ABSTRACT
The science of seating involves many facets, one of which is the impact of posture on central nervous system integrity and mental performance. Posture effects were present in the elderly but the young; the greatest lying-sitting-standing differences were among the old unfit group. In 1990, Cann analysed the effects of age, gender, posture-induced arousal, task loading, task difficulty, and length of response-stimulus interval. Cann hypothesized that the tasks which were more difficult would be more sensitive to posture-induced arousal. In some circumstances, like those described in this chapter, posture effects are real, but in many cases, statements such as that catch-phrase, are completely erroneous. The reticular activation system of the brain is located in the brainstem, where it serves as a direct sensory pathway to the cerebral cortex. Testing the hypothesis that an under-aroused central nervous system in the elderly was responsible for a large portion of age-related slowing of behaviour and reaction time, Woods speculated that postural stimulation would improve their reactive performance.
