Attention and spatial resolution. Landolt squares. Vernier. Broken lines. : p<0.05 ; : p<0.1. *. Performance. Eccentricity (in deg). Spatial resolution. Our ability to resolve small details ( spatial resolution ) is maximal at fovea and declines as we move away from fixation.
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Landolt squares . Vernier Broken lines : p<0.05 ; : p<0.1 * Performance Eccentricity (in deg) 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 Acuity tasks: 2 Yeshurun & Carrasco, 1998
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
. : p<0.05 ; : p<0.1 * Spatial resolution • However, heightened resolution is not always optimal
Performance periphery fovea Eccentricity Texture segmentation task + performance peak
+ Performance performance peak periphery fovea Eccentricity Texture segmentation task resolution too low resolution too high e.g., Gurnsey et al. 1996; Joffe & Scialfa 1995; Kehrer 1989, 1997; Morikawa 2000; Potechin & Gurnsey 2003 Performance due to the mismatch between texture scale and average size of spatial filters as a function of eccentricity. Central performance drop (CPD):due to spatial resolution being too high at central locations. Average spatial filter size
valid SMALL TEXTURE SCALE (viewing distance: 57 cm) LARGE TEXTURE SCALE (viewing distance: 28 cm) neutral Attention & Texture segmentation • Exogenous attention automatically enhances resolution, even when it impairs performance • e.g., Yeshurun & Carrasco 1998; 2000; Talgar & Carrasco, 2002 10
valid neutral 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 Low Spatial Frequencies High Spatial Frequencies Baseline
valid valid small texture scale (viewing distance: 100 cm) large texture scale (viewing distance: 50 cm) neutral neutral Attention & Texture segmentation • Endogenous attention benefits performance at all eccentricities, suggesting a more flexible mechanism • Yeshurun, Montagna & Carrasco 2008 12
valid + + neutral _ _ EXOGENOUS ENDOGENOUS Performance at central locations impairs improves Performance at peripheral locations improves improves either increased or decreased? increased Spatial resolution small filters sensitivity FLEXIBILITY? AUTOMATICITY Spatial resolution: increase + Performance decrease? _ Eccentricity Eccentricity Yeshurun, Montagna & Carrasco (2008) Carrasco, Loula & Ho (2006) Yeshurun & Carrasco (1998; 2000)