My true face: Unmasking one's own face representation. Laura Mora et al. Acta Psychologica, Volume 191, November 2018, Pages 63-68. https://doi.org/10.1016/j.actpsy.2018.08.014
Highlights
• Size distortions are intrinsic to self-face representation, characterised for a tendency to overestimate its width.
• Self-face length perception is compartmentalised into upper and bottom regions.
• The metric map for self-face representation shows larger distortion for the nose, followed by the mouth and the eyes.
• There is an asymmetrical representation of the face, with over representation of the right hemispace.
• Face representation relies on influences from visual experience, typical body posture, frequency of use and functionality.
Abstract: Face recognition has been the focus of multiple studies, but little is still known on how we represent the structure of one's own face. Most of the studies have focused on the topic of visual and haptic face recognition, but the metric representation of different features of one's own face is relatively unknown. We investigated the metric representation of the face in young adults by developing a proprioceptive pointing task to locate face landmarks in the first-person perspective. Our data revealed a large overestimation of width for all face features which resembles, in part, the size in somatosensory cortical representation. In contrast, face length was compartmentalised in two different regions: upper (underestimated) and bottom (overestimated); indicating size differences possibly due to functionality. We also identified shifts of the location judgments, with all face areas perceived closer to the body than they really were, due to a potential influence of the self-frame of reference. More importantly, the representation of the face appeared asymmetrical, with an overrepresentation of right side of the face, due to the influence of lateralization biases for strong right-handers. We suggest that these effects may be due to functionality influences and experience that affect the construction of face structural representation, going beyond the parallel of the somatosensory homunculus.
Friday, September 14, 2018
People’s judgments of morally-significant events were affected by the likelihood of the event: They were more upset about events that were unexpected (a robbery at a clothing store) than events that were more expected (a robbery at a convenience store)
Powell, Derek, and Zachary Horne. 2018. “Expectations Bias Moral Evaluations.” PsyArXiv. September 13. doi:10.31234/osf.io/s7fu2
Abstract: People’s expectations play an important role in their reactions to events. There is often disappointment when events fail to meet expectations and a special thrill to having one’s expectations exceeded. We propose that expectations influence evaluations through information-theoretic principles: less expected events do more to inform us about the state of the world than do more expected events. An implication of this proposal is that people may have inappropriately muted responses to morally significant but expected events. In two preregistered experiments, we found that people’s judgments of morally-significant events were affected by the likelihood of that event. People were more upset about events that were unexpected (e.g., a robbery at a clothing store) than events that were more expected (e.g., a robbery at a convenience store). We argue that this bias has pernicious moral consequences, including leading to reduced concern for victims in most need of help.
Abstract: People’s expectations play an important role in their reactions to events. There is often disappointment when events fail to meet expectations and a special thrill to having one’s expectations exceeded. We propose that expectations influence evaluations through information-theoretic principles: less expected events do more to inform us about the state of the world than do more expected events. An implication of this proposal is that people may have inappropriately muted responses to morally significant but expected events. In two preregistered experiments, we found that people’s judgments of morally-significant events were affected by the likelihood of that event. People were more upset about events that were unexpected (e.g., a robbery at a clothing store) than events that were more expected (e.g., a robbery at a convenience store). We argue that this bias has pernicious moral consequences, including leading to reduced concern for victims in most need of help.
Cross-national gender differences in the enrollment in & completion of science, technology, engineering, & mathematics M. Open Online Courses: Females were less likely than males to enroll in STEM MOOCs, but were equally likely to complete them
Cross-national comparison of gender differences in the enrollment in and completion of science, technology, engineering, and mathematics Massive Open Online Courses. Suhang Jiang et al. PLOS One, https://doi.org/10.1371/journal.pone.0202463
Abstract: Massive Open Online Courses (MOOCs) have the potential to democratize education by providing learners with access to high-quality free online courses. However, evidence supporting this democratization across countries is limited. We explored the question of MOOC democratization by conducting cross-national comparisons of gender differences in the enrollment in and completion of science, technology, engineering, and mathematics (STEM) MOOCs. We found that while females were less likely than males to enroll in STEM MOOCs, they were equally likely to complete them. Further, a higher probability to enroll in STEM MOOCs and smaller gender gaps in STEM MOOC enrollment and completion were found in less gender-equal and less economically developed countries.
