EEB 522 Seminar Series- Josh LaPergola & Giuseppe Ferro

Communication, Cognition, and Communal Living: Referential Alarm Calls in Social Birds -Josh La Pergola; Social Media Battle for Attention: Opinion Dynamics in the Wilds of Competing Networks - Giuseppe Ferro
Oct 5, 2023, 12:30 pm1:30 pm
Guyot 10
Open to public



Event Description

Josh LaPergola:

Alarm-calling, a behavior in which a sender alerts conspecific receivers to the presence of a threat, poses an evolutionary conundrum because of its costly nature: the signaler risks drawing the attention of the threat. An intriguing form of this behavior is referential alarm-calling in which the sender produces one or more signals that are associated with distinct classes or categories of threats, such as terrestrial or aerial predators. This behavior has been documented in a variety of group-living, cooperative vertebrates, including rodents, meerkats, non-human primates, and birds, but many, if not most, of these cases invoke kin selection as an evolutionary explanation because receivers are typically close relatives. I worked with other members of the Riehl Lab to study alarm-calling behavior of an obligate communally breeding species where groups predominantly consist of non-kin, the Greater Ani. The results of multiple years of field observations paired with relatedness analyses and playback experiments show that (1) Greater Anis produce at least one functionally referential signal, an alarm call (the high cackle) given in response to aerial threats (flying raptors), (2) this call is primarily given in the presence of non-kin, and (3) individuals hearing this call respond adaptively by fleeing to cover. These results suggest that referential alarm-calling in Greater Ani groups represents a form of cooperation among unrelated co-parents whose fitness interests are aligned by their obligate communal breeding system. Additionally,  it remains an open question whether these referential signals conjure mental representations of the external referent or reflect only the internal motivational or emotional state of the signaler. Future work will focus on whether the aerial alarm calls of the Greater Ani and other group-living birds are actually referential and not just “functionally” so.

Giuseppe Ferro:

In the age of information abundance, our attention is a coveted resource. Social media platforms vigorously compete for our engagement, influencing the evolution of our opinions. With recommendation algorithms often accused of creating "filter bubbles," where like-minded individuals interact predominantly with one another, it's crucial to understand the consequences of this unregulated attention market.

To address this, we present a model of opinion dynamics on a multiplex network. Each layer of the network represents a distinct social media platform, each with its unique characteristics. Users, as nodes in this network, share their opinions across platforms and decide how much time to allocate in each platform depending on its perceived quality, much like how animals migrate and interact in various habitats.

Our model reveals two key findings:

  • When examining two platforms-one with a neutral recommendation algorithm and another with a homophily-based algorithm-we uncover that even if users spend the majority of their time on the neutral platform, opinion polarization can persist.
  • By allowing users to dynamically optimize their social energy allocation across platforms in accordance with their homophily or diversity preferences, we unveil intricate and diverse dynamics.

These results underscore the significance of acknowledging how individuals gather information from a multitude of networks. Furthermore, they emphasize that policy interventions on a single social media platform may yield limited impact.

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