A parasitic selfish gene that affects host promiscuity

Selfish genes demonstrate transmission bias and invade sexual populations despite conferring no benefit to their hosts. While the molecular genetics and evolutionary dynamics of selfish genes are reasonably well characterized, their effects on hosts are not. Homing endonuclease genes (HEGs) are one well-studied family of selfish genes that are assumed to be benign. However, we show that carrying HEGs is costly for Saccharomyces cerevisiae, demonstrating that these genetic elements are not necessarily benign but maybe parasitic. We estimate a selective load of approximately 1-2 in 'natural' niches. The second aspect we examine is the ability of HEGs to affect hosts' sexual behaviour. As all selfish genes critically rely on sex for spread, then any selfish gene correlated with increased host sexuality will enjoy a transmission advantage. While classic parasites are known to manipulate host behaviour, we are not aware of any evidence showing a selfish gene is capable of affecting host promiscuity. The data presented here show a selfish element may increase the propensity of its eukaryote host to undergo sex and along with increased rates of non-Mendelian inheritance, this may counterbalance mitotic selective load and promote spread. Demonstration that selfish genes are correlated with increased promiscuity in eukaryotes connects with ideas suggesting that selfish genes promoted the evolution of sex initially. © 2013 The Authors Published by the Royal Society. All rights reserved

Anthropogenic noise affects risk assessment and attention: the distracted prey hypothesis

Many studies have focused on the effects of anthropogenic noise on animal communication, but only a few have looked at its effect on other behavioural systems. We designed a playback experiment to test the effect of noise on predation risk assessment. We found that in response to boat motor playback, Caribbean hermit crabs (Coenobita clypeatus) allowed a simulated predator to approach closer before they hid. Two hypotheses may explain how boat noise affected risk assessment: it masked an approaching predator's sound; and/or it reallocated some of the crabs' finite attention, effectively distracting them, and thus preventing them from responding to an approaching threat. We found no support for the first hypothesis: a silent looming object still got closer during boat motor playbacks than during silence. However, we found support for the attentional hypothesis: when we added flashing lights to the boat motor noise to further distract the hermit crabs, we were able to approach the crabs more closely than with the noise alone. Anthropogenic sounds may thus distract prey and make them more vulnerable to predation

Detecting affiliation in colaughter across 24 societies

Laughter is a nonverbal vocal expression that often communicates positive affect and cooperative intent in humans. Temporally coincident laughter occurring within groups is a potentially rich cue of affiliation to overhearers. We examined listeners’ judgments of affiliation based on brief, decontextualized instances of colaughter between either established friends or recently acquainted strangers. In a sample of 966 participants from 24 societies, people reliably distinguished friends from strangers with an accuracy of 53–67%. Acoustic analyses of the individual laughter segments revealed that, across cultures, listeners’ judgments were consistently predicted by voicing dynamics, suggesting perceptual sensitivity to emotionally triggered spontaneous production. Colaughter affords rapid and accurate appraisals of affiliation that transcend cultural and linguistic boundaries, and may constitute a universal means of signaling cooperative relationship

Detecting affiliation in colaughter across 24 societies

Laughter is a nonverbal vocal expression that often communicates positive affect and cooperative intent in humans. Temporally coincident laughter occurring within groups is a potentially rich cue of affiliation to overhearers. We examined listeners' judgments of affiliation based on brief, decontextualized instances of colaughter between either established friends or recently acquainted strangers. In a sample of 966 participants from 24 societies, people reliably distinguished friends from strangers with an accuracy of 53-67%. Acoustic analyses of the individual laughter segments revealed that, across cultures, listeners' judgments were consistently predicted by voicing dynamics, suggesting perceptual sensitivity to emotionally triggered spontaneous production. Colaughter affords rapid and accurate appraisals of affiliation that transcend cultural and linguistic boundaries, and may constitute a universal means of signaling cooperative relationships

Erratum: Detecting affiliation in colaughter across 24 societies (Proceedings of the National Academy of Sciences of the United States of America (2016) 113 (4682-4687) DOI: 10.1073/pnas.1524993113)

The authors note that Table 1 appeared incorrectly. The corrected table appears below. (Table Presented)

Greater Traditionalism Predicts COVID-19 Precautionary Behaviors Across 27 Societies

People vary in the extent to which they embrace their society’s traditions, impacting a range of social and political phenomena. People also vary in the degree to which they perceive disparate dangers as salient and necessitating a response. Over evolutionary time, traditions likely regularly offered direct and indirect avenues for addressing hazards; consequently, via multiple possible pathways, orientations toward tradition and toward danger may have become associated. Emerging research documents connections between individual differences in traditionalism and variation in threat responsivity in general, and pathogen-avoidance motivations in particular. Importantly, because threat-mitigating behaviors can conflict with competing priorities, the precise associations between traditionalism and pathogen avoidance likely depend on contextually contingent costs and benefits. The COVID-19 pandemic requires individuals to make decisions about consequential and costly pathogen-avoidance behaviors that can clash with other priorities. The pandemic therefore provides a real-world setting in which to test the posited relationship between traditionalism and pathogen avoidance across socio-political contexts. Across 27 societies (N = 7,844), we find that costly COVID-19-avoidance behaviors positively correlate with greater endorsement of traditional norms and values in a majority of countries. Accounting for the conflict that arises in some societies between public health precautions and competing priorities, such as the exercise of personal liberties, reveals a consistent relationship between traditionalism and COVID-19 precautions across an even wider range of social and cultural contexts. These findings support the thesis that traditionalism is associated with an enhanced tendency to attend to hazards

Greater traditionalism predicts COVID-19 precautionary behaviors across 27 societies

People vary both in their embrace of their society’s traditions, and in their perception of hazards as salient and necessitating a response. Over evolutionary time, traditions have offered avenues for addressing hazards, plausibly resulting in linkages between orientations toward tradition and orientations toward danger. Emerging research documents connections between traditionalism and threat responsivity, including pathogen-avoidance motivations. Additionally, because hazard-mitigating behaviors can conflict with competing priorities, associations between traditionalism and pathogen avoidance may hinge on contextually contingent tradeoffs. The COVID-19 pandemic provides a real-world test of the posited relationship between traditionalism and hazard avoidance. Across 27 societies (N = 7844), we find that, in a majority of countries, individuals’ endorsement of tradition positively correlates with their adherence to costly COVID-19-avoidance behaviors; accounting for some of the conflicts that arise between public health precautions and other objectives further strengthens this evidence that traditionalism is associated with greater attention to hazards