Abstract: Massive Open Online Courses (MOOCs) have the potential to democratize education by providing learners with access to high-quality free online courses. However, evidence supporting this democratization across countries is limited. We explored the question of MOOC democratization by conducting cross-national comparisons of gender differences in the enrollment in and completion of science, technology, engineering, and mathematics (STEM) MOOCs. We found that while females were less likely than males to enroll in STEM MOOCs, they were equally likely to complete them. Further, a higher probability to enroll in STEM MOOCs and smaller gender gaps in STEM MOOC enrollment and completion were found in less gender-equal and less economically developed countries.
Thursday, September 13, 2018
Refutation: Some say that too many arguments might lead to counterproductive skepticism & reactance; but a larger number of counterarguments (4-6) led to as much or more belief reduction compared to a smaller number
Refutations of Equivocal Claims: No Evidence for an Ironic Effect of Counterargument Number. K.H.Ecker et al. Journal of Applied Research in Memory and Cognition, https://doi.org/10.1016/j.jarmac.2018.07.005
Abstract: This study investigated the refutation of equivocal claims using counterarguments. Common sense suggests that more counterarguments should be more effective at inducing belief change. However, some researchers have argued that in persuasive reasoning, using too many arguments might lead to counterproductive skepticism and reactance. Thus, there have been calls to actively curtail the number of counterarguments used in refutations to avoid risking an “overkill backfire effect”—an ironic strengthening of beliefs from too many counterarguments. In three experiments, we tested whether calls to limit the number of counterarguments are justified. We found that a larger number of counterarguments (between four and six) led to as much or more belief reduction compared to a smaller number of (two) counterarguments. This was not merely an effect arising from a simple numerosity heuristic, as counterarguments had to be relevant to affect beliefs: irrelevant counterarguments failed to reduce beliefs even though perceived as moderately persuasive.
Refutations of Equivocal Claims: No Evidence for an Ironic Effect of Counterargument Number.
Abstract: This study investigated the refutation of equivocal claims using counterarguments. Common sense suggests that more counterarguments should be more effective at inducing belief change. However, some researchers have argued that in persuasive reasoning, using too many arguments might lead to counterproductive skepticism and reactance. Thus, there have been calls to actively curtail the number of counterarguments used in refutations to avoid risking an “overkill backfire effect”—an ironic strengthening of beliefs from too many counterarguments. In three experiments, we tested whether calls to limit the number of counterarguments are justified. We found that a larger number of counterarguments (between four and six) led to as much or more belief reduction compared to a smaller number of (two) counterarguments. This was not merely an effect arising from a simple numerosity heuristic, as counterarguments had to be relevant to affect beliefs: irrelevant counterarguments failed to reduce beliefs even though perceived as moderately persuasive.
Refutations of Equivocal Claims: No Evidence for an Ironic Effect of Counterargument Number.
