Bisensory vs summed-unisensory improvement on two speech-reception tasks

Area of Science:

• Cognitive Psychology
• Auditory Perception
• Visual Perception

Background:

• Speech reception performance is enhanced when auditory and visual stimuli are combined (A/V mode) compared to simply summing unimodal scores (A+V mode).
• The differential impact of practice and feedback on A+V versus A/V speech reception modes remains unclear.

Purpose of the Study:

• To investigate whether practice and feedback lead to greater performance improvements in the combined auditory-visual (A/V) speech reception mode or in separate auditory (A) and visual (V) modes.
• To determine the independence of skill acquisition across A, V, and A/V speech reception modalities.

Main Methods:

• Twenty normal young adults participated in a speech reception task using auditory-visual (A/V) stimuli presented on a color TV.
• Participants completed pre- and post-training tests, with a training phase involving feedback on either auditory (A) or visual (V) input, followed by A/V testing.

Main Results:

• Significant improvement was observed in unimodal training (A or V), increasing from 28.8% to 35.0% correct words.
• Performance in the combined A/V mode showed a more substantial improvement, increasing from 68.5% to 86.0% correct words.
• No significant correlation was found between individual improvements in A+V and A/V modes, suggesting independent skill acquisition.

Conclusions:

• Practice and feedback yield greater gains in the combined auditory-visual (A/V) speech reception mode compared to unimodal (A or V) training.
• The acquisition and utilization of auditory, visual, and combined auditory-visual speech reception skills are independent and modality-specific.
• Optimal training conditions may vary for each speech reception mode.