Individual behaviours are becoming key issues for governments to grapple with, especially in relation to urban environments. New research funding opportunities indicate that understanding consumer perception is no longer enough: people are judged by their actions, and these actions both inform and are moulded by external parameters. The underlying imperative driving this observational agenda is the need to persuade individuals to behave otherwise, and in particular to behave more sustainably and respectfully. It is perhaps the case that built environment professionals, and the clients and bodies whose interests they serve, are by now sold on the idea of planning and designing urban environments to be ever more sustainable and inclusive. However, the inhabitants of the places they create often prefer to act differently, sometimes subversively, generating new and unforeseen tensions that might precipitate minor adaptations, or even raise the prospect of wholesale redevelopment.

In this issue, four authors consider a range of analytical tools and historical perspectives at our disposal in relation to our increasingly urban existence. Each offers a means to articulate changes that have taken place within urban landscapes in different parts of the world. They are each concerned with investigating the impact that such changes have on the structure, identity and visibility of place. Central to their analysis is the figure of the urban pedestrian, and the extent to which different qualities and categories of urban spatiality have conditioned and reshaped their urban interactions.

Dorina Pojani presents a penetrating account of pedestrian shopping malls in the context of North America. She asks why these often failed and how subsequent planning policy and commercial practice initiated a turnaround. Pojani focuses on the example of Third Street Promenade in Los Angeles, as a planned downtown street-as-mall dating back to the 1960s. By the 1980s it had become an economic failure and was redeveloped. The redevelopment of this type of leisure space has tended to produce a distinctly codified, scripted environment, borrowing strategies from highly themed entertainment environments. In such spaces, pedestrian movement is heavily managed and directed, and events and activities are programmed to take place in a quasi-public arena. It was not only environmental improvements, but also the total management of the Santa Monica mall that enabled it to adjust to meet the expectations of today's consumers, for whom browsing and socialising require specific, accessible and easily identifiable urban configurations.

Brent Ryan's piece on Detroit looks at the issue of city block restructuring, presenting a detailed study of the street frontages in the downtown area. Ryan evaluates the extent to which the removal and reconstruction of urban blocks has effectively altered the urban grain, and hence changed the experience of the city through change of use, loss of connectivity and legibility, as smaller more subdivided blocks became larger superblocks. Detroit has a precarious existence, and unlike Santa Monica has been on a continuous downward spiral since the 1930s. What was an aspirational urban environment of glittering skyscrapers fuelled by a burgeoning automotive industry is now an image of decay and dereliction, dependent on inward investment simply to keep the local economy afloat. As such, urban intervention is necessarily laissez-faire, waiting for any business opportunity to be able to deliver jobs and maintain the city's economic viability. Detroit is simply engaged in a process of rewriting its urban structure in order to remain fit for purpose, sadly now with a greatly reduced sense of aspiration.

Parvin, Ye Min and Beisi's study looks at the shifting structure of another densely developed urban environment, namely Hong Kong. They put forward an integrated quantitative model with which to examine the effects of particular urban design strategies. Their particular focus is the multi-level movement that is characteristic of Hong Kong, with its many raised walkways, podia, subways, malls and atria. In this kind of environment, the urban pedestrian exists on many different vertical levels, and this suggests that more variegated forms of visibility are in operation and which inform their urban wayfinding. The mental maps we construct of cities are largely two-dimensional, even in situations where there is a complex natural topography. However, once there are opportunities to move more fluidly within the urban environment, and particularly where walking is separated from vehicular traffic, the mental maps become more complex and pedestrian behaviours more varied. The authors of this paper argue that this produces an important spatial quality in a given place.

The last paper by Renate Bornberg advocates a means of categorising public open space in a system that draws inspiration from key historic and vernacular cultures. As a phenomenological approach, the idea of Topos embodies more than a set of unique physical parameters: it also encompasses other place-specific qualities that are more to do with collective memory and meanings derived through social use and established over time. Site surveys rarely take sufficient account of detailed ethnographic information that might be available in the same way as feasibility studies and briefing documents rarely take into account habitual experiential dimensions. If we are to enrich our urban environment and ward off the tendency towards homogeneity and banality, it will become increasingly important for planners and urban designers to tune into the less visible attributes of place, to find ways to engage with local tacit knowledge about a place, and to find new ways of working with this creatively and intuitively.

Human behaviour is an intriguing and sometimes inexplicable conundrum. Urban design can and should welcome a move towards engaging more systematically and sensitively with aspects of our day-to-day actions, experiences and motivations. However, any recourse to determinism is to be avoided: behaviouralism in the 1960s became worryingly prescriptive, and led to a great many schemes that have long since been discredited. The challenge for the design community is to make use of any new light that is shed on individual behaviour to encourage and support less profligacy and at the same time greater equality and diversity of use and enjoyment.