Alexandra Alvergne | University of Oxford (original) (raw)

Papers by Alexandra Alvergne

PLOS Biology, Dec 5, 2019

Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologist... more Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormonedependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.

Open Psychology

Sexual prejudice and its negative consequences remain major issues in Western societies, and nume... more Sexual prejudice and its negative consequences remain major issues in Western societies, and numerous studies have tried to pinpoint its sociocultural underpinnings. However, most research has operationalized sexual prejudice via self-report measures or via implicit association tests (IATs), although it surfaces in language use and can be traced in spontaneous speech. Here, we report results from an experimental study investigating sexual prejudice in a corpus of spontaneous speech samples. Specifically, we tested in a context-sensitive sentiment analysis approach which attitudes (negative vs. positive) and emotions (joy, sadness, anger, fear, disgust) were voiced by the participants in response to picture prompts displaying homosexual couples. We also considered the sociocultural basis of prejudicial attitudes, in particular the effects of the participants’ cultural background (France vs. Maghreb), age and gender. We find strong effects of cultural background and gender both on the...

Frontiers in Ecology and Evolution

Reproduction is one of the most energetically demanding life-history stages. As a result, breedin... more Reproduction is one of the most energetically demanding life-history stages. As a result, breeding individuals often experience trade-offs, where energy is diverted away from maintenance (cell repair, immune function) toward reproduction. While it is increasingly acknowledged that oncogenic processes are omnipresent, evolving and opportunistic entities in the bodies of metazoans, the associations among reproductive activities, energy expenditure, and the dynamics of malignant cells have rarely been studied. Here, we review the diverse ways in which age-specific reproductive performance (e.g., reproductive aging patterns) and cancer risks throughout the life course may be linked via trade-offs or other mechanisms, as well as discuss situations where trade-offs may not exist. We argue that the interactions between host–oncogenic processes should play a significant role in life-history theory, and suggest some avenues for future research.

Data: corpus_integral.csv FEEL_1.csv mauvais.txt neg_hetero_corrected.txt participant_info_used.t... more Data: corpus_integral.csv FEEL_1.csv mauvais.txt neg_hetero_corrected.txt participant_info_used.txt pos_hetero_corrected.txt R script: polarities.R sentiments_discrete.R

Sexual stereotyping and its negative consequences remain major issues in Western societies. Sexua... more Sexual stereotyping and its negative consequences remain major issues in Western societies. Sexual prejudice is often nurtured by the socio-cultural background in which individuals grow up, making differences in sexual prejudice especially visible in multicultural societies. In France, one example of such a multicultural society with a high number of French citizens with recent migratory background from Maghreb, the socio-cultural basis of sexual prejudice has largely remained unexplored. Here, we report results from an experimental study investigating sexual stereotyping in France. We base our analyses on an elicited corpus of spontaneous speech samples. We consider in particular the effects of the participants’ cultural background (France vs. Maghreb), age and gender on the expression of prejudicial attitudes. Specifically, we tested in a context-sensitive sentiment analysis approach which attitudes (negative vs. positive) and emotions (joy, sadness, anger, fear, disgust) were voi...

PLOS Biology, 2019

Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologist... more Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormonedependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.

Recent estimates indicate half of Ethiopian girls aged 15 to 19 have experienced female genital m... more Recent estimates indicate half of Ethiopian girls aged 15 to 19 have experienced female genital mutilation/cutting (FGMC). Establishing whether and how pro-FGMC norms are maintained through social transmission is a key priority for global eradication efforts. Here, we present the first large-scale socio-centric social network study estimating social influence and social selection on preference for cutting female relatives using data from 5163 Ethiopian Arsi Oromo adults. Bayesian modelling, which accounts for network dependence in cross-sectional data, finds signals of 'contagion' within chatting, respect, and money-borrowing networks. This indicates social influence contributes to FGMC maintenance. We find no clear evidence of social selection within marriage advice networks, suggesting these networks are not implicated in FGMC maintenance. Contrary to assumptions underpinning current eradication efforts, we find negligible evidence that FGMC is a social-coordination norm (with only 6.3% endorsement), or an empirical or normative expectation. We conclude by making intervention design recommendations.

