THE ORIGINAL TWITTER

A Bird’s Eye View of Social Networks

Introvert or extrovert?

The two terms hover over the research of Gregory Kohn (Ph.D. ’15) like the birds that inhabit the aviaries of the Animal Behavior Farm, aka the lab of PBS professor Meredith West and senior scientist Andrew King, where Kohn has worked and studied, first as a Ph.D. student, then as a post-doctoral researcher.

he question, suggests Kohn — introvert or extrovert? — is as pertinent to non-human animals as it is to humans. And in his own work the sociability of each individual animal adds up to a collective pattern of social organization, a social network differentiated by gender in which males and females generally play different roles.

In social mammals from elephants to apes, baboons and horses, Kohn explains, studies of sociability have brought to light overall differences between female and male group members in which females consistently interact with familiar, mostly female, individuals, while males are flexible and more varied in their interactions. Together the two tendencies provide a balance between stability and change within the networks, making it easier and more likely for the social organization to thrive and perpetuate itself.

ow Kohn’s research shows for the first time that this social dynamic extends to birds. In a study of brown-headed cowbirds, Kohn has demonstrated that the social bonds between particular female cowbirds are sustained across changes in group size and membership. Males by contrast fluctuate in their associations, forming new associations in a way that integrates new members.

Counting how often an individual seeks out social contact and with whom, whether with the same or varying individuals, Kohn has measured degrees of sociability in the society of brown-headed cowbirds. And these differences add up into telling patterns.

“If they don’t have the right developmental context, they’re not going to act like cowbirds.”

Social Gateways…

An ordinary, even somewhat drab looking brown and black bird, cowbirds at the Animal Behavior Farm have been the unwitting proponents for a line of reasoning that puts social networks into the foreground of theories about learning and development, not only in cowbirds, but in numerous social species. The unique conditions at the Farm/Lab, have allowed for this. As the largest aviary in Indiana, with a complex of four interconnected aviaries the size of a football field, the Animal Behavior Farm is specially equipped, unlike almost any other lab in the country, to both recreate conditions in the wild and maintain a certain amount of control.

In the wild, for example, it is extremely difficult to track the consistency of social interactions among cowbirds. Yet, here they have a system for labeling and observing the same cowbirds over time and bringing together or varying group populations.

Laying their eggs in the nests of other species, cowbirds, Kohn explains, which are raised by other species, would seemingly be the perfect candidate for a genetically programmed view of development. How else would they find their way back to their kind and reproduce?

Yet, Kohn contends, “The opposite is true.” Decades of studies at the Animal Behavior Farm suggest that “external stimulation from the social environment teaches them how to be cowbirds.”

Cowbirds initially find their way back to the company of cowbirds in their search for the same food on edge habitats. There they interact with other cowbirds, who unlike other birds, will respond in kind to their characteristic head-down display. Getting this favorable response from other cowbirds, says Kohn, “may make them more likely to hang out with each other” and draws them into cowbird society.

…and their Unexpected Consequences

Yet, the entry into cowbird society is not a foregone conclusion. Mistakes can happen and when the usual social and environmental variables are not in place, cowbirds can become something other than your typical cowbird.

In fact what initially drew Kohn to the lab of West and King, he explains, was a study in which the researchers sought to find out what happened to male cowbirds raised in the company of canaries before being introduced to the company of female cowbirds. For one year, the males did not have access to female cowbirds. They were then were put into aviaries with canaries and receptive female cowbirds. The results: cowbirds who thought they were canaries. Indifferent to female cowbirds, the male cowbirds only pursued the canaries.

“If they don’t have the right developmental context,” says Kohn, “they’re not going to act like cowbirds. They don’t have a genetic safety net that tells them how to behave.”

Kohn would now like to determine whether this form of social organization extends to other birds and has introduced two new species to the Farm, quail and budgies. Once again, he is counting degrees of sociability, to record who interacts with whom, how often and how selectively, to see if the numbers add up in similar ways and into similar social configurations.

Introvert or extrovert?

Counting out the social interactions of individual birds will illuminate collective patterns. More than the sum of its parts, social networks become the central platform for processes of development and learning, and for keeping these processes stable across time. As West and King describe it, these networks are a distributed system for success, much like an RBI in baseball. A hitter in baseball cannot get an RBI without the hitters ahead of him, the skills of the pitcher and opposing fielders, and a manager who knows which batting order will work best. Likewise, the success of a single cowbird depends on numerous social and environmental factors working in tandem.

As Kohn explains, “Social networks provide the stage for socialization and development, for both humans and (other) animals. Processes that create social behavior are probably very similar across all social species. But of course specific behaviors between species are very different.”

“It’s not necessarily a matter of genes, it’s that the social network provides the conditions for learning. It’s fixed in the sense that it’s a process that keeps on happening. But that doesn’t mean it’s inevitable.”

A Lingering Question

What does all of this imply, if anything, about the fixity of male and female social behavior, albeit among non-human animals?

“To me,” says Kohn, “it shows that it’s not female or male behaviors that are fixed. It’s the social network that is stable. Yet at the same time, social systems are constantly renewing themselves. Let’s say you have a change such as a depleted food source. That might change the social network in a way that is self-perpetuating.

“Change happens,” he adds, “when there is variation within social systems. It’s not necessarily a matter of genes, it’s that the social network provides the conditions for learning. It’s fixed in the sense that it’s a process that keeps on happening. But that doesn’t mean it’s inevitable.”