Processing of transient signals in the visual system of the European starling (Sturnusvulgaris) and humans

The double-pulse resolution (DPR) measures the processing performance for transient visual signals as the threshold duration for detecting a temporal gap between two light flashes in relation to gap duration. The DPR of four European starlings (Sturnus vulgaris) and four humans was measured in an operant Go/NoGo procedure. We applied the method of constant stimuli and determined thresholds using signal-detection theory. The starling DPR (22.2 ms ± 2.3 ms SE) was significantly shorter than human DPR (35.2 ms ± 1.3 ms SE; p < 0.01, t-test). The difference suggests that starlings have a higher temporal resolution for transient visual signals than humans.

Research highlights
► A high visual temporal resolution is required for birds that rapidly move through the environment.
► A measure of visual temporal resolution can be derived studying the ability to perceive two brief signals in a sequence separately – this measure termed double-pulse resolution (DPR) refers to the minimum temporal gap that allows separating two light flashes.
► DPR in a common bird species, the European starling, reaches 22 ms and is found to be superior to that of human subjects (35 ms).
► This result matches the ecological requirements of a bird that rapidly maneuvers through a structured environment such as the branches of a tree.