The Body Action Coding System II: muscle activations during the perception and expression of emotion

Area of Science:

• Psychology
• Neuroscience
• Kinesiology

Background:

• Emotional expression and perception research traditionally focused on facial cues.
• Body postures are increasingly recognized for their role in emotional communication.
• Limited understanding exists regarding the specific muscle activity underlying emotional body language.

Purpose of the Study:

• To expand the Body Action Coding System (BACS) by incorporating additional muscle activity.
• To investigate muscle activation patterns during the active expression of fear and anger.
• To examine subconscious muscle responses during the passive perception of fearful and angry body postures.

Main Methods:

• Utilized surface electromyography (sEMG) to measure muscle activity.
• Assessed activity in neck, forearm, lower back, and calf muscles.
• Recorded muscle responses during both active emotional expression and passive viewing of emotional body language.

Main Results:

• Forearm muscles showed significant activity during anger and moderate activity during fear expression.
• Calf muscles were more recruited during fearful expressions compared to angry ones.
• Subtle, automatic muscle responses occurred during emotion perception, including forearm activation for fear and back muscle activation for anger.

Conclusions:

• The Body Action Coding System (BACS) is the first coding system based on objective muscle activity.
• Distinct muscle activation patterns differentiate the expression and perception of fear and anger.
• This research provides a foundation for developing systems that recognize or generate emotional body language for virtual environments and robotics.