MANUAL DEXTERITY PERFORMANCE UNDER REDUCED WORKING TEMPERATURES

This research investigates the relationships between manual dexterity performance, reduced ambient temperatures, exposure time to the ambient temperatures and simple reaction time. Human subject testing, statistical modeling and analyses were used in this research. The objectives of this research were: (1) To determine if a decrement in human manual dexterity performance occurs with a reduction in ambient temperature. (2) To determine if simple reaction time is decreased by exposure to reduced ambient temperatures. (3) To describe the relationships between the cold exposure time, the performance level of a manual task, and the reaction time at reduced ambient temperatures. (4) To determine if the exposure to reduced ambient temperatures alters the MTM-1\u27s element motions, combined motions, and simultaneous motions. This includes (1) identifying the effect of the reduced temperatures on work methods as well as MTM-1 element motions, and (2) recommending a methodology that may yield predictive models for manual tasks under reduced temperatures. The experiment was conducted in a controlled environmental chamber with the hand skin temperature continuously monitored. The manual dexterity performance was analyzed by evaluating a video tape of the assembly task performed. The simple reaction time task involved pushing several sequential lighted push buttons. The performance task scores were the completion time of these tasks. Performance was measured for 12 subjects at six ambient temperatures (35(DEGREES)F, 40(DEGREES)F, 45(DEGREES)F, 50(DEGREES)F, 55(DEGREES)F and 60(DEGREES)F) during one-hour exposure trials. The data analysis indicated that a decrement of manual dexterity performance due to the reduced temperatures does exist. Within the exposure time of one hour, the simple reaction times were not affected by the reduced ambient temperatures. Neither the dexterity performance nor the simple reaction time was significantly different at different exposure times (25, 35, 45 minutes) to the reduced ambient temperature. Recommendations are made for an analysis procedure for tasks at cold working environments using MTM-1