Two people at work at their desks have heads like unlit light bulbs.

Mental Effort

The absentminded professor will remind everyone of mental effort, distracted by a big idea from everything else going on in the world. People who must now work from home with online conferencing share the concentration fatigue that is familiar to those with hearing loss; only they call it zoom fatigue.

Even more familiar to most of us, driving to a friend’s new house is hard because of the mental effort, while driving home after work is easy.

What’s amazing is how often we drive on autopilot and manage to reach our destination, which we can do when the route is familiar and our task has been well learned. We are particularly vulnerable to automatic driving when we are tired or bored and we “switch off” our attention to the road, though we often aren’t aware of what we’re missing. One result is nine deaths per day.

Although the deaths are tragic, explaining driving on autopilot makes psychology useful. We can distinguish two modes of behavior, one that requires mental effort and another that does not.

Psychologists like to phrase this as a difference between controlled and automatic processing. Paying attention in controlled processing for new learning requires mental effort, but automatic processing for habitual behavior does not. This is not a hard and fast dichotomy, since a lot of behavior requires both modes.

Some important differences between controlled and automatic processing were identified by Schneider and Chein. For our purposes, it’s worthwhile to note that automatic processing is hard to direct consciously, while controlled processing is mostly voluntary. Automatic processing doesn’t produce learning; controlled processing does.

Conscious control requires paying attention, and we feel the effort. It’s often not accompanied by physical effort, and even when it is, there’s some evidence that mental effort results from a decision to undertake the task rather than from any physical effort, which might involve frowning, sympathetic arousal, or the problem-solving entailed by sports or musical performance or simply driving home.

When we’re exerting mental effort it’s hard to take on additional tasks, though it’s hard to demonstrate that the brain runs out of steam (actually glucose). The very structure of the brain may limit how much we can accomplish by mental effort.

Our experience of mental effort as a sense of concentration may not be a good way to separate controlled from automatic processing because of flow, which some writers have characterized as “effortless attention”, when we exert mental effort without the feeling of exertion. However, some investigations have reported signs and self-reports of mental effort even during flow.

Some automatic behavior is reflexive: startle, for instance, and many so-called voluntary activities rely on a number of reflexes that we don’t think about.. Our nervous systems have evolved to facilitate the development of such behavior. Other automatic behavior began as controlled skills and underwent an interesting transition. This is the story of how we develop habits. This is where the biopsychosocial approach comes in.

Buddha statue on a green hillside

BIO: The energy cost of thinking is both manageable and interesting. The brain’s output is organized and conducted through synaptic transmission, which is mainly responsible for the high energy cost. Some of this energy can be stored using glia, but oxygen is always a just-in-time inventory.

Oxygen and glucose are supplied by blood to the brain, which provides a clue to the abilities of our prehistoric ancestors. However, although the entire brain relies on blood, it is unequally distributed. Some regions of the brain are more active than others, and this attracts greater blood flow, called the BOLD response, in the active areas.

Although glucose is essential for sustaining brain activity, it’s important to note that thinking is not exactly proportional to blood glucose depletion. As already noted, astrocytes can store glucose and glucose is sometimes related only indirectly to brain metabolism.

If you don’t mind a brief side trip, take a moment to consider astrocytes, which are more interesting (and more numerous) than anyone suspected a decade ago.

The feeling of mental effort is correlated with executive function in the brain, with metabolic changes and perhaps the formation of myelin and new synapses. Directing lower functions is executive control, which encompasses much more than reflexes and habits and develops over years in early childhood.

The frontal lobes (including Broca’s area) are chiefly responsible for executive control, so that you can pat your head and rub your stomach at the same time. The parietal lobes are important in directing attention. For example, any child but a scion of the Bach or Mozart families will hear this fugue as noise. I think most adults will be able to listen to the same little melody popping up in different voices, thanks to more developed attention (except Millennials and alpha males, who dislike such music, according to published research. ☺  But wait!)

Has it struck you how mental effort diminishes as we practice a task?  A baby has to focus attention on walking and talking, but it becomes automatic, just as driving will for a teenager. We perform all of them with very little mental effort. Such behaviors are stored in procedural or striatal memory rather than declarative (hippocampal) memory. Behavioral control below the cerebral cortex does not seem to contribute to mental effort.

In particular, activity in the cingulate cortex and the insula may be closely associated with mental effort.

