Newcastle upon Tyne, whereas she lived in the West End, in the house we now live in together. Newcastle, like many cities, asks its citizens to divide household waste into recyclable and non-recyclable categories, collected on different days. I was uncertain, as I recall, about the proper categorization of some kind of plastic. I wanted to behave well and sort correctly, and was therefore anxious to have the right information about what the rules were. She said something to the effect that she wouldn't expend too much effort on getting things like this right, since her bin would be quite likely to be set fire to anyway before it could be collected. It turned out that her attitude was not without foundation. Various things did indeed get set ablaze in that part of Newcastle at that time, a problem that thankfully seems to have abated somewhat. Even when recycling bins did not burn, they would often be either kicked over or used improperly by someone else once on the street, resulting in a mixed load that the recycling lorry would refuse to take. Thus, she was absolutely correct in her assessment of the futility of expending much effort in the direction of conscientious recycling; such effort would end up being undermined by the action of others. Her lightly-made comment made a remarkable impression on me, for several reasons. First, over the years I have thought a fair amount about the ageold question of whether people are basically good (helpful, prosocial, cooperative), or whether they are basically selfish. This question has a very clear answer: it depends. Humans have motivations to deliver social benefits to others, but these are not their only motivations, and the expression of these motivations is contingent and conditional. Most obviously, and as illustrated by the blazing bin example, the expression of prosocial motivations depends on expectations about what others in the population might (or might not) do. This means that if you want to understand when people will behave prosocially and when they will not, you need to know a lot about their ecology (what kinds of things are going on in the surrounding population?), and you also need to know a lot about human psychology (how exactly do the information-processing mechanisms that take cues from the local environment in order to adjust an individual's social decisions work?). The second reason that her comment struck me was that our respective houses were in the same city and only around 3km apart, yet clearly the behaviour going on around them was utterly different. Rubbish bins would never be set fire to where I lived. It was-and I mean this as more 6 Tyneside Neighbourhoods area deprivation (e.g. living in neighbourhood where many other people are poor). This is because the population of Britain is strongly assorted by income, so that most people living in neighbourhoods with many poor people are themselves poor. The best evidence suggests, though, that for many gradients, there is an effect of area-level deprivation above and beyond the effects of indivi...