John M Mcnamara

John M Mcnamara
University of Bristol | UB · School of Mathematics

Doctor of Philosophy
Game theory in biology, especially with individual differences. Developmental plasticity.

About

306
Publications
47,291
Reads
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25,133
Citations
Citations since 2017
38 Research Items
7037 Citations
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201720182019202020212022202302004006008001,0001,200
201720182019202020212022202302004006008001,0001,200
201720182019202020212022202302004006008001,0001,200
Additional affiliations
August 1995 - December 2015
University of Bristol
Position
  • Professor of Mathematics and Biology

Publications

Publications (306)
Article
Full-text available
Animals, including humans, differ in a wide range of physical and cognitive abilities ranging from measures of running speed and physical strength to learning ability and intelligence. We consider the evolution of ability when individuals interact pairwise over their contribution to a common good. In this interaction, the contribution of each is as...
Article
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Interactions in social groups can promote behavioural specialization. One way this can happen is when individuals engage in activities with two behavioural options and learn which option to choose. We analyse interactions in groups where individuals learn from playing games with two actions and negatively frequency-dependent payoffs, such as produc...
Article
Variation in stress responses has been investigated in relation to environmental factors, species ecology, life history and fitness. Moreover, mechanistic studies have unravelled molecular mechanisms of how acute and chronic stress responses cause physiological impacts (‘damage’), and how this damage can be repaired. However, it is not yet understo...
Article
The idea of applying game theory to problems in biology was given a formal basis nearly 50 years ago. Since then, the theory has advanced, and there have been numerous applications of it to a diversity of empirical systems. Most of this work takes a straightforward functional approach, finding a behavioral strategy that is evolutionarily stable in...
Article
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Most analyses of the origins of cultural evolution focus on when and where social learning prevails over individual learning, overlooking the fact that there are other developmental inputs that influence phenotypic fit to the selective environment. This raises the question of how the presence of other cue ‘channels’ affects the scope for social lea...
Article
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We focus on learning during development in a group of individuals that play a competitive game with each other. The game has two actions and there is negative frequency dependence. We define the distribution of actions by group members to be an equilibrium configuration if no individual can improve its payoff by unilaterally changing its action. We...
Article
Matching describes how behaviour is related to rewards. The matching law holds when the ratio of an individual’s behaviours equals the ratio of the rewards obtained. From its origins in the study of pigeons working for food in the laboratory, the law has been applied to a range of species, both in the laboratory and outside it (e.g., human sporting...
Article
Limited flexibility in behaviour gives rise to behavioural consistency, so that past behaviour is partially predictive of current behaviour. The consequences of limits to flexibility are investigated in a population in which pairs of individuals play a game of trust. The game can either be observed by others or not. Reputation is based on trustwort...
Article
Full-text available
Most analyses of the origins of cultural evolution focus on when and where social learning prevails over individual learning, overlooking the fact that there are other developmental inputs that influence phenotypic fit to the selective environment. This raises the question how the presence of other cue 'channels' affects the scope for social learni...
Article
All organisms have a stress response system to cope with environmental threats, yet its precise form varies hugely within and across individuals, populations, and species. While the physiological mechanisms are increasingly understood, how stress responses have evolved remains elusive. Here, we show that important insights can be gained from models...
Chapter
The chapter defines and discusses some of the central concepts in biological game theory. Strategies, which are rules for choosing actions as a function of state, play a pivotal role. It is explained how the theory operates at the level of strategies rather than attempting to follow the details of the underlying genetics that code for them. This is...
Chapter
The actions and state of an individual in one generation can affect the state of offspring in the next generation, and hence the ability of these offspring to leave offspring themselves. This chapter deals with games in this multigenerational setting. Projection matrices are used to keep track of the state and number of descendants in successive ye...
Chapter
Standard examples in biological game theory are introduced. The degree of cooperation at evolutionary stability is analysed in models that deal with situations such as the Prisoner’s Dilemma, the Tragedy of the Commons and the conflict of interest between parents over care of their common young. Several models of aggressive interactions are treated...