Proceedings. Biological sciences / The Royal Society, Jan 7, 2014

The negative wealth-fertility relationship brought about by market integration remains a puzzle t... more The negative wealth-fertility relationship brought about by market integration remains a puzzle to classic evolutionary models. Evolutionary ecologists have argued that this phenomenon results from both stronger trade-offs between reproductive and socioeconomic success in the highest social classes and the comparison of groups rather than individuals. Indeed, studies in contemporary low fertility settings have typically used aggregated samples that may mask positive wealth-fertility relationships. Furthermore, while much evidence attests to trade-offs between reproductive and socioeconomic success, few studies have explicitly tested the idea that such constraints are intensified by market integration. Using data from Mongolia, a post-socialist nation that underwent mass privatization, we examine wealth-fertility relationships over time and across a rural-urban gradient. Among post-reproductive women, reproductive fitness is the lowest in urban areas, but increases with wealth in all...

Evolutionary Thinking in Medicine, 2016

Evolutionary Human Sciences

Evolutionary perspectives on menopause have focused on explaining why early reproductive cessatio... more Evolutionary perspectives on menopause have focused on explaining why early reproductive cessation in females has emerged and why it is rare throughout the animal kingdom, but less attention has been given to exploring patterns of diversity in age at natural menopause. In this paper, we aim to generate new hypotheses for understanding human patterns of diversity in this trait, defined as age at final menstrual period. To do so, we develop a multilevel, interdisciplinary framework, combining proximate, physiological understandings of ovarian ageing with ultimate, evolutionary perspectives on ageing. We begin by reviewing known patterns of diversity in age at natural menopause in humans, and highlight issues in how menopause is currently defined and measured. Second, we consider together ultimate explanations of menopause timing and proximate understandings of ovarian ageing. We find that ovarian ageing is highly constrained by ageing of the folliclethe somatic structure containing the oocytesuggesting that menopause timing might be best understood as a by-product of ageing rather than a facultative adaptation. Third, we investigate whether the determinants of somatic senescence also underpin menopause timing. We show that diversity in age at menopause can be, at least partly, explained by the genetic, ecological and life-history determinants of somatic ageing. The public health implications of rethinking menopause as the by-product rather than the catalyst of biological ageing are discussed.

Trends in Ecology & Evolution

Evolution, Medicine, and Public Health

Background and objectives: The underlying reasons why some women experience debilitating premenst... more Background and objectives: The underlying reasons why some women experience debilitating premenstrual symptoms and others do not are largely unknown. Here, we test the evolutionary ecological hypothesis that some negative premenstrual symptoms may be exacerbated by the presence of chronic sexually transmitted infections (STIs). Methodology: 34 511 women were recruited through a digital period-tracker app. Participants were asked: (i) Have you ever been diagnosed with a STI? (ii) If yes, when was it, and were you given treatment? Those data were combined with longitudinal cycle data on menstrual bleeding patterns, the experience of pain and emotions and hormonal contraceptive use. Results: 865 women had at least two complete menstrual cycle data and were eligible for analysis. Before diagnosis, the presence of an infection predicts a ca. 2-fold increase in the odds of reporting both headache, cramps and sadness during the late luteal phase and sensitive emotions during the wider luteal phase. After diagnosis, the odds of reporting negative symptoms pre-menstrually remain unchanged among STI negative individuals, but the odds of reporting sensitive emotions decrease among STI positive individuals receiving a treatment. No relationships between STIs, pain and emotions are observed among hormonal contraceptive users. Conclusions and implications: The results support the idea that a negative premenstrual experience might be aggravated by the presence of undiagnosed STIs, a leading cause of infertility worldwide. Caution is warranted in extrapolating the results as the data are self-reported, inflammatory levels are unknown and the tracker is biased towards recording negative premenstrual symptoms among Western individuals.

