Dr Joah Madden

About me:

Joah Madden is an Associate Professor in the School of Psychology, working in the Centre for Research in Animal Behaviour

Office hours:

Monday 8:30-9:30

Tuesday 11:30-12:30

Current Research Projects:

The Evolution of Cognition

How does natural selection and evolution act on underlying, general cognitive processes such as learning, memory or executive control, which shape specific behaviours in wild-living animals?

I tackle this question using a novel study system, the ring-necked pheasant Phasianus colchicus

1. How do individuals differ in their performance on psychometric tests?

2. What are the fitness consequences of such differences?

3. What factors affect the inheritance and expression of individual cognitive performance?

The evolution of cognition is one of the most important, yet poorly understood issues in modern biology. The field of comparative cognition has generated a wealth of research into the cognitive processes underpinning animal behaviour, yet the evolutionary forces that have driven and shaped these processes are poorly understood. To progress the field, we need to determine three things: First, do individuals differ in their cognitive performance (CP) such that selection has variation on which to act? Second, is an individual’s CP heritable, and how is its expression shaped by non-genetic factors? Third, does an individual’s CP predict their fitness by determining their survival or reproductive chances? Answers to each of these questions are all significant steps in themselves, and each individually deepens our understanding of the evolution of cognition, but the real strength of this project is that they can be addressed in synchrony in a single, free-living study system. This will permit a more robust framework in which to tackle the broad question of how cognitive performance may evolve that can then be applied to a broader set of taxa and conditions.

Why Pheasants? Large numbers of birds can be bred and reared under controlled conditions, probed with established psychometric tests proven on domestic chickens and released into the wild where their fates can be tracked and their wild behaviour observed both directly and remotely.

Previous Research Projects:

My PhD thesis “Sex, costs and bowerbird tastes” originated as classical study of behavioural ecology, testing a series of models of sexual selection, but introduced me to the range of influences, usually studied under the guise of Psychology, that determine and shape individual’s behaviour.

My work in cognition and learning in the wild has included a demonstration that complexity of sexual display relates to brain size, and that cognition may be an important factor in mechanisms of sexual display and mate choice. This can involve both visual and vocal displays I have explored how learning of male display traits may lead to inter-population ‘cultural’ differences. I conducted a series of experimental studies asking how young, including those of brood parasites, learn to produce attractive begging calls and respond to species specific alarm calls, and decide when to stop begging. My ongoing work on bowerbirds has had two strands focusing on learning and cognition. The first involves my testing mechanisms of learning of male sexual traits (social vs. trial and error) across a whole population using experimental manipulation and tracking contacts and spread over the population. The second focuses on quantifying individual variation across a suite of cognitive performances and relating this to fitness proxies. Data for both these sets of studies have been collected and are in the process of analysis and writing.

My work on social influences on behaviour started by considering simple dyadic factors in which an individuals’ signal, be they sexual or begging, can be modulated by the behaviour of others, including heterospecifics. I have extended this simplistic approach and helped develop new methods to probe the effects of polyadic interactions utilizing social network analysis. This has allowed me to describe in detail animal social networks and separate out genetic and behavioural mechanisms underlying their structure, and observe how network structure can explain transmission of infectious disease across groups. I have gone beyond simply describing networks, and have used the paradigm of SNA to allow me to perturb the networks and observed knock-on effects across groups as a whole, and to test how network structure may facilitate the origin and persistence of reciprocal cooperationA. I have used hormonal manipulations to demonstrate that a suite of prosocial behaviours in group living animals may have a single governing pathway.

My work on how developmental mechanisms determine behaviour is more recent, but draws on observations that I made of how sexual and begging signals were shaped early in life. I have been rearing pheasants under a range of different conditions for the first eight weeks of life, and then observing and testing how adult morphology and behaviour has been affected. Early life manipulations have focused on sex ratio and dietary complexity. Bias in sex ratio can affect adult patterns of female mate choice and copulation rates, modulated by differences in perinatal steroid hormone levels provoked by aggression early in life. I also find that assays of individual’s behaviour early in life can predict their susceptibility to apparently un-targeted harvesting by humans. Preliminary analysis of the dietary complexity data suggest that foraging ability, dietary breadth, dietary conservatism and gut morphology may all be governed by diet early in life. This work has attracted interest and funding from the Game and Wildlife Conservation Trust and I continue to develop projects in this area with them.

I adopt an integrative approach to research leading me to publish beyond my central interests, with work on classical behavioural ecology and conservation biology. This allows me to cross traditional research boundaries and draw together novel insights from disparate fields.

Associate Professor at the University of Exeter (2014-present)

Senior Lecturer at the University of Exeter (2009-2014)

Lecturer at the University of Exeter (2007-2009)

Post-docs at the University of Cambridge with Nick Davies and Tim Clutton-Brock (2002-2007)

Research posts with the RSPB (Royal Society for the Protection of Birds) (2001-2002)

Research post with the BTO (British Trust for Ornithology) (1997)