Wednesday, February 9, 2022

By contrast to other tastes, sour taste does not appear to have been lost in any major vertebrate taxa; but for most species, sour taste is aversive: Animals, including humans, that enjoy the sour taste triggered by acidic foods are exceptional

The evolution of sour taste. Hannah E. R. Frank, Katie Amato, Michelle Trautwein, Paula Maia, Emily R. Liman, Lauren M. Nichols, Kurt Schwenk, Paul A. S. Breslin and Robert R. Dunn. Proceedings of the Royal Society B: Biological Sciences, February 9 2022. https://doi.org/10.1098/rspb.2021.1918

Abstract: The evolutionary history of sour taste has been little studied. Through a combination of literature review and trait mapping on the vertebrate phylogenetic tree, we consider the origin of sour taste, potential cases of the loss of sour taste, and those factors that might have favoured changes in the valence of sour taste—from aversive to appealing. We reconstruct sour taste as having evolved in ancient fish. By contrast to other tastes, sour taste does not appear to have been lost in any major vertebrate taxa. For most species, sour taste is aversive. Animals, including humans, that enjoy the sour taste triggered by acidic foods are exceptional. We conclude by considering why sour taste evolved, why it might have persisted as vertebrates made the transition to land and what factors might have favoured the preference for sour-tasting, acidic foods, particularly in hominins, such as humans.

(e) Consequences of sour taste preferences for hominins

Regardless of whether rotting fruits played a role in the shift of the acid preference curve in hominins, we hypothesize that the existence of acid taste preference may have strongly influenced the later relationship between hominins and rotten fruits and other rotten foods. Based on studies in the laboratory, three groups of microorganisms compete during the rot of fruits [78], single-celled budding yeasts (most of which are from the Saccharomycetales clade of fungi), filamentous fungi (such as Penicillium) and lactic acid bacteria. While all of these organisms produce short-chain fatty acids when they ferment fruit, yeasts also tend to produce alcohol, and lactic acid bacteria produce lactic acid. Rotten fruits that become dominated by filamentous fungi can be dangerous [79]. However, rotten fruits that become dominated by yeasts and lactic bacteria are often ‘improved’ from the perspective of consumers. Rot due to lactic acid bacteria and yeasts often increases food caloric, free amino acid and vitamin content and hence improves digestibility by breaking down fibre and plant toxins [8084]. Therefore, in challenging nutritional environments, fruits rotted by yeasts or lactic acid bacteria likely represented a valuable food source that could increase chances of survival [4]. If the acid-preference of the MRCA (whenever acquired) allowed it to more readily consume heavily fermented fruit, or at least the subset of that fruit rotted by lactic acid bacteria, they might have been able to take advantage of a novel source of safe calories.

There exists molecular evidence that the last common ancestor of gorillas, chimpanzees and humans consumed fermented fruits. For example, a single amino acid replacement in the ADH4 gene in the lineage shared by humans and African apes resulted in a 40-fold improvement in ethanol oxidation [85]. This change would have allowed the MRCA to consume yeast-fermented fruits on the ground with higher concentrations of both ethanol and acids [85] without concomitant neurological toxicity (or drunkenness; [53]). This ability may have allowed the MRCA to survive and reproduce more effectively in nutritionally challenging, seasonal environments, particularly as climate change resulted in more fragmented and open habitats. At about the same time, the MRCA acquired a third copy of the HCA3 gene encoding G protein-coupled receptors for hydroxycarboxylic acids, such as lactic acid, produced by the fermentation of dietary carbohydrates by lactic acid bacteria [86]. While this gene is found in all great apes, it is most strongly activated in chimpanzees, gorillas and humans, with humans exhibiting the strongest effects, suggesting that, in some form acid-producing bacteria (and the detection of their products) played a larger role in apes than in other primates and in humans than in non-human apes. As has been considered elsewhere, a fondness for acidic foods, particularly when combined with preferences for umami tastes, may have predisposed ancestral humans to eventual intentional control of rotting to yield more favourable outcomes, which is to say, fermentation [4,87].

Positive effect of swearing on strength: Humorous disinhibition as a potential mediator

Effect of swearing on strength: Disinhibition as a potential mediator. Richard Stephens et al. Quarterly Journal of Experimental Psychology, February 8, 2022. https://doi.org/10.1177/17470218221082657

Abstract

Introduction: Swearing fulfils positive functions including benefitting pain relief and physical strength. Here we present two experiments assessing a possible psychological mechanism, increased state disinhibition, for the effect of swearing on physical strength.

Method: Two repeated measures experiments were carried out with sample sizes N=56, and N=118. Both included measures of physical performance assessing, respectively, grip and arm strength, and both included the Balloon Analogue Risk Task (BART) to measure risky behaviour. Experiment 2, which was pre-registered, additionally assessed flow, emotion including humour, distraction including novelty, self-confidence and anxiety.

Results: Experiments 1 and 2 found that repeating a swear word benefitted physical strength and increased risky behaviour, but risky behaviour did not mediate the strength effect. Experiment 2 found that repeating a swear word increased flow, positive emotion, humour and distraction and self-confidence. Humour mediated the effect of swearing on physical strength.

