Turns out, cognitive growth isn’t linear. What does this mean, for parents and teachers?
Executive Function Development in Children: Hot Versus Cool Matters
It is important to recognize that being able to reason cognitively does not necessarily correlate with having the self-control to execute. One element of asynchronous development is in a child’s ability to know and ability to do, especially during times of heightened emotion. Because of this, even if children are able to repeat instructions or cognitively understand the rules, they may not be able to complete the task. Understanding this difference is useful in understanding the space children are coming from and knowing how to best support them in becoming both strong cognitive thinkers and have the ability to regulate their thoughts, emotions, and behaviors.
Executive function (EF) refers to a set of complex brain processes involved in retrieving and utilizing information (Bjorklund & Causey, 2018, p. 250). Most notably, executive functioning is associated with cognitive flexibility, or the ability to shift between tasks; working memory, or the ability to think about and store information; and, inhibitory control (Bjorklund & Causey, 2018, p. 250, 266). EF processes are also involved in conscious control over thoughts, emotions, and actions (Zelazo & Carlson, 2012).
These types of cognitive processes develop. As a result, EF in young children differs from EF in slightly older children or adolescents, and EF in adolescents differs from EF in adults (Bjorklund & Causey, 2018, p. 27). Changes in executive functions correlate with brain changes (Zelazo & Carlson, 2012). Most of these changes occur as a function of changes in the prefrontal cortex (Bjorklund & Causey, 2018, p. 53). Comprised of multiple layers of neurons that surround the brain, the neocortex is the area primarily responsible for thinking. The prefrontal cortex, part of the neocortex, is involved in executive functions and higher cognitive processes, like problem solving, strategy use, inhibitory control, cognitive flexibility, and self-regulation (Bjorklund & Causey, 2018, p. 53, 249, 264). During the first two years of life, there is a rapid development of the prefrontal lobes (Bjorklund & Causey, 2018, p. 54). While EF improves most rapidly during preschool years, there is also a period of growth around adolescence (Bjorklund & Causey, 2018, p. 262; Zelazo & Carlson, 2012). EF takes time to fully develop and the prefrontal cortex is one of the last brain structures to reach maturity (Bjorklund & Causey, 2018, p. 262). This helps account for differences in cognitive abilities and behaviors related to self-regulation.
Executive function is also related to brain capacity (Kleinknecht, 2020a). Research suggests that people have a limited resource capacity, meaning that people can only do or pay attention to so many things at a given time (Bjorklund & Causey, 2018, p. 249). People only have so much capacity in their short-term memory. Within that store, people need room for both storage and manipulation of information in order to follow rules, make informed decisions, or engage in other cognitive or social processes (Bjorklund & Causey, 2018, p. 251; Kleinknecht, 2020a). Memory (or digit) span refers to the number of, usually unrelated, items one is able to recall (Bjorklund & Causey, 2018, p. 253). It is a reflection of the size of one’s short-term store. Younger children have limited room for the storage of information, but do not have any space in their store for manipulation of information (Kleinknecht, 2020a). This makes it much harder for them to follow rules or regulate their emotions or behaviors. With age, children are able to store more pieces of information (Kleinknecht, 2020a). As children’s brains (especially their frontal lobes) develop and their EF capabilities expand, they become more adept at cognitive flexibility, strengthen their ability to inhibit, and their working memory increases (Bjorklund & Causey, 2018, p. 260, 262). Children’s ability to do more, and do more effectively, increases with age.
When thinking about children’s ability to engage in social or cognitive processes, it is also important to consider the biological constraints on development. Most relevant to the process of EF development are chronotropic and architectural. Chronotropic constraints refer to the limits on developmental timing, for example when the brain is most ready for language acquisition (Bjorklund & Causey, 2018, p. 27-28). Architectural constraints refer to the development of the brain, for example the timing and progression of neural pathways or structures (Bjorklund & Causey, 2018, p. 27-28). These constraints limit what children are able to process or engage in. What children are able to understand and do changes throughout their lives as their brains and experiences change.
