Attention and spatial resolution Spatial resolution Our ability

Attention and spatial resolution

Spatial resolution • Our ability to resolve small details (spatial resolution) is maximal at fovea and declines as we move away from fixation Antis, 1974 • Most everyday life tasks benefit from heightened resolution Landolt squares Broken lines Vernier Yeshurun & Carrasco, 1998 Performance Acuity tasks: 2 Eccentricity (in deg)

Attention and spatial resolution Attention improves performance in tasks limited by the visual system‘s spatial resolution, which decreases with eccentricity: • Visual search • Acuity tasks • Texture segmentation

Visual search • Performance decreases with target eccentricity • Attention reduces this performance decrement, consistent with enhanced spatial resolution Carrasco & Yeshurun, 1998

Acuity task • Attention improves performance in Landolt-square (acuity) and Vernier (hyperacuity) tasks • Effect increases with eccentricity Yeshurun & Carrasco, 1999

Acuity task attention decreases gap threshold at cued location and increase it at uncued location Montagna, Pestilli, & Carrasco, 2009

Spatial resolution • However, heightened resolution is not always optimal

Texture segmentation task Performance + performance peak fovea Eccentricity periphery

Texture segmentation task Performance due to the mismatch between texture scale and average size of spatial filters as a function of eccentricity. Performance + e. g. , Gurnsey et al. 1996; Joffe & Scialfa 1995; Kehrer 1989, 1997; Morikawa 2000; Potechin & Gurnsey 2003 resolution too low resolution too high performance peak periphery fovea Eccentricity Central performance drop (CPD): due to spatial resolution being too high at central locations. Average spatial filter size

Attention & Texture segmentation • Exogenous attention automatically enhances resolution, even when it impairs performance e. g. , Yeshurun & Carrasco 1998; 2000; Talgar & Carrasco, 2002 SMALL TEXTURE SCALE valid (viewing distance: 57 cm) neutral LARGE TEXTURE SCALE (viewing distance: 28 cm) 10

Attention & Texture segmentation • Exogenous attention enhances resolution by increasing the sensitivity of high spatial frequency selective filters: - adapting to high (but not to low spatial frequencies) eliminates the CPD and the central attentional impairment Carrasco, Loula & Ho, 2006 Baseline valid neutral High Spatial Frequencies Low Spatial Frequencies

Attention & Texture segmentation • Endogenous attention benefits performance at all eccentricities, suggesting a more flexible mechanism Yeshurun, Montagna & Carrasco 2008 small texture scale valid (viewing distance: 100 cm) neutral large texture scale valid (viewing distance: 50 cm) neutral 12

EXOGENOUS Performance at central locations Performance at peripheral locations increase decrease? improves small filters sensitivity AUTOMATICITY either increased or decreased? FLEXIBILITY? valid neutral Performance Spatial resolution: impairs increased Spatial resolution ENDOGENOUS + + _ _ Eccentricity Carrasco, Loula & Ho (2006) Yeshurun & Carrasco (1998; 2000) Eccentricity Yeshurun, Montagna & Carrasco (2008)