60 Fighting Crime With Mathematics

One major problem in crime-fighting is that a police crackdown in one neighborhood may simply push criminal behavior into a nearby area. In March two mathematicians, working with an anthropologist and a criminologist, announced a way to quantify this reaction. “Crimes tend to cluster together in space and time, forming hot spots,” says UCLA mathematician Martin Short, the study’s lead author. Drawing on real-world data, his team developed a model showing that hot spots come in two varieties. One type forms when an area experiences a large-scale crime increase, such as when a park is overrun by drug dealers. Another develops when a small number of criminals—say, a pair of burglars—go on a localized crime spree. The model suggests that a focused police response can relatively easily extinguish larger hot spots because the criminals there scatter randomly, making it unlikely that they will resume coordinated unlawful activity nearby. But for smaller crime waves, crooks just migrate together into an adjacent neighborhood, where they are likely to start another spree. By analyzing police reports as they come in, Short hopes to determine which type of hot spot is forming so police can handle it more effectively. DANIEL LAMETTI

78 Good Listeners Get Inside Your Head

What is it like to get inside another
person’s head? You already
know the answer, according to
Princeton neuroscientist Lauren
Silbert. She placed herself in an
fMRI brain scanner and noted
her neural response when she
spoke about a vivid memory (two
boys fighting over her at her high
school prom). Later she and her
collaborators scanned the brains
of a group of volunteers as they
listened to a recording of her story.
The outcome, published last
June, was remarkable. Among the
listeners who paid close attention
to the story—as measured by a
subsequent questionnaire—brain
activity paralleled the activity in
Silbert’s own brain. More surprising,
among the most attentive
listeners, key brain regions lit up
before her words even came out,
suggesting anticipation of what
she would say next. “The more
you anticipate someone, the more
you’re able to enter their space,”
Silbert says. AMY BARTH
Discover Magazine Jan 2011