Social networks predict selective observation and information spread in ravens

Abstract

Animals are predicted to selectively observe and learn from the conspecifics with whom they share social connections. Yet, hardly anything is known about the role of different connections in observation and learning. To address the relationships between social connections, observation and learning, we investigated transmission of information in two raven (Corvus corax) groups. First, we quantified social connections in each group by constructing networks on affiliative interactions, aggressive interactions and proximity. We then seeded novel information by training one group member on a novel task and allowing others to observe. In each group, an observation network based on who observed whose task-solving behaviour was strongly correlated with networks based on affiliative interactions and proximity. Ravens with high social centrality (strength, eigenvector, information centrality) in the affiliative interaction network were also central in the observation network, possibly as a result of solving the task sooner. Network-based diffusion analysis revealed that the order that ravens first solved the task was best predicted by connections in the affiliative interaction network in a group of subadult ravens, and by social rank and kinship (which influenced affiliative interactions) in a group of juvenile ravens. Our results demonstrate that not all social connections are equally effective at predicting the patterns of selective observation and information transmission.

Keywords: Corvus corax; information transmission; network-based diffusion analysis; observation networks; order of acquisition diffusion analysis; social networks.

Figure 1.

Photo of a raven opening the Velcro (also see electronic supplementary material, videos S1 and S2).

Figure 2.

Observation and affiliative interaction networks. Arrows in the observation networks (a,b) indicate gaze direction of naive ravens, and point towards the informed ravens whose task-solving behaviour they observed. Arrows in the affiliative interaction networks (c,d) point towards the recipient of the affiliative interaction. Circles represent females, rectangles represent males. Line thickness is proportional to the connection frequency (strength). Blue solid lines indicate reciprocal connections, black dashed lines indicate non-reciprocal connections. All connections in the observation network are non-reciprocal; the observation network includes only the observations made by naive ravens before they solved the task for the first time. Numbers indicate task-solving order, asterisks indicate the trained females. Same coloured nodes in juveniles (b,d) represent kin groups. The nodes are spatially arranged in a circle layout, based on ID, for the ease of comparison between networks.

Figure 3.

Task solving, observation and affiliative interactions. Instrength rank in the affiliative network is correlated with task-solving order (a) and with instrength rank in the observation network (b). Lower rank numbers indicate higher centrality.