Failure of colour and contrast polarity identification at threshold for detection of motion and global form

We used identification at threshold to systematically measure binding costs in two visual modalities. We presented a conjunction of two features as a signal stimulus and concurrently measured detection and identification performance as a function of three threshold variables: duration, contrast and coherence. Discrepancies between detection and identification sensitivity functions demonstrated a consistent processing cost to visual feature binding. Our findings suggest that feature binding is indeed a genuine problem for the brain to solve. This simple paradigm can transfer across arbitrary feature combinations and is therefore suitable to use in experiments addressing mechanisms of sensory integration.