As I write this, I am listening to KCRW streaming radio, eavesdropping on my deskmate’s phone interview, keeping an eye on breaking news and chatting with my editor on Instant Messenger. That’s a pretty typical moment in my professional life, so its hard to imagine what a group of neuroscientists at the University of California, San Francisco, are suggesting, which is that my ability to work this way will diminish as I age.
Lead researcher Dr. Adam Gazzaley and his team used functional MRI scans to measure volunteers’ brain activity during a multitasking experiment. The researchers looked at two groups: one with an average age of 24, the other with an average age of 69. Participants were first asked to study photos of an outdoor landscape; that task was interrupted with a picture of a face, whose gender and age participants were asked to determine. Then, people were asked to recall details from the original outdoor photo. (More on Time.com: Walking and Talking: Why Oldsters Shouldn’t Try It)
Researchers found the brains of older subjects were less capable of disengaging from the interruption and re-establishing the neural connections necessary to switch back to focusing on the original memory.
Some experts had speculated older people become more deeply engaged in what interrupts them, making it harder for them to shift their focus back to the original task at hand.
But Gazzaley, head of the UCSF Neuroscience Imaging Center, said his study showed young adults and elderly were paying the same level of attention to the interfering image of the face.
Instead, it was the act of switching from one task to another that older adults found so arduous.
The findings help explain why we endure more “senior moments” with age, those bouts of forgetfulness that leave us standing in front of an open refrigerator wondering what on earth we went there to find. The problem involves working memory — the short-term memory that allows us to retain and manage enough information to learn, do tasks or follow a conversation. Multitasking slows down working memory, and the impact is worse in the elderly. (More on Time.com: Can Exercise Keep Us from Aging?)
“Events such as these increase in frequency as we get older — the classic senior moment. We now understand that this is not necessarily a memory problem per se, but often the result of an interaction between attention and memory,” Gazzaley told the New York Times‘ Bits blog. “For example, a phone call or text that interrupts us on the way to the refrigerator will negatively impact our ability to remember what we were going to the refrigerator to get in the first place.”
The study was published online this week in the Proceedings of the National Academy of Sciences.