Aarhus University Seal

IMC Affiliated Researcher Jessie Barker has just published two new papers investigating signalling in two very different contexts.

Signalling is a key part of almost all interactions. Signals help us find out otherwise hidden qualities of another individual, and allow us to reveal information about ourselves. How do we know that signals provide reliable information on average, and how do we interpret them correctly? These questions have been studied across disciplines, from economics to evolutionary biology.


Noisy communities and signal detection: why do foragers visit rewardless flowers?

E.M. Lichtenberg, J.M. Heiling (co-first author), J.L. Bronstein & J.L. Barker
Philosophical Transactions of the Royal Society B

This new paper is part of a special issue on ‘Signal detection theory in recognition systems’. Recognition is a key part of almost all biological interactions, from finding a mate to avoiding predators. However, there is a lot of potential for costly mistakes, from acceptance errors (e.g. feeding a cuckoo chick) to rejection errors (e.g. not feeding your own chick). Signal detection theory is used by behavioural ecologists to understand how animals minimise these errors in recognition. In this paper, IMC Affiliated Researcher Jessie Barker and colleagues apply this framework to a question that has puzzled plant ecologists: why do some flowers not offer rewards to foraging animals? They suggest that as there is a high degree of overlap in the signals that rewarding and rewardless flowers display to foragers (e.g. colour and scent), and a high degree of variation in the amount reward associated with a given signal (e.g. the volume of nectar a flower contains), foragers will make mistakes and visit rewardless flowers. Signal detection theory therefore not only provides insight into animal foraging strategies but also into which plant reproductive strategies – here, whether or not to offer a reward – will evolve and persist.

Link to article.



Greener than thou: people who protect the environment are more cooperative, compete to be environmental, and benefit from reputation

P. Barclay & J.L. Barker
Journal of Environmental Psychology


This new paper shows how evolutionary theory predicting when people cooperate with others can be applied to promote pro-environmental behaviour. Specifically, IMC Affiliated Researcher Jessie Barker and her colleague Pat Barclay show in a mathematical model that pro-environmental behaviour can function as a signal of people’s valuation of others and thus their willingness to cooperate. This means that when there is an audience observing these signals, people (unconsciously) compete to be more environmental than others. The authors compare multiple theories about why people behave environmentally, and in four economic experiments find most support for the theory of signalling cooperative intent. Participants donated more to a conservation charity when competing to be chosen by an observer for another cooperative game; and these participants both gave and received more in the subsequent game. Understanding why people behave pro-environmentally can help us encourage such behaviour in real settings. 

Link to article.