Detecting the rapid disappearance of social partners may be particularly useful for these fish, which move quickly but cannot see very far in the murky waters of their natural habitat. Animals can therefore infer danger by detecting when members of their social group vanish from their field of view.

This “social-off” detection could drive escape, as disappearing or escaping virtual schools caused similar escape behavior in observers – even in the absence of a direct threat.

Neural populations in the colliculus and thalamus are activated by the rapid escape of visual stimuli moving like social partners. These same cells were are also driven by the sudden disappearance of social stimuli, but unaffected by disappearing stimuli without social relevance.

Danionella show more effective escapes in groups because they see their neighbors escape, and will even escape upon observing virtual conspecifics escape (VR Danionella courtesy of postdoc Geoff Meyerhof).

Here we studied how groups of glassfish (Danionella cerebrum) use vision of their social partners to enable collective escape from danger.

Congratulations Ruben, and Cornell!