WAIST-TO-HIP RATIO AND IQ

Thesis Submitted to The College of Arts and Sciences of the UNIVERSITY OF DAYTON

In Partial Fulfillment of the Requirements for The Degree Master of Arts in Clinical Psychology

By Justine Elizabeth Kelly

UNIVERSITY OF DAYTON Dayton, Ohio May 2014

WAIST-TO-HIP RATIO AND IQ

Name: Kelly, Justine Elizabeth APPROVED BY:

_______________________________________ Susan T. Davis Faculty Advisor ______________________________________ Melissa J. Layman-Guadalupe Committee Member ______________________________________ Carolyn E. Roecker-Phelps Committee Member

Concurrence: _______________________________________ Carolyn E. Roecker-Phelps Chair, Department of Psychology

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ABSTRACT

WAIST-TO-HIP RATIO AND IQ

Name: Kelly, Justine Elizabeth University of Dayton Advisor: Dr. Melissa Layman-Guadalupe This study investigated the relationship between waist-to-hip ratio (WHR) and intelligence quotient scores (IQ), and whether this relationship might be affected by variations in body image, locus of control, or self-efficacy. Female college students (N=51) completed a brief IQ test and a series of personality measures, and were then measured at the hips and waist to calculate WHR. The current study did not replicate the previous findings of a link between WHR and IQ; further investigation is needed to determine whether there truly is a relationship between WHR and IQ as indicated by earlier research, and if such a link does exist, whether personality variables would be useful to include in the examination. In the current study, further analyses indicated relationships between body image and WHR as well as body mass index (BMI). Social self-efficacy was found to be related to verbal IQ scores as well as leadership roles.

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ACKNOWLEDGEMENTS

I wish to express my gratitude to Dr. Melissa Layman-Guadalupe for working with me on this project throughout the entire process, and for always being at the ready when I needed her. I would also like to thank Dr. Susan Davis and Dr. Carolyn Roecker-Phelps for serving on my thesis committee and offering their suggestions and support. Completion of this project did not come easily to me and their willingness to continue assisting is deeply appreciated. I also need to thank my husband Matthew, who always encouraged me to work for a little while longer and made it possible for me to do so.

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TABLE OF CONTENTS

ABSTRACT…………………………………………………………………………….. iii ACKNOWLEDGEMENTS…………………………………………………………….. iv LIST OF TABLES……………………………………………………………………… vi CHAPTER I: INTRODUCTION……………………………………………………….. 1 CHAPTER II: METHOD………………………………………………………………. 12 CHAPTER III: RESULTS...……...……..………………………………………………20 CHAPTER IV: DISCUSSION ………………………..………………………………...27 REFERENCES ………………………………………………………………………….32 APPENDICES A. Demographic Survey……….............................................................................40 B. Items Similar to Those of the SB5 ABIQ………….........................................41 C. Body Appreciation Scale (BAS)……………...................................................42 D. Self-Efficacy Scale (SES)……………….........................................................44 E. Ascription of Responsibility Questionnaire (ARQ)..........................................46 F. Informed Consent………..................................................................................49 G. Debriefing……………………….……………................................................51

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LIST OF TABLES

1. Means and Standard Deviations for the Continuous Study Variables………………...22

2. Correlations Between Main Study Variables………………………………………....23

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CHAPTER I INTRODUCTION

Intelligence and its correlates have long been the topic of great interest and rigorous study and debate. Research pertaining to intelligence “has dominated the psychological literature for decades” (Kaufman & Lichtenberger, 2006) and has also piqued the interest of the general public as evidenced by frequent reporting of academic findings by popular mass media outlets. Indeed, one primary source for the current study was produced into news segments played on major American news networks, during January of 2008 (e.g., Fortin, 2008; McGinnis, 2007). Another subject of much intrigue in both the academic world and popular culture is the concept of sexual attractiveness: Over $160 billion is spent annually in the global market for cosmetics, fitness, and plastic surgery (“Pots of Promise,” 2003), and hundreds of peer-reviewed articles spanning several disciplines investigating human attractiveness can be found with minimal effort. One well-documented facet of human female sexual attractiveness is that of waist-to-hip ratio (WHR) (Singh & Randall, 2007). Waist-to-hip ratio is calculated by dividing the measurement of a person’s waist circumference by the measurement of that person’s hip circumference, and it refers to the degree to which a woman can be described as “curvy.” A high WHR indicates a woman with a waist which is roughly the same size as or larger than her hips, while a low WHR describes a woman whose waist is much smaller than

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her hips. Women with smaller WHR values are typically judged by others to be more attractive on average than women with larger WHR values (Singh & Randall, 2007). Recently, one research finding has indicated that WHR is negatively correlated with intelligence in women (Lassek & Gaulin, 2008), finding that higher WHR values are associated with lower measured cognitive ability. The present study sought to replicate these findings and to determine whether other factors, such as positive body image, selfefficacy, and locus of control could be mediating this finding. Waist-to-Hip Ratio Research has demonstrated that women with smaller waist-to-hip ratios (i.e., a curvier figure) are perceived as more attractive by both men and women in cultures around the world (Singh, 1993, 2004; Singh & Randall, 2007; Furnham, Moutafi, & Baguma, 2002). Other studies have argued that body mass index (BMI) is equal to or better than WHR for predicting ratings of attractiveness (Puhl & Boland, 2001; Swami, Caprario, Tovée, & Furnham, 2006). However, most researchers agree that the two are in a practically inseparable covariant relationship for the purposes of predicting or measuring physical attractiveness. Men and women in Western cultures typically find women with WHRs of 0.6 to 0.7 and BMIs of 17 to 20 to be most attractive (Singh, 1993). For the purpose of this study, WHR was treated as the primary indicator of female physical attractiveness because of its apparent relationship (as perceived by men and women) with other constructs such as fertility, general physical health, and intelligence. One proposed explanation for the higher ratings of attractiveness for women with low WHRs is that men perceive women with small waists and large hips as more fertile than those with high WHRs. One obvious potential explanation for such an evolution is

