In pancreatic tumors obtained in autopsy from seven patients, that interval turned out to be an average of 11.7 years. It took another 6.8 years on average for tumors to appear outside the pancreas. Martin Nowak, a mathematician and evolutionary biologist at Harvard University, contributed the mathematical model that enabled the team to probe backward in time.
“We were surprised and very pleased by this result,” Vogelstein says. This long lead time might eventually enable doctors to spot genetic or protein abnormalities linked to the cancer, he says.
Men imprisoned for murder and other serious offenses have a well-earned reputation for taking dangerous risks. But their problems with risk assessment go deeper than that, a new study finds.
Relative to men who haven’t been incarcerated, prisoners generally have a harder time assessing the probability of big gains as well as harsh losses, says psychologist Thorsten Pachur of the University of Basel, Switzerland, who conducted the investigation with Yaniv Hanoch and Michaela Gummerum, both psychologists at the University of Plymouth in England. In experimental lotteries, prisoners display little appreciation of the benefits they stand a good chance of winning and frequently opt for smaller but sure rewards, Pachur and his colleagues conclude in the October Psychonomic Bulletin and Review.
- If prisoners generally don’t appreciate or consider the consequences of risky options, “increasing punishment will not necessarily be successful in reducing crime,” Pachur says. Former prisoners may also find it difficult to see the potential upside of taking a chance on an entry-level job or educational opportunities, the scientists suggest.
- Programs to enhance prisoners’ thinking skills should include sessions on how to understand the likelihood of various risky decisions to yield gains or losses, Pachur says. Current prison programs in England teach about moral reasoning, empathy and controlling impulses but have had little success in reducing crime.
- “This article demonstrates that there is not one factor that makes some people risk takers and others risk avoiders,” remarks psychologist Timothy Pleskac of Michigan State University in East Lansing. Reduced sensitivity to likely pluses and minuses of risky decisions may partly explain criminal behavior, but researchers know little about risk assessment among prisoners, Pleskac cautions.
Men imprisoned for serious offenses may prefer to use intuitive, simplifying rules of thumb to assess risks of all types, leading them to ignore useful information about potential gains and losses, Pachur hypothesizes. It’s also possible that prisoners have often encountered situations with potentially big gains or losses — such as collecting millions of dollars in a successful bank robbery or spending decades in prison for a sexual assault — and thus become insensitive to the consequences of such decisions.
Pachur’s team administered lottery tasks to 51 men, ages 21 to 72, in a British medium-security prison and 50 British men in the same age range who had no prison records. Prisoners, who received a small amount of money for their participation, had been sentenced to an average of 23.5 years behind bars.
Most tasks involved choosing between a lottery and a sure outcome. In some trials, the lottery offered either a 5 percent or a 95 percent chance of winning or losing £100, and the sure option varied between a gain or loss of £0 to £100, in steps of £5. In other trials, participants indicated whether they would choose a lottery with a 50 percent chance of losing £50 and a 50 percent chance of winning amounts that varied from £0 to £600.
A mathematical model of decision making known as cumulative prospect theory was used to calculate the extent to which prisoners and nonprisoners reacted to changes in the value of possible lottery gains and losses as well as to differences in the probability of winning or losing from one lottery to the next.
Prisoners took greater risks than nonprisoners on lotteries involving potential losses but became less risk-seeking than nonprisoners in lotteries featuring high-probability gains. Mathematical modeling indicated a generally diminished appreciation among prisoners for how much they could win or lose in lotteries.Doctors might also find it worthwhile to scan the pancreas using ultrasound for signs of a tumor in patients at risk, says study coauthor Christine Iacobuzio-Donahue, a pathologist and cancer researcher also at Johns Hopkins University. For example, during a routine endoscopy doctors view the stomach with a camera-tipped tube threaded down the throat. Adding an ultrasound attachment could scan the nearby pancreas for aberrant growths, she says. Cancer confined to the pancreas is often treatable with surgery, she notes.
In the other study, Iacobuzio-Donahue teamed with British researchers to explore the nature of chromosomal instability in pancreatic tumors from 13 patients. The researchers found that these patients often had a distinct pattern of chromosomal rearrangements called fold-back inversions, in which strings of DNA are looped and folded back upon themselves. Where the strings bent they snapped, Iacobuzio-Donahue says, and reattached. The origin and consequences of these rearrangements are unclear, but their pattern appears different from such rearrangements seen in breast cancer, the researchers note.
