bims-chumac 2022-02-20 papers

Issue of 2022–02–20
five papers selected by
Thomas Krichel, Open Library Society

Elife. 2022 Feb 18. pii: e65031. [Epub ahead of print]11

A meta-analysis of the association between male dimorphism and fitness outcomes in humans.

Linda H Lidborg, Catharine Penelope Cross, Lynda G Boothroyd.

Humans are sexually dimorphic: men and women differ in body build and composition, craniofacial structure, and voice pitch, likely mediated in part by developmental testosterone. Sexual selection hypotheses posit that, ancestrally, more 'masculine' men may have acquired more mates and/or sired more viable offspring. Thus far, however, evidence for either association is unclear. Here, we meta-analyze the relationships between six masculine traits and mating/reproductive outcomes (96 studies, 474 effects, N = 177,044). Voice pitch, height, and testosterone all predicted mating; however, strength/muscularity was the strongest and only consistent predictor of both mating and reproduction. Facial masculinity and digit ratios did not significantly predict either. There was no clear evidence for any effects of masculinity on offspring viability. Our findings support arguments that strength/muscularity may be sexually selected in humans, but cast doubt regarding selection for other forms of masculinity and highlight the need to increase tests of evolutionary hypotheses outside of industrialized populations.

Keywords: evolutionary biology; human

DOI: https://doi.org/10.7554/eLife.65031

Int J Environ Res Public Health. 2022 Jan 29. pii: 1535. [Epub ahead of print]19(3):

Mobile Dating Applications and the Sexual Self: A Cluster Analysis of Users' Characteristics.

Alexandru Mateizer, Eugen Avram.

The online environment has had a profound sociocultural impact, and its implications pose new challenges to modern-day societies. The digital sexual and dating domains have dramatically affected sexual and romantic behavior and norms, and yet, no empirical studies have addressed the role of the sexual self-concept in driving sexual and romantic online behavior. The aim of this study is to identify reliable sexual self-configurations through a cluster analysis approach and determine whether these profiles are informative in relation to app use motives and sexual outcomes. For this purpose, a total of 244 subjects were recruited. Survey questions measured a set of demographic parameters, motives for app use, online sexual activities, attachment orientations, the sexual self-concept and sexual satisfaction. Five clusters were identified, including two with high levels of sexual drive ("Driven" and "Adventurous"), two with low levels of sexual drive ("Unassured" and "Naïve") and one with an intermediate level of sexual drive ("Competent"). The clusters differed on gender, attachment styles, app use patterns and sexual characteristics. These findings provide insight into how the sexual self-concept relates to the interaction between individuals and the online sexual and dating scenes.

Keywords: cluster analysis; dating; mobile dating applications; online sexual activities; sexual satisfaction; sexual self

DOI: https://doi.org/10.3390/ijerph19031535

Proc Biol Sci. 2022 Feb 23. 289(1969): 20212476

More than just a pretty face? The relationship between immune function and perceived facial attractiveness.

Summer Mengelkoch, Jeff Gassen, Marjorie L Prokosch, Gary W Boehm, Sarah E Hill.

It has long been hypothesized that attractiveness provides a cue to a target's health and immunocompetence. However, much of the research testing this hypothesis has relied on a small number of indirect proxies of immune function, and the results of this research have been mixed. Here, we build on this past research, examining the relationship between target attractiveness and (i) self-reported health, (ii) in vivo measures of inflammation and white blood cell count/composition, and (iii) in vitro tests of targets' immune function, including (c1) leucocyte proliferation in response to immunological stimulants, (c2) phagocytosis of Escherichia coli bioparticles, (c3) NK cell-mediated lysis of target tumour cells, and (c4) Staphylococcus aureus growth in isolated plasma. Results revealed multiple, sometimes sex-differentiated, relationships between targets' immune function and others' perceptions of their attractiveness. Together, this work suggests complex, often sex-differentiated relationships between immune function, health, and attractiveness.

Keywords: attractiveness; evolution; health; immune function; sex differences; sexual selection

DOI: https://doi.org/10.1098/rspb.2021.2476

Cogn Res Princ Implic. 2022 Feb 16. 7(1): 17

Are estimates of faces' ages less accurate when they wear sunglasses or face masks and do these disguises make it harder to later recognise the faces when undisguised?

Craig Thorley, Benjamin Acton, Jesse Armstrong, Shanade Ford, Margaret Gundry.

This study examined whether our ability to accurately estimate unfamiliar faces' ages declines when they are wearing sunglasses or surgical-style face masks and whether these disguises make it harder to later recognise those faces when undisguised. In theory, both disguises should harm age estimation accuracy and later face recognition as they occlude facial information that is used to determine a face's age and identity. To establish whether this is the case, we had participants estimate the age of unfamiliar faces that were pictured wearing no disguises, sunglasses, or face masks. The participants then completed a face recognition test where they had to distinguish between the previously seen faces and new faces. Importantly, none of faces wore disguises in this latter test. Participants' estimates of the undisguised faces' ages were inaccurate by a Median of 5.15 years. Their accuracy barely changed when the faces wore sunglasses but declined by a Median of 1.30 years when they wore face masks. Moreover, subsequent undisguised face recognition was less likely to occur when the faces previously wore sunglasses or face masks, with large effects observed. These findings demonstrate the relative importance of different facial areas when estimating faces' ages and later recognising them. They also have implications for policing as they suggest it may be harder for eyewitnesses to accurately estimate the age of criminals who wear face masks during offences, and it may be harder for them to later recognise criminals in line-ups if the criminals wear sunglasses or face masks during offences.

Keywords: Age estimation; Age perception; COVID-19; Disguises; Face masks; Face recognition; Sunglasses

DOI: https://doi.org/10.1186/s41235-022-00370-0

Animals (Basel). 2022 Jan 19. pii: 230. [Epub ahead of print]12(3):

Wanna See My Dog Pic? A Comparative Observational Study of the Presentation of Animals on Online Dating Profiles in Vienna and Tokyo.

Christian Dürnberger, Svenja Springer.

Online dating applications offer new ways for people to search for social contacts. While previous studies have indicated that the inclusion of animals in profiles can increase users' dating success rates, the question of how many users display animals, and what kinds of animals are shown on dating profiles, has not yet been empirically investigated. Using a structured observational study of profiles in Vienna and Tokyo on a popular online dating app (n = 2400), we therefore looked at how many profiles show animals and what kinds of animals are shown. We found that 15.5% of the investigated profiles had at least one photo showing an animal. In both cities, dogs were the most frequently shown animal. Taking the cities together, they appeared in 46.4% of the animal pictures, as compared with cats at 25.7%. Other animals such as exotic animals (9.9%), farm animals (6.4%) or horses (4.6%) played a minor role. Users were significantly more likely to show cats in Tokyo (35.8%) than they were in Vienna (18.0%). We found that users in Vienna; women; and older adults were more likely to present animals on their profiles than were users in Tokyo; men; and younger users. Sexual orientation showed no significant differences in the analyses.

Keywords: cats; dogs; human–animal relationship; observational study; online dating application

DOI: https://doi.org/10.3390/ani12030230