Emergent features, attention, and perceptual glue in visual form perception.

Grouping of line segments into unitary shapes and attempted to identify procedures to diagnose when such grouping is taking place is examined. The 13 experiments reported here indicate that perceptual glue is not needed to explain known findings about grouping, a claim that agrees with conclusions by other investigators using other criteria. Rather, emergent features alone may suffice to explain grouping, provided that reliable and accurate diagnostic criteria can be identified.