Siva's+Research

=**__//Reaction Time//__**= =__**//Reaction time related to experience//**__= Among the general public, people tend to think of middle age as being roughly 45 years of age, after which there are obvious age-related declines in cognitive-motor functioning. Once “over the hill”, experience and wisdom, the consolation prizes of age, are hoped to be sufficient to either attenuate this decline or at least compensate for it indirectly. Aging research has shown that this general conception is incorrect. There is much evidence that memory and speed on a variety of cognitive tasks may peak much earlier [|[]. However, the pervasive intuition may still have merit if declines are restricted to laboratory tasks and are not noticeable in, or relevant to, real world performance. A complete understanding of the “over-the-hill” intuition would therefore seem to require a look for age-related declines in direct measures of real world performance. =**//__Reaction time at night__//**= The same factors affecting reaction in daylight conditions operate at night. Light level per se, has little effect on reaction time. For example, one study found that under scotopic vision, decreasing light levels by a factor of ten only slowed reaction time by 20-25 msec (1/40 to 1/50 second.) However, there are new variables at work. For example, a light which might have low contrast and low conspicuity during the day because the background is bright could become highly conspicuous at night and produce faster reaction times. Always remember that contrast is what matters: people see contrast, not light. =**//__Reaction time related to age__//**= Although most basic research finds that older people respond slower than younger ones, the data on older drivers' braking times are not entirely clear. One problem is that different studies have used different definitions of older; that is, sometimes "older means 50, sometimes it could mean 70. Moreover, some studies find no slowing of reaction time with age. Instead, they conclude that the older driver's greater experience and tendency to drive slower compensate all or in part for the decline in motor skills.
 * This article should not be interpreted to mean that human perception-reaction time is 1.5 seconds. There is no such thing as the human perception-reaction time. Time to respond varies greatly across different tasks and even within the same task under different conditions. It can range from .15 second to many seconds. It is also highly variable. In many cases, the very concept of perception-reaction time simply doesn't apply. ||

= I got most of my work from [] .=