People’s interpretation of new evidence is often biased by their previous choices (confirmation bias); choices bias the accumulation process by selectively altering the weighting (gain) of subsequent evidence, akin to selective attention
Confirmation Bias through Selective Overweighting of Choice-Consistent Evidence. Bharath Chandra Talluri et al. Current Biology, https://doi.org/10.1016/j.cub.2018.07.052
Highlights
• People’s interpretation of new evidence is often biased by their previous choices
• Talluri, Urai et al. developed a new task for probing the underlying mechanisms
• Evidence consistent with an observer’s initial choice is processed more efficiently
• This “choice-induced gain change” affects both perceptual and numerical decisions
Summary: People’s assessments of the state of the world often deviate systematically from the information available to them [1]. Such biases can originate from people’s own decisions: committing to a categorical proposition, or a course of action, biases subsequent judgment and decision-making. This phenomenon, called confirmation bias [2], has been explained as suppression of post-decisional dissonance [3, 4]. Here, we provide insights into the underlying mechanism. It is commonly held that decisions result from the accumulation of samples of evidence informing about the state of the world [5, 6, 7, 8]. We hypothesized that choices bias the accumulation process by selectively altering the weighting (gain) of subsequent evidence, akin to selective attention. We developed a novel psychophysical task to test this idea. Participants viewed two successive random dot motion stimuli and made two motion-direction judgments: a categorical discrimination after the first stimulus and a continuous estimation of the overall direction across both stimuli after the second stimulus. Participants’ sensitivity for the second stimulus was selectively enhanced when that stimulus was consistent with the initial choice (compared to both, first stimuli and choice-inconsistent second stimuli). A model entailing choice-dependent selective gain modulation explained this effect better than several alternative mechanisms. Choice-dependent gain modulation was also established in another task entailing averaging of numerical values instead of motion directions. We conclude that intermittent choices direct selective attention during the evaluation of subsequent evidence, possibly due to decision-related feedback in the brain [9]. Our results point to a recurrent interplay between decision-making and selective attention.
Highlights
• People’s interpretation of new evidence is often biased by their previous choices
• Talluri, Urai et al. developed a new task for probing the underlying mechanisms
• Evidence consistent with an observer’s initial choice is processed more efficiently
• This “choice-induced gain change” affects both perceptual and numerical decisions
Summary: People’s assessments of the state of the world often deviate systematically from the information available to them [1]. Such biases can originate from people’s own decisions: committing to a categorical proposition, or a course of action, biases subsequent judgment and decision-making. This phenomenon, called confirmation bias [2], has been explained as suppression of post-decisional dissonance [3, 4]. Here, we provide insights into the underlying mechanism. It is commonly held that decisions result from the accumulation of samples of evidence informing about the state of the world [5, 6, 7, 8]. We hypothesized that choices bias the accumulation process by selectively altering the weighting (gain) of subsequent evidence, akin to selective attention. We developed a novel psychophysical task to test this idea. Participants viewed two successive random dot motion stimuli and made two motion-direction judgments: a categorical discrimination after the first stimulus and a continuous estimation of the overall direction across both stimuli after the second stimulus. Participants’ sensitivity for the second stimulus was selectively enhanced when that stimulus was consistent with the initial choice (compared to both, first stimuli and choice-inconsistent second stimuli). A model entailing choice-dependent selective gain modulation explained this effect better than several alternative mechanisms. Choice-dependent gain modulation was also established in another task entailing averaging of numerical values instead of motion directions. We conclude that intermittent choices direct selective attention during the evaluation of subsequent evidence, possibly due to decision-related feedback in the brain [9]. Our results point to a recurrent interplay between decision-making and selective attention.
People with higher IQs not only being unable to solve problems unresolved, but are in some cases unwilling to address them; higher IQ is not always highly relevant to the problems, and in some cases, may displace other skills that better would apply to the solution of the problems
Why Real-World Problems Go Unresolved and What We Can Do about It: Inferences from a Limited-Resource Model of Successful Intelligence. Robert J. Sternberg. J. Intell. 2018, 6(3), 44; https://doi.org/10.3390/jintelligence6030044
Abstract: In this article I suggest why a symposium is desirable on the topic of why, despite worldwide increases in IQ since the beginning of the 20th century, there are so many unresolved and dramatic problems in the world. I briefly discuss what some of these problems are, and the paradox of people with higher IQs not only being unable to solve them, but in some cases people being unwilling to address them. I suggest that higher IQ is not always highly relevant to the problems, and in some cases, may displace other skills that better would apply to the solution of the problems. I present a limited-resource model as an adjunct to the augmented theory of successful intelligence. The model suggests that increasing societal emphases on analytical abilities have displaced development and utilization of other skills, especially creative, practical, and wisdom-based ones, that better could be applied to serious world problems. I also discuss the importance of cognitive inoculation against unscrupulous and sometimes malevolent attempts to change belief systems.
