A study by Scott-Samuel & Hess found that the perception of element motion is influenced by changes in the spatial appearance within the Ternus display which suggests that apparent motion is mediated entirely by a long-range motion process. Research undertaken by Kramer and Yantis in 1997 found that perceptual grouping of the elements also appears to have important implications. Kramer and his colleagues found an increase in observers perceiving group motion when the elements in the display seemed to form a logical group in contrast to when they were independently arranged.