Understanding Age and Society using Natural Populations

A major issue facing almost all human societies around the globe is rapid ageing of the population. For example, over the past 40years alone, the average age in the UK has increased from 34 to over-40, and, in the next 30 years, the amount of over-65 year olds is predicted to double from today's number and reach ~20million individuals. As age affects almost all aspects of life, including behaviour, health, and reproduction, these changes in age composition are expected to have enormous consequences for society. But, as this is the first time in history that human populations have ever experienced 'ageing' in this way, it is exceptionally difficult to make predictions regarding these changes.

Interestingly, ageing is now known to not only occur in humans, but also across the animal kingdom. A broad range of studies have found evidence of ageing in hundreds of species, ranging from insects to whales. In fact, natural animal populations have become widely accepted as particularly useful for understanding how individuals age, and the mechanisms that underpin how individuals change as they grow older. In this proposal, I demonstrate that natural populations also have great, but previously unrecognized, potential for understanding how societies age, particularly due to the following three complementary reasons:

Firstly, unlike the human population (which has never 'aged' before), many animal societies have shown large variation in their population age compositions whilst being monitored. Therefore, this will allow me to develop an understanding of ageing societies based on previous patterns of ageing within the population (instead of relying entirely on predictions into the future). Secondly, recent advances in animal tracking technologies have given rise to hundreds of studies that quantify wild animal social networks in great detail, often over individuals' entire lifetimes and across multiple generations. I propose that such fine-scale datasets will allow the examination of fundamental processes governing how individuals' social behaviour changes as they age, and how this structures societies over time. Finally, experiments are often key to separating 'correlation from causation' across all fields, and this is particularly important in research surrounding sociality (as the behaviour of one individual automatically affects the behaviour of those it interacts with). My previous research has developed a novel method for experimentally manipulating a wild bird social system. I will use this unique approach to determine how individual age directly effects society structure and social processes (such as the development and spread of new information and cooperative behaviour).

Therefore, through amassing and analyzing various species' and populations' social networks over time and across various age compositions, along with carrying out social experiments within a model study system, I will take full advantage of the unrecognized opportunities that natural populations offer in terms of gaining novel insights into the interplay between age and society. This research will provide a new understanding of how age shapes individuals' social behaviour and emerging society structure, the ecological and evolutionary forces affecting this effect, and the consequences of age for the fundamental social processes of information transmission and cooperation.

Individuals' behaviour, health, survival and reproduction are broadly related to their age. Indeed, population age structure is often a fundamental component of any society. For instance, the societal-level impacts of age have recently become a major issue for human populations, as rapid ageing of societies across the globe is currently taking place. Yet, predictive models of ageing within human societies are particularly challenging to parameterize or test as - over the entirety of history - human populations have never 'aged' before. Further, how the structure of societies, in terms of their social network structure, may change over time and depend on individual's ages remains almost completely reliant on broad assumptions with little empirical framework, and extremely difficult to test experimentally.

Animal populations are widely recognized as particularly important for understanding individual-level ageing and the mechanisms underlying this. I propose that natural animal societies also have extensive, but currently unrealised, potential for understanding how age influences societies. Such potential is due to the massive amounts of data available detailing the social networks between individuals over their entire lifetimes, the natural variation in age structure of animal societies, and the ability to experimentally test the consequences of age for sociality directly. I will utilise the unique opportunities that wild animal populations present to (i) establish a fundamental framework for how societies change over time and age, (ii) assess how individuals' social behaviour (as quantified by their network positions) may change with age and (iii) experimentally determine the societal-level consequences of this for social processes. This will vastly extend our currently limited knowledge of the interplay between age and society, and enable novel breakthroughs in how individual-level properties affect social processes through shaping the social network structure.

The project will significantly advance the current understanding of the interplay between age and sociality in natural populations. Additionally, I have also identified key impact areas and how I aim to capitalize over the fellowship (see Pathways to Impact and diagrammatic work-plan for details).

First, human populations around the world are currently ageing rapidly in an unprecedented manner, which is predicted to affect almost all aspects of public health, such as health care, work and retirement, transportation, housing etc. Therefore, the topic of age and society is currently of upmost importance. The proposed research has strong potential for advancing understanding surrounding the issue of human population ageing, both in terms of methodological development and novel fundamental insights. In particular, this will be maximized through close collaboration with the Institute for Population Ageing, and through organizing two cross-disciplinary working group meetings.

Second, the general interest that the public holds in the parallels between the social lives of animals and that of humans means this project holds exceptional opportunity for public engagement. This will be taken full advantage of through using Oxford University Press Office for wide-scale media publicity surrounding research findings, collaborating with new initiatives (e.g. Frontiers in Young Minds) and primary school teachers to make child-friendly versions of the research freely available to school children around the world, and continued engagement in public seminars and direct school outreach activities.

Finally, the advances in RFID systems to be made during this project offer various applications (including reducing usage of lab animals) in terms of improving animal research. I will develop the applications of this technology with potential users, and advertise the potential abilities via publication and interdisciplinary conference presentations.

In sum, throughout the project, I will address various objectives related to these important areas of impact, and will achieve this through managed activities that will correspond well with the primary research.