Human orientation sensitivity during object perception

Orientation information is crucial for object perception, yet little is known about how it is encoded in complex images. The precision of orientation coding has been traditionally investigated using simple stimuli such as single Gabors. We developed an image manipulation technique that allows us to vary the complexity of an image using multiple Gabors. We also developed a paradigm to assess orientation discrimination thresholds in complex object images. In the present study we ask how well such measures capture the efficiency of coding orientation information during object perception. The relative fit of two models (Hard Threshold and Equivalent Noise) and their ability to explain changes in threshold with the addition of external noise are compared.