Defining thumb reach envelopes for handheld devices.

Objective: Our objective is to provide thumb reach envelopes to help guide the placement of controls on handheld devices and to provide useful methods to gather and analyze thumb reach data.

Background: With the proliferation of handheld, interactive devices, such as cameras, mobile phones, game systems, and remote controls, human factors professionals involved in designing these products need data to help guide the placement of controls. Previous studies have not provided adequate two-dimensional thumb reach envelopes for the primary control surfaces of handheld devices.

Not just standing there: the use of postural coordination to aid visual tasks.

Postural control is an integral part of all physical behavior. Recent research has indicated that postural control functions in a manner that facilitates other higher order (suprapostural) tasks. These studies, while showing that postural sway is modulated in a task specific manner, have not examined the form of postural coordination that allows for the achievement of these higher behavioral goals.