by Kai Gohil, U6P
"According to a study by researchers at four British universities, for each 15-point increase in IQ, the likelihood of getting married increases by around 35% for a man but decreases by around 58% for a woman. Why?"
Introduction to IQ
IQ ("intelligence quotient") is defined as a number used to express the relative intelligence of a person (Britannica, 2024).
Therefore, if one were to have a 15-point increase in IQ, it would suggest that such a person is relatively more intelligent. This increase is significant, as past research (involving a meta-analysis on the effect of education on IQ) demonstrates that, on average, a year of education can increase IQ from 1-5 points (Ritchie, S.J. & Tucker-Drob, E.M., 2018). Therefore it can be fairly assumed that (at a maximum) 3 years of schooling would equate to a 15-point increase in IQ. Although it does not appear to be a notable increase, placing it in terms of the British Education system, this could be the difference between a Year 9 student and a Year 12 student; this is a significantly large difference in problem-solving abilities and intelligence. Additionally, due to the circumstances of the research, it can be understood that a 15-point increase in IQ is significant. For example, the research used a meta-analysis technique - blending 28 previous studies, to collect large volumes of quantitative data. This data can be statistically analysed to draw highly objective, valid conclusions on the effect of education on IQ. Furthermore, the meta-analysis technique also meant that over 600,000 participants were involved in this research, indicating that the sample is highly representative of the target population (the worldwide population). Thus, the results gathered on the effect of education on IQ can certainly be generalised to the whole population - ensuring the external validity of the research.
Neurological Effects of Greater IQ
Having established that a 15-point increase in IQ can be considered significant, we must explore the effects, both neurologically and behaviourally, that such an increase would have on a person.
Firstly, from a neurological perspective, research (Genç, E. et al., 2018) has suggested that an increase in IQ is correlated with a lower dendrite density and arborization (fine, branched structures at the end of neurons) in the cerebral cortex (involved with a range of intellectual functions, including memory and language). This finding may be logically confusing as it suggests that more neurons don't necessarily equate to greater intelligence. Alternately it suggests that neuronal circuitry associated with higher intelligence is organised in a more sparse, yet efficient manner. This ensures a more streamlined information processing system which would lead to reduced cortical activity during reasoning. This clear neurophysiological difference suggests that there are potential innate, biological reasons for differences in IQ. However, it must be noted that this study was done using a correlational analysis technique, meaning, a clear cause-effect relationship could not be established, so it would be inaccurate to completely assume that the difference in the biology causes changes in IQ. Still, it would be reasonable to believe that there is at least some association between the variables, due to the use of objective, experimental methods to collect data which ensured that any conclusions drawn were valid to a significant extent. Hence, the research (Genç, E. et al., 2018) explains that those of higher intelligence will have a greater processing speed and network efficiency, as explained by the sparse, yet efficiently organised dendritic arbor.
Behavioural Effects of Greater IQ
Behaviourally, these differences in the brain neurocircuitry can also be described: previous research, using an fMRI scan to investigate decision-making under risk, elicited that decisions which were considered 'too risky' or 'too cautious' were directly correlated with greater activation of the anterior cingulate cortex (a part of the cerebral cortex) during a game of blackjack (Hewig, J. et al., 2009). This suggests that a high cortical activity would lead to a greater amount of suboptimal decisions (note: this study is primarily correlational, however, the study itself chooses to use the phrasing 'lead' to describe the link between co-variables) and conversely, it would be acceptable to say that a lower cortical activity would therefore lead to more favourable decisions. Hence - connecting the ideas about IQ, cortical activity and decision-making together - it could be stated that those people with a 15-point increase in IQ are more likely to be bolder, decisive and focused due to their efficient reasoning.
