Head size and intelligence: A correlational study
ABSTRACT
This study aimed to investigate the relationship between head size and intelligence. A cross-sectional research design was used in the study. Twenty (20) respondents with ages from 12-18 years were purposively selected. Ages, head circumferences and IQ scores were obtained from each of the respondents. One way ANOVA revealed a no significant difference among the respondents in reference to their ages, head sizes and intelligence (p < 0.05). Regression analysis revealed a no significant relationship between the respondents’ head circumferences and IQ scores (R2 = 0.002). Thus, this study concluded that having large head size doesn’t account for one’s intellectual ability.
- Statement of the problem
There has been a prominent aphorism that when one is intelligent, he must have a big head. When it comes to intelligence, does brain size, as correlated to head circumference, matter?
Various studies have made a link between the circumference of a person’s head to intelligence quotient (IQ) (Brandt et al. 464). Significant positive correlations have been reported between head circumference and developmental scores in respondents who are seven years old (Ounsted et al. 375). On the other hand, some studies have reported a low correlation between IQ and any brain measure or head circumference (Tramo et al. 1246).
Intelligent quotient (IQ) is a measure of intelligence that is influenced by several factors. These factors include, but are not limited to, environmental, genetic, social and cultural factors (Graves et al. 86). As there are several studies that have documented varying and contrasting findings between IQ and head circumference, the association between the two variables is a thesis that is yet to be studied further to fully analyze as to whether the two variables are highly correlated or not. Thus, this study aimed to investigate the correlation between head circumference and IQ among purposively selected respondents.
- Statement of working hypothesis
The alternative hypothesis of this study is the respondents who have larger head circumference have higher intelligence quotient (IQ).
- Experimental design and methods
The study utilized a cross-sectional and correlational research design. Thirty (30) teenagers with ages from 12-18 years old in our community were purposively selected to be respondents in the study. Since the involved were those in the age of minority, these respondents were given a waiver or informed consent emphasizing the study and its objectives. The informed consent is a form where the respondents and his/her respective guardian were requested to sign on. Those who failed to sign on the said waiver were automatically removed from the study. In the study, only 20 respondents appropriately signed and returned the said waiver.
The respondents with appropriately signed waiver were asked to fall in a queue while each respondent’s head circumference was being measured using a tape measure. The head circumference was measured and recorded in centimeter (cm). Also, the respondents’ ages were asked. After a respondent’s head circumference was measured and his/her age was recorded, the measurements and ages were written on a piece of a paper and plotted on a table. Also, once the measurement was done, the respondents were given an IQ test to be answered in 30 minutes. This IQ test involved multiple-choice type of questions gauging one’s on language, arithmetic and spatial skills. The scores of the respondents were graded and recorded on a zero-based percentage scoring criteria (i.e., when one got 15 correct scores out of 30 his score is 50%).
When all respondents’ head circumferences and IQ were appropriately recorded, the data was input on a table and further statistical analysis were employed to confirm or negate the alternative hypothesis. The analysis included regression analysis (i.e. Pearson product moment correlation) and analysis of variance.
- Results
The table below shows the respondents and their respective ages, head circumferences and IQ scores.
Further, to investigate the relationship between the respondents’ head circumferences and their corresponding IQ scores, a regression analysis (Pearson product moment correlation) was utilized.
Figure 1 shows the scatterplot diagram of the regression analysis.
Figure 1. Regression analysis on head circumference and IQ score.
Through regression analysis, it was found out that there is a no significant relationship between head circumference and IQ score (R2 = 0.002). It can be inferred that one’s head size may not significantly account or correlated to his/her intellectual capacity. Thus the alternative hypothesis of the study (i.e., there is a positive relationship between head circumference and intelligence) was denied.
- Conclusions/future directions
Based on the data obtained from 20 respondents, this study concluded that, contrary to the notion, head circumference does not have a relationship with intelligence.
- References
Works Cited
Brandt, Ingeborg, Elisabeth J. Sticker, and Michael J. Lentze. "Catch-up growth of head
circumference of very low birth weight, small for gestational age preterm infants and mental development to adulthood." The Journal of pediatrics 142.5 (2003): 463-470.
Graves, A. B., et al. "Head circumference as a measure of cognitive reserve. Association with
severity of impairment in Alzheimer's disease." The British Journal of Psychiatry 169.1 (1996): 86-92.
Ounsted, M., V. A. Moar, and A. Scott. "Head circumference and developmental ability at the
age of seven years." Acta Paediatrica 77.3 (1988): 374-379.
Tramo, Mark Jude, et al. "Brain size, head size, and intelligence quotient in monozygotic
twins." Neurology 50.5 (1998): 1246-1252.
