Abstract
In this study, two and three-dimensional slides were made of eight defensive formations as though viewed from six offensive positions in the line (excepting center) and the quarterback position. Two equated groups were trained tachistoscopically at 1/100 sec. with their respective slide series. The group trained with two-dimensional slides had a higher percentage of correct responses (79.3%). After slide training, when tested at one second on football defensive formations with line players, both groups were able to identify the formations with equal accuracy (approximately 95%).