It’s 2031, and you are among the first humans to set foot on Mars. You and the other pioneering astronauts have discovered that there is actually a small amount of oxygen in the Martian atmosphere, but you need to figure out how to extract it. The future colonization of the Red Planet depends on your success in this task.
Imagine you’re the leader of this mission, and you have two oxygen extraction systems that might work. You need to pick someone to test the two competing systems, and you have two equally qualified candidates. One is an up-and-comer, just turned 20 and eager to make his mark. The other is 67, a veteran. Which do you put in charge of this crucial job?
The underlying question here, of course, is about cognitive aging: Does age affect complex decision making, for better or worse? It’s well known that certain abilities decline with advanced age—most notably processing speed—but what about that vast reservoir of decision making experience? Does that count? Does seasoned judgment trump the nimble-mindedness of youth, or the other way around?
Texas A&M psychological scientist Darrell Worthy decided to test this in the laboratory, to actually pit 20-somethings against seniors in a head-to-head contest of wits. The Mars scenario is one of two scenarios he used in the competition, and it was designed to test a particular kind of learning, one in which the ultimate decision depends on analyzing the results of earlier choices. Specifically, the volunteers ran many trials of the two competing extraction systems, each trial yielding an amount of oxygen. This oxygen was stored in one tank, but it was ultimately transferred to a larger tank. The goal was to recognize shifting probabilities in order to see which system was most efficient at yielding the required accumulation of oxygen over time. In other words, the individual trials didn’t matter so much as the big picture, the fluctuations in the overall reward structure.
The other task was a less complex gambling scenario. It involved simply learning by trial and error which of four choices gave the highest yield on each trial—and exploiting that knowledge in order to win a game. Worthy and his colleagues recruited 20-something and 60-something volunteers, and had them perform both tasks.
So, two cheers for aging. As reported on-line in the journal Psychological Science, the younger volunteers were indeed better at the gambling task, which required figuring out simple, unchanging probabilities. This suggests an age-related deficit in this kind of decision making. But the 60-somethings showed a clear, age-related advantage in solving the Martian problem, which required higher order, holistic learning about the changing relationships between choices and rewards.
The scientists interpret these results as evidence for a fundamental difference between older and younger adults’ approaches to decision making. It appears that 20-somethings are more efficient at identifying the most rewarding choices, but slower to form hypotheses about the dynamic relationships between past and future choices. The latter form of problem solving, the scientists emphasize, is much closer to the dilemmas faced in real life. Aging may bring some cognitive declines, but it may also lead to the insight and wisdom needed for the best decisions.
Wray Herbert’s book, On Second Thought, is out in paperback. Excerpts from his two blogs—“We’re Only Human” and “Full Frontal Psychology”—appear regularly in The Huffington Post and in Scientific American Mind.