Chapter
The chapter introduces reinforcement learning in game-theory models. A distinction is made between small-worlds models with Bayesian updating and large-worlds models that implement specific behavioural mechanisms. The actor–critic learning approach is introduced and illustrated with simple examples of learning in a coordination game and in the Hawk...
Chapter
Many social interactions are extended over time, with sequences of decisions by the participating individuals. An interaction can include negotiation between partners as well as learning about each other’s characteristics and qualities. The classical game-theoretical concepts of normal- and extensive-form games and perfect and Stackelberg equilibri...
Chapter
The concept of an Evolutionarily Stable Strategy (ESS), which is a stronger stability condition than that of a Nash equilibrium, is introduced. A simple evolutionary dynamic, adaptive dynamics, is also introduced. This leads to the concept of convergence stability under adaptive dynamics. It is shown that these two stability criteria are independen...
Chapter
Many games focus on a part of the life of an organism. The payoff structure of the game then represents how the game affects fitness proxies such as mean lifetime reproductive success, which are concerned with the whole of the life of the organism. However, the traditional approach of specifying payoffs in advance of the analysis of the game can le...
Chapter
Often traits interact, so that considering the evolution of each in isolation gives too limited an account. As is demonstrated in this chapter, it is then crucial to allow for the co-evolution of traits when analysing evolutionary stability. In particular this is important when there there is disruptive selection. Criteria for stability are present...
Chapter
There is typically considerable between-individual variation in trait values in natural populations. Game theory has often ignored this, treating individuals as the same. However, the existence and amount of variation is central to many predictions in biological game theory, as this chapter illustrates. Variation is central to signalling systems an...
Chapter
Important areas for future developments of game theory in biology are put forward. These include several issues that are dealt with in the book, such as trait co-evolution, the consequences of variation, time structure, and the embedding of games into an ecological context and into the lives of individuals. New areas are also suggested, with Tinber...
Book
Game theory in biology seeks to predict social behaviour and other traits that influence how individuals interact. It does this by tentatively assuming that current traits are stable endpoints of evolution by natural selection. The theory is used to model aggressive behaviour, cooperation, negotiation, and signalling, as well as phenotypic attribut...
Chapter
The chapter starts with an introduction to game theory in biology, describing its overall aims. The basic concept of frequency dependence is then presented, together with a number of illustrative biological examples. Next, the modelling approach is outlined, emphasizing that the theory aims to predict phenomena by seeking stable evolutionary endpoi...
Article
The timing of migration and migratory steps is highly relevant for fitness. Because environmental conditions vary between years, the optimal time for migration varies accordingly. Therefore, migratory animals could clearly benefit from acquiring information as to when it is the best time to migrate in a specific year. Thus, environmental predictabi...
Article
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In social interactions, including cooperation and conflict, individuals can adjust their behaviour over the shorter term through learning within a generation, and natural selection can change behaviour over the longer term of many generations. Here we investigate the evolution of cognitive bias by individuals investing into a project that delivers...
Article
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The behavioural sciences have been strongly influenced for several decades by signal detection theory (also known as "error management theory" and "ROC analysis"). The theory provides simple logic about how individuals should behave in order to maximize their expected payoff in a single decision; for instance, the theory predicts that as the probab...
Chapter
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This chapter focuses on reasoning from the ultimate, evolutionary perspectives and not much more regarding proximate hypothesizing about behaviour. The main motivation is to highlight that using quantitative genetic approaches facilitates our ability to specify precise hypotheses about how behaviour is likely to evolve within populations over the s...
Article
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Genetic polymorphism can contribute to local adaptation in heterogeneous habitats, for instance, as a single locus with alleles adapted to different habitats. Phenotypic plasticity can also contribute to trait variation across habitats, through developmental responses to habitat-specific cues. We show that the genetic architecture of genetically po...
Article
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1.The theory of life‐history evolution investigates how growth‐reproduction trade‐offs drive evolution of body size in uni‐ and multivoltine (one or more generations per year) arthropods. Existing theory does not predict how the length of the feeding season (season length hereafter) affects body size in semivoltine (i.e. juvenile period longer than...
Article
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In the last decades, developmental origins of health and disease (DOHaD) has emerged as a central framework for studying early‐life effects, that is, the impact of fetal and early postnatal experience on adult functioning. Apace with empirical progress, theoreticians have built mathematical models that provide novel insights for DOHaD. This article...