The Impact of Greater IQ on Marriage
Applying Ancient Greek perspectives, we can explain the effect of gender differences on marriage probability for individuals with a 15-point IQ increase. Many centuries ago, thinkers developed the idea coined the 'Athenian Civic Model'. This framework reflected the democratic ideal of the city-state, delving into constructions of masculinity - including female masculinity, in Ancient Greece (Rubarth, S., 2014). A key aspect of this model was the definition of gender-specific behaviours and qualities, and most relevant is the definition of decisiveness, intelligence and boldness as solely masculine traits (Penrose, W.D., 2016). The Athenians also considered 'female masculinity', suggesting that females who did express such masculinity, were labelled as potentially disruptive to society and nature. Within traditional Athenian views, such behaviours were often attributed to 'tolma' (audacity) rather than the 'andreai' (courage). Furthermore, within the Hippocratic medical treatise, "On Regimen", masculine females were however they were not seen as the desired outcome for procreation (Penrose, W.D., 2016). Thus, it could be understood that a 15-point increase in IQ would lead to a more 'masculine' individual and that depending on the gender of an individual, the social perception of this individual would vary.
From a female focus, according to Athenian societal norms, an increase in IQ would create less desirable women for procreation (Penrose, W.D., 2016). As indicated by previous research there is an intrinsic link between procreation and marriage (Lee, P., George, R.P. & Bradley, G.V., 2011). Further research suggests that partners with a greater desire to procreate are more likely to commit to a stable relationship ideal for rearing children - like a marriage (Buss, D.M., 1994). Therefore, if a woman was to be less desirable for procreation, it would indicate that commitment to another individual would be less likely. Neurobiologically, this mechanism can further be described - the hormone oxytocin, the neurotransmitter involved in forming emotional bonds and attachment, is released during sexual intercourse (Young, L.M. & Alexander, B., 2012). Logically, this would be a key component to procreation and as other research demonstrates, this neurotransmitter is vital for the formation of strong emotional bonds to create a stable environment for child-rearing (Young, L.M. & Alexander, B., 2012) and so would evidently influence the likelihood of marriage. However, it must be considered - despite traditional norms - that procreation is not the only factor influencing the decision of a marriage (Ball, C.A., 2014) and due to the fact that oxytocin within the brain is not directly manipulated to establish a cause-effect link, we are only limited to stating that there is evidence supporting the claim that desire to procreate influences marriage decisions. This opposes the idea that the desire for procreation is the sole cause of the decision to marry your partner. Despite this, it would still be reasonable to assume that the influence of procreation on marriage decisions is significant on both a biological and neurological basis. Hence, it can be stated that women with a 15-point increase in IQ can be seen as more 'masculine' and so would be less likely to marry.
From a male focus, according to Athenian societal norms, an increase in IQ would create more masculine men (Penrose, W.D., 2016). As indicated by traditional views and research, these masculine traits, like assertiveness and decision-making, play a large role in mate selection and would thus increase the chance of marriage for men (Buss, D.M., 1994). The evidence supplied is from a book based on a study involving primary data collection from 37 different cultures to gather both attitudes and beliefs about mating and long-term relationships. Seeing as this study was cross-cultural and collected rich, detailed qualitative data, it ensured that any conclusions drawn from the study could be generalised to various cultures across the world and thus the findings from this study would be high in external validity. This ensures that our explanation that more masculine men are more likely to commit to a long-term relationship - like marriage - is valid. However, this overall train of thought is not ideal - some research suggests that masculine men, though seen as attractive, are preferred for shorter-term relationships rather than longer-term relationships (like marriage) (Holzleitner, I. J., & Perrett, D. I., 2017). This provides contrasting evidence for the question posed, but due to the significantly lower sample size in the contrasting study (500 women VS 10,000 women), it would be sensible to accept the supporting evidence as the contrasting evidence has a much lower generalisability. Therefore, it would be rational to explain that more masculine men are more likely to find and commit to a long-term partner (e.g. in marriage).
Having established both explanations as to why a 15-point increase in IQ can increase marriage probability in men by 35% but decrease by 58% for women, it must be indicated that this explanation is not perfect. This explanation requires many assumptions (including that the Athenian Civic Model is still representative nowadays). Therefore any conclusions drawn must be taken with a pinch of uncertainty - this essay simply explores for one explanation and may, as a result, be reductionist.
Conclusion
Despite this, this argument still concludes that a 15-point increase in IQ would lead to a more efficient cerebral cortex neurocircuitry, which would lead to a more decisive individual. Using the Athenian Civic Model, this boldness and decisiveness create a more masculine individual; who, for women, is seen as less desirable in marriage but conversely, for men, is seen as a more desirable figure in marriage. This therefore provides a clear (though extrapolated) explanation to the question posed.
Bibliography
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