On the Rational and the Emotional in Transport Analysis

Yesterday a PhD student posted a series of questions regarding the analysis of the choice of acquiring and using a car on the mailing list of the UTSG (universities’ transport studies group). He had spoken with experts in marketing and psychology who claimed (a) that this choice is both rational (travel utility – price, time, etc) and emotive (symbolism of a brand for an individual and their self image), and (b) that transport analysis — and more specifically analysis using discrete choice models — only considered the rational side of things, ignoring the emotive. With his post he wanted to canvass the views of transport academics on these matters, and asked three questions:

  1. Is (b) above true and discrete choice modelling deficient in the way it approaches matters such as ‘symbolism of a brand’ or ‘aversion to a mode’?
  2. If it isn’t, how does discrete choice modelling account for such things?
  3. Has any work actually quantified the % split between the ‘rational’ and the ’emotive’ when choosing to acquire and/or use a car.  Could this percentage vary by culture?

These are interesting questions and I couldn’t resist responding. This is (and edited version of) what I wrote:

I am afraid that the experts you have spoken to are not aware of recent developments in discrete choice modelling in transport studies. There is a growing number of empirical studies using discrete choice models to account for what you term ’emotive’ factors (more on this below). These studies tend to adopt one of the following approaches:

  1. Include measures of people’s attitudes, beliefs and values directly into the utility function — a good example of this line of work is provided by the work of Pat Mokhtarian at UC Davis. For an example of a study of vehicle choice, see her co-authored paper ‘What type of vehicle do people drive?‘ published in 2004 in Transportation Research A.
  2. Use a latent class model whereby people are endogenously classified into groups with similar preferences/attitudes as part of the choice model. I don’t have an example of this approach in the context of vehicle type choice at hand, but this approach is increasingly used (see e.g. Walker and Li’s 2007 paper ‘Latent lifestyle preferences and household location decisions‘ in Journal of Geographical Systems) and is directly applicable to decisions about what sort of vehicle people drive.

However, there is also a problem with the way the three questions are framed. There is a long history of dualistically opposing the ‘rational’ and the ’emotional’ in mainstream western thought, but evidence from a wide variety of sources suggests that this opposition is in itself very problematic: it is not possible to separate the two. In the neurosciences, for instance, it is now increasingly accepted that emotions are indispensable to good, or at least effective, decision-making — the work of Antonio Damasio is a key source here. In fact, one could argue that the opposition of the rational and the emotional is a somewhat curious particularity of the vagaries of mainstream western philosophy, and certainly not shared by all the mainstream philosophers of the past centuries. David Hume and some of the utilitarians, for instance, already acknowledged that the rational and the emotional were entangled in complex ways in (good) decision-making. These arguments imply that your third question is very problematic from a philosophical point of view — the question cannot be addressed in a meaningful way if one also wants to incorporate non-Western countries/cultures.

At the same time, there is much to say in favour of the criticisms articulated by the experts from marketing and psychology, but the key here is to distinguish between the ‘rational’ and the ‘instrumental’. In mainstream discrete choice modelling of travel behaviour, decisions regarding vehicle ownership, and so on, there has long been a tendency to privilege the instrumental aspects of behaviour — e.g. how can I get to X the quickest, at the lowest monetary costs and with the highest level of comfort? This one-sided focus on the instrumental has a long and complex genealogy and derives in part from theoretical considerations but also reflects data availability issues and the difficulty of constructing reliable measurements of the more-than-instrumental factors that mediate people’s decision-making.

The ‘expressive’ dimensions of behaviour and decisions about vehicle ownership have long been side-lined in transport modelling, and until fairly recently there has been little attention for the links between transport and identity (and symbolism) and for the links between transport/movement, sensory experience, affects and feelings. The most powerful work on those expressive dimensions can nonetheless be found outside the body of research drawing on discrete choice models; two strands of work would be particularly useful to consider:

  1. Research informed by thinking from behavioural psychology — see e.g. the work of Linda Steg (among others her 2005 paper ‘Car use: lust and must‘ in Transportation Research Part A)
  2. Research belonging to what John Urry and Mimi Sheller have called the ‘new mobilities paradigm’ — the best place to start here would be the work of Peter Merriman (his 2009 paper ‘Automobility and the geographies of the car‘ in Geography Compass provides an excellent introduction to this line of thinking)

Considering the more-than-instrumental is important in choice modelling; models that only consider the instrumental dimensions of individuals’ decision-making — e.g. travel time, travel cost, comfort, reliability — seem to systematically over-predict the extent to which people will change their behaviour or choices compared to what happens in the real world. The more-than-instrumental must be given much more attention if we want to move towards more sustainable transport systems.

