Ledge and wedge: Younger and older adults' perception of action possibilities

Younger (college age) and older adults (65 years or older) decided whether they could squeeze sideways through narrow doorways and inch sideways along narrow ledges while walking over a raised platform. Doorways and ledges varied in width from 0 to 64 cm. Doorway and ledge widths were presented with a psychophysical staircase procedure and each participant received ~ 33 trials per condition. Participants' behaviors were recorded from overhead frontal and side views; doorway and ledge widths were also recorded. At the end of each session, participants' body size was measured in the doorway.