Background: Contraceptive discontinuation is a major barrier to reducing global unmet needs for f... more Background: Contraceptive discontinuation is a major barrier to reducing global unmet needs for family planning, but the reasons why women discontinue contraception are poorly understood. Here we use data from Ethiopia to investigate (i) the magnitude of contraceptive discontinuation in 2005-2011, (ii) how the risk of discontinuation varies with method type and education level and (iii) the barriers to continuation. Our main hypothesis is that contraceptive discontinuation is driven by the experience of physiological side-effects associated with the use of hormonal contraception, rather than a lack of education. Methods: We used a mixed methods explanatory sequential design to explain the quantitative results in more details through the qualitative data. First, we analysed quantitative data from the 2011 Ethiopian Demographic and Health Survey to study patterns of contraceptive discontinuation and method choice using multilevel multiprocess models. Second, we conducted semi-structur...

Trends in Ecology and Evolution, Mar 31, 2010

Female and male mate choice preferences in humans both vary according to the menstrual cycle. Wom... more Female and male mate choice preferences in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with other phases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to bring evolutionary benefits in terms of reproductive success. New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences. Here, we review support for such conclusions and speculate on the consequences of pillinduced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes.

Journal of Evolutionary Psychology, 2008

PLOS ONE, 2015

Theoretical studies predict that it is not possible to eradicate a disease under voluntary vaccin... more Theoretical studies predict that it is not possible to eradicate a disease under voluntary vaccination because of the emergence of non-vaccinating "free-riders" when vaccination coverage increases. A central tenet of this approach is that human behaviour follows an economic model of rational choice. Yet, empirical studies reveal that vaccination decisions do not necessarily maximize individual self-interest. Here we investigate the dynamics of vaccination coverage using an approach that dispenses with payoff maximization and assumes that risk perception results from the interaction between epidemiology and cognitive biases. We consider a behaviour-incidence model in which individuals perceive actual epidemiological risks as a function of their opinion of vaccination. As a result of confirmation bias, sceptical individuals (negative opinion) overestimate infection cost while pro-vaccines individuals (positive opinion) overestimate vaccination cost. We considered a feedback between individuals and their environment as individuals could change their opinion, and thus the way they perceive risks, as a function of both the epidemiology and the most common opinion in the population. For all parameter values investigated, the infection is never eradicated under voluntary vaccination. For moderately contagious diseases, oscillations in vaccination coverage emerge because individuals process epidemiological information differently depending on their opinion. Conformism does not generate oscillations but slows down the cultural response to epidemiological change. Failure to eradicate vaccine preventable disease emerges from the model because of cognitive biases that maintain heterogeneity in how people perceive risks. Thus, assumptions of economic rationality and payoff maximization are not mandatory for predicting commonly observed dynamics of vaccination coverage. This model shows that alternative notions of rationality, such as that of ecological rationality whereby individuals use simple cognitive heuristics, offer promising new avenues for modelling vaccination behaviour.

Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior, 2011

Male-male competition can shape some behavioral or morphological traits of males. Here we investi... more Male-male competition can shape some behavioral or morphological traits of males. Here we investigate if this competition could play a role in the persistence of the polymorphism of handedness in human populations. A negative frequency-dependent selection mechanism has been hypothesized, based on the fact that left-handed men may benefit from a "surprise" advantage during fighting interactions because they are rare in human populations. This advantage may thereby enhance the probability of survival of left- handed men and/or their reproductive success through an increase in social status. In this study, we first explored the association between hand preference and lifetime fighting behavior in a population of 1,161 French men. No effect of hand preference on the probability of fighting was detected, suggesting that the innate propensity to fight does not differ between left- and right-handers. However, among men who had been involved in at least one fight during their life...