Article
Background: A parent feeding its young during the breeding season faces a trade-off between mortality risk and provisioning young with food for growth. Question: How should the parent behave to maximize reproductive success when mortality to both parent and young are considered? Mathematical method: Using an optimality model, we establish new for...
Article
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There can be genetic conflict between genome elements differing in transmission patterns, and thus in evolutionary interests. We show here that the concept of genetic conflict provides new insight into local adaptation and phenotypic plasticity. Local adaptation to heterogeneous habitats sometimes occurs as tightly linked clusters of genes with amo...
Article
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Most optimal foraging models assume that the foraging behaviour of small birds depends on a single state variable, their energy reserves in the form of stored fat. Here, we include a second state variable-the contents of the bird's gut-to investigate how a bird should optimise its gut size to minimise its long-term mortality, depending on the avail...
Article
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Approaches to understanding adaptive behaviour often assume that animals have perfect information about environmental conditions or are capable of sophisticated learning. If such learning abilities are costly, however, natural selection will favour simpler mechanisms for controlling behaviour when faced with uncertain conditions. Here, we show that...
Article
Signal detection theory has influenced the behavioural sciences for over 50 years. The theory provides a simple equation that indicates numerous ‘intuitive’ results; e.g. prey should be more prone to take evasive action (in response to an ambiguous cue) if predators are more common. Here, we use analytical and computational models to show that, in...
Chapter
In many situations across biology and economics, there is often one individual, or “agent,” that invests effort into a beneficial task and also one individual that, in contrast, foregoes the effort of investing, and instead simply exploits the efforts of another. What makes an individual choose to invest in production versus exploiting the efforts...
Article
Full-text available
Addressing the obesity epidemic depends on a holistic understanding of the reasons that people become and maintain excessive fat. Theories about the causes of obesity usually focus proximately or evoke evolutionary mismatches, with minimal clinical value. There is potential for substantial progress by adapting strategic body mass regulation models...
Article
Cooperative interactions among individuals are ubiquitous despite the possibility of exploitation by selfish free-riders. One mechanism that may promote cooperation is "negotiation": individuals altering their behaviour in response to the behaviour of others. Negotiating individuals decide their actions through a recursive process of reciprocal obs...
Article
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Background and objectives: Peoples’ attempts to lose weight by low calorie diets often result in weight gain because of over-compensatory overeating during lapses. Animals usually respond to a change in food availability by adjusting their foraging effort and altering how much energy reserves they store. But in many situations the long-term availab...
Article
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There are many inputs during development that influence an organism's fit to current or upcom-ing environments. These include genetic effects, transgenerational epigenetic influences, environmental cues and developmental noise, which are rarely investigated in the same formal framework. We study an analytically tractable evolutionary model, in whic...
Article
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There are many situations where relatives interact while at the same time there is genetic polymorphism in traits influencing survival and reproduction. Examples include cheater-cooperator polymorphism and polymorphic microbial pathogens. Environmental heterogeneity, favoring different traits in nearby habitats, with dispersal between them, is one...
Data
Details of model description, results and individual-based simulations. (PDF)
Article
Full-text available
Aim: The tendency for animals at higher latitudes to be larger (Bergmann’s rule) is generally explained by recourse to latitudinal effects on ambient temperature and the food supply, but these receive only mixed support and do not explain observations of the inverse to Bergmann’s rule. Our aim was to better understand how ecological variables might...
Article
Information transfer and utilization is ubiquitous in nature. Animals can increase their reproductive value by changing their behavior in light of new information. Previous work has shown that the reproductive value of information can never be negative given an animal behaves optimally. Statistical decision theory uses Bayes’ theorem as a mathemati...
Data
Appendix S1 Critical temperatures. Appendix S2 Supplementary figures. Appendix S3 Effect of temperature.
Article
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To explore the logic of evolutionary explanations of obesity we modelled food consumption in an animal that minimizes mortality (starvation plus predation) by switching between activities that differ in energy gain and predation. We show that if switching does not incur extra predation risk, the animal should have a single threshold level of reserv...
