biology would have to be popping up all over the place.

Andrew Ellington, of the Center for Systems and Synthetic Biology at the University of Texas, Austin, “I can’t tell you what the probability is. It’s a chapter of the story that’s pretty much blank.”

Given that rather bleak-sounding assessment, it may be surprising to learn that Ellington is actually pretty upbeat. But that’s how he and two colleagues come across in a paper in the latest Science. The crucial step from nonliving stuff to a live cell is still a mystery, they acknowledge, but the number of pathways a mix of inanimate chemicals could have taken to reach the threshold of the living turns out to be many and varied. “It’s difficult to say exactly how things did occur,” says Ellington. “But there are many ways it could have occurred.

The first stab at answering the question came all the way back in the 1950s, when chemists Stanley Miller and Harold Urey passed an electrical spark through a beaker containing methane, ammonia, water vapor and hydrogen, thought at the time to represent Earth’s primordial atmosphere.

Scientists have learned so much, in fact, that the number of places life might have begun has grown to include such disparate locations as the hydrothermal vents at the bottom of the ocean; beds of clay; the billowing clouds of gas emerging from volcanoes; and the spaces in between ice crystals.

The number of ideas about how the key step from organic chemicals to living organisms might have been taken has multiplied as well: there’s the “RNA world hypothesis” and the “lipid world hypothesis” and the “iron-sulfur world hypothesis” and more, all of them dependent on a particular set of chemical circumstances and a particular set of dynamics and all highly speculative.

“Maybe when they do,” says Ellington, “we’ll all do a face-plant because it turns out to be so obvious in retrospect.” But even if they succeed, it will only prove that a manufactured cell could represent the earliest life forms, not that it actually does. “It will be a story about what we think might have happened, but it will still be a story.”

The story Ellington and his colleagues have been able to tell already, however, is a reason for optimism. We still don’t know the odds that life will arise under the right conditions. But the underlying biochemistry is abundantly, ubiquitously available—and it would take an awfully perverse universe to take things so far only to shut them down at the last moment.

from Newcastle University in the UK, wanted to determine whether the connection was due to people reacting to the environment around them, or because those who are generally less trusting were more likely to live in troubled areas. Prior research showed that kids who grew up in such neighborhoods were less likely to graduate from high school and more likely to develop stress that can lead to depression.

The study took 50 students, sent half of them to a low income, high crime neighborhood and the other half to an affluent neighborhood with little crime.

Before the students ventured into their respective areas, the researchers interviewed the neighborhood residents and found that residents of the high-crime neighborhood harbored more feelings of paranoia and lower levels of social trust compared to the residents of the other neighborhood.

The students in the study were not from either neighborhood, and did not know what the study was about. They were were dropped off by a taxi and told to deliver envelopes containing a packet of questions to a list of residential addresses. They spent 45 minutes walking around their assigned neighborhood distributing the envelopes. When the students returned, the researchers surveyed them about their experience, their feelings of trust, and their feelings of paranoia.

Despite the short amount of time they spent in the neighborhoods, the students picked up the prevailing social attitudes of the residents living in those environments; those who went to the more dangerous neighborhood scored higher on measures of paranoia and lower on measures of trust compared to the other group, just as the residents had.

Not only that, but their levels of reported paranoia and trust were indistinguishable from the residents who spent years living there.

That came as an intriguing surprise to other experts. Ingrid Gould Ellen, the director of the Urban Planning Program at New York University Wagner Graduate School of Public Service, studies how the make-up of neighborhoods can impact the attitudes and interactions of people who live in them

found that kids who live on blocks where violent crimes occurred the week before they took a standardized test performed worse on those tests than students from similar backgrounds who were not exposed to a violent crime in their neighborhood before their exam.

paranoia and lack of trust set in after just a short time in the more troubled neighborhood suggested how powerful the influence of these environments can be.

For urban planners, the findings confirm what most probably understood instinctively — that people do tend to make snap judgments about both their environments and the people in them based on visual cues such as broken windows and abandoned houses. But the results also show how these cues can influence deeper perceptions and mental states as well.