Researchers have noted development of executive function within the first year of life. While inhibitory control takes a long time to fully develop, during the first year of life children become increasingly capable of inhibiting their behavioral responses (Bjorklund & Causey, 2018, p. 54). One of Jean Piaget’s developmental assessments, the object permanence task, which required children to search for a hidden toy, indicates that young children display inhibitory behavior (Bjorklund & Causey, 2018, p. 54). Inhibition refers to the ability to suppress irrelevant information from working memory (Bjorklund & Causey, 2018, p. 256). Piaget’s task required children to not execute a previous response. As children’s frontal lobes developed, they became better able to inhibit responses. Interestingly, researchers found that even when children “knew” the right answer, they were unable to stop themselves from executing their past response (Bjorklund & Causey, 2018, p. 54). In order to change their response, they needed to both learn a new response and possess the capability to inhibit the old one. Research now indicates that there are different pathways for “knowing” and “doing”. Just because a child knows what they are supposed to do, does not mean they have the capacity to do it.
Neuroimaging shows that there is one area of the brain that is responsible for cognitive processing and one area that is responsible for emotional processing (Brock, Rimm-Kaufman, Nathanson, & Grimm, 2009). Processes that operate in more neutral contexts are known as “cool EF” (Zelazo & Carlson, 2012). Examples of cool EF are executive functions like reading or math, problem solving, and strategy use. Processes that operate in emotionally charged situations are known as “hot EF” (Zelazo & Carlson, 2012). Hot EF relates to things like self-control, self-regulation, impulsivity, perspective taking, and engagement in inappropriate versus appropriate behavior (Bjorklund & Causey, 2018, p. 260-261).
In many cases, children are required to utilize their “hot” system on a daily basis to make everyday decisions, specifically tasks with an emotional component (Brock et al., 2009; Zelazo & Carlson, 2012). “Cool” EF tasks do not elicit the same emotional reaction or have the same emotional consequences (Brook et al., 2009). As a result, children have an easier time responding appropriately when utilizing their “cool” system. Emotional responses take up brain space (Kleinknecht, 2020b). Children and adolescents, especially younger ones, already have limited brain capacity. When they are in an emotional space, their ability to use cognitive skills is significantly decreased. One’s ability to inhibit behavior or thoughts decreases with decreasing energy levels or increasing emotional responses because activating cognitive processes requires energy (Bjorklund & Causey, 2018, p. 256-257).
Biological and behavioral development support the notion that the hot and cool EF trajectories are different. Frontal cortex development and myelination continue through adolescence (Bjorklund & Causey, 2018, p. 262). Neural pathways and brain areas associated with emotion regulation develop later than other systems, supporting the idea that the cool EF system come on board before the hot EF system (Bjorklund & Causey, 2018, p. 262; Brock et al., 2009). One study found that when they switched the construct from a “hot” representation (emotionally charger) to a “cooler” representation (more neutral), it was much easier for the children to engage with and be successful at the task (Zelazo & Carlson, 2012). These findings suggest that having to operate from the hot system places greater demands on the child. It is a more difficult system to utilize and it takes longer to develop (Zelazo & Carlson, 2012).
When evaluating children’s problem behaviors, it is common to find that many of those behaviors arise, despite the children understanding the instructions or “right” way to behave. One well-known study on children’s behavior is the marshmallow test. During this experiment, children are presented with a certain number of treats and told they could eat those immediately or have more treats if they wait. Most children who participate in this test know that they will get more treats if they wait and can even tell others that they should wait in order to get more treats. However, many of those same children are unable to follow that advice themselves. Cool EF skills allow them to weigh their options and think rationally about the situation (Brock et al., 2009). However, hot EF skills are needed to resist temptation versus seeking immediate gratification (Brock et al., 2009). When emotions are heightened in any way, the hot EF system is activated, making engaging in higher cognitive processes more challenging, especially if the child is young. With age, children become more able to inhibit mental and behavior responses; take in more information, from both internal and external sources, that can be used to make informed choices; and, develop more efficient executive and cognitive skills (Bjorklund & Causey, 2018, p. 256-257).
Having an awareness of children’s hot and cool EF systems is important for understanding how best to interact with them, both personally or professionally, such as in an educational setting. While some elements of executive function may be more fixed, there are elements of both EF systems that are malleable (Zelazo & Carlson, 2012). There are multiple reasons why working to enhance children’s EF systems is worthwhile. In the short-term, executive function skills are necessary for school achievement and social interactions. Within an academic setting, cool EF skills are needed to remember instruction (i.e. working memory) and stay on task (i.e. inhibitory control) (Brock et al., 2009). Hot EF skills are also needed for school engagement. Hot EF skills allow students to down-regulate their emotions, attend to academic instruction, be present in the academic setting, and control their behaviors (Brock et al., 2009).
