Monday, October 14, 2019

The Rare Sides of Twin Research: Representation of Self-Image; Twins With Kleine–Levin Syndrome; Heteropaternal Lemur Twins; Risk of Dental Caries/In the Media

The Rare Sides of Twin Research: Important to Remember/Twin Research Reviews: Representation of Self-Image; Twins With Kleine–Levin Syndrome; Heteropaternal Lemur Twins; Risk of Dental Caries/In the Media: High-Society Models; ‘Winkelevii’ Super Bowl Twins; Multiple Birth × Three; Twin Sister Surrogate; A Presidential Twin? Nancy L. Segal. Twin Research and Human Genetics, October 14 2019.

Abstract: This article explores some rare sides of twin research. The focus of this article is the sad plight of the Dionne quintuplets, born in Canada in 1934. However, several other studies belong in this category, such as Dr Josef Mengele’s horrifying twin research conducted at the Auschwitz concentration camp, Dr John Money’s misguided attempt to turn an accidentally castrated male twin into a female, Russian scientists’ cruel medical study of conjoined female twins and Dr Peter Neubauer’s secret project that tracked the development of separated twins. Reviews of current twin research span twins’ representation of self-image, twins with Kleine–Levin Syndrome, heteropaternal twinning in lemurs and factors affecting risk of dental caries. Media coverage includes a pair of high-society models, a book about the ‘Winkelevii’ twins, Super Bowl twin teammates, a family with three sets of fraternal twins, a twin sister surrogate and a near presidential twin.

Male Qualities and Likelihood of Orgasm in Women: Consistent findings regarding males who elicit orgasm more frequently pertain to their sexual behavior (being attentive, patient, & receptive to instruction) rather than their traits

Male Qualities and Likelihood of Orgasm. James M. Sherlock and Morgan J. Sidari. In T.K. Shackelford, V.A. Weekes-Shackelford (eds.), Springer Encyclopedia of Evolutionary Psychological Science, 2020,

Male traits and sexual behaviors that predict the likelihood of female orgasm.

In contrast to male orgasm, the female orgasm is enormously variable in frequency during penetrative sex. While men almost always ejaculate during penile-vaginal intercourse, women orgasm far less frequently from penetrative sex alone and experience significant variation in orgasm frequency with different partners (Lloyd 2005).  While variation in women.s orgasm frequency is poorly understood, evolutionary psychology tends to view variation in behavior as adaptive and responsive to environmental conditions.  Current evolutionary theories regarding the female orgasm can be broadly divided into two positions: those that focus on selection on male sexual function and those that focus on selection on female sexual function. The by-product hypothesis concerns the former and posits that the capacity of women to experience orgasm is a consequence of strong selection pressure on males' capacity to reach orgasm. This position is based on similarities between male and female orgasm as well as the observation that the male glans penis and female clitoris arise from homologous tissue during development. In contrast, the mate choice hypothesis argues that variation in female orgasm frequency during sexual intercourse is reflective of varying quality of their male partners. [...]

Mate-Choice Hypotheses of Female Orgasm
Given the high gestational cost of rearing human offspring women should be driven to select mates of high quality. Under the sire-choice hypothesis, quality tends to be defined as the ability to pass favorable genetic traits onto offspring (i.e., heritable traits) that will contribute to offspring fitness.  In contrast, the pair-bonding hypothesis postulates that male traits that are likely to benefit the woman through increased care and investment in offspring ought to promote orgasm. Traits that have been identified as theoretically important to each theory can be seen in Table 1 below.

Male Qualities and Likelihood of Orgasm, Table 1
Partner traits distinguishing mate-choice hypotheses (For review see Sherlock et al. 2016)

> Sire choice
Physical attractiveness - Height - Athleticism - Muscularity - Voice depth - Physical fitness - Humor - Creativity - Dominance - Body odor pleasantness

> Pair-bonding
Faithfulness - Warmth - Earning potential - Kindness

Mate-Choice Traits that Predict Orgasm Likelihood

The sire-choice hypothesis has been more extensively tested than the pair-bonding hypothesis and some evidence does suggest that women may be more likely to orgasm when their partner possesses traits putatively associated with genetic quality. [...]

Few studies to date have thoroughly investigated pair-bonding traits in the context of female orgasm frequency. However, Costa and Brody (2007) have observed that greater orgasm frequency is associated with overall relationship quality. [...]

Alternative Considerations
While some male traits have been reported to covary with orgasm frequency, this may not represent a causal relationship. Firstly, it is possible that women who orgasm more frequently may be more likely to select particular types of partners than women who orgasm infrequently. For example, women who report a higher orgasm frequency may choose to have sex with more physically attractive men. These men are likely to have more experience in short-term sexual relationships and therefore may be more effective at eliciting orgasm in their partners. [...]