Data
In this section we describe the details of the agent's activity bouts over the course of a simulation, and show how the behaviour di↵ers as the c 1 , c 3 and c 4 parameters are systematically varied. In a single simulation the agent was allowed to forage for 200 steps, with t = 0.001 (i.e., 200, 000 time steps total). The simulations were altered s...
Article
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Obesity is an important medical problem affecting humans and animals in the developed world, but the evolutionary origins of the behaviours that cause obesity are poorly understood. The potential role of occasional gluts of food in determining fat-storage strategies for avoiding mortality have been overlooked, even though animals experienced such c...
Article
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The development of multicellular organisms involves a delicate interplay between genetic and environmental influences. It is often useful to think of developmental systems as integrating available sources of information about current conditions to produce organisms. Genes and inherited physiology provide cues, as does the state of the environment d...
Article
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Depression is a major medical problem diagnosed in an increasing proportion of people and for which commonly prescribed psychoactive drugs are frequently ineffective. Development of treatment options may be facilitated by an evolutionary perspective; several adaptive reasons for proneness to depression have been proposed. A common feature of many e...
Article
A striking feature of human decision making is the fourfold pattern of risk attitudes, involving risk-averse behavior in situations of unlikely losses and likely gains, but risk-seeking behavior in response to likely losses and unlikely gains. Current theories to explain this pattern assume particular psychological processes to reproduce empirical...
Article
Strong asymmetries in parental care, with one sex providing more care than the other, are widespread across the animal kingdom. At present, two factors are thought to ultimately cause sex differences in care: certainty of parentage and sexual selection. By contrast, we here show that the coevolution of care and the ability to care can result in str...
Article
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Human reproductive patterns have been well studied but the mechanisms by which physiology, ecology and existing kin interact to affect the life history need quantification. Here, we create a model to investigate how age-specific interbirth intervals adapt to environmental and intrinsic mortality, and how birth patterns can be shaped by competition...
Article
Abstract An organism's phenotype can be influenced by maternal cues and directly perceived environmental cues, as well as by its genotype at polymorphic loci, which can be interpreted as a genetic cue. In fluctuating environments, natural selection favors organisms that efficiently integrate different sources of information about the likely success...
Article
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We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and examine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has previously been included in models of decision making, the question of what benefit it may provide to an animal’s...
Article
One possible explanation for the widespread existence of cooperation in nature is that individuals cooperate to establish reputations and so benefit in future interactions with others. We consider a class of games in which individuals contribute to a common good at a cost to themselves. Population members vary in type, that is, in the cost paid for...
Article
When given a choice between options with uncertain outcomes, people tend to be loss averse, risk averse regarding potential gains and risk prone regarding potential losses. These features of human decision making are captured by prospect theory (PT)—a hugely influential descriptive model of choice, but one which lacks any unifying principle that mi...
Article
The primary function of lipid storage by animals is as an energy source for surviving periods without food. However, muscle and organ protein can be metabolised for energy, and empirical studies have shown that the onset of protein metabolism begins before the exhaustion of lipid reserves. Since protein tissues are important for reasons other than...
Article
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Migratory vertebrates adjust their movements in response to environmental change. Throughout their migrations, they gather information, integrate environmental and internal state data, and make decisions about the timing and orientation of migratory movements. Understanding this class of animal decision-making has both basic and applied interest be...
Article
An aspect of life history that has seen increasing attention in recent years is that of strategies for financing the costs of offspring production. These strategies are often described by a continuum ranging from capital breeding, in which costs are met purely from endogenous reserves, to income breeding, in which costs are met purely from concurre...
Article
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Models and experiments on adaptive decision-making typically consider highly simplified environments that bear little resemblance to the complex, heterogeneous world in which animals (including humans) have evolved. These studies reveal an array of so-called cognitive biases and puzzling features of behaviour that seem irrational in the specific si...
Article
Understanding decisions is the fundamental aim of the behavioural sciences. The theory of rational choice is based on axiomati principles such as transitivity and independence of irrelevant alternatives (IIA). Empirical studies have demonstrated tha the behaviour of humans and other animals often seems irrational; there can be a lack of transitivit...
