A popular topic these days, though maybe not as popular as when I was younger, is the concept of the IQ test, which is designed to measure your intelligence quotient. An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. According to Wikipedia:

“Historically, IQ was a score obtained by dividing a person’s mental age score, obtained by administering an intelligence test, by the person’s chronological age, both expressed in terms of years and months. The resulting fraction is multiplied by 100 to obtain the IQ score. For modern IQ tests, the average raw score  is defined as IQ 100 and scores each standard deviation up or down are defined as 15 IQ points greater or less. As such, around two-thirds of the population scores [are supposedly] between IQ 85 and IQ 115.”

Now, I put an extra emphasis on supposedly above. You can probably take a guess as so why I did this, and if you guessed that it has to do with differential scoring among ethnic and racial groups then you would be correct. That brings into question: why do some groups of people have higher average scores on IQ tests than others?

Despite coming into being over a century ago, IQ tests are still widely used today to measure an individual’s mental ability. In America, these tests show significant differences in scores (lower) when it comes to demographics of different racial and ethnic backgrounds other than white. According to Daniel Murdock, there are two potential reasons for this. 

Firstly, there is a possible genetic factor that could impact intelligence testing. Most researchers believe there is a reaction range to IQ, in which heredity places an upper and lower limit on the IQ that can be cultivated. This has been found through family studies, that show that intelligence is highly correlated among members in immediate family. Further supporting studies are twin studies that show that intelligence is more highly correlated among monozygotic twins than dizygotic twins. Interestingly enough, adoption studies that show that the IQ scores of adopted children somewhat resemble those of their biological parents, giving weight to the biological/hereditary perspective.

There’s also an environmental perspective to consider. While studies have supported genetic factors, we can’t do away with how the environment can play a part in the development of intelligence. To this end, we must understand the concept of epigenetics. Epigenetics is “the study of the process by which genetic information is translated into the substance and behavior of an organism: specifically, the study of the way in which the expression of heritable traits is modified by environmental influences or other mechanisms without a change to the DNA sequence” according to Dictionary.com. Simply put, epigenetics is the study of how the environment manipulates the expression of genes without actually causing structural changes to the genes.

To that end, we must find support for the influence of the environment on IQ – family and adoption studies. Adoption studies provide evidence that our upbringing plays an important role in our mental ability – adopted children show some resemblance to their adoptive parents in IQ. Family studies also show that siblings who are reared together are more similar in IQ than siblings reared apart.

Similarly, when children are removed from deprived environments and placed in homes that are more conducive for learning, they show increases in IQ. While all this so far works on a more individual basis, it serves to set the stage for the big picture: groups.

What in the environment could cause these patterns and changes in IQ? Socioeconomic Status, Health, and Nutrition, and Education. This is true on an individual level as well as it is on a group level. The quotation below was pulled directly from the source as I personally couldn’t find a better and more concise way of putting across what the author said:

• “Socioeconomic environment: Racial and ethnic minority children are more likely to experience socioeconomic disadvantages, which are correlated with lower IQ scores.” (Group Differences in Intelligence Test Scores, 2018)
• “Health and nutrition: Racial and ethnic minority children are statistically more likely to be exposed to poorer nutrition, prenatal health care, and postnatal health care. Poor health and nutrition can negatively affect cognitive development and functioning.” (Group Differences in Intelligence Test Scores, 2018)
• “Education: Racial and ethnic minority children are more likely to be exposed to poorer quality schools than white children, which limits opportunities for cognitive development.” (Group Differences in Intelligence Test Scores, 2018)

Inspired by the Week 12 SHT topic, this blog post is meant to help me properly articulate my thoughts within the topic of systemic racism and its consequences on the population. However, there is no room here for politics so I’ll leave it at this: the ethnic and racial differences in IQ scoring have nothing to do with biological or genetic limitations specific to one or more racial or ethnic groups. These scores are a product of the environment, the system under which they live and experience.

