Women’s Preferences for Penis Size: A New Research Method Using Selection among 3D Models
PMC (PubMed Central)
US National Library of Medicine
National Institutes of Health
Nicole Prause, (see Cosmo article) # 1 ,* Jaymie Park, 1 , ‡ Shannon Leung, 1 , ‡ and Geoffrey Miller# 2
Heather Hoffmann, Editor
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Women’s preferences for penis size may affect men’s comfort with their own bodies and may have implications for sexual health. Studies of women’s penis size preferences typically have relied on their abstract ratings or selecting amongst 2D, flaccid images. This study used haptic stimuli to allow assessment of women’s size recall accuracy for the first time, as well as examine their preferences for erect penis sizes in different relationship contexts. Women (N = 75) selected amongst 33, 3D models. Women recalled model size accurately using this method, although they made more errors with respect to penis length than circumference. Women preferred a penis of slightly larger circumference and length for one-time (length = 6.4 inches/16.3 cm, circumference = 5.0 inches/12.7 cm) versus long-term (length = 6.3 inches/16.0 cm, circumference = 4.8 inches/12.2 cm) sexual partners. These first estimates of erect penis size preferences using 3D models suggest women accurately recall size and prefer penises only slightly larger than average.
Both men and women often have reported discomfort with the appearance of their genitals.[DH- see other photo book of penises] While not as common of a concern as body weight, muscularity, amount of head hair and body hair, or height, penis size was a concern for 68.3% of 200 men in one study . Concerns about genital appearance are unique compared to other concerns about physical appearance. First, only intimate partners generally know the appearance of genitals. In contrast to the penis, body weight, acne, and other features are easily observed, informing feelings of attraction early in interactions. While indicators of penis size include ethnicity  and finger length and ratio [3, 4], most proposed cues of penis size, including male height and foot size , weight [6, 7], shoe size , and age , are unreliable. Second, no diet, pill, or exercise regime affects the size or shape of genitals. However, about half of men in one study believed that they could change their penis size through non-surgical means . Little can be done to change the appearance of the penis. Contrary to some public opinion, it also is worth noting that discomfort with the appearance of the penis is not impacted , or is positively impacted , by viewing sex films. Given that only intimate partner(s) view the penis, the appearance is relatively immutable, and sex films are not causing dissatisfaction, partner perceptions of the penis appearance seem to most likely to impact men’s feelings about the features of their penis.
The expectations that men have about women’s penis size preferences appear to drive anxiety and dissatisfaction more than some inborn dissatisfaction. In the first questionnaire to examine the nature of dissatisfaction with the penis directly, three of the ten items concerned a partner’s perception . These included “I will be alone and without a partner” and “I will be laughed at by a partner in a sexual situation”. These anxieties may be unnecessary. For example, while men and women agreed that the “ideal” penis length was longer than what they thought was average, men mistakenly reported that women would find an even longer penis ideal than the women actually did . Furthermore, most men seeking surgery to increase their penis size (e.g., [14, 15]), actually fall within the normal penis size range .
Concerns about penis size affect men’s sexual satisfaction and functioning. Of course, penis size need not affect sexual functions like orgasm, sexual drive, or pain experience. However, men who are less satisfied with their penis report more sexual health problems . A smaller penis decreases sexual confidence , which may be why penis size is related to sexual function. Another reason penis size may be related to sexual functioning is that anxiety concerning the partner’s response may be calculated as a cost of the relationship, which leads him to experience broad sexual dissatisfaction .
The context of the sexual relationship could influence penis size preferences. For example, the goal of the sexual interaction with a one-night partner tends to be pleasure . Women recognize that infection risks are higher from a one-night partner . While women adjust their behaviors for this risk, being less likely to engage in anal sex  and more likely to use condoms  with one-night partners, such risky behaviors themselves are often experienced as pleasurable . On the other hand, vaginal intercourse always causes tears in the vaginal mucosa  especially in the sensitive posterior fourchette , so women might prefer a smaller penis less likely to stress their physiology for regular, long-term mates. Thus, women might shift their preferences for penis size depending on the type and duration of sexual relationship.
Studies of penis size preference to date have relied on numerical size estimates, vague qualitative descriptions, or 2-D line drawings. For example, some studies have asked participants to specify penis length preferences in centimeters . Another study asked participants to indicate their preference from reading erotic passages with three qualitative penis size options (small, medium, large) . Yet, humans judge sizes most accurately when visual and haptic information are available together . Both sources of data are usually available in sexual interactions. Thus, in this study, three-dimensional (3D) models were used with the hope of increasing accuracy, ecological validity, and external validity. Also, most studies of penis size preference have portrayed or asked about the penis in its flaccid state [30, 31]. This may be problematic, because the relationship between erect and flaccid sizes has been reported as negligible [32, 33] moderate (r = .44 in , r = .78 in ), and strong (rho = .77 in , r = .79 in ). It is unclear how well flaccid size reflects erect size. Of course, intercourse can occur only with a sufficiently rigid penis . Thus, it seemed important to characterize preferences for penis size in its erect state. The current study used 3D models of erect phalluses to characterize women’s penis size preferences for the first time.
Three-dimensional (3D) printing is just beginning to be used to assess shape perception and categorization. On the one hand, visual 2D information as compared to haptic information (from 3D) result in similar solutions for object similarity . Each mode of information (visual or haptic) also improves categorization in the other domain [38, 39]. 3D printing could allow representation of highly problem-specific, complex structures . Haptic information from 3D objects improved shape identification compared to raised lines alone  and improves later performance in the visual domain , possibly by improving discriminability . Also, haptic information is robust to differences in perceptual acuity, such as occur with aging , which make such stimuli attractive when the visual acuity of participants may vary. This study extends the existing work using 3D stimuli to assess size preferences. This approach also permitted characterization of women’s ability to accurately recall the size of erect phallus models for the first time.
When flaccid and “stretched” penis sizes are characterized , largely by self-measurement , they predict erect size surprisingly poorly. Yet there are relatively few studies of erect penis size. This may reflect cultural taboos against researchers or doctors interacting with men who are in a sexually aroused state. One study had men judge their own erect size in relation to a banknote’s length . Two studies of erect penis sizes provided kits for home measurement [47, 48]. Such self-measurements of length and circumference show fairly good test-retest reliability (r = .68 to .90, ). Pharmacologically-induced, physician-measured erections identified an average length of 12.89 cm (SD = 2.91) and circumference of 12.3 cm (SD = 2.9; ). These were somewhat shorter in length (M = 14.15, SD = 2.7), yet similar in circumference (M = 12.23, SD = 2.2), compared to a recent, large survey .
Women’s penis preferences may vary with their relationship expectations. Women prefer more masculine partners for shorter-term sexual relationships . Women also value intelligence more, and attractiveness less, for long term, as compared to short term, partners . More masculine traits, such as lower voice pitch  and (to some extent) larger penis size [51, 52] are correlated with testosterone levels, which also may influence men’s mating goals and attractiveness. Since a larger penis size is perceived as more masculine [53, 54], we predict women will prefer a larger penis for shorter-term sexual relationships.
Women likely make penis size judgments partly using their recalled experiences. Yet, it is unclear how accurately women can recall penis size. Exposed to nude male images, women do attend to the genital area [55, 56]. People can generally recall if a penis was described as “large”, “medium”, or “small”, or not described at all . In the current study, women’s ability to recall penis size was tested by match-to-sample recall, both immediately and after a delay of ten minutes.
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