The Introduction of the Introduction

I am a visual thinker, and a graphomaniac with a passion for notebooks - the analog ones. During my studies, I wrote tons of notebooks about the most disparate topics. Some of this effort readily served my understanding and helped me designing, carrying out and eventually concluding my projects - some part (most?) of it remained on page but never really scratched the surface of my practical needs.

However, my brain effectively understand things when I write and read concepts from my own handwriting, and keep them in the drawers of long term memory - even if they are completely useless. So here I am with a somewhat encyclopedic knowledge of theories of psychological development, brain anatomy and world mythology.

This series of posts is a transcription of my handwritten notes. I tend to be very graphical, so this version will not necessarily reflect the format of the original, but will constitute a more formal translation into words of its content.

To the visual thinkers out there, I am aware that my formulation of things will probably not help you very much with learning - however, I do fill up my formulations with lots of examples that, I hope, will inspire your own examples. Since associative thinkers easily fascinates me, I try my best with equations here and there, to feed you with relationships. To the verbal thinkers, I am sorry if this is not as fluent as most of your handbooks - although they tell me I am not that bad. I spent my whole life struggling with an education system that is made by and designed for verbal thinkers, so I guess we are even!

A disclaimer: most of these texts date back to my PhD years, mostly 2016-2018. I will try to amend anything that is outdated, but some of the references and sources may not be considered recent anymore. I am sure there are new articles and books, but since this is a personal project, I have very little time to dedicate to it.

The Key Questions of Developmental Psychology

Most people assume that I got into Developmental psychology because I like children. However, I definitively got into Developmental Psychology because I like questions. And everybody knows that women intrinsically prefer questions!

Many of the fundamental questions of Developmental Psychology are retellings of the Where do we come from question, just incredibly more specific. It is a little bit like someone, one day, asked: “What is a fish?", and the developmental psychologist answered: “Well, what is a sea bass? And a shark? And what is a salmon…"

Actually, the most challenging aspect of developmental questions is that every question contains several other questions.

Let’s start with one of the oldest questions of Developmental Psychology: do children have to start building up their knowledge from scratch, thus heavily depending on experience, or do they possess some kind of a pre-determined scheme¹?

This question has planted several other questions - that have only being fueled by the fact that the old question has been answered - nope, children do not start from scratch.

For instance, how do children progress from their initial state to successive states - does it happen as a gradual accumulation of knowledge, or do they shift from one stage to another? Or do these processes even co-occur and intertwine²? And again, is any kind of specific knowledge mostly innate, or dramatically shaped by experience - for instance, are social skills determined by innate, general mechanisms, and to what extent they depend on the social context³?

Traces of Empiricism and Seeds of Nativism

These questions pave the ground of the most essential debate of Developmental Psychology: the Nature vs Nurture debate, or the Innateness vs Environment diatribe. For almost all developmental processes - the how do children progress - there is a nativist and an empiricist account⁴.

An empiricist account puts the focus on the environment, and argue that any developmental process, such as language acquisition, develops via statistical learning based on the available input. Somehow, this is a less favoured point of view by modern scientists and the general public (but it is has not always been that way).

A nativist account would argue that the inputs that we encounter in real life are not sufficient for successful learning. After all, infants learn to speak at surprisingly fast rates, even if their experience of language consists of random sampling from a limited number of sources. So, there must be a pre-specified universal grammar that allows humans of all ages - even infants - to unwrap and understand reality. From this concept, the notion of a language learning module/device has evolved⁵.

Despite the fact that these approaches share the same aim - the description of developmental changes - for example, of language acquisition - they differ in the way they explain those changes, and they propose different models of what happens to subtend those changes. Several models of language acquisition/development in general exist, but they often contain assumptions about what kind of changes happen in the brain, and when.

This is a broad distinguish - that historically has been formalised with far more detailed predictions.

Circles and Stairways

A historically relevant empiricist conceptualisation of psychological development is the Social Contextualism of Lev Vygotsky, that brought further organisation to the definition of Ecological Systems, previously formulated by Urie Bronfenbrenner. Contextualism postulates that humans exist inside nested circles in reciprocal correlation⁶:

• Closer to the individual, the smaller circle or micro-system, such as the immediate environment of children - their family.

• Micro-systems connect to each other, forming a meso-system, for example, a school

• The environment surrounding the micro-system that has indirect effects on it is the exo-system, for example, the parents' workplace

• The larger cultural context where these relationships take place also play a role, and constitute the macro-system encompassing all the smaller units

According to Contextualism, individuals' movements within and between these circles determined the functions and dysfunctions of developing humans. Most of all, social interactions would play a pivotal role as they would determine the exchange of information, the harmony within a circle, and the reward for progress⁷.

Nowadays, thanks to studies of genetics and quantitative neuroscience, the role of social interactions in directly shaping developmental outcomes has been significantly scaled down. Families and schools are seen as environments, rather than circles or systems - we easily define a school as its desks, chairs and blackboards, rather than as a network of families. However, modern developmental psychology still echoes the idea that the social world is nested - sometimes contradicting the widespread notion that development is staged/linear -, and of a multi-level correlation between social interactions and development.

Contextualism was deeply relativist - nativist theories on the other hand sought to apply to development the same universal rules of biology and evolution⁸.

With technological advancement and better quantitative tools, developmental scientists observed that different developmental processes shared a common feature: the individual’s state shifted between stages of growing complexity, as if developmental milestones were localised on the steps of an imaginary stairway.

Prenatal development has clear biological milestones, and occurs through neatly timed steps - germinal (0-2 weeks since egg fertilisation), embryonic (3-8 weeks) and fetal (9 weeks till birth). This is possible thanks to genetic pathways that activate at specific times and trigger morphological changes⁹. However, staged-like progression occurs postnatally too. Reflexes, sleep, vision, hearing and habituation all change across the first years, but their progression is not at all seamless. For example, active sleep characterized by rapid eye movements (REM) replaces newborns' quiet sleep¹⁰, transient reflexes such as primitive reflexes stop occurring¹¹, and visual acuity quickly supersedes blurry, colour-blind vision¹².

Even if the majority of biological milestones remains undetected, postnatal staged-like progression has been interpreted as an indirect proof that systems that switch off and on at precise times influence the individual’s behaviour, as well as the migration of cells and the morpho-genesis of tissues prenatally. In the next post of this series, I will cover the postulates of Jean Piaget, that through the observation of his own children in the 1920s formulated the Stage Theory of Cognitive Development.