Great Ideas from the Brain Sciences: Executive Functions–The Works
By: Mirela C. C. Ramacciotti
Last month we delved into the beginnings of Executive Functions, or EFs for short. I hope some core EF concepts stayed with you. To start, EFs convey consciously-made plans of action. One way to understand this is thinking about it as a filtering process. When you want to select information that is necessary to execute something, anything that is not important gets discarded. Second, actions need to be aligned, or organized, to allow for performance. Third, if a plan is to be followed till execution, attention must be channeled into it. As attention is a costly and limited resource, we must be aware when to use it well; otherwise, our gears will shift into automatic mode. Fourth, rehearsal is necessary and desired. It allows our short-term memory to update and manipulate information needed to perform our plans accordingly. Fifth, EFs serve an ultimate purpose: they organize our behavior. Overall, we are now ready to start upon the novelty that the turn of this century brought to EFs.
In 2000, two leading researchers, Akira Miyake and Naomi Friedman, from the University of Colorado at Boulder, brought a different perspective to EFs. Their focus was on individual differences in applying EFs. To discriminate between possible differences, they used statistical models in EF tasks performed by a group of 137 college students. Their aim was to see whether goal maintenance–keeping goals in mind–would demand a single function or a set of distinct functions when executing different tasks. What they discovered–and expanded later in 2012–was groundbreaking. There is a common denominator that unites the distinct functions–they called it common EF–but they found three clearly distinct elements: inhibition, shifting, and updating. Before we examine each in turn, it is important to say that these are not the only EFs available.
- Inhibition means the ability to control actions. Teachers in bilingual contexts deal with that the whole time. For instance, students have to control and keep in check their mother language to be able to use the target language. That’s the reason we call this ability inhibitory control.
- Updating means the ability to monitor and update information. Now, when we talk about monitoring, we presume that information has been stored. And when we say “update,” it means that the stored information gets refreshed or more precise according to the needs of the task in hand. This demands constant work that gets done in short snippets. Thus, we commonly refer to this as working memory.
- Shifting means the ability to alternate between tasks or mental models. This is a step beyond simple execution. Notice that to perform a task well, one needs to plan and execute it. The same needs to be done for the other task that follows. When one is able to alternate between them, cognitive control shines through. That’s why we call this cognitive flexibility.
Knowing that EFs are jointly necessary to translate thoughts into action means understanding that they demand a powerful human capacity–that of planning. Further, knowing that functions are distinct means that they may spring from the same source but grow into different and separable functions. This became known as the unity-diversity framework. There are plenty of examples of how this happens every day in the classroom. Take, for instance, the moment of routine setting that usually starts off each class in grade school. The teacher lists a series of actions to be followed throughout the class. Students need to control their desire to do whatever they want in order to follow the routine. At the same time, they need to keep in mind what they are doing and what is to be done next. Finally, they have to be able to select strategies that may fit one action but which may not be necessary for another, demanding resources of cognitive control. Using their underlying common EF ability, students devote considerable attention to how they inhibit, update, and shift their attentional gears to perform their school tasks throughout the day.
Nowadays, we also know that EFs get strengthened and more differentiated across the lifespan until they dwindle and become less separable towards the end of life. This is referred to as the differentiation-dedifferentiation hypothesis. In this scenario, we would observe a change from a unified factor in preschool (common EF), moving towards a two-factor (working memory and inhibition/shifting) in primary school, with a third factor (shifting) in adolescence, and back to a single dimension in old age (MacPherson et al., 2019). Note that inhibition seems to converge with the common EF factor, that is, across time, there seems to be no distinction between them (Miyake & Friedman, 2012).
Another finding that Miyake and Friedman reported in their 2012 study is the importance of the genetic contribution. It seems that EFs do run in families. However, far from seeing this only as a bane, let’s talk about the boon. This is also a major finding, and it brings to fore another great mind behind how EFs work. Her name is Adele Diamond.
