Current Biology: Visual sensory networks and effective information transfer in animal groupsPosted by sleblanc on Sep 9 2013 in Headlines, Scientific article, Video • 1 comment
In our recent paper, “Visual sensory networks and effective information transfer in animal groups”, published in Current Biology, we combine experiments with model selection methods to reveal the interaction networks over which information spreads through fish schools.
In the experiment, we first show that a minority of ‘informed’ fish, trained to associate a green laser target with food, can effectively lead an otherwise-untrained group to the target. During these leadership events, fish exhibit a relatively discrete “response” in which they begin directed movement toward the target. We track the spread of these responses through the group, and test different hypotheses for the interaction network over which the responses spread. Our results reveal that explicitly taking into account the visual nature of interactions (i.e. who can see whom within the group, and how much) provides a better predictor of information transfer than do more traditionally-used interaction models, such as those that assume individuals interact with all neighbors within a fixed distance (metric interactions) or with a fixed number of nearest neighbors (topological interactions). Moreover, we show that these visual interaction networks are structurally different from those specified by metric or topological assumptions, with potentially important consequences for information transfer.
For more information, see the videos below, or read the full paper.
Using novel software, we reconstruct the visual field of each individual over time. This information allows us to determine, for each focal individual, the angular area of all other individuals on its retina at each point in time. The video above shows the visual field of one fish over time, represented by rays (red lines) emanating from each of its eyes. Those individuals that exceed a threshold angular area on its retina are considered to be influential neighbors, and are indicated with red dots.
Information flow through a group. Each fish is marked with a red (informed) or blue (uninformed) dot, and circles appear when each individual responds. These responses can be seen to propagate through the group in a wave.