References:

Group Differences in Intelligence Test Scores. (2018, February 1). Retrieved from https://study.com/academy/lesson/group-differences-in-intelligence-test-scores.html.

https://en.wikipedia.org/wiki/Intelligence_quotient

https://www.dictionary.com/browse/epigenetics

What is synesthesia? Here I attempt to explain the phenomenon and some relevant theories in layman’s terms. So, what is it? According to some researchers:

• “Synesthesia is a hereditary condition in which a triggering stimulus evokes the automatic, involuntary, affect-laden, and conscious perception of a sensory or conceptual property that differs from that of the trigger.” – Richard E. Cytowic Aka. The coupling of two or more modalities
  • Modality: a partial aspect of perception as a whole. One of the five senses.
  • Directionality: While commonly senses cross in only one direction, in very real cases, it can be bidirectional. People will hear colors and colors will have a sound.
• “Synesthesia is commonly thought to be a phenomenon of fixed associations between an outside inducer and a vivid concurrent experience.” Krischner & Nikolic

What it’s not:

• Crazy, attention-seeking, and prone to fantasy
• Merely remembering childhood associations from coloring books or refrigerator magnets, which is why they imagined that A was read, or D was green
• Engaging in metaphor that was no different that talking about warm or loud colors, sharp cheese, or bitter cold
• Burned-out junkies suffering the residual effects of their assumed drug use

Fun facts:

• 1812 – George Tobias Ludwic Sachs – First reported clinical case of synesthesia, George wrote a medical dissertation on himself claiming himself as being polymodal.
  • Polymodal: experiencing more than one type of synesthesia
• In-depth research into the phenomenon of Synesthesia didn’t start until around 1980. It was orignially not studied because it was, at the time, no scientific, verifiable, or observable. It was too idiosyncratic and first person reports were not reliable. Through current research, however, these idiosyncratic elements can now be attributed to neural plasticity, genetic polymorphism, and environmental effects. Synesthesia also gained an iffy reputation because it was so romanticised by the arts. Behaviorism peaked between 1920 and 1940, which further pushed interest away from the phenomenon.

Knowing that synesthesia is the concurrent experience of one sense as a result of stimuli affecting another sense, we continue on to the formation:

• First is the concept called “one shot synesthesias which are occasionally generated one off synesthetic experiences.” These one-shots share all the properties with the classical synesthetic associations except that they occur extremely rarely. They are quite literally one-shots, versus being the continuous condition that affects synesthetes throughout their lives. Through this, we can conclude that since one-off synesthetic experiences exist, synesthesia cannot be prewired at birth but instead dynamically develops after early childhood.
  • Because many synesthetic experiences deal with the processing of symbols, it only makes sense that a human would only be able to have synesthesia once the connections that allow the processing of things like language are formed.
  • This process occurs in most human infants around the age of 2.

Understanding the basics, we’ll get into the nitty gritty of things. We’ll briefly discuss one of the prominent theories behind synesthesia in this blog post: cross-activation theory. The cross-activation theory was first proposed by Ramachandran and Hubbard in a 2001 study and finds its basis in a process called synaptic pruning.

• Synaptic pruning is exactly what its sounds like: pruning or cutting back extra synaptic connections in the brain that are no longer needed.

Cross-activation theory suggests that synesthesia occurs due to an increase in neural connection between two sensory modalities caused by the brain not pruning enough synaptic connections during early childhood to keep the different modalities entirely separate. In English: the brain doesn’t trim the neural connections between different areas of the brain that process different senses like it does in the average, neurotypical person. Their theory stems from the observation that the brain areas involved in letters and the brain areas involved in colors are actually right next to each other in the brain. Associating words and letters with colors is actually one of the most common forms of synesthesia, also called grapheme synesthesia.

I personally find this to be the most interesting and easily understood of the theories behind the condition and one that I could actually explain. I tried my best to put this into English so please let me know how I did!

Links:

• Hubbard, E.M., Brang, D. & Ramachandran, V.S. The cross-activation theory at 10. J Neuropsychol 5, 152-77 (2011).
• Hubbard, Edward M. “Neurocognitive Mechanisms of Synesthesia.” Neuron, Cell Press, 2 Nov. 2005, www.sciencedirect.com/science/article/pii/S0896627305008354?via%3Dihub.
• Cytowic, R. E. (2018). Synesthesia. Cambridge, MA: The MIT Press.
• Bradford, Alina. “What Is Synesthesia?” LiveScience, Purch, 18 Oct. 2017, www.livescience.com/60707-what-is-synesthesia.html.