Combined Effects of Noise and Vibration on Mental Performance.
Final rept. Sep 70-Feb 71,
AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OHIO
Pagination or Media Count:
Two experiments were conducted to determine the combined effects of noise and vibration on mental performance. In experiment 1, ten subjects were tested on a combination short term memory and subtraction task during exposure to four different intensities of broadband noise. Another group of ten subjects was tested using the same noise intensities in combination with 0.25g peak vertical vibration at 5Hz. Noise alone, and vibration with low level noise 80 dB and 90 dB re 0.0002 dynesq cm had no adverse effects on task performance while the highest level of noise 110 dB combined with vibration to produce a significant reduction in the number of correct responses. In experiment 2, the second group of subjects used in experiment 1 was tested during exposure to the following conditions no vibration control, vibration at 5 Hz - 0.25g, 7 Hz - 0.30g, and 11 Hz - 0.50g, all combined with 80 dB noise. Subsequently these same vibration conditions were presented with 107 dB noise. High intensity noise and vibration combined to produce a greater decrement in performance than either stressor alone. Vibration at 5 Hz was a more sensitive frequency for mental subtraction performance than 7Hz and 11 Hz when the three frequencies were presented in conjunction with high intensity noise. Author