Keywords: components; creativity; inoculation; intelligence; limited-resource model; wisdom
Abstract: In this article I suggest why a symposium is desirable on the topic of why, despite worldwide increases in IQ since the beginning of the 20th century, there are so many unresolved and dramatic problems in the world. I briefly discuss what some of these problems are, and the paradox of people with higher IQs not only being unable to solve them, but in some cases people being unwilling to address them. I suggest that higher IQ is not always highly relevant to the problems, and in some cases, may displace other skills that better would apply to the solution of the problems. I present a limited-resource model as an adjunct to the augmented theory of successful intelligence. The model suggests that increasing societal emphases on analytical abilities have displaced development and utilization of other skills, especially creative, practical, and wisdom-based ones, that better could be applied to serious world problems. I also discuss the importance of cognitive inoculation against unscrupulous and sometimes malevolent attempts to change belief systems.
Keywords: components; creativity; inoculation; intelligence; limited-resource model; wisdom
Deception detection advances: From observing target persons' nonverbal behavior to analyzing their speech; from differences in levels of arousal to detection of cognitive processes or strategies adopted to be convincing; & from passively observing target persons to actively interviewing them
Deception and truth detection when analyzing nonverbal and verbal cues. Aldert Vrij. Applied Cognitive Psychology, https://doi.org/10.1002/acp.3457
Summary: In this article, I present my view on the significant developments and theoretical/empirical tipping points in nonverbal and verbal deception and lie detection from the last 30 years and on prospects for future research in this domain. I discuss three major shifts in deception detection research: (a) From observing target persons' nonverbal behavior to analyzing their speech; (b) from lie detection based on differences between truth tellers and liars' levels of arousal to lie detection based on the different cognitive processes or strategies adopted to appear convincing; and (c) from passively observing target persons to actively interviewing them to elicit or enhance verbal cues to deceit. Finally, I discuss my ideas for future research, focusing on initiatives from my own lab. Hopefully, this will stimulate other researchers to explore innovative ideas in the verbal deception research domain, which already has seen so much progress in the last decade.
Summary: In this article, I present my view on the significant developments and theoretical/empirical tipping points in nonverbal and verbal deception and lie detection from the last 30 years and on prospects for future research in this domain. I discuss three major shifts in deception detection research: (a) From observing target persons' nonverbal behavior to analyzing their speech; (b) from lie detection based on differences between truth tellers and liars' levels of arousal to lie detection based on the different cognitive processes or strategies adopted to appear convincing; and (c) from passively observing target persons to actively interviewing them to elicit or enhance verbal cues to deceit. Finally, I discuss my ideas for future research, focusing on initiatives from my own lab. Hopefully, this will stimulate other researchers to explore innovative ideas in the verbal deception research domain, which already has seen so much progress in the last decade.
Brain and psychological determinants of placebo pill response in chronic pain patients
Brain and psychological determinants of placebo pill response in chronic pain patients. Etienne Vachon-Presseau, Sara E. Berger, Taha B. Abdullah, Lejian Huang, Guillermo A. Cecchi, James W. Griffith, Thomas J. Schnitzer & A. Vania Apkarian. Nature Communications, volume 9, Article number: 3397 (2018). https://www.nature.com/articles/s41467-018-05859-1
Abstract: The placebo response is universally observed in clinical trials of pain treatments, yet the individual characteristics rendering a patient a ‘placebo responder’ remain unclear. Here, in chronic back pain patients, we demonstrate using MRI and fMRI that the response to placebo ‘analgesic’ pills depends on brain structure and function. Subcortical limbic volume asymmetry, sensorimotor cortical thickness, and functional coupling of prefrontal regions, anterior cingulate, and periaqueductal gray were predictive of response. These neural traits were present before exposure to the pill and most remained stable across treatment and washout periods. Further, psychological traits, including interoceptive awareness and openness, were also predictive of the magnitude of response. These results shed light on psychological, neuroanatomical, and neurophysiological principles determining placebo response in RCTs in chronic pain patients, and they suggest that the long-term beneficial effects of placebo, as observed in clinical settings, are partially predictable.