Article
In his paper 'Parental investment: a prospective analysis', Maynard Smith (1977, Animal Behaviour, 25,1-9) introduced a game-theoretic approach to understanding the evolution of parental behaviour and addressed the broad issue of which sex should provide care for the young. This paperwas important in that it introduced the use of game theory to the...
Article
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Moods can be regarded as fluctuating dispositions to make positive and negative evaluations. Developing an evolutionary approach to mood as an adaptive process, we consider the structure and function of such states in guiding behavioural decisions regarding the acquisition of resources and the avoidance of harm in different circumstances. We use a...
Article
Most examples of the application of evolutionary game theory to problems in biology involve highly simplified models. I contend that it is time to move on and include much more richness in models. In particular, more thought needs to be given to the importance of (i) between-individual variation; (ii) the interaction between individuals, and hence...
Conference Paper
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Efficient action selection is a crucial aspect of animal behaviour. Different competing physiological and behavioural requirements must be satisfied in the most effective manner possible, and these will have different and changing importances to the animal over time. In managing the competition between different behaviours, pathological outcomes su...
Article
Apparently irrational biases such as overconfidence, optimism, and pessimism are increasingly studied by biologists, psychologists, and neuroscientists. Functional explanations of such phenomena are essential; we argue that recent proposals, focused on benefits from overestimating the probability of success in conflicts or practising self-deception...
Article
A fundamental issue in foraging theory is whether it is possible to find a simple currency that characterizes foraging behaviour. If such a currency exists, then it is tempting to argue that the selective forces that have shaped the evolution of foraging behaviour have been understood. We review previous work on currencies for the foraging behaviou...
Article
Choice in Changing Environments Animals, including humans, generally tend to judge the world on relative, rather than absolute, terms. For example, the value of a particular object or reward is generally determined based on comparison to other rewards we have received in the past or to those that others have received. Such contrast effects can have...
Article
Guidelines for submitting commentsPolicy: Comments that contribute to the discussion of the article will be posted within approximately three business days. We do not accept anonymous comments. Please include your email address; the address will not be displayed in the posted comment. Cell Press Editors will screen the comments to ensure that they...
Article
A placebo is a treatment which is not effective through its direct action on the body, but works because of its effect on the patient's beliefs. From an evolutionary perspective, it is initially puzzling why, if people are capable of recovering, they need a placebo to do so. Based on an argument put forward by Humphrey [Great expectations: the evol...
Article
Abstract Animals live in complex environments in which predation risk and food availability change over time. To deal with this variability and maximize their survival, animals should take into account how long current conditions may persist and the possible future conditions they may encounter. This should affect their foraging activity, and with...
Article
The relationship between positive and negative reinforcement and the symmetry of Thorndike's law of effect are unresolved issues in operant psychology. Here we show that, for a given pattern of responding on variable interval (VI) schedules with the same programmed rate of food rewards (positive reinforcement VI) or electric shocks (negative reinfo...
Article
Full-text available
Adaptation in dynamic environments depends on the grain, magnitude and predictability of ecological fluctuations experienced within and across generations. Phenotypic plasticity is a well-studied mechanism in this regard, yet the potentially complex effects of stochastic environmental variation on optimal mean trait values are often overlooked. Usi...
Article
Personality differences can be found in a wide range of species across the animal kingdom, but why natural selection gave rise to such differences remains an open question. Frequency-dependent selection is a potent mechanism explaining variation; it does not explain, however, the other two key features associated with personalities, consistency and...
Article
Full-text available
Organisms living in periodically varying environments adjust their life history events to the changes in food availability. When these changes are not entirely predictable animals face a trade-off between maintaining physiological preparedness (which can be costly) and being unprepared (which decreases the chances of successful reproduction). To in...
Article
The storage of lipids to buffer energy shortage may incur such costs as increased vulnerability to predation, and animals may be more muscular in order to reduce such costs. If muscle and lipid mass interact to determine survival, then both the muscularity and the adiposity of animals will be affected by factors such as predator density and food av...
Article
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We investigate the optimal behaviour of an organism that is unable to obtain a reliable estimate of its mortality risk. In this case, natural selection will shape behaviour to be approximately optimal given the probability distribution of mortality risks in possible environments that the organism and its ancestors encountered. The mean of this dist...