Attention and luminance detection: A quantitative analysis

Two experiments investigated the effects of spatial cues on the detection of luminance targets in global (nonlocalizing) and local (poststimulus probe) detection tasks. Cuing effects were quantified by fitting a variety of single-and multiple-channel signal-detection models to the data from individual observers. The local detection data showed enhanced sensitivity at cued locations, consistent with previous findings. Models for global detection in which cues affected both sensitivity and criterion or criterion alone could not be distinguished reliably on the basis of goodness-of-fit statistics. However, estimated model parameters showed that under global detection conditions, sensitivity was enhanced at cued locations by a factor of around 2. Results are discussed relative to a model in which Poisson-coded sensory representations are modulated by spatial attention.