Abstract: The placebo response is universally observed in clinical trials of pain treatments, yet the individual characteristics rendering a patient a ‘placebo responder’ remain unclear. Here, in chronic back pain patients, we demonstrate using MRI and fMRI that the response to placebo ‘analgesic’ pills depends on brain structure and function. Subcortical limbic volume asymmetry, sensorimotor cortical thickness, and functional coupling of prefrontal regions, anterior cingulate, and periaqueductal gray were predictive of response. These neural traits were present before exposure to the pill and most remained stable across treatment and washout periods. Further, psychological traits, including interoceptive awareness and openness, were also predictive of the magnitude of response. These results shed light on psychological, neuroanatomical, and neurophysiological principles determining placebo response in RCTs in chronic pain patients, and they suggest that the long-term beneficial effects of placebo, as observed in clinical settings, are partially predictable.
Social conformity: Compliance occurs when individuals conform in public, but not in private; acceptance occurs when group influence is internalised, in private and in public; the magnitude of compliance increases as the size of the majority increases
Quantifying compliance and acceptance through public and private social conformity. Sophie Sowden et al. Consciousness and Cognition, https://doi.org/10.1016/j.concog.2018.08.009
Highlights
• Most measures of social conformity conflate compliance and acceptance.
• Compliance occurs when individuals conform in public, but not in private.
• Acceptance occurs when group influence is internalised, in private and in public.
• Our task reveals the presence of compliance and acceptance on a within-subject basis.
• The magnitude of compliance increases as the size of the majority increases.
Abstract: Social conformity is a class of social influence whereby exposure to the attitudes and beliefs of a group causes an individual to alter their own attitudes and beliefs towards those of the group. Compliance and acceptance are varieties of social influence distinguished on the basis of the attitude change brought about. Compliance involves public, but not private conformity, while acceptance occurs when group norms are internalised and conformity is demonstrated both in public and in private. Most contemporary paradigms measuring conformity conflate compliance and acceptance, while the few studies to have addressed this issue have done so using between-subjects designs, decreasing their sensitivity. Here we present a novel task which measures compliance and acceptance on a within-subjects basis. Data from a small sample reveal that compliance and acceptance can co-occur, that compliance is increased with an increasing majority, and demonstrate the usefulness of the task for future studies of conformity.
Highlights
• Most measures of social conformity conflate compliance and acceptance.
• Compliance occurs when individuals conform in public, but not in private.
• Acceptance occurs when group influence is internalised, in private and in public.
• Our task reveals the presence of compliance and acceptance on a within-subject basis.
• The magnitude of compliance increases as the size of the majority increases.
Abstract: Social conformity is a class of social influence whereby exposure to the attitudes and beliefs of a group causes an individual to alter their own attitudes and beliefs towards those of the group. Compliance and acceptance are varieties of social influence distinguished on the basis of the attitude change brought about. Compliance involves public, but not private conformity, while acceptance occurs when group norms are internalised and conformity is demonstrated both in public and in private. Most contemporary paradigms measuring conformity conflate compliance and acceptance, while the few studies to have addressed this issue have done so using between-subjects designs, decreasing their sensitivity. Here we present a novel task which measures compliance and acceptance on a within-subjects basis. Data from a small sample reveal that compliance and acceptance can co-occur, that compliance is increased with an increasing majority, and demonstrate the usefulness of the task for future studies of conformity.
The truth about tattoos: The tattooed and non-tattooed are similarly honest in low-and high-stakes tasks
The truth about tattoos. Bradley J. Ruffle, Anne E. Wilson. Economics Letters, https://doi.org/10.1016/j.econlet.2018.08.024
Highlights
• The tattooed and non-tattooed are similarly honest in low-and high-stakes tasks.
