The Intelligence

There are multiple ways to quantify intelligence, and it varies depending on the categorization method employed. For example, Sternberg’s model divides intelligence into three types: analytical, creative, and practical. This model is often utilized in fields like Cultural Dimension Theory (CDT) or management studies. In contrast, the Wechsler Adult Intelligence Scale (WAIS) is mainly used for clinical diagnostic purposes, and it is the only intelligence assessment model with legal validity and scientific credibility. In WAIS, the population average is set at 100, with a standard deviation (SD) of 15. It is important to note that not all tests use the same standard deviation. For instance, the test administered by MENSA Korea resembles the perceptual reasoning subset of the WAIS and uses an SD of 24 for normalization. Thus, a score of IQ 160 on the MENSA Korea test is equivalent to an FSIQ score of 138 on the WAIS. Conversely, scoring an FSIQ of 160 (perfect scores across all subtests) on WAIS would translate to an IQ of 196 on the MENSA Korea test—a rather exceptional and near-unhuman level. Currently, the mainstream theory in cognitive science that describes intelligence is the Cattell-Horn-Carroll (CHC) theory, which divides intelligence into general intelligence and subordinate components, specifically crystallized intelligence and fluid intelligence. The concept of theory of mind as discussed in developmental psychology seems distinct from what I originally understood in philosophical psychology. To avoid confusion, I will refer to the former as ToM and the latter as PoM. ToM refers to a specific socio-cognitive ability that enables young children to begin understanding the perspectives of others, often used to diagnose developmental conditions such as autism spectrum disorders (ASD), as seen in diagnostic tools like CARS or ADOS. In other words, the notion of ToM involves positing an imagined mental faculty to assess one’s capacity for empathy and understanding of others. However, ToM falls short of fully explaining non-severe autism spectrum cases involving intellectual disabilities that can be detected in early childhood. On average, about 40% of individuals with autism spectrum disorders (ASD) possess above-average FSIQ, leading to a phenomenon called masking where individuals mimic the behavior of neurotypical individuals to fit in once they accumulate sufficient experiential knowledge. According to CHC theory, socialization in individuals with ASD may be linked to crystallized intelligence (Gc), which encompasses the ability to acquire and apply social knowledge. This ability is correlated with general intelligence (g). The extent of empathy is related to sociability, whereas social competence is more closely tied to one’s ability to infer and apply unspoken social rules. Hence, social competence is not some mysterious entity disconnected from intelligence; rather, much of it is likely shaped by learning and development, even during early childhood, as influenced by logical reasoning and fluid intelligence (Gf). It follows that the degree of such reasoning abilities typically correlates with performance on the Wechsler scales. Therefore, interpreting better outcomes among ASD individuals with higher intelligence as being attributable to IQ is a more plausible perspective compared to the limitations of ToM. If we follow this line of reasoning, we may say that after the formative period of identity development, the human brain enters a plastic state of Gf transitioning into Gc. Thus, it might be possible to define individuals with low intrinsic cognitive flexibility as simply falling within the autism spectrum. Additionally, a recent theory called the Parieto-Frontal Integration Theory (P-FIT) has emerged, which explains intelligence based on the locations of the frontal and parietal lobes—specific areas of the brain that are highly activated during intellectual activity—as well as the structure and function of the neural networks within them. This sounds fascinating, and I plan to explore it after reviewing a general overview of neuroscience.