Does Slime Mould Help Us to Rethink Land-based Transport Networks?

Today I read a fascinating piece on the Guardian‘s website about a study conducted by Andrew Adamatzky. He and his colleagues have conducted a series of great experiments on slime mould and the way in which this one-celled organism grows and builds a network or system linking different food resources. Its relative simplicity in evolutionary terms notwithstanding, this organism is known to behave ‘smartly’ and build its networks more or less rationally.

Adamatzky and colleagues poured agar on a globe and cut out the seas and oceans, so that the agar configuration resembled Earth’s land masses. They also placed oat flakes on the positions of the world’s megacities and other urban concentrations. They placed the slime mould on the flake representing Beijing and then observed how it built its network. Details are available here or here. They have previously used this methodology in a study of Australia’s major population concentrations and the road networks connecting them, available here.

A key finding of the study on the globe as a whole is that the slime mould’s network “approximates over 76% of the Silk Road routes and the Asian Highway routes”. The implication being that these historically emerged transport networks are quite rational — if not optimal — in terms of their structure. Indeed, Adamatzky writes that his research and findings “will help to design future transcontinental pathways”.

For a long time I have been fascinating by the idea of optimality in transport networks and the specific way in which optimal travel behaviour has been defined in travel behaviour studies (i.e. either in terms of minimising travel times or in terms of the optimisation of the ‘costs’ of travel and the ‘benefits’ to be reaped at the destination). So I very much welcome work such as Adamatzky’s because it sheds new light on the ‘trick’ by neo-classical economists to transpose the principle of least effort from physics to human behaviour. Perhaps there is an evolutionary edge to this principle, which the neo-classical economists grasped intuitively but were unable to prove? There must be literature on addressing this question and I would grateful for any references! Anyway, I mention neo-classical economics here because this body of thought has had such a profound influence on the history of transport and travel behaviour modelling.

At the same time, I am rather sceptical about Adamatzki’s claim that slime mould behaviour can really help us understand the configuration of surface transport networks. For there is a big difference between slime moulds’ quest for food and transport-land use interactions. At least in Adamatzki’s oat flaked world, the location and size of food sources are given (as an inevitable if understandable consequence of his experimental set-up). Though I clearly am no expert on slime mould, I would think that its spatial behaviour is essentially responsive: it reacts to a given state of affairs. And this differs fundamentally from ‘real world’ developments: as decades of transport geography research tell us, urban developments and transport infrastructure development co-evolve. There is no given and static world of cities; their size and growth is very much a consequence of how they are positioned and articulated in major transport networks (not only land-based transport but also maritime and aviation networks, and increasingly internet backbone networks).

So, to really help us understand the evolution of land-based transport networks, Adamatzki should re-design his experiment and add flakes at nodes in the networks built by the slime mould (and a set of rules would need to be deviced regarding how much the extra flakes would need to be added, although deriving those rules would be a less than straightforward task!). In this way feedback effects and positive reinforcement and ultimately the co-evolution of urban development and transport networks could be mimicked.

My hunch is that the slime mould’s networks would develop rather differently if that co-evolution were taken into account.

Thinking Climate Change Mitigation in Transport

A few weeks ago the special section of Journal of Transport Geography that David Banister, Jillian Anable and myself guest edited has been published. This special section introduces a range of theoretical approaches that can help (transport) scholars to better understand climate change mitigation and reduced use of carbon-intensive energy sources in transport. The general idea is that new understandings — and especially social science approaches — are needed alongside more mainstream transport studies perspectives emphasising the importance of green infrastructures and technologies and pricing measures, given that transport planning and practice has made little headway in reducing transport’s deep dependence on fossil fuels.