Discussion: Consistent effects of swearing on physical strength indicate that this is a reliable effect. Swearing influenced several constructs related to state disinhibition including increased self-confidence. Humour appeared to mediate the effect of swearing on physical strength, consistent with a hot cognitions explanation of swearing-induced state disinhibition. However, as this mediation effect was part of an exploratory analysis, further pre-registered experimental research including validated measures of humour is required.

Keywords: swearing, disinhibition, risk-taking, humour, confidence, mediation


Tuesday, February 8, 2022

Some suggest that humans are ‘domesticated’ apes; the wolf–dog comparison has been used to support the idea of the human self-domestication hypothesis, but more recent results are not in line with this claim

Comparing wolves and dogs: current status and implications for human ‘self-domestication’. Friederike Range, Sarah Marshall-Pescini. Trends in Cognitive Sciences, Feb 7 2022. https://doi.org/10.1016/j.tics.2022.01.003

Highlights

Domestication is thought to alter the temperament of a species, making it less fearful and aggressive and more social, thereby promoting their sociocognitive abilities. Some authors suggest that humans are ‘domesticated’ apes.

The wolf–dog comparison has been used to support the idea of the human self-domestication hypothesis, but more recent results are not in line with this claim.

Genetic and behavioral studies of free-ranging, pet, and captive pack-living dogs, as well as different subspecies of wolves, can further our understanding of the dog domestication process.

Current dog domestication hypotheses focus on explaining specific dog–human interactions rather than trying to understand dogs as a social species.

Dog domestication is best understood as an adaptation to a new, human-dominated niche, which included selective pressures by humans.

Abstract: Based on claims that dogs are less aggressive and show more sophisticated socio-cognitive skills compared with wolves, dog domestication has been invoked to support the idea that humans underwent a similar ‘self-domestication’ process. Here, we review studies on wolf–dog differences and conclude that results do not support such claims: dogs do not show increased socio-cognitive skills and they are not less aggressive than wolves. Rather, compared with wolves, dogs seek to avoid conflicts, specifically with higher ranking conspecifics and humans, and might have an increased inclination to follow rules, making them amenable social partners. These conclusions challenge the suitability of dog domestication as a model for human social evolution and suggest that dogs need to be acknowledged as animals adapted to a specific socio-ecological niche as well as being shaped by human selection for specific traits.

Concluding remarks

Although the idea that one selection process might explain the emergence of several traits in humans and domesticated species is exciting, the reality is more complex because species are exposed to different selective pressures in their natural environments. Concerning dogs, their behavior and cognition likely reflect changes in their socio-ecology, going hand in hand with human-enacted selective pressures favoring animals that can be easily inhibited and controlled, allowing humans to exploit the skills of dogs for their own use. However, these data do not support the claims of the HSD hypothesis of a general tamer temperament and higher socio-cognitive skills in dogs compared with wolves. Nevertheless, dog domestication might be a good model to further our understanding of the factors affecting human out-group dynamics and increased propensity for rule-following/adherence to social norms. Finally, we would like to caution researchers to consider the genetic make-up and social experience of their study populations when comparing wolves and dogs. Instead of formulating new domestication hypotheses to explain tiny differences in behavior or cognition, we would like to encourage researchers to also see dogs as a species adapted to their unique ecological niche and not only as a human-made product, and to test hypotheses using different paradigms.
Outstanding questions
Is the difference in fear reactions to humans and human artifacts of wolves and dogs (at least partly) a result of ‘selection for shyness’ in wolves? To investigate this question, different wolf subspecies need to be studied.
Does selection against aggression have a snowball effect on other aspects, such as the social structure of a species? Conversely, does adaptation to a new, more stable foraging niche with small, distributed food items bring about similar changes to those observed during dog domestication? To answer the first question, cognitive and behavioral studies of Belyaev’s ‘tame foxes’, including how these animals interact with conspecifics, would be valuable. To answer the second, a better understanding of how social cognition and behavior changes in canids adapting to an urban environment would be needed.
Which (combination of) hypotheses under which conditions might lead to the observed traits in dogs? Computer models might shed light on this question.
How varied is the social system of both wolves and dogs in the ‘wild’? Can such variability be exclusively explained by the respective ecological conditions? For example, would feral dogs living off hunting (rather than scavenging) show a social structure comparable to that of wolves (e.g., dingoes cooperatively hunt large prey, such as kangaroos)? Or are there consistent differences between the social organization of wolves and dogs, which cannot be explained by the ecological conditions they live in?
Do wolves and dogs perceive humans differently? Do they see humans as social partners at the same eye-level or rather someone to whom they look up to? How much does that depend on specific experiences?
Is the lower inclination of dogs to challenge hierarchies compared with wolves a good model for human evolution? To answer this question, we need to explore whether, compared with chimps (or bonobos), humans are more prone to accept the decisions of their leaders and, thus, avoid potentially costly conflicts with them.

Men & women tend to exhibit meaningful differences in personality & psychopathology, as well as in omnibus morphometry & regional morphometric brain differences, but those differences appear unrelated to the psychological differences

Structural brain differences do not mediate the relations between sex and personality or psychopathology. Courtland S. Hyatt et al. In press at the Journal of