Context effects on texture border localization bias

Observers are able to locate precisely a border defined by changes in texture orientation. The prevailing theory is that such localization takes place using a hierarchical, filter-rectify-filter mechanism. An alternative theory is that contextual modulation causes the border elements to stand out. Here we show that perceived border location is inconsistent with contextual modulation from iso-oriented elements. The perceived location of a vertical border defined by vertical texture on one side, and horizontal texture on the other side, is biased towards the vertical texture. We found the same bias in a single row of texture. Therefore, the bias is not due to contextual influences from surrounding iso-oriented elements. Contextual influences between cross-oriented elements can explain the data.