• Results are robust to controls for socio-demo and number and placement of tattoos.
• Few subjects cheat maximally in either the low-or high-stakes task.
• Strategic cheating is limited to a small minority of subjects.
Abstract: Despite their ubiquity, tattoos continue to be associated with dishonesty. Notwithstanding, we find few differences in the reporting behavior of tattooed and non-tattooed individuals in either a low-stakes or a high-stakes honesty-detection task.
Highlights
• The tattooed and non-tattooed are similarly honest in low-and high-stakes tasks.
• Results are robust to controls for socio-demo and number and placement of tattoos.
• Few subjects cheat maximally in either the low-or high-stakes task.
• Strategic cheating is limited to a small minority of subjects.
Abstract: Despite their ubiquity, tattoos continue to be associated with dishonesty. Notwithstanding, we find few differences in the reporting behavior of tattooed and non-tattooed individuals in either a low-stakes or a high-stakes honesty-detection task.
Wednesday, September 12, 2018
Deceiving participants about the goals or content of a study is permitted in psychological research but is banned in economics journals and subject pools; experiments show that this ban is not necessary
Krasnow, Max, Rhea M. Howard, and Adar Eisenbruch. 2018. “The Importance of Being Honest?.” PsyArXiv. September 12. doi:10.31234/osf.io/9rsth
Abstract: Deceiving participants about the goals or content of a study is permitted in psychological research but is banned in economics journals and subject pools. This ban is intended to protect a public good: if experiencing deception causes participants to be suspicious in future studies, and suspicion influences their behavior, then the entire field suffers. We report a survey on psychologists and economists’ attitudes towards deception (N=568), and a large, non-deceptive multi-site study in which we measured participants’ histories, suspicion levels, and behavior in four common economic tasks (N=636). Economists reported wide ranging negative attitudes towards deceptive methods and support for the deception ban. However, the results of the behavioral study undercut the rationale of the deception ban: participants’ present suspicion unrelated to past experiences of deception, and suspicious participants behaved identically to credulous participants. We conclude that banning deceptive methods cannot be justified as the protection of a public good.
Abstract: Deceiving participants about the goals or content of a study is permitted in psychological research but is banned in economics journals and subject pools. This ban is intended to protect a public good: if experiencing deception causes participants to be suspicious in future studies, and suspicion influences their behavior, then the entire field suffers. We report a survey on psychologists and economists’ attitudes towards deception (N=568), and a large, non-deceptive multi-site study in which we measured participants’ histories, suspicion levels, and behavior in four common economic tasks (N=636). Economists reported wide ranging negative attitudes towards deceptive methods and support for the deception ban. However, the results of the behavioral study undercut the rationale of the deception ban: participants’ present suspicion unrelated to past experiences of deception, and suspicious participants behaved identically to credulous participants. We conclude that banning deceptive methods cannot be justified as the protection of a public good.
Understanding Changes in Attitudes Toward Suicide Between 1980s and 2010s in the US: largely unaccepting of suicide, except in the case of incurable disease, a greater percentage found suicide to be acceptable in the 2010s
Understanding Changes in Attitudes Toward Suicide Between 1980s and 2010s in the United States. Yi Tong, Julie A. Phillips. Social Science Quarterly, https://doi.org/10.1111/ssqu.12522
Objectives: This study examines individual characteristics associated with suicide acceptability in the United States and how (1) effects of these characteristics on attitudes have changed over time and (2) the degree to which shifts in attitudes are explained by changes in population characteristics.
Methods: We use General Social Survey (GSS) data from the 1980s (n = 4,840) and 2010s (n = 5,607) and conduct an Oaxaca decomposition.
Results: Although Americans remain largely unaccepting of suicide, except in the case of incurable disease, a greater percentage found suicide to be acceptable in 2010s than in 1980s. Individuals who are male, white, more educated, less religious, and more politically liberal find suicide more acceptable. Changes over time in population composition (e.g., rising education levels and declines in religion) account for about 50 percent of the rise in suicide acceptability between 1980s and 2010s.
