Colin Ellard examines a study of the new urban paradigm that fosters 'deep sharing'.

Sharing Cities: A Case for Truly Smart and Sustainable Cities Duncan McLaren and Julian Agyeman. MIT Press: 2016.

9780262029728

As urbanizing countries grapple with the need to provide sustainable energy and transport for their burgeoning cities, start-up companies are creating a culture and economy of sharing. Many are commercial. The global home-rental 'community' Airbnb, for instance, has an estimated 60 million users in 34,000 cities. US-based transport company Uber, which links registered drivers with passengers by way of smartphones, is active in more than 360 cities across 6 continents. Car-sharing services such as Zipcar are also widespread, attracting millennials who blanch at the costs of car ownership (environmental as well as financial). In Medellin, Colombia, water tanks are being repurposed to create public spaces that offer classrooms, cafes and theatres. Credit: EPM

Commercially mediated sharing can have a dark side. Sharing can skew local economies. Property owners turning to Airbnb may convert entire buildings to de facto hotels in cities such as New York, potentially contributing to housing crises. And Uber uses a surge-pricing algorithm to match supply and demand, meaning that users can face unpredictably high fares during periods of peak demand.

There is an alternative: bottom-up ventures that are digital or based in communities, rather than commercial. In Sharing Cities, environmental consultant Duncan McLaren and urban-policy scholar Julian Agyeman lay out, with impressive depth, clarity and wisdom, a comprehensive prescription for a sharing paradigm that incorporates such models. Noting that sharing has been a sociocultural and informal practice for millennia, McLaren and Agyeman also reveal the promise and pitfalls of such an approach at a time when neoliberal economic policies emphasizing individualistic profit often trump public goods and services.

Sharing Cities explores the potential in dense urban spaces for 'deep sharing' of goods, resources, services, talent and experience through the Internet, with its rapid, extensive linking of lenders and borrowers. The models that the authors examine include barter clubs, credit unions, cooperative land trusts and co-housing to online and other peer-to-peer (P2P) networks and supper clubs. As they point out, commercial services barely scratch the surface of what is possible in a true sharing economy. For example, decentralized P2P networks such as TaskRabbit — in which users can exchange skills and services without strong corporate oversight — can facilitate substantial sharing networks with minimal supervision. Public-transport systems can be considered a form of sharing, because the costs of mobility are shared between many.

Each chapter focuses on a particular aspect of sharing (production, consumption, politics, justice), and opens with a vignette of a city that exemplifies it. San Francisco, California — a hotbed of entrepreneurial start-up culture driven in part by Silicon Valley — is used to illustrate consumption. That kick-starts a discussion of open skills and knowledge sharing on online collaborative platforms that fly in the face of conventional commercial secrecy.

Medellin, Colombia, is used as an example of sharing in the context of social justice, as a result of the city's spectacularly successful overturning of social marginalization over the past decade. This has been achieved through an ongoing architectural transformation of water tanks into shared public spaces, as well as the introduction of its sustainable Metroplus bus rapid transit system. McLaren and Agyeman describe how other cities can foster inclusivity and sharing through prudent adjustments in policy and priorities, provision of open data and more thoroughgoing input from citizens at the grass-roots level.

As I worked my way through each chapter, I rode a crest of optimism about the imminence of real change, only to crash back to reality as I realized how difficult it is to ensure that sharing transformations are transparent, equitable and just. The authors never flinch from tackling the complexities and contradictions inherent in these examples. They present exquisitely balanced explanations of both the potential of sharing and its vulnerability to corruption by opportunistic invaders seeking to maximize profit over fairness.

In many cases, as McLaren and Agyeman show, overcoming conflicts between bottom-up and profit-driven sharing ventures demands reconfiguration of urban policy. Two examples of this are participatory budgeting, in which citizens share responsibility for allocating resources, and shared land ownership, which emphasizes a public commons. Both deter the exclusions often generated by gentrification.

My only criticism is with one of the book's key premises: that humans are evolutionarily predisposed to share across the board. The authors point to work in developmental psychology showing that babies are aware of fairness and injustice (M. F. H. Schmidt and J. A. Sommerville PLoS ONE 6, e23223; 2011). Yet there is no shortage of evidence in evolutionary psychology — and everyday life — for the human tendency towards selfishness under some circumstances, towards some classes of others. And theoretical work has suggested that under many conditions common in human society, cooperation is likely to collapse (A. J. Stewart and J. B. Plotkin Proc. Natl Acad. Sci. USA 111, 17558–17563; 2014). Indeed, even the cited work by Schmidt and Sommerville shows that more than one-third of the infants in the study kept the best 'loot' for themselves.

In part, such differences are surely what underlie the constant push–pull between new sharing paradigms and the ventures that co-opt and parasitize them. It would have helped the balance of McLaren and Agyeman's argument to describe some of the seamy underbelly of our evolutionary heritage as well as the rosier side of our natures.

Author information Affiliations Colin Ellard is a cognitive neuroscientist at the University of Waterloo in Canada, specializing in the study of the relationship between human psychology and urban design. His latest book is Places of the Heart. Colin Ellard Authors Colin Ellard View author publications You can also search for this author in PubMed Google Scholar Corresponding author Correspondence to Colin Ellard.

Rights and permissions Reprints and Permissions