Abstract
GOAL. In texture segmentation tasks constrained by spatial resolution, exogenous (involuntary) attention improves performance at peripheral locations where resolution is too low, but impairs performance at central locations where resolution is already too high (central performance drop, CPD). Exogenous attention automatically increases resolution at all eccentricities by increasing sensitivity of high spatial frequency filters. Conversely, endogenous (voluntary) attention benefits performance across all eccentricities, suggesting a flexible mechanism that optimizes performance. Can endogenous attention flexibly adjust resolution as a function of eccentricity? If so, how? Alternatively, does endogenous attention benefit performance across eccentricity through means other than adjusting resolution (e.g., increasing signal-to-noise ratio)? METHODS. To investigate the mechanisms underlying the effects of endogenous attention on texture segmentation, we combined a cueing paradigm with selective adaptation. After adapting to either high or low spatial frequency patterns, observers reported the presence or absence of a target that could appear at several eccentricities in a texture display. Central valid precues directed voluntary attention to the upcoming target’s location. Postcues ruled out location uncertainty. Attention effects were evaluated against a neutral precue condition; adaptation effects against a control condition (no spatial frequency modulation). RESULTS. Selective adaptation to high or low spatial frequencies affected performance compared to the control condition. Adapting to low spatial frequencies resulted in a more pronounced CPD and a shift of the performance peak towards more peripheral locations. Conversely, adapting to high spatial frequencies diminished the CPD and shifted the performance peak towards central locations. Moreover, adapting to high, but not to low spatial frequencies, eliminated the attentional benefit at central locations. These results suggest that endogenous attention flexibly adjusts spatial resolution. Endogenous attention optimizes performance across all eccentricities, either enhancing or decreasing resolution, and does so by adjusting the sensitivity of high spatial-frequency filters.
Meeting abstract presented at VSS 2012