ABSTRACT
Significant decrements in selective attention have been examined when workers need to ignore common stimuli in order to detect infrequent flaws in a product on the assembly line or when selectively attending to a foreman’s oral orders while tuning out background assembly line conversation. In the presence of industrial solvents, metals, pesticides, or other central nervous system toxicants, deficits in selective attention are intensified, as measured by the classic selective attention task known as the Stroop Test (Anger, 1991).
The term selective attention means the ability to respond selectively to certain stimuli while ignoring others. Stroop (1935) initially designed this test to examine the degree of response time interference between two aspects of a stimulus. A subject’s response time without interference was simply the time it took the person to say an underlined colorblock among three displayed colors. In the presence of interference, the longer response times were due to the extra time it took subjects to respond to the ink color rather than the printed color-word which spells a different color. Interference in the task comes from both identifying the ink color, which is more difficult because people are more directed toward reading words, and from response competition between saying the ink color and the color word. Later studies (Flowers and Stoup, 1977; Hock and Egeth, 1970) found response competition to be the stronger of the two interference effects.
