Postural activity and visual vigilance performance during rough seas.

Background: Motion of a ship at sea often challenges crew performance. In previous studies, the influence of rough weather on stance at sea has been evaluated in terms of the likelihood of staggers or falls. Few studies have evaluated the influence of sea state on visual performance.

Visual vigilance performance and standing posture at sea.

Background: Research on land has demonstrated interactions between visual tasks and the control of stance. Variations in visual tasks can influence postural activity; conversely, changes in stance can influence quantitative measures of visual performance. At sea, crewmembers may alter their bodily movements to compensate for ship motion while simultaneously adjusting movements to optimize visual performance.

Interpersonal postural coordination on rigid and non-rigid surfaces.

When two standing people converse with each other there is an increase in their shared postural activity, relative to conversation with different partners. We asked pairs of participants to converse with each other or with experimental confederates while standing on rigid and nonrigid surfaces. On the rigid surface, shared postural activity was greater when participants conversed with each other than when they conversed with confederates.