The approaches highlighted in the special section include: the sociotechnical transitions approach and multi-level perspective advanced by Frank Geels and others; theories of social practices a.k.a. practice theory; and behavioural economics. Each approach is introduced by one or a team of leading experts — Frank Geels, Matt Watson, and Paul Dolan & Robert Metcalfe, respectively — and its value and usefulness is then evaluated by a expert in the field of transport or mobility studies — Lorraine Whitmarsh, Thomas Birtchnell, and Erel Avineri. In this way each perspective is discussed from two sides and the views of both the protagonist and the transport/mobility scholar sympathetic to the approach.

The special section also contains the paper about rethinking travel habits I authored with David and Jillian (as discussed previously), and a commentary by John Urry. More details are available here.

Approaches to Time in Transport Studies

This week I have been to the wonderful Forge Network summer school in York organised by Greg Marsden and Elizabeth Shove on ‘Time, Travel and Everyday Life‘ and attended by young researchers in a range of disciplines (transport, geography, sociology, etc.) from the UK and a number of European countries.

I gave one of the talks, and mine was on different theoretical understandings of time in transport and mobilities research and how understandings of time can be used to change current transport research and planning practice. I used the works of Barbara Adam, David Harvey and Henry Lefebvre to highlight how time (a) is a multi-faceted construct intimately tied to space and matter, and (b) understood in very partial ways in mainstream transport research and practice.

With regard to the first point, I discussed Harvey’s distinction between absolute time (a Newtonian, linear and immovable grid), relative space-time (dependent on the frame of the observer as proposed by Einstein) and relational spacetime (emergent from the relations between entities as suggested by Leibniz, quantum mechanism and complexity theory, among others) and criticised Harvey’s idea that time is all three, arguing that (space)time is ultimately relational. I also discussed Lefebvre’s distinction between linear and cycles rhythms and times, whereby the former pertain to a man-made pure repitition as epitomised in clock-time and the latter to nature and the cosmos where each re-occurence differs from a previous manifestion. And I drew on Adam’s timescapes framework to argue that mainstream transport research and practice are deeply commited to her five ‘C’s. That is, in transport research, planning and practice time is commonly and continually:

a) constructed, through the privileging of clock time to the exclusion of almost any other form of time;

b) commodified and monetarised, among others through the widespread use of values of time;

c) compressed, primarily through the valorisation of acceleration (i.e. the assumption that travel time is a waste and disutility) in transport appraisal (cost-benefit analysis) and basically all micro-economic theory inflected thinking about transport;

d) colonising the future, among others because of the failure to reduce transport’s extreme dependence on oil and its contribution to anthropogenic climate change; and

e) considered something that must be controlled in that the different features of time (such as the duration, timing, etc. of travel time) must be shaped and steered in some way or another, and this perhaps best exemplified with the preoccupation in some circles of research and planning with the reliability and travel times and transport networks.

I do believe, however, that the deep commitment to Adam’s five ‘C’s and the privileging of absolute and linear understandings of time in mainstream transport research and planning are ultimately a barrier to making transport more environmentally sustainable and socially just and to more effective transport policies. As the privileging of these understandings is one of the factors that got us where we are at the present (i.e. transport as a major contributor to both carbon consumption and social inequalities), we — researchers and practitioners in transport, urban planning and cognate fields — need to reconsider how we ‘think’ time (and space) in relation to transport and travel behaviour. So, in the end my talk was a plea for (a) more sophistated understandings of time (and space) in transport research and planning, and (b) greater attention being paid to relational and cyclical understandings of time in connection to transport as these allow us to better understand how the users of transport systems act and respond to the situations they face whilst travelling. I sought to illustrate the latter point by contrasting mainstream transport studies of how travellers respond to travel time variability and my own research on this topic and on what arriving late at a destination is and means (as summarised here and here).

I do realise of course that talk about the nature of time (and space) and how it relates to transport & mobility is rather abstract and philosophical, and in many ways challenges common-sense understandings of how the world is. But those common-sense understandings are partly responsible for the non-sustainable nature of contemporary transport systems, and bringing the typically taken-for-granted understandings of time (and space) into focus and challenging them is one way in which social scientists can make a major contribution to transport policy and practice.

I would be very happy to share the slides of my talk with anyone who is interested. Just drop me an e-mail.