In metacontrast a masking stimulus reduces the visibility of an
adjacent target stimulus. This effect has been interpreted in terms of
magno-/parvocellular interactions. It has also been found that a
second masking stimulus, which precedes the primary mask by about 90 ms
reduces the masking effect. This reduction, which is termed “target
recovery,” has been hypothesized to reflect parvocellular inhibition
of the magnocellular system. However, this is problematic because the time
course of this effect is much larger than would be expected from
magno-/parvocellular interactions. For this and other reasons, it is
difficult to understand metacontrast in terms of magno- and parvocellular
mechanisms.