Research in fields for which self-reported behaviors can be compared with factual data reveals that misreporting is pervasive and often extreme. The degree of misreporting is correlated with the level of social desirability, i.e., the need to respond in a culturally appropriate manner. People who are influenced by social desirability tend to over-report culturally desired behaviors and under-report undesired behaviors. This paper reviews socially desirable responding in sexual behavior research. Given the very private nature of the sexual activity, sex researchers generally lack a gold standard by which to compare self-reported sexual behaviors and have relied on the anonymity of participants as the methodology to assure honest answers on sexual behavior surveys. However, indirect evidence indicates that under-reporting (e.g., of a number of sexual partners, receptive anal intercourse, condom use) is common. Among the general population, several studies have now reported that even with anonymous responding, there are significant correlations between a variety of self-reported sexual behaviors (e.g., use of condoms, sexual fantasies, exposure to pornography, penis size) and social desirability, with evidence that extreme under- or over-reporting is as common as is found in other fields. When asking highly sensitive questions, sex researchers should always include a measure of social desirability and take that into account when analyzing their results.

Obesity has become a true pandemic. In the United States, over two thirds of adults are obese or overweight. The prevalence of obesity has doubled since 1980. The increase in the prevalence of obese and overweight individuals has happened too rapidly for it to be due to an alteration in the genome. The gastrointestinal, sensory (taste and olfaction), and brain feeding mechanisms that developed during the past 2 million years were highly adaptive for ancestral hunter-gatherers living in an environment with limited high-density foods and periods of food deprivation. Today, however, humans in industrialized countries live in what has been called an "obesogenic environment." The nonhomeostatic brain reward circuitry that was acquired during evolution to seek out and eat as many nutritionally high-dense foods as possible is able to overrule the physiological inhibitory mechanisms that were designed to limit meal size and weight gain.

In previous studies, researchers had students rate single nonverbal behaviors as signals conveying and inferring sexual consent. In real-life interactions, young people use an array of behaviors occurring concurrently or successively to interpret sexual consent. With use of a 7-point scale (0 = Definitely No, 6 = Definitely Yes), students at a southeast public university were asked to rate their perceptions of nine nonverbal behaviors as signals of sexual consent, nine combinations of two of those behaviors, and eight combinations of three behaviors. There were significant effects for both gender and number of behaviors (p < .001). Over 43% of women answered “0” to all behaviors and combinations of behaviors, whereas only 20.3% of men answered “0” to all. The mean ratings for men were greater than those for women under all three conditions and increased with the number of behaviors. At least one third of men responded with “3” (the midpoint of the scale) or greater to seven of the eight combinations of three behaviors, whereas the percentage of women responding “3” or greater never exceeded 18% for any of the individual behaviors or combinations. It is concluded that as the number of nonverbal behaviors increases the subjective interpretation of sexual consent also increases, thus also increasing the chances of unwanted sexual advances.

Most men believe that the average length of an erect penis is greater than 6 inches (15.24 cm). This belief is due, in part, to several often-cited studies that relied on self-reported measurements, with means of about 6.2 inches (15.75 cm) for heterosexual men and even greater for gay men. These studies suffered from both volunteer bias and social desirability bias. In this review, the combined mean for 10 studies in which researchers took measurements of erect penises was 5.36 inches (13.61 cm; n = 1,629). For 21 studies in which researchers measured stretched penises, the mean was approximately 5.11 inches (12.98 cm; n = 13,719). Based on these studies, the average length of an erect penis is between 5.1 and 5.5 inches (12.95–13.97 cm), but after taking volunteer bias into account, it is probably toward the lower end of this range. Studies show that a majority of men wish they were larger, with some choosing penile lengthening surgery. These surgeries are considered by the American Urological Association to be risky. Most men seeking surgery have normal sized penises. Counseling with factual information about penis size might be effective in alleviating concerns for the majority of men who worry about having a small penis.

Summary: Objective: The objective of this study was to determine whether there is an association between under‐reporting of body weight and social desirability as is found with self‐reports of energy intake.Methods: Twenty‐seven lean individuals (mean body mass index ± standard deviation = 21.6 ± 2.0 kg m⁻²) and 26 individuals with obesity (mean body mass index = 35.4 ± 4.8 kg m⁻²) were e‐mailed a questionnaire on which they had to state their body weight and conduct a home food inventory. The next day, research team members went to their homes to weigh the participants, conduct their own food inventory and administer the Marlowe–Crowne scale for social desirability.Results: Among individuals with obesity, lower social desirability scores were associated with a greater degree of under‐reporting body weight (r = +0.48, p < 0.02). Among lean individuals, the correlation was negative but statistically non‐significant (p = −0.22, p > 0.10). Nine individuals with obesity were extreme under‐reporters (2.27 kg or more), and eight of these had social desirability scores in the bottom half of the Marlowe–Crowne scale (p < 0.01). Six under‐reported on the home food inventory by three or more items.Conclusions: Individuals with obesity and low social desirability scores are more likely than others to be extreme under‐reporters of body weight, possibly due to a lack of awareness of their own weight.