Conclusions: Results hint at shifting societal patterns, but the causal direction between attitudes and behavior cannot be determined.
Objectives: This study examines individual characteristics associated with suicide acceptability in the United States and how (1) effects of these characteristics on attitudes have changed over time and (2) the degree to which shifts in attitudes are explained by changes in population characteristics.
Methods: We use General Social Survey (GSS) data from the 1980s (n = 4,840) and 2010s (n = 5,607) and conduct an Oaxaca decomposition.
Results: Although Americans remain largely unaccepting of suicide, except in the case of incurable disease, a greater percentage found suicide to be acceptable in 2010s than in 1980s. Individuals who are male, white, more educated, less religious, and more politically liberal find suicide more acceptable. Changes over time in population composition (e.g., rising education levels and declines in religion) account for about 50 percent of the rise in suicide acceptability between 1980s and 2010s.
Conclusions: Results hint at shifting societal patterns, but the causal direction between attitudes and behavior cannot be determined.
Bonobos voluntarily hand food to others but not toys or tools
Bonobos voluntarily hand food to others but not toys or tools. Christopher Krupenye, Jingzhi Tan, Brian Hare. Philosophical Transactions of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2018.1536
Abstract: A key feature of human prosociality is direct transfers, the most active form of sharing in which donors voluntarily hand over resources in their possession. Direct transfers buffer hunter-gatherers against foraging shortfalls. The emergence and elaboration of this behaviour thus likely played a key role in human evolution by promoting cooperative interdependence and ensuring that humans' growing energetic needs (e.g. for increasing brain size) were more reliably met. According to the strong prosociality hypothesis, among great apes only humans exhibit sufficiently strong prosocial motivations to directly transfer food. The versatile prosociality hypothesis suggests instead that while other apes may make transfers in constrained settings, only humans share flexibly across food and non-food contexts. In controlled experiments, chimpanzees typically transfer objects but not food, supporting both hypotheses. In this paper, we show in two experiments that bonobos directly transfer food but not non-food items. These findings show that, in some contexts, bonobos exhibit a human-like motivation for direct food transfer. However, humans share across a far wider range of contexts, lending support to the versatile prosociality hypothesis. Our species' unusual prosocial flexibility is likely built on a prosocial foundation we share through common descent with the other apes.
Abstract: A key feature of human prosociality is direct transfers, the most active form of sharing in which donors voluntarily hand over resources in their possession. Direct transfers buffer hunter-gatherers against foraging shortfalls. The emergence and elaboration of this behaviour thus likely played a key role in human evolution by promoting cooperative interdependence and ensuring that humans' growing energetic needs (e.g. for increasing brain size) were more reliably met. According to the strong prosociality hypothesis, among great apes only humans exhibit sufficiently strong prosocial motivations to directly transfer food. The versatile prosociality hypothesis suggests instead that while other apes may make transfers in constrained settings, only humans share flexibly across food and non-food contexts. In controlled experiments, chimpanzees typically transfer objects but not food, supporting both hypotheses. In this paper, we show in two experiments that bonobos directly transfer food but not non-food items. These findings show that, in some contexts, bonobos exhibit a human-like motivation for direct food transfer. However, humans share across a far wider range of contexts, lending support to the versatile prosociality hypothesis. Our species' unusual prosocial flexibility is likely built on a prosocial foundation we share through common descent with the other apes.
