Re-semblance and re-evolution: Paramorphism and semiotic co-option may explain the re-evolution of similar phenotypes

The independent emergence of similar features in phylogenetically nonallied groups of organisms has usually been explained as the result of similar selection pressures particular to specific environments. This explanation has been more or less helpful in elucidating convergent resemblances among organisms since the times of Darwin. Nevertheless, intensive research has brought new knowledge on the emergence of structural similarity among organisms, especially during the last two decades. We now have manifold evidence of the phenomena of evolutionary re-entries or re-evolution, which happens when a particularcharacter present in one organic taxon also appears in another taxon which does not share an immediate ancestry. This is not the re-appearance of the same character, but rather of a similar one. Here I propose a model of threefold origin of similar phenotypic features in unrelated organisms stemming from intrinsic, extrinsic and semiosic causation. It is suggested that neither externalist nor internalist explanations per se, nor any combination thereof, are sufficient to cover all the manifold instances of character re-evolution. There is also a special group of resemblances that consists of what is originated, shaped, and retained in evolution due to meaning attributed to them by particular organic subjects. These cases cannot be fully understood without inviting a biosemiotic approach. Integrating Uexküll’s theory of meaning with the recent evolutionary developmental perspective could complete our understanding of phenotypic re-evolution

Monsters we met, monsters we made: On the parallel emergence of phenotypic similarity under domestication

Creatures living under the rule of domestication form a communicative union based on shared morphological, behavioural, cognitive, and immunological resemblances. Domestic animals live under particular conditions that substantially differ from the original (natural) settings of their wild relatives. Here we focus on the fact that many parallel characters have appeared in various domestic forms that had been selected for different purposes. These characters are often unique for domestic animals and do not exist in wild forms. We argue that parallel similarities appear in different groups in response to their interaction with the umwelt of a particular host. In zoosemiotic sense, the process of domestication represents a kind of interaction in which both sides are affected and eventually transformed in such a way that one is more integrated with the other than in the time of initial encounter

Mutual understanding and misunderstanding in biological systems mediated by self-representational meaning of organisms

Modern biology gives many casuistic descriptions of mutual informational interconnections between organisms. Semiotic and hermeneutic processes in biosphere require a set of “sentient” community of players who optimize their living strategies to be able to stay in game. Perceptible surfaces of the animals, semantic organs, represent a special communicative interface that serves as an organ of self-representation of organic inwardness. This means that the innermost dimensions and potentialities of an organism may enter the senses of other living being when effectively expressed on the outermost surfaces of the former and meaningfully interpreted by the later. Moreover, semantic organs do not exist as objectively describable entities. They are always born via interpretative act and their actual form depends on both the potentialities of body plan of a bearer and the species-specific interpretation of a receiver. As such the semantic organs represent an important part of biological reality and thus deserve to be contextualized within existing comparative vocabulary. Here we argue that the study of the organic self-representation has a key importance for deeper insight into the evolution of communicative coupling among living beings

She Always Steps in the Same River: Similarity Among Long-Term Partners in Their Demographic, Physical, and Personality Characteristics

In mate choice, individuals consider a wide pool of potential partners. It has been found that people have certain preferences, but intraindividual stability of mate choice over time remains little explored. We tested individual consistency of mate choice with respect to a number of demographic, physical, and personality characteristics. Only mothers were recruited for this study, because we wanted to find out not only whether women choose long-term partners with certain characteristics but also whether the father of their child(ren) differs from their other long-term (ex-)partners. Women (N = 537) of 19–45 years of age indicated the demographic, physical (by using image stimuli), and personality characteristics of all of their long-term partners (partners per respondent: mean = 2.98, SD = 1.32). Then we compared the average difference between an individual’s long-term partners with the expected average difference using a permutation test. We also evaluated differences between partners who had children with the participants (fathers) and other long-term partners (non-fathers) using permutation tests and mixed-effect models. Our results revealed that women choose long-term partners consistently with respect to all types of characteristics. Although effect sizes for the individual characteristics were rather weak, maximal cumulative effect size for all characteristics together was high, which suggests that relatively low effect sizes were caused by high variability with low correlations between characteristics, and not by inconsistent mate choice. Furthermore, we found that despite some differences between partners, fathers of participants’ child(ren) do fit their ‘type’. These results suggest that mate choice may be guided by relatively stable but to some degree flexible preferences, which makes mate choice cognitively less demanding and less time-consuming. Further longitudinal studies are needed to confirm this conclusion

Human perception of fighting ability: facial cues predict winners in Mixed Martial Arts fights

In antagonistic encounters, the primary decision to be made is to fight or not. Animals may then possess adaptations to assess fighting ability in their opponents. Previous studies suggest that humans can assess strength and fighting ability based on facial appearance. Here we extend these findings to specific contests by examining the perception of male faces from paired winners and losers of individual fights in mixed martial arts sporting competitions. Observers, unfamiliar with the outcome, were presented with image pairs and asked to choose which of the 2 men was more likely to win if they fought while other observers chose between the faces based on masculinity, strength, aggressiveness, and attractiveness. We found that individuals performed at rates above chance in correctly selecting the winner as more likely to win the fight than the loser. We also found that winners were seen to be more masculine, stronger, and more aggressive than losers. Finally, women saw the winners as more attractive than the losers. Together these findings demonstrate that 1) humans can predict the outcome of specific fighting contests based on facial cues, 2) perceived masculinity and strength are putative cues to fighting success available from faces, and 3) facial cues associated with successful male–male competition are attractive to women

