The developing brain, symbolic logic, white matter, & object permanence
Natalia Baron UA ‘26 and Jim Stellar
We did a previous blog on metacognition in college students and before that a blog on early childhood development and autism. Now we are back to development. Believe it or not, we think these two ideas are related. What we want to take up here is what gets wired up in the baby’s brain and how does it make them smart? Also, then, what can we learn from that process that applies to the cognitive-emotional integration in college students growing from experiential activities?
To start with babies, when a young baby looks at a ball rolling across a surface, it probably eye-tracks it with an evolutionarily old brain circuit involving the superior colliculus in the brain stem, itself an evolutionary older part of the brain. When the ball goes behind a screen, the baby leaves its eyes where the ball disappeared and picks it up again when it comes out the other side – just like a lizard which has very little neocortex. But somewhere around 6 months, that changes. When the ball goes behind the screen the now older baby jumps its eyes to the other side of the screen and waits for the ball to come out. If the ball does not come out at the right time, the baby expresses surprise. This baby has a concept, an abstract concept, of the ball’s trajectory, not just its current position. That concept depends on symbolic reasoning in the evolutionary new neocortex and on something called object permanence.
What is object permanence? We all know that babies love to play peek-a-boo, the main reason that babies love to play is because they genuinely believe that the individual behind the hands has disappeared. And when they open their hands up again, the individual reappears, and the baby laughs or is in shock. That is an example of how the skill of object permanence in the infant brain is not present. Playing with an infant that is six months old or younger, their skill of object permanence is not yet present. According to researchers, object permanence is defined as knowing that objects continue to exist when they cannot be directly observed or sensed. This cognitive skill plays a crucial role in their development and shapes how they continue to interact with the world and people around them. As infants continue their rapid development, the cognitive skill of object permanence will also rapidly grow.
Areas of the brain connected to object permanence. This topic has long been an interest of neuroscience, and JS remembers discussing it in a seminar way back in the day when he was in graduate school. But to start more recently, a broadly focused 2006 paper on many tasks led us to a 1989 paper where the dorsolateral prefrontal cortex was implicated by looking at how non-human primates with brain lesions there compared to kids on the same object permanence task. Human children’s brains measured with near-infrared or electroencephalography that monitored neocortical activity showed frontal lobe involvement. This may not be surprising as the frontal lobe has a reputation for planning and knowing that an object still exists when one can no longer see it, seems like it takes a bit like planning. That planning may specifically depend on the dorsolateral prefrontal cortex in monkeys and humans although this paper is from 1989, results in infants from more modern brain scanners (e.g. fMRI, DTI – diffusion tensor imaging) would be useful and may be a subject of a future blog.
As noted above, the frontal lobe is important to planning in general and even to high-level operant performance although animals without a frontal cortex do show operant (Skinnerian) learning and performance. During early development, the frontal lobe is going through rapid proliferation of neurons, and through these formations of neurons and synapses, the function of the frontal cortex peaks. Other brain areas we want to also highlight include other lobes of the brain such as the occipital lobe which is involved in vision and therefore also in object permanence. According to this 2017 study, “Eye-tracking can be used to assess unbiased information about gaze direction in response to visual stimuli in infants. Eye tracking research is a good tool to measure visual attention, gaze following, preference, and memory”. Therefore, we conclude that eye tracking plays a vital role in object permanence because it is a sign of development of cognitive abilities.
The infant brain is quite amazing in many ways. The infant brain is rapidly growing from the bottom up, making billions of neural connections. Even in the womb, toward the end of pregnancy, the fetus is able to learn, such as the recognition of the mothers voice, different kinds of smells, and even some food flavors. In the infant period, the brain continues to be very “plastic.” It is interesting to consider how infant brain plasticity plays a role in behavior. Of course, some of the first or earliest forms of behavior in development in infants are reflexes. For example, infants show motor reflexes as early as soon as birth. For example, the grasping reflex. If you place your finger out for the baby to grab, the baby wraps its hand around your finger, and you might think the baby loves you as that is so cute. But,it is really just a motor reflex! Later when the child grasps your finger, it is an expression of affection, but not now.
If you look at Piaget’s stages, infants (0-2 years old) are in the sensorimotor stage meaning that their primary focus is on sensory experiences on top of the reflexive responses like the grasping reflex. However, at this stage an infant’s ability to recognize object permanence is slim, especially from birth to around 8 months. They don’t understand that objects continue to exist when they are out of their sight. Whereas around that 8 month mark, young children begin to develop object permanence.
In one study, researchers proposed a perceptual model that explains how young infants may perceive object persistence without needing complex cognitive processes. The model suggested that infants use visual and sensory information to track objects over time. However, in the controversy there was empirical evidence showing that infants as young as 3 to 4 months demonstrate behaviors indicating the understanding of object permanence. Challenging earlier theories, like Piagets, suggesting that object permanence develops around 8 months. On the other hand, authors discussed the developmental pathways that lead to emergence of object permanence, mainly highlighting the role of maturation and experience shaping this understanding. Which leads to the importance of the developing brain in infants.
As for brain activity, according to this study, researchers found that there was an increased activity in the frontal lobe when infants were engaged in tasks that required them to understand that objects continue to exist even when they are not visible. Therefore, this study suggests that the frontal lobe plays a crucial role in the development of object permanence.
Where does this leave us? First, even as the infant brain’s structure is just processing basic things like object permanence, it is super complicated and it is very likely that many discoveries will yet be made, particularly with advanced and safe brain scanners, that will add critical nuance or significantly change what we think. Second, much of this blog series is about cognitive emotional integration where the frontal cortex is bringing value processing from the limbic system up to the cognitive level, or trying to do so. Remember the often repeated phrase from Pascal “The heart has reasons that reason does not know.” We believe that experiences help the cognitive system figure out its heart reasons. The same thing is true within the cognitive systems. Lizards can eye-track like a very young baby, but that is not the same as a concept of a visual trajectory. In the motor system, a grasp reflex in an infant looks like love and it will be a gesture of love later on to grasp someone’s finger, but not at this developmental stage. All of these operations involve what Gary Marcus called a bit of kluging where the old systems seem like they need to be better integrated by the newer evolutionary systems. Third, this operation is super important to education, particularly at a young age. We (teachers, clinicians) do a good job with behavioral observations. We will do a better job of understanding and acting when we know more about what is going on “under the hood.”
