Helping the waiter to hold his tray: Rigid haptic linkage promotes inter-personal motor coordination

Area of Science:

• Neuroscience
• Human Motor Control
• Biomechanics

Background:

• Balancing a tray requires rapid compensation for weight changes when items are removed.
• Self-initiated actions allow for predictable adjustments, unlike external perturbations.

Purpose of the Study:

• To investigate the coordination strategies employed when one or two individuals stabilize a tray during glass removal.
• To understand the role of haptic feedback in multi-person object manipulation.

Main Methods:

• Experimental setup involving one or two participants holding a tray.
• A third person or one of the holders removed a glass from the tray.
• Analysis of compensatory movements and coordination patterns.

Main Results:

• Two individuals stabilizing a tray demonstrated exceptional coordination during glass removal.
• The haptic link provided by the rigid tray significantly contributed to this coordinated response.
• Coordination was observed regardless of whether the glass remover was one of the tray holders or a third party.

Conclusions:

• The rigid platform serves as a crucial haptic link, enabling sophisticated inter-personal coordination for dynamic balance.
• Individuals should wait for a waiter's attention before removing a glass to ensure stability.
• Assisting the waiter by helping to hold the tray can improve stability during item removal.