB caused the greatest deterioration in the BD spans. The 8SB and the two RBs resulted in significantly better scores than the 2SB, but were statistically no different from each other. The speech spectrum noise caused negligible deteriorations on the BD spans and was statistically similar to the quiet background condition.

Conclusions: Results showed that the lexical-semantic information in the masker (2SB) causes the greatest deterioration in the WM scores, followed by acoustic–phonetic information (8SB and RBs). Energetic masking resulted in minimal deterioration on the BD spans. These results are further discussed based interpretations from different theories and models of working memory and speech perception.

Keywords: Working memory, informational masking, backward digit span