The scent of attractiveness: levels of reproductive hormones explain individual differences in women's body odour
The scent of attractiveness: levels of reproductive hormones explain individual differences in women's body odour. Janek S. Lobmaier, Urs Fischbacher, Urs Wirthmüller, Daria Knoch. Philosophical Transactions of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2018.1520
Abstract: Individuals are thought to have their own distinctive body odour which reportedly plays an important role in mate choice. In the present study we investigated individual differences in body odours of women and examined whether some women generally smell more attractive than others or whether odour preferences are a matter of individual taste. We then explored whether levels of reproductive hormones explain women's body odour attractiveness, to test the idea that body odour attractiveness may act as a chemosensory marker of reproductive fitness. Fifty-seven men rated body odours of 28 healthy, naturally cycling women of reproductive age. We collected all odours at peak fertility to control for menstrual cycle effects on body odour attractiveness. Women's salivary oestradiol, progesterone, testosterone and cortisol levels were assessed at the time of odour collection to test whether hormone levels explain body odour attractiveness. We found that the men highly agreed on how attractive they found women's body odours. Interestingly, women's body odour attractiveness was predicted by their oestradiol and progesterone levels: the higher a woman's levels of oestradiol and the lower her levels of progesterone, the more attractive her body odour was rated. In showing that women's body odour attractiveness is explained by levels of female reproductive hormones, but not by levels of cortisol or testosterone, we provide evidence that body odour acts as a valid cue to potential fertility.
Abstract: Individuals are thought to have their own distinctive body odour which reportedly plays an important role in mate choice. In the present study we investigated individual differences in body odours of women and examined whether some women generally smell more attractive than others or whether odour preferences are a matter of individual taste. We then explored whether levels of reproductive hormones explain women's body odour attractiveness, to test the idea that body odour attractiveness may act as a chemosensory marker of reproductive fitness. Fifty-seven men rated body odours of 28 healthy, naturally cycling women of reproductive age. We collected all odours at peak fertility to control for menstrual cycle effects on body odour attractiveness. Women's salivary oestradiol, progesterone, testosterone and cortisol levels were assessed at the time of odour collection to test whether hormone levels explain body odour attractiveness. We found that the men highly agreed on how attractive they found women's body odours. Interestingly, women's body odour attractiveness was predicted by their oestradiol and progesterone levels: the higher a woman's levels of oestradiol and the lower her levels of progesterone, the more attractive her body odour was rated. In showing that women's body odour attractiveness is explained by levels of female reproductive hormones, but not by levels of cortisol or testosterone, we provide evidence that body odour acts as a valid cue to potential fertility.
Sex differences in personality are larger in gender equal countries: Replicating and extending this effect
Sex differences in personality are larger in gender equal countries: Replicating and extending a surprising finding. Erik Mac Giolla, Petri J. Kajonius. International Journal of Psychology, https://doi.org/10.1002/ijop.12529
Abstract: Sex differences in personality have been shown to be larger in more gender equal countries. We advance this research by using an extensive personality measure, the IPIP‐NEO‐120, with large country samples (N > 1000), from 22 countries. Furthermore, to capture the multidimensionality of personality we measure sex differences with a multivariate effect size (Mahalanobis distance D). Results indicate that past research, using univariate measures of effect size, have underestimated the size of between‐country sex differences in personality. Confirming past research, there was a strong correlation (r = .69) between a country's sex differences in personality and their Gender Equality Index. Additional analyses showed that women typically score higher than men on all five trait factors (Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness), and that these relative differences are larger in more gender equal countries. We speculate that as gender equality increases both men and women gravitate towards their traditional gender roles.
Abstract: Sex differences in personality have been shown to be larger in more gender equal countries. We advance this research by using an extensive personality measure, the IPIP‐NEO‐120, with large country samples (N > 1000), from 22 countries. Furthermore, to capture the multidimensionality of personality we measure sex differences with a multivariate effect size (Mahalanobis distance D). Results indicate that past research, using univariate measures of effect size, have underestimated the size of between‐country sex differences in personality. Confirming past research, there was a strong correlation (r = .69) between a country's sex differences in personality and their Gender Equality Index. Additional analyses showed that women typically score higher than men on all five trait factors (Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness), and that these relative differences are larger in more gender equal countries. We speculate that as gender equality increases both men and women gravitate towards their traditional gender roles.
Subscribe to:
Comments (Atom)
Posts
