Aimee Martin1, Karl Gegenfurtner1; 1University of Giessen
Categorical effects can be observed with different stimulus properties, with color being a prime example. Perceptual studies have found quicker reaction times and higher accuracy rates in detecting changes across color categories, compared to corresponding changes within a category. However, it is not entirely clear which factors primarily contribute to this effect, such as language, low level perceptual features, and/or attention. Studies often show that attention can be biased towards exact feature values, such that only a particular color (e.g., a specific shade of blue) will capture attention. Using typical attention tasks with finely grained colors, we aimed to see whether these attentional effects relate to color categories. A spatial cueing task was used, whereby participants searched for either a blue or green singleton target across different blocks (counter-balanced across participants). Cues were shown prior to the target display, with a singleton cue (50% valid to target location) that varied in hue from blue to green in DKL color space and contained the category border between blue and green. Another condition included cues that were the peaks of a category (e.g., green) with the targets falling into the same category, i.e. not crossing over a category boundary. Results showed that validity effects (e.g., RTs quicker on valid vs invalid trials) were higher for cues that belonged to the same category as the target, compared to when the cues were from different categories. There were no systematic differences in validity effects between the different cues when the targets were the same distance apart, and yet were from the same category. Overall, this demonstrates that the observed attentional effects directly relate to categorical perception of color.
Acknowledgements: DFG Sonderforschungsbereich SFB TRR 135 project C2