Spatial cueing effects in perceptual decisions of humans, monkeys, and bees

摘要

Although the influence of predictive spatial cues on perceptual decisions has been studied in humans and monkeys, few studies have directly compared cueing effects across species (Bowman et al., 1993). Here, we investigate the effects of spatial cueing and its interaction with target detectability in a similarly structured paradigm across humans, monkeys, and bees and compare the results to a Bayesian ideal observer. Methods: Humans and monkeys participated in the same spatial two alternative forced choice task in which a Gaussian signal of varying detectability (SNRs=0, 2.7, 4.0) embedded in white noise had to be localized. Subjects indicated the target location by making a rapid eye movement towards it. Prior to the onset of the stimulus, a brief precue was presented indicating the target location with 75% accuracy. Bees were trained to fly to one of two boxes containing a target of colored cardboard. The distractor box contained a similar piece of cardboard with a color that varied in its discriminability from the target (e.g. blue/blue vs. blue/grey). A secondary black cardboard served as a cue and co-occurred with the target on 80% of the trials. Results: Cueing effects, defined as the difference in proportion correct for validly and invalidly cued trials, were present for all three species but less than those predicted by an optimal Bayesian observer. These effects were comparable for humans and monkeys, but smaller for bees. However, consistent with ideal observer predictions, cueing effects increased with decreasing detectability of the target for all three organisms. Conclusions: Our results show that the influence of spatial cues on perceptual decisions is pervasive across species. The modulation of the cueing effect with signal strength for all three organisms is consistent with a Bayesian mechanism whereby sensory data are weighted by prior probabilities.