Differences in Working Memory Capacity Affect Online Spoken Word Recognition: Evidence From Eye Movements

Area of Science:

• Cognitive Psychology
• Auditory Neuroscience
• Speech Perception

Background:

• Individual differences in working memory capacity are crucial for speech comprehension, particularly in noisy settings.
• Previous research indicates that increased memory load (e.g., digit recall) can slow down spoken word recognition.

Purpose of the Study:

• To investigate how varying memory spans influence the time course of spoken word recognition under different cognitive loads.
• To determine if the impact of memory preload on speech processing differs between individuals with high and low memory spans.

Main Methods:

• Utilized the visual world eye-tracking paradigm to monitor participants' fixation patterns on objects.
• Compared spoken word recognition performance between participants with higher and lower memory spans.
• Manipulated cognitive load by requiring participants to remember either one (low load) or four (high load) spoken digits.

Main Results:

• Memory span differences did not affect word recognition with low cognitive load.
• Under high cognitive load, lower memory span listeners showed a significant delay (approx. 550ms) in discriminating target words from phonologically similar competitors compared to higher span listeners.
• These span differences impacted the online processing timeline but not offline accuracy.

Conclusions:

• The interference effect of memory preload on speech processing is amplified in individuals with smaller memory spans.
• Eye-tracking is a valuable tool for assessing online speech processing and revealing subtle cognitive influences.
• Cognitive capacity differences, even in young adults with normal hearing, are critical factors in understanding speech perception in challenging auditory environments.