Surely not another book on behavioural economics? Several Nobel prizes have been awarded to pioneers in this field, which is itself at least fifty years old now. Finance journals are flooded with kilometres of articles dedicated to outlining new manifestations or nuances related to prospect theory or the disposition effect. Is there really much more we can learn about the forces that drive us to make rational and irrational decisions?

Yes, is the short answer to that question, although this does not imply more behavioural economics so much as an expanded intellectual paradigm. In order to understand economic behaviour more comprehensively, we need to think beyond the obsession with purely cognitive bias and the rather bizarre reliance on using WEIRD (Western, Educated, Industrialised, Rich, Democratic) MBA students as cannon fodder for experimental studies. Instead, we need to embrace the cultural and social factors that shape our economic action. Refreshingly, this is something that even behavioural economists themselves have started to recognise.

For example, David Hirshleifer (Reference Hirshleifer2015: 44) has argued that behavioural economics needs to ‘draw on social psychology and sociology as well as cognitive psychology and decision theory, and will require focused attention to the microstructure of social transactions’. Hirshleifer calls this new paradigm of thought ‘social finance’. In his presidential address to the American Finance Association, social finance was hailed by its progenitor as a ‘once in a generation research opportunity’ and ‘a new way to understand human behavior’ (Hirshleifer, Reference Hirshleifer2020: 1817).

This is all well and good, but the last thing we probably want is economists who have merely read Nudge (Thaler and Sunstein, Reference Thaler and Sunstein2009), Thinking Fast and Slow (Kahneman, Reference Kahneman2011), or Cognitive Psychology for Dummies (Hills and Pake, Reference Hills and Pake2016) to start telling us how society works. One of the main problems with intellectual approaches dominated by economics is that they are anthropologically ignorant (Bourdieu, Reference Bourdieu2005). Supplementing economics with a smattering of cognitive psychology will only take us so far. Instead, does it not make more sense to draw on expertise from the wider social sciences to make sense of the things that economics and cognitive psychology alone simply cannot?

Mercifully, this is what Adam Hayes does in his latest book, Irrational Together (2025). Drawing from wider sociological framings that cleverly meld Weber, Bourdieu, Zelizer, Mauss, Durkheim, Callon, and others, Hayes systematically and convincingly draws attention to various areas of economic activity that simply cannot be adequately explained by behavioural economics. What we are treated to is a book about economic behaviour that significantly exceeds the bounds of behavioural economics. This is important work, both academically and for shaping popular understandings of economic behaviour.

The book itself is wide ranging and draws from examples as diverse as an interchange on tipping from the HBO show Curb Your Enthusiasm through to more academic empirical work looking at how Haredi Jews in Israel divide economic roles in the household. This is all combined with careful sociological theorising that is at once accessible and erudite – no mean feat. As such, those new to the field of economic sociology are given an easy entry point through the many and varied empirical examples; whilst those well versed in economic sociology are offered a helpful vista both onto how their own work builds upon other disciplines and how it can be made relevant to the general reader.

Bourdieu looms large over the book. Indeed, Chapter 1 is called ‘A Feel for the Game’. The first empirical examples used in the book build on previous work by Tversky and Kahneman on loss aversion – a canonical concept in behavioural economics. Hayes reruns some of the original Tversky and Kahneman experiments around loss aversion but overlays the stocks of economic and cultural capital that participants possess finding that one’s portfolio of capitals and, by extension, their field position, significantly impacts one’s appetite for embracing or averting losses. More economic capital tends towards a more risk-taking disposition, whereas more cultural capital tends towards a more loss-averting disposition.

A particularly vivid chapter looks at the world of personal finance and how individuals try to balance friends, family, and finance. Hayes refers to this as the ‘relational balance sheet’ and draws on the relational sociology of Viviana Zelizer in order to show how certain behavioural economic concepts like the endowment effect – where individuals tend to value what they possess more than what they do not – would benefit from being analysed in the context of the webs of relationships within which individuals find themselves.

This is illustrated via experiments which show clearly that people value items, from coffee mugs to houses, more highly if they have received them from a dear friend (the mug) or a close relative (the house). Moreover, this has implications too for decisions about whether to sell the item (or potentially rent it, in the case of the house), for how much, and so on. The key point is that our financial decisions are entangled in our webs of relationships and that our attitudes towards goods and assets are not purely financial. We might hold onto a house that our dead grandmother bequeathed us, not because it makes more financial sense to do so, but because we are unconsciously trying to ‘safeguard a relational connection’ (125).

Beyond the various experiments that appear to have been conducted primarily, if not purely, for the purposes of the book, readers are also treated to summaries of some of Hayes’ recent published work in journals such as Socio-Economic Review or Economy and Society, notably studies looking at how robo-advisor apps try to shape the ‘ideal’ economic actor or how ultra-orthodox communities in Israel are markedly split in terms of gender when it comes to attitudes towards competitiveness, risk-taking, and financial acumen. This latter study is particularly interesting in that is shows the cultural contingency of gender differences. Whereas most behavioural studies tend to illustrate higher degrees of risk-taking and competitiveness among men, the particular distribution of labour in Haredi communities shows how these insights do not hold across all cultural contexts. Paying attention to social structures can therefore also be a bulwark against gender essentialism.

Culture, relationships, and social structures all matter. These are the key messages of the book and while those already versed in economic sociology do not need convincing in this regard, rarely do we see such a wide-ranging application of this approach. Generally, we might read about one specific group of people behaving in one specific way in one specific set of circumstances. Irrational Together offers myriad groups, behaviours, and circumstances, masterfully synthesised to make the case for paying serious attention to social structures. A focus on cognitive structures alone just won’t cut it.

As a point of criticism, one wonders whether the book is a missed opportunity to take economics to task. The book does finish rather abruptly where it might have developed an argument around the differences and complementarities between sociology and economics. For all its transcendence of the limitations of behavioural economics, the book still presents itself as complementary to economics in many ways. This is no doubt a pragmatic and laudable attempt to try and build bridges between disciplines that tackle the same empirical subject matter. However, there are also fundamental points of incommensurability between the sociological and the economic enterprises. Anyone who has tried to present sociological work to an economics audience will be acutely aware of these. Exploring the potential of, and limits to, a meaningful synthesis of sociology and economics at the end of the book would have been a worthwhile endeavour. Something for the future, perhaps.