Toward a New Approach to Cross-Cultural Distinctiveness and Typicality of Human Faces: The Cross-Group Typicality/ Distinctiveness Metric

In the present research, we took advantage of geometric morphometrics to propose a data-driven method for estimating the individual degree of facial typicality/distinctiveness for cross-cultural (and other cross-group) comparisons. Looking like a stranger in one’s home culture may be somewhat stressful. The same facial appearance, however, might become advantageous within an outgroup population. To address this fit between facial appearance and cultural setting, we propose a simple measure of distinctiveness/typicality based on position of an individual along the axis connecting the facial averages of two populations under comparison. The more distant a face is from its ingroup population mean toward the outgroup mean the more distinct it is (vis-à-vis the ingroup) and the more it resembles the outgroup standards. We compared this new measure with an alternative measure based on distance from outgroup mean. The new measure showed stronger association with rated facial distinctiveness than distance from outgroup mean. Subsequently, we manipulated facial stimuli to reflect different levels of ingroup-outgroup distinctiveness and tested them in one of the target cultures. Perceivers were able to successfully distinguish outgroup from ingroup faces in a two-alternative forced-choice task. There was also some evidence that this task was harder when the two faces were closer along the axis connecting the facial averages from the two cultures. Future directions and potential applications of our proposed approach are discussed

Predictors of Fighting Ability Inferences Based on Faces

Facial perception plays a key role in various social interactions, including formidability assessments. People make relatively accurate inferences about men's physical strength, aggressiveness, and success in physical confrontations based on facial cues. The physical factors related to the perception of fighting ability and their relative contribution have not been investigated yet, since most existing studies employed only a limited number of threat potential measures or proxies. In the present study, we collected data from Czech Mixed Martial Arts (MMA) fighters regarding their fighting success and physical performance in order to test physical predictors of perceived fighting ability made on the basis of high-fidelity facial photographs. We have also explored the relationship between perceived and actual fighting ability. We created standardized 360° photographs of 44 MMA fighters which were assessed on their perceived fighting ability by 94 raters (46 males). Further, we obtained data regarding their physical characteristics (e.g., age, height, body composition) and performance (MMA score, isometric strength, anaerobic performance, lung capacity). In contrast to previous studies, we did not find any significant links between the actual and the perceived fighting ability. The results of a multiple regression analysis have, however, shown that heavier fighters and those with higher anaerobic performance were judged as more successful. Our results suggest that certain physical performance-related characteristics are mirrored in individuals' faces but assessments of fighting success based on facial cues are not congruent with actual fighting performance

Like Father, Like Child? Paternal Age at Birth and Offspring's Facial Asymmetry and Distinctiveness

Paternal age at birth, a potential proxy of mutation load transmitted to the offspring, has previously been related to the offspring’s health, biological condition and reproductive potential. As higher facial asymmetry and distinctiveness serve as putative markers of the lower genetic quality of an individual, we hypothesize that more advanced paternal age at birth will be related to children’s higher levels of facial asymmetry and distinctiveness. To the best of our knowledge, this is the first study evaluating the link between paternal age at birth and facial asymmetry in offspring. Based on archived photographs of 159 children born within 47 Polish families, we have conducted facial geometric morphometric measurements and calculated the levels of facial asymmetry and distinctiveness. The relationship between paternal age at birth and the offspring’s facial features was explored with the use of Bayesian Linear Mixed-effects Models, controlling for sex, age and birth order of the offspring, and maternal age at child’s birth. No associations between paternal age at birth and facial asymmetry or distinctiveness in children were found. The lack of such a relationship might be a result of the potentially insufficient influence of newly accumulated paternal mutations affecting the offspring’s phenotype or higher importance of maternal (prenatal) and postnatal environments in shaping facial features

Men’s preferences for women’s breast size and shape in four cultures

The morphology of human female breasts typical for their permanent fat deposits appears to be unique among primates. It has been previously suggested that female breast morphology arose as a result of sexual selection. This is supported by evidence showing that women with larger breasts tend to have higher estrogen levels; breast size may therefore serve as an indicator of potential fertility. However, breasts become less firm with age and parity, and breast shape could thus also serve as a marker of residual fertility. Therefore, cross-culturally, males are hypothesized to prefer breast morphology that indicates both high potential and residual fertility. To test this, we performed a survey on men´s preferences for breast morphology in four different cultures (Brazil, Cameroon, the Czech Republic, Namibia). As stimuli, we used two sets of images varying in breast size (marker of potential fertility) and level of breast firmness (marker of residual fertility). Individual preferences for breast size were variable, but the majority of raters preferred medium sized, followed by large sized breasts. In contrast, we found systematic directional preferences for firm breasts across all four samples. This pattern supports the idea that breast morphology may serve as a residual fertility indicator, but offers more limited support for the potential fertility indicator hypothesis. Future studies should focus on a potential interaction between the two parameters, breast size and firmness, which, taken together, may help to explain the relatively large variation in women's breast sizes