Studies found that there are also long-term outcomes from childhood hot EF systems. Children who exhibited lower levels of self-control were more likely to exhibit problem behavior as they grew up (Bjorklund & Causey, 2018, p. 260-261). Childhood self-control also predicted adult outcomes, like criminal behavior, substances use, and physical health (Bjorklund & Causey, 2018, p. 260-261). Hot EF processes are connected to a variety of psychological outcomes. Because of this, fostering both cool EF cognitive processes and hot EF regulatory processes.
One way to foster executive function abilities in children is to provide scaffolded learning opportunities. Children benefit from supported learning (Kleinknecht, 2020c). Working within a child’s zone of proximal development is the most optimal way to support their learning. The zone of proximal development is the difference between a child’s actual independent abilities and the child’s potential abilities if given guidance (Bjorklund & Causey, 2018, p. 78). Scaffolding involves being sensitive to a child’s abilities and responding through gradually decreasing assistance or increasing the difficulty of the task in order to increase a child’s understanding (Bjorklund & Causey, 2018, p. 78). This type of teaching can be achieved through having conversations slightly above a child’s vocabulary level, talking about topics slightly beyond a child’s range of understanding, and encouraging question asking (Kleinknecht, 2020c). Children also learn through observation. Social learning is when children acquire knowledge through watching others, without specific instructions or reinforcements (Bjorklund & Causey, 2018, p. 401). Because children learn through observation and social interaction, providing children with ample social opportunities, as well as modeling regulatory behaviors is another way to enforce EF skills. Modeling self-regulation can be a useful tool in teaching children how to regulate their own behaviors and emotions.
It is also important to provide an environment that nurtures growth. Ways to do this include providing opportunities to build vocabulary, creating and enforcing age-appropriate rules, and playing games, like Simon Says (Kleinknecht, 2020c). Elaborative make-believe can also be useful is teaching children about emotion or behavior regulation, perspective taking, and rule following (Kleinknecht, 2020c). Another aspect of creating a positive environment is providing for physiological needs that support executive function. Stress, hunger, loneliness, and lack of sleep impair executive functioning skills, as well as require the child to tap into their “hot” system (Bjorklund & Causey, 2018, p. 257). Ensuring that children are fed, well-rested, and have strategies to manage their stress are all ways to help strengthen their EF systems.
Finally, maintaining an understanding of child development, as it relates to their EF systems, especially their “hot” system, is crucial to fostering growth. First, it is important to remember the biological constraints that children are experiencing. There are some things that their brains are truly unable to process or engage with. Placing unrealistic expectations on them creates undue stress and activates the “hot” system, making it even more difficult to engage in higher cognitive processes. Additionally, research shows that growth trajectories are not linear. Each child has a unique developmental trajectory and the accomplishment of one task does not necessarily equate to the accomplishment of another or the guarantee of the successful accomplishment of the same task again (Kleinknecht, 2020c). When working with children, recognizing that growth is a process and exhibiting patience is critical.
A common phrase spoken to children is “Use your words!” This phrase is typically utilized when children are exhibiting a behavior that parents are upset with. In other words, it is an emotionally charged scenario, for both the adult and the child. During these types of situations, the hot EF system is activated and the instruction to use your words will not be effective (Kleinknecht, 2020b). When children are tapped into their emotional system, they will struggle even more with responding in a rational, cognitively-based way. As a result, the most effective response would to work to co-regulate with the child. Working to help the child regulate their emotions and behaviors, find words for their emotions, and providing a safe space for the expression of emotions is far more effective than placing unmeetable demands on an already emotionally tapped-out child.
With a deeper understanding of how the child’s brain develops, along with the understanding that children may have different needs during emotionally-charged situations, provides an opportunity to offer adequate support, teach regulatory behaviors, and foster long-term EF growth.
Bjorklund, D., & Causey, K. (2018). Children’s Thinking (6th ed.). Thousand Oaks, CA: SAGE Publications.
Brock, L. L., Rimm-Kaufman, S. E., Nathanson, L., & Grimm, K. J. (2009). The contributions of ‘hot’ and ‘cool’ executive function to children’s academic achievement, learning-related behaviors, and engagement in kindergarten. Early Childhood Research Quarterly, 24(3), 337–349. https://doi.org/10.1016/j.ecresq.2009.06.001
Kleinknecht, E. (2020a) Lecture, PSY 353, on 04-13-20
(2020b) Lecture, PSY 353, on 04-27-20
(2020c) Lecture, PSY 353, on 05-01-20
Zelazo, P., & Carlson, S. (2012). Hot and cool executive function in childhood and adolescence: Development and plasticity. Child Development Perspectives., 6(4), 354–360. https://doi.org/info:doi/