As an alternative to these global approaches, physiological studies have suggested a piecemeal compensation where corrections, based on efference copy (Duhamel, Colby, & Goldberg,
1992; Goldberg & Bruce,
1990; Sommer & Wurtz,
2004,
2006; Wurtz,
2008), are applied to the representations of only a few attended items on the retinotopic maps of saccade control centers (Gottlieb, Kusunoki, & Goldberg,
1998; Kusunoki, Gottlieb, & Goldberg,
2000). This shift of activity for each target to its expected post-saccadic location, called “remapping,” starts before the target lands and is seen even if the target is removed during or even before the saccade and so never lands there (Duhamel et al.,
1992; Umeno & Goldberg,
2001). The remapping produces a crude spatiotopy for attended items (Cavanagh, Hunt, Afraz, & Rolfs,
2010; Rolfs, Jonikaitis, Deubel, & Cavanagh,
2011), and if it actually underlies the space constancy we experience, then displacements of any unattended items should not be seen (widely reported as the change blindness phenomenon; Cavanaugh & Wurtz,
2004; O'Regan, Rensink, & Clark,
1999; Rensink, O'Regan, & Clark,
1997). Critically, this blindness occurs only for non-attended items (Rensink et al.,
1997). The correction in this “remapping” proposal is applied to individual attended targets, and so, unlike global correction schemes, there is no assumption that the correction be the same everywhere. It is the same efference copy vector that drives the correction for each target, but the conversion of the vector to a shift on the roughly log polar coordinates of the saccade control maps is idiosyncratic to each location and direction. Indeed, in two models of this process (Keith & Crawford,
2008; Quaia, Optican, & Goldberg,
1998), the link between the target location and the saccade vector that predicts the post-saccadic location must be learned independently for each location and saccade. Location-specific mislocalizations are a general property of peri-saccadic position judgments (Honda,
1989; Matin & Pearce,
1965) and specifically of the compression effects seen around the time of the saccade (Morrone, Ross, & Burr,
1997; Ross, Morrone, & Burr,
1997). If these effects are related to the updating of locations required for spatial constancy, they are most likely the intermediate results of shifting of coordinates rather than the final values of correction that interest us here. Nevertheless, we will compare any local variations in position judgments that we find here with those found in peri-saccadic mislocalization experiments.