Abstract
Human cue validity effects in many cueing tasks can be explained with a weighted linear (Kinchla, et al., P & P, 1995) or Bayesian (Shimozaki, et al., 2001, ARVO; Eckstein, et al., JOV, 2001) integration model that preferentially weights the cued location, without proposing either an improved quality of processing at the cued location, or limited attentional resources. Precue effects with a 100% valid simultaneous cue (Dosher & Lu, VR, 2000), however, are not predicted by a Bayesian (ideal) observer, which ignores the precue and considers only the test location indicated by the simultaneous cue. One explanation of these precueing effects is that attention improves the tuning of the perceptual template (or excludes irrelevant external noise) at the test location when the precue and simultaneous cue agree. Another hypothesis is that observers (unlike an ideal observer) are unable to ignore information from the precued location when the precue is invalid (i.e., attentional leaking). Classification images were used to estimate human perceptual templates at the precued (invalid trials) and test locations (valid and invalid). Two observers (LL and JT) participated in a cued contrast discrimination of a 50 ms Gaussian signal in image noise at four possible locations, with a 150 ms precue (62.5% valid) and a simultaneous cue (100% valid). LL had large precue effects (d′ 0.5), and her invalid precued classification image was not significantly different from the test location classification image. JT had no precue effects, and his invalid precued classification image did not differ from zero. Also, for both observers, no difference was found for the test location classification images in the valid and invalid precued trials. For this task, we conclude that precueing validity effects (for LL) were due to the inability to ignore information at the invalid precue location (attentional leaking), and not the improved tuning of perceptual templates at the test location.
Support: NIH-RO1 53455, NASA NAG 9-1157