Only one study to date has investigated how women.s orgasm frequencies have varied with different sexual partners. Sherlock et al. (2016) had single women with more than two male sexual partners report on a range of characteristics of the man with whom orgasm was the easiest and the man with whom orgasm was the most difficult (or did not occur at all). By comparing high- and low-orgasm men, several traits emerged as important in predicting ease of orgasm. High-orgasm men tended to be higher in humor, attractiveness, creativity, emotional warmth, faithfulness, and body odor pleasantness, consistent with both sire-choice and pair-bonding hypotheses.

Male Sexual Behavior
Importantly, Sherlock et al. (2016) also observed that a number of sexual behaviors differed between high- and low-orgasm males. Specifically, high-orgasm males were more likely to be focused on their partner.s pleasure, engage in oral sex, use sex toys, spend more time on foreplay, and stimulate their partner's clitoris during sex.  Women were also more likely to communicate their sexual position preferences and stimulate their clitoris when having sex with high-orgasm partners. [...] [...] Across all three studies, orgasm was more likely to occur with manual stimulation of the clitoris during intercourse (Frederick et al. 2017; Richters et al. 2006; Sherlock et al. 2016). Consequently, any contribution of male traits (e.g., attractiveness) to female orgasm needs to be considered in the context of variation in male sexual behavior. Further complicating these results is the likely association between male traits and sexual behaviors. [...]

Despite some consistency in male traits associated with orgasm across several studies, there is reason to be cautious interpreting these results without first accounting for male sexual behavior. The most prominent trait associated with increases in the likelihood of female orgasm is attractiveness (Andersson 1994; Gallup et al. 2014; Grammer et al. 2003; Shackelford et al. 2000; Sherlock et al.  2016), yet the causal pathway between attractiveness and female orgasm could be inverse to the current theorizing. That is, women could come to view their partners as more attractive if they are more frequent benefactors of orgasms. In sum, the most consistent findings regarding males who elicit orgasm more frequently pertain to their sexual behavior rather than their traits. Women are more likely to achieve orgasm with a partner who is attentive, patient, and receptive to instruction.

Female Mate Choice; Mate selection; Orgasm; Pair-bonding; The Evolution of Genitalia

Effects of the over-the-counter pain reliever acetaminophen, which can alter consumers’ emotional experiences and their economic behavior well beyond soothing their aches and pains, has also memory effects

Drug influences on consumer judgments: emerging insights and research opportunities from the intersection of pharmacology and psychology. Geoffrey R. O. Durso, Kelly L. Haws, Baldwin M. Way. Marketing Letters, October 10 2019.

Abstract: Recent evidence at the intersection of pharmacology and psychology suggests that pharmaceutical products and other drugs can exert previously unrecognized effects on consumers’ judgments, emotions, and behavior. We highlight the importance of a wider perspective for marketing science by proposing novel questions about how drugs might influence consumers. As a model for this framework, we review recently discovered effects of the over-the-counter pain reliever acetaminophen, which can alter consumers’ emotional experiences and their economic behavior well beyond soothing their aches and pains, and also present novel data on its memory effects. Observing effects of putatively benign over-the-counter medicines that extend beyond their originally approved usages suggests that many other drugs are also likely to influence processes relevant for consumers. The ubiquity of drug consumption—medical or recreational, legal or otherwise—underscores the importance of considering several novel research directions for understanding pharmacological-psychological interactions on consumer judgments, emotions, and behaviors.

Keywords: Decision making Emotion Memory Pharmaceuticals Substances Acetaminophen

Check also Conference Talk—SMPC 2019: Effect of Acetaminophen on Emotional Sounds. Lindsay A. Warrenburg. 2019.

Description: The capacity of listeners to perceive or experience emotions in response to music, speech, and natural sounds depends on many factors including dispositional traits, empathy, and enculturation. Emotional responses are also known to be mediated by pharmacological factors, including both legal and illegal drugs. Existing research has established that acetaminophen, a common over-the-counter pain medication, blunts emotional responses to visual stimuli (e.g., Durso, Luttrell, & Way, 2015). The current study extends this research by examining possible effects of acetaminophen on both perceived and felt responses to emotionally-charged sound stimuli. Additionally, it tests whether the effects of acetaminophen are specific for particular emotions (e.g., sadness, fear) or whether acetaminophen blunts emotional responses in general. Finally, the study tests whether acetaminophen has similar or differential effects on three categories of sound: music, speech, and natural sounds. The experiment employs a randomized, double-blind, parallel-group, placebo-controlled design. Participants are randomly assigned to ingest acetaminophen or a placebo. Then, the listeners are asked to complete two experimental blocks regarding musical and non-musical sounds. The first block asks participants to judge the extent to which a sound conveys a certain affect (on a Likert scale). The second block aims to examine a listener’s emotional responses to sound stimuli (also on a Likert scale). In light of the fact that some 50 million Americans take acetaminophen each week, this study suggests that future studies in music and emotion might consider controlling for the pharmacological state of participants.