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pregnancy. Rebuffe-Scrive (1987, as cited in Singh & Randall, 2007,) reminds us that high WHR is indicative of pregnancy; if a woman is already pregnant, she is not currently fertile and will not be favored as a mate (Singh & Randall, 2007). However, more attention has been given to the fact that women are capable of becoming pregnant after menarche and before menopause when their estrogen levels are highest; it is also during this time that they have the lowest WHRs (Bjӧrntorp, 1991). Healthy WHR for a woman of child-bearing age ranges from 0.67 to 0.80 (National Academy of Sciences, 1991). A multicultural sample of 200 men and women aged 17 to 26 years rated female figures with low WHRs as “easy to bear children” and “easy to become pregnant” (Furnham, McClelland, & Omer, 2003), and the same study found a significant correlation between ratings of fertility and ratings of sexual attractiveness. Other studies have yielded similar results (Furnham, Petrides, & Constantinides, 2005; Swami, Miller, Furnham, Penke, & Tovée, 2005), suggesting that men have evolved to experience sexual attraction to fertile women. However, Lassek and Gaulin (2008) have refuted this claim on the basis that no consistent evidence exists to support the link between low WHR and fertility, citing a slew of studies (e.g. Pall, Stephens, & Azziz, 2006, and van Hooff, Voorhorst, Kaptein, & Hirasing, 1999) which do not find any difference in WHR between healthy women and women who are amenorrheic, infertile, or suffering from hormonal imbalances. A second notion set forth by attractiveness researchers is that men find women with low WHRs to be more sexually attractive because they are healthier. Ample evidence exists to support this assertion, today: Adults with higher WHRs are at increased risk for a variety of metabolic diseases, including elevated blood sugar leading to Type II diabetes, hypertension, elevated triglycerides and low-density (“bad”)

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cholesterol, and lowered high-density (“good”) cholesterol (Bertrais et al., 1999; Larsson et al., 1984). However, Lassek and Gaulin (2008) challenge this theory on an evolutionary basis because, they argue, complications with obesity such as cardiovascular disease and metabolic syndrome are a modern problem and would have been unlikely to exist on any significant scale during previous millennia. Having presented arguments against the fertility and health explanations for men’s higher attractiveness ratings of women with lower WHRs, Lassek and Gaulin (2008) proposed and tested a novel hypothesis for this phenomenon: Men are attracted to women with lower WHRs because women with such figures possess superior cognitive abilities to women with larger WHRs, and are more likely to produce offspring with superior cognitive abilities. They begin their argument by citing a number of research studies (e.g. Phinney et al., 1994) which state that fat stored upon the hips and buttocks of women is the source of the particular fat (long-chain polyunsaturated fatty acids, particularly omega-3 fatty acids) that is critical to neural development in humans. This, coupled with earlier observations that women’s WHR tends to increase with the number of children she bears (Lassek & Gaulin, 2006), indicates that the purpose of sexually dimorphic fat distribution could be to support cognitive development and ability in offspring. Men, desiring offspring with strong cognitive abilities and, therefore, increased chance of survival, are drawn to women with plenty of gluteofemoral fat and thus a low WHR. In addition to the potential for providing offspring with sufficient instrumental fatty acids for cognitive development, Lassek and Gaulin (2008) also speculate that the patterns of heredity and the availability of long-chain polyunsaturated fatty acids in

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women with low WHRs would create a relationship between low WHR and superior cognitive performance in the women themselves. Lassek and Gaulin (2008) tested this hypothesis using a sample of 2,259 adult, premenopausal women (aged 18-49 years) who were measured for WHR and assessed for cognitive ability using an average of their scores on two subtests from the Neurobehavioral Evaluation System (Letz, 1990): the Serial Digit Learning Test and the Symbol Digit Substitution Test. They controlled for age, number of children borne, household income, age at first birth, and race using multiple linear regression. The results of their multiple regression analysis estimated that up to 6% of the variance in scores could be attributed to WHR. Although Lassek and Gaulin (2008) were the first to seek evidence of a link between WHR and cognitive function in women of reproductive age, the notion that WHR and cognitive function may be related has been explored before. Previous research has indicated that larger waist circumferences in older adults is correlated with cognitive decline and dementia (Jagust, Harvey, Mungas, & Haan, 2005; Waldstein & Katzel, 2006). Jagust and colleagues sampled 112 adults and found that there was a significant negative relationship between WHR and various physical indicators of dementia, such as smaller hippocampal volume. Waldstein and Katzel concluded that 3 to 13% of the variance in performance on neuropsychological tasks could be attributed to central obesity, based on a sample of 90 adults. These researchers attributed the decline in cognitive function to blood pressure and other vascular disease, which is commonly associated with higher WHRs, rather than the type of fat stored in the abdomen. However, in a study of 917 adults of both sexes, Dore, Elias, Robbins, Budge, and Elias

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(2008) found that inverse relationships between waist circumference and cognitive function (R2 =-.10, p