Stable eye versus mouth preference in a live speech-processing task

Area of Science:

• Cognitive Psychology
• Psycholinguistics
• Human-Computer Interaction

Background:

• Gaze behavior, specifically looking at the mouth, is crucial for speech perception.
• Previous research primarily used screen-based methods to study eye-mouth gaze patterns.
• The eye-mouth-index (EMI) quantifies looking behavior towards eyes versus mouth.

Purpose of the Study:

• To investigate the eye-mouth-index (EMI) in a live setting during speech processing.
• To determine if EMI differs between familiar (English) and unfamiliar (Finnish) languages.
• To explore the relationship between EMI, language familiarity, and speech perception accuracy.

Main Methods:

• 38 adult participants were observed in a live, face-to-face setting.
• Participants viewed an experimenter speaking sentences in English and Finnish.
• The eye-mouth-index (EMI) was calculated based on gaze patterns.

Main Results:

• No significant difference in EMI was found between familiar and unfamiliar languages.
• Total mouth looking time did not predict sentence identification accuracy.
• EMI was higher during instruction phases compared to speech processing phases.

Conclusions:

• Stable individual differences exist in eye-mouth gaze patterns.
• Gaze behavior during speech processing is flexible and situation-dependent.
• EMI is not solely determined by the need for auditory-visual speech cues.