1 / 1

Background

ECVP 2008 , August 24-28 , 200 8, Utrecht , the Netherlands. Crowding and visual complexity Endel Põder Laboratory of Experimental Psychology, KU Leuven, Belgium and Institute of Psychology, University of Tartu, Estonia E-mail: endel.poder@ut.ee. Background

nova
Download Presentation

Background

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ECVP 2008, August24-28, 2008,Utrecht, the Netherlands Crowding and visual complexityEndel PõderLaboratory of Experimental Psychology, KU Leuven, Belgiumand Institute of Psychology, University of Tartu, EstoniaE-mail: endel.poder@ut.ee Background At the last ECVP (Põder, 2007 Perception36 Supplement, 41) I suggested that visual complexity of a display (target + flankers) could explain the different crowding effects with different numbers of flankers. Purpose of this study To measure the effect of complexity with stimuli that can vary in several feature dimensions. However, complexity was highly (negatively) correlated with the number of flanker objects identical to the target of a given trial (R ≈ -0.75). A simple random selection mechanism could explain the results. Methods Stimuli: Gabor patches, varied in three feature dimensions – orientation, spatial frequency, and color. Target surrounded by 6 flankers (target-flanker distance 0.8 deg). Exposure: 60 ms. Eccentricity of target: 4 degrees (random positions around the fixation). Task: to identify the target (8-alternative forced-choice). Complexity was defined as heterogeneity of visual features in a display. A simple measure – total variance across the feature dimensions (p – proportion of objects with a given feature): Experiment 2 The correlation between target and flankers was removed. Only the complexity of flankers was manipulated, target varied independently. Examples of different complexity: Experiment 1 The features of the all objects (target and flankers) were included in the complexity manipulation. Examples of different complexity: 0.0 0.14 0.28 0.50 0.72 Results Still a significant effect of complexity. Complexity fixed within blocks Complexity varied trial-by-trial 0.0 0.12 0.24 0.37 0.49 0.61 0.73 Results Performance improved (crowding reduced) with simpler groups of stimuli. Conclusions Visual complexity affects crowding with multidimensional stimuli even if the target and flankers are statistically unrelated. Possibly, a target pop-out plays some role. But the complete explanation is not so simple.

More Related