PSYCHO: At the outset of learning a skill like driving, we focus attention consciously and we sweat every detail. The feeling of mental effort is inescapable and sometimes exhausting. If the task does not overwhelm us, it becomes a habit with repetition, and the feeling of mental effort shrinks.

Habits have interested psychologists from Thorndike to the present. Learning a habit is a hit-or-miss, error-prone process, but then habits become stubbornly automatic, residing no longer in the cerebral cortex but mostly in the basal ganglia, which links skills to habits

It’s remarkable when some particular context or goal triggers a long sequence of behavior. We routinize behavior that we want to repeat until about 45 percent of our activities (pp. 27-28 of the journal, not your Adobe Reader) occur “on automatic”. When the context or goal changes becomes inappropriate, we start to make mistakes. In principle, at least, that’s when we start to pay attention.

Rewiring the striatum–i.e., changing habits, compulsions and addictions–can be very hard, though it’s a cinch compared to changing beliefs.

Does this mean that every skill becomes a reflex, do you think–especially if we overlearn it–that is, practice it beyond the beginning of mastery?

The trick about overlearning is that it transforms what you learn. Early learning involves the cerebral cortex as a voluntary activity. (Though this might be an illusion.) The skill is transferred to the basal ganglia and cerebellum, where a sequence of movements for, say, controlling a robot or perfecting a tennis serve*, can be triggered as a whole, without conscious participation. In fact, conscious intrusions will ruin the performance, which is stored in procedural memory.

*It’s funny that we can “groove” a tennis serve or a golf swing but not a free throw in basketball, though some writers do apply the principles I described above to all three.

But consider the free throw, as many have. Why can’t well-coordinated, highly trained, intensely motivated players sink a ball when they want to? It’s not just the fans trying to distract the shooter and I doubt that it’s loneliness. It seems rather to reflect the operation of the top levels of the brain, the cerebral cortex. When an athlete can make a highly-practiced behavior completely automatic, the golf ball, tennis ball, fist or arrow hits the target. Evidently a foul shot never attains that degree of automaticity, which is ruled by the unconscious brainstem rather than the conscious cortex.

If your skill is unpaid and unprofessional, you may want to dispense with expertise. It’s not necessary to acquire the knife skills of an international chef if all you want to do is learn to core a pineapple. And for young people, overlearning can turn into overuse injuries.

On the other hand, isn’t it amazing what happens after much practice? The memories that support driving have been transformed by practice. Furthermore, your driving will resist further change; it has been hyperstabilized by overlearning. We can benefit by going way beyond mastery.

But, as Max Cynader tells us, we are tempted to take the easy way out. We are cognitive misers. We should be mindful, breathing through our noses, yet when we have done a task many times it bores us and it’s hard to pay attention. Or there are other interesting things happening and we get distracted. If we’re on the road, bad things can happen.

Habits and automaticity go by other names as well. Daniel Kahneman popularized the pervasiveness of intuitive (system 1) decisions, which are not as bad as we tend to think, though they are swayed by cognitive biases.

Rational, system 2 decisions (not the pathological kind) don’t guard against biases as well as we’d hope, and they follow the ruts of our prior beliefs. They’re not a path to truth as often as we’d like.

As a result, writers can find plenty of examples where decisions-without-attention or fast-and-frugal thinking are the rule, from sports to medicine. Even betting.

Psychology is full of bright lines that set up dichotomies like system 1 (fast, emotional) and system 2 (slow, logical) thinking, nature versus nurture, or fight-or-flight responses. With many either-or choices, the majority of observations fall in the middle, exhibiting some or none of both extremes. (Think of body vs. mind, or normal vs. abnormal.)

SOCIAL: You can catch it from others, mental effort, like coughing, yawning, scratching an itch, and laughing. When a companion exerts more mental effort, we do too.

Mental effort affects our relationships with others. Among the cognitive behaviors that are obvious in teaching, It strikes me as being as widespread as any educator could imagine.

Yet mental effort is context-sensitive. No evidence has come to light to show that the amount of mental effort we perceive will be predicted by a personality trait, or IQ, or genotype. Instead it varies with the situation, the task (think of cognitive load), and—interestingly—the disorder

In my opinion it is dangerous to ascribe mental effort to a universal law. When authors attribute our behavior as cognitive misers to a law or principle of least effort, they are sloganeering, using it the way we refer to a “law of supply and demand” or “Stigler’s law of misonymy”, rather than propounding a cosmic regularity. Despite hundreds of articles, (cliché warning) there remains much to be done.

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