PLOS Biology, Dec 5, 2019

Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologist... more Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormonedependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.

Open Psychology

Sexual prejudice and its negative consequences remain major issues in Western societies, and nume... more Sexual prejudice and its negative consequences remain major issues in Western societies, and numerous studies have tried to pinpoint its sociocultural underpinnings. However, most research has operationalized sexual prejudice via self-report measures or via implicit association tests (IATs), although it surfaces in language use and can be traced in spontaneous speech. Here, we report results from an experimental study investigating sexual prejudice in a corpus of spontaneous speech samples. Specifically, we tested in a context-sensitive sentiment analysis approach which attitudes (negative vs. positive) and emotions (joy, sadness, anger, fear, disgust) were voiced by the participants in response to picture prompts displaying homosexual couples. We also considered the sociocultural basis of prejudicial attitudes, in particular the effects of the participants’ cultural background (France vs. Maghreb), age and gender. We find strong effects of cultural background and gender both on the...

Frontiers in Ecology and Evolution

Reproduction is one of the most energetically demanding life-history stages. As a result, breedin... more Reproduction is one of the most energetically demanding life-history stages. As a result, breeding individuals often experience trade-offs, where energy is diverted away from maintenance (cell repair, immune function) toward reproduction. While it is increasingly acknowledged that oncogenic processes are omnipresent, evolving and opportunistic entities in the bodies of metazoans, the associations among reproductive activities, energy expenditure, and the dynamics of malignant cells have rarely been studied. Here, we review the diverse ways in which age-specific reproductive performance (e.g., reproductive aging patterns) and cancer risks throughout the life course may be linked via trade-offs or other mechanisms, as well as discuss situations where trade-offs may not exist. We argue that the interactions between host–oncogenic processes should play a significant role in life-history theory, and suggest some avenues for future research.

Data: corpus_integral.csv FEEL_1.csv mauvais.txt neg_hetero_corrected.txt participant_info_used.t... more Data: corpus_integral.csv FEEL_1.csv mauvais.txt neg_hetero_corrected.txt participant_info_used.txt pos_hetero_corrected.txt R script: polarities.R sentiments_discrete.R

Sexual stereotyping and its negative consequences remain major issues in Western societies. Sexua... more Sexual stereotyping and its negative consequences remain major issues in Western societies. Sexual prejudice is often nurtured by the socio-cultural background in which individuals grow up, making differences in sexual prejudice especially visible in multicultural societies. In France, one example of such a multicultural society with a high number of French citizens with recent migratory background from Maghreb, the socio-cultural basis of sexual prejudice has largely remained unexplored. Here, we report results from an experimental study investigating sexual stereotyping in France. We base our analyses on an elicited corpus of spontaneous speech samples. We consider in particular the effects of the participants’ cultural background (France vs. Maghreb), age and gender on the expression of prejudicial attitudes. Specifically, we tested in a context-sensitive sentiment analysis approach which attitudes (negative vs. positive) and emotions (joy, sadness, anger, fear, disgust) were voi...

PLOS Biology, 2019

Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologist... more Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormonedependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.

Recent estimates indicate half of Ethiopian girls aged 15 to 19 have experienced female genital m... more Recent estimates indicate half of Ethiopian girls aged 15 to 19 have experienced female genital mutilation/cutting (FGMC). Establishing whether and how pro-FGMC norms are maintained through social transmission is a key priority for global eradication efforts. Here, we present the first large-scale socio-centric social network study estimating social influence and social selection on preference for cutting female relatives using data from 5163 Ethiopian Arsi Oromo adults. Bayesian modelling, which accounts for network dependence in cross-sectional data, finds signals of 'contagion' within chatting, respect, and money-borrowing networks. This indicates social influence contributes to FGMC maintenance. We find no clear evidence of social selection within marriage advice networks, suggesting these networks are not implicated in FGMC maintenance. Contrary to assumptions underpinning current eradication efforts, we find negligible evidence that FGMC is a social-coordination norm (with only 6.3% endorsement), or an empirical or normative expectation. We conclude by making intervention design recommendations.