Adele Diamond, a Canadian psychologist, started studying EFs in children. At present, she spearheads a developmental cognitive neuroscience lab dedicated to understanding the mechanisms of EFs. In her lab’s own definition, EFs are: “‘thinking outside the box’ and flexibly adjusting to unexpected change (cognitive flexibility and creative problem-solving), reasoning and mentally playing with and relating ideas and facts (working memory), and giving considered responses rather than impulsive ones, resisting temptations, resisting distractions, and staying focused (self-control, discipline, and selective attention)” (source). Thus, her lab’s focus is not solely on what EFs are but how they contribute to a life of better physical, social, and emotional health.
Some powerful findings have emerged from Diamond’s lab such as the importance of perceptual change. For instance, in a 2021 study (Ling et al., 2021), they investigated how 3 year-olds were capable of performing conditional reasoning (if-then). They found that, with small changes to how stimuli look, children displayed such abilities at that very early age. Another finding relates to how EFs may suffer from mild stress. In a different 2021 study (Zareyan et al., 2021), Diamond’s lab found that the sort of stress that stems from social evaluation (like when one frets about what others may think of them) impairs EFs. Most amazing was their systematic review of EF interventions across the life span. They found that mindful movement practices, e.g., taekwondo & t’ai chi, show the best results for improving EFs, followed by school programs (Diamond & Ling, 2019). What is most striking, though, is the 2007 study by Diamond et al. They showed that regular play, instead of time away from it, improves EFs. They suggested that if EFs could be supported and challenged regularly during the school-day through play, benefits generalized and transferred to new activities. In other words, an EF “daily diet” boosts EF development and mental health.
With that in mind, the works of EFs lay bare the boon that is at the heart of teaching: teach the whole student by considering every aspect of their development.
References
Diamond, A., Barnett, W. S., Thomas, J., & Munro, S. (2007). Preschool program improves cognitive control. Science, 318, 1387–1388. https://doi.org/10.1126/science.1151148
Diamond, A. & Ling, D. S. (2019). Review of the evidence on, and fundamental questions about, efforts to improve executive functions, including working memory. In J. Novick, M. F. Bunting, M. R. Dougherty, & R. W. Engle (Eds.), Cognitive and working memory training: Perspectives from psychology, neuroscience, and human development, pp.143-431. Oxford University Press. https://doi.org/10.1093/oso/9780199974467.003.0008
Ling, D. S., Wong, C. D., & Diamond, A. (2021). Children only 3 years old can succeed at conditional “if, then” reasoning much earlier than anyone had thought possible. Frontiers in Psychology, 11, 57189. https://doi.org/10.3389/fpsyg.2020.571891
MacPherson, S. E., Gillebert, C. R., Robinson, G. A., & Vallesi, A. (2019). Intra- and inter-individual variability of executive functions: Determinant and modulating factors in healthy and pathological conditions. Frontiers in Psychology, 10, 432. https://doi.org/10.3389/fpsyg.2019.00432
Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A., & Wager, T. D. (2000). The unity and diversity of executive functions and their contributions to complex “frontal lobe” tasks: A latent variable analysis. Cognitive Psychology, 41(1), 49-100. https://doi.org/10.1006/cogp.1999.0734
Miyake, A., & Friedman, N. P. (2012). The nature and organization of individual differences in executive functions: Four general conclusions. Current Directions in Psychological Science, 21(1), 8-14. https://doi.org/10.1177/0963721411429458
Zareyan, S., Zhang, H., Wang, J., Song, W., Hampson, E., Abbott, D., & Diamond, A. (2021). First demonstration of double dissociation between COMT-Met158 and COMT-Val158 cognitive performance when stressed and when calmer. Cerebral Cortex, 31,1-16. https://doi.org/10.1093/cercor/bhaa276
Mirela C. C. Ramacciotti is presently engaged as an external lecturer on the topics of Mind, Brain, and Education and the Bayesian Brain at the Graduate Level Course with the Psychology Department at the University of São Paulo. She holds a PhD in Neuroscience and Behavior and another in Human Communication Disorders.