ABSTRACT
Twenty male graduate students, 22-30 years of age, were asigned by a table of randome numbers to two groups, and visual reaction time performance with and without backscatter was measured. The subjects' task was to observe a 5 cm dial face whose needle deflected 2 mm either left or right of center. Meter deflections were either preceded by 10 light pulse from a Grimes "360 strobe or they were not preceded by light pulses. Two measures of performance were recorded: 1) voice reaction time in milliseconds, and 2) errors. Error rate (3.5%) did not discriminate between groups or conditions. Reaction time was almost twice as long with backscatter than without backscatter (1,556 ms and 854 ms, respectively). This RT increase was highly reliable statistically. Variability of RT performance increased markedly with backscatter. In practical terms, the results suggest that the effects of backscatter could induce a cumulative performace decrement in instrument scanning which might endanger air safety.