Proceedings. Biological sciences / The Royal Society, Jan 7, 2014

The negative wealth-fertility relationship brought about by market integration remains a puzzle t... more The negative wealth-fertility relationship brought about by market integration remains a puzzle to classic evolutionary models. Evolutionary ecologists have argued that this phenomenon results from both stronger trade-offs between reproductive and socioeconomic success in the highest social classes and the comparison of groups rather than individuals. Indeed, studies in contemporary low fertility settings have typically used aggregated samples that may mask positive wealth-fertility relationships. Furthermore, while much evidence attests to trade-offs between reproductive and socioeconomic success, few studies have explicitly tested the idea that such constraints are intensified by market integration. Using data from Mongolia, a post-socialist nation that underwent mass privatization, we examine wealth-fertility relationships over time and across a rural-urban gradient. Among post-reproductive women, reproductive fitness is the lowest in urban areas, but increases with wealth in all...

Evolutionary Thinking in Medicine, 2016

Evolutionary Human Sciences

Evolutionary perspectives on menopause have focused on explaining why early reproductive cessatio... more Evolutionary perspectives on menopause have focused on explaining why early reproductive cessation in females has emerged and why it is rare throughout the animal kingdom, but less attention has been given to exploring patterns of diversity in age at natural menopause. In this paper, we aim to generate new hypotheses for understanding human patterns of diversity in this trait, defined as age at final menstrual period. To do so, we develop a multilevel, interdisciplinary framework, combining proximate, physiological understandings of ovarian ageing with ultimate, evolutionary perspectives on ageing. We begin by reviewing known patterns of diversity in age at natural menopause in humans, and highlight issues in how menopause is currently defined and measured. Second, we consider together ultimate explanations of menopause timing and proximate understandings of ovarian ageing. We find that ovarian ageing is highly constrained by ageing of the folliclethe somatic structure containing the oocytesuggesting that menopause timing might be best understood as a by-product of ageing rather than a facultative adaptation. Third, we investigate whether the determinants of somatic senescence also underpin menopause timing. We show that diversity in age at menopause can be, at least partly, explained by the genetic, ecological and life-history determinants of somatic ageing. The public health implications of rethinking menopause as the by-product rather than the catalyst of biological ageing are discussed.

Trends in Ecology & Evolution

Evolution, Medicine, and Public Health

Background and objectives: The underlying reasons why some women experience debilitating premenst... more Background and objectives: The underlying reasons why some women experience debilitating premenstrual symptoms and others do not are largely unknown. Here, we test the evolutionary ecological hypothesis that some negative premenstrual symptoms may be exacerbated by the presence of chronic sexually transmitted infections (STIs). Methodology: 34 511 women were recruited through a digital period-tracker app. Participants were asked: (i) Have you ever been diagnosed with a STI? (ii) If yes, when was it, and were you given treatment? Those data were combined with longitudinal cycle data on menstrual bleeding patterns, the experience of pain and emotions and hormonal contraceptive use. Results: 865 women had at least two complete menstrual cycle data and were eligible for analysis. Before diagnosis, the presence of an infection predicts a ca. 2-fold increase in the odds of reporting both headache, cramps and sadness during the late luteal phase and sensitive emotions during the wider luteal phase. After diagnosis, the odds of reporting negative symptoms pre-menstrually remain unchanged among STI negative individuals, but the odds of reporting sensitive emotions decrease among STI positive individuals receiving a treatment. No relationships between STIs, pain and emotions are observed among hormonal contraceptive users. Conclusions and implications: The results support the idea that a negative premenstrual experience might be aggravated by the presence of undiagnosed STIs, a leading cause of infertility worldwide. Caution is warranted in extrapolating the results as the data are self-reported, inflammatory levels are unknown and the tracker is biased towards recording negative premenstrual symptoms among Western individuals.

