Memory fades with age, and now imagination seems to disappear with it, too. Harvard University researchers asked volunteers in their 20s and those around 70 to construct within three minutes a future event using as much detail as possible. The younger adults created significatly richer scenarios. The results, presented in the January Psychological Science, support the notion that picturing what is to come requires the ability to recall past experiences and piece them together to form a coherent scenario. Imagine that—if you can. —Philip Yam


As men grow older, their testosterone levels gradually but progressively wane, a decline linked with an increase in fat and drops in strength, cognition and bone mass. Unfortunately, testosterone supplements seem to do little to thwart these changes. Researchers found that testosterone supplements did decrease body fat and increase lean body mass in older men with low testosterone levels. But the subjects were no stronger and showed no improvement in mobility, cognition or bone mineral density. The January 2 Journal of the American Medical Association describes the outcomes. —Charles Q. Choi


Mice kept downwind from two steel mills and a major highway developed 60 percent more mutations in their sperm than their brethren inhaling HEPA-filtered air did. The sperm stem cells became damaged after just three weeks of exposure, perhaps because of oxidative stress triggered by the particulates. Because the sperm were still functional, the mutations could be passed on to off-spring. The findings show up in the January 15 Proceedings of the National Academy of Sciences USA. —Philip Yam