Here is a title I stumbled upon last week in my local newspaper :
Brain drain starts at age 45 – not age 60.
Given that I turned 48 last September, I froze and immediately started to panic (at a pace that I used to think was “quick as a flash” when I was still laboring under the illusion of being young). “You’re toast, pal”, I said to myself. “Face it: you crossed the border. You’re already a “has been”…Next stop, dementia ! How long do you still have to learn, teach, facilitate or mediate?!”
Since it was breakfast time, and my morning glucose level was still at its peak, my decaying but sensible orbital frontal cortex intervened and decided to look at the actual source for this statement in the British Medical Journal rather than allow my entire psyche to get too depressed by a tabloid headline – here it is, by the way. What does it really say? In a study that was conducted in the British Civil Service (5198 men and 2192 women, aged 45-70 at the beginning), participants were given tests of memory, reasoning, vocabulary, and phonemic and semantic fluency, and were assessed three times over 10 years. The study shows that over these 10 years, the capacity of reasoning of a large cohort of British civil servants declined on average by 3.6% for subjects who were aged 45-49 at the beginning of the study, and by 9.6% for those aged 65-70. “So what?”, you might say. Is this a reflection of what it must be like to work in Whitehall or to be stuck in a routine job for 10 years? No information was provided of how often these civil servants changed jobs or whether they were involved in any significant continuing professional development. In fact, as the BMJ article points out, “The participants are mostly white collar workers in relatively stable employment and two thirds [were] men”. A review by Heden & Gabrieli (Nat Rev Neurosci. 2004 Feb;5(2):87-96) suggests that there is no evidence of significant cognitive decline before the age of 60 (so I’m good for another 12 years).
The real question, however, is how much dumber would we be with 3.6% or even 9.6% less reasoning capacities compared to when we were younger? Such a decrease may not be a big deal – unless you were already operating with borderline minimal cognitive capacity. The real novelty of this research is probably that it’s one of the first longitudinal studies actually showing a gradual “brain drain” in a stable work environment. True, this decrease in brain function may be linked to age, but it is just as likely to be linked to environmental factors and whether the average participant was regularly exercising his/her brain on a regular basis. The Nature Neuroscience Review mentioned above uses data from another longitudinal study, which shows a more complex and interesting story (have a look for instance at the “inductive reasoning” curve):
It is not surprising – and certainly not shocking – our brains may start to decline a little bit every year without new stimulation and learning experiences. The trick may be not to sink into apathy, but to continuously stimulate the mind with new learning experiences, eat as much Omega-3 fatty acid-rich food, and exercise (physically as well as intellectually) and also try not to read or give too much instinctive credence to alarming headlines, possibly written too fast by brain-drained journalists.
But what is really “brain drain”? We are not talking here of mass migration of educated people from one country to another, but the cognitive capacity of an individual brain over time. Much more important than age is the daily type of “brain drain” we all experience, which is far more significant and affects all of us without being conscious of it. It’s called ego or decision depletion. Our brains need optimal levels of glucose and oxygen resources to function well cognitively. Yet the brain’s ability to control or manage its use of these limited resources is limited, especially as if we have to think hard as the day progresses. Our cognitive skills decline as we deplete these basic resources, and if we do not refill, we lose our cognitive capacities and even our self-control.
A recent paper in PNAS 2011 shows the troubling news that what a judge had for breakfast, or when and what (s)he had for a tea break is far more likely to impact a defendant than having a good lawyer. This 2010 study by Danziger et al. (2010) surveyed 112 judicial rulings that were collected over 50 days in a 10-month period, by eight Jewish-Israeli judges (two females) who preside over two different parole boards that serve four major prisons in Israel. The astonishing observation made by the researches was that the percentage of favorable rulings dropped gradually from around 65% to nearly zero % within each “decision session” (defined as a period of successive rulings between two tea breaks) and returned abruptly to 65% after a break:
It’s a little bit frightening to read in the same paper that: “the likelihood of a favorable ruling is greater at the very beginning of the work day or after a food break than later in the sequence of cases“.
Morality: if you ever go to be judged, better to bring with you a small box of chocolates to refresh the tribunal (a good lawyer may also be helpful). And if the judge is older than 45, it won’t hurt to bring a bigger box.