Background: Contraceptive discontinuation is a major barrier to reducing global unmet needs for f... more Background: Contraceptive discontinuation is a major barrier to reducing global unmet needs for family planning, but the reasons why women discontinue contraception are poorly understood. Here we use data from Ethiopia to investigate (i) the magnitude of contraceptive discontinuation in 2005-2011, (ii) how the risk of discontinuation varies with method type and education level and (iii) the barriers to continuation. Our main hypothesis is that contraceptive discontinuation is driven by the experience of physiological side-effects associated with the use of hormonal contraception, rather than a lack of education. Methods: We used a mixed methods explanatory sequential design to explain the quantitative results in more details through the qualitative data. First, we analysed quantitative data from the 2011 Ethiopian Demographic and Health Survey to study patterns of contraceptive discontinuation and method choice using multilevel multiprocess models. Second, we conducted semi-structur...

Trends in Ecology and Evolution, Mar 31, 2010

Female and male mate choice preferences in humans both vary according to the menstrual cycle. Wom... more Female and male mate choice preferences in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with other phases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to bring evolutionary benefits in terms of reproductive success. New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences. Here, we review support for such conclusions and speculate on the consequences of pillinduced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes.

Journal of Evolutionary Psychology, 2008

PLOS ONE, 2015

Theoretical studies predict that it is not possible to eradicate a disease under voluntary vaccin... more Theoretical studies predict that it is not possible to eradicate a disease under voluntary vaccination because of the emergence of non-vaccinating "free-riders" when vaccination coverage increases. A central tenet of this approach is that human behaviour follows an economic model of rational choice. Yet, empirical studies reveal that vaccination decisions do not necessarily maximize individual self-interest. Here we investigate the dynamics of vaccination coverage using an approach that dispenses with payoff maximization and assumes that risk perception results from the interaction between epidemiology and cognitive biases. We consider a behaviour-incidence model in which individuals perceive actual epidemiological risks as a function of their opinion of vaccination. As a result of confirmation bias, sceptical individuals (negative opinion) overestimate infection cost while pro-vaccines individuals (positive opinion) overestimate vaccination cost. We considered a feedback between individuals and their environment as individuals could change their opinion, and thus the way they perceive risks, as a function of both the epidemiology and the most common opinion in the population. For all parameter values investigated, the infection is never eradicated under voluntary vaccination. For moderately contagious diseases, oscillations in vaccination coverage emerge because individuals process epidemiological information differently depending on their opinion. Conformism does not generate oscillations but slows down the cultural response to epidemiological change. Failure to eradicate vaccine preventable disease emerges from the model because of cognitive biases that maintain heterogeneity in how people perceive risks. Thus, assumptions of economic rationality and payoff maximization are not mandatory for predicting commonly observed dynamics of vaccination coverage. This model shows that alternative notions of rationality, such as that of ecological rationality whereby individuals use simple cognitive heuristics, offer promising new avenues for modelling vaccination behaviour.

Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior, 2011

Male-male competition can shape some behavioral or morphological traits of males. Here we investi... more Male-male competition can shape some behavioral or morphological traits of males. Here we investigate if this competition could play a role in the persistence of the polymorphism of handedness in human populations. A negative frequency-dependent selection mechanism has been hypothesized, based on the fact that left-handed men may benefit from a "surprise" advantage during fighting interactions because they are rare in human populations. This advantage may thereby enhance the probability of survival of left- handed men and/or their reproductive success through an increase in social status. In this study, we first explored the association between hand preference and lifetime fighting behavior in a population of 1,161 French men. No effect of hand preference on the probability of fighting was detected, suggesting that the innate propensity to fight does not differ between left- and right-handers. However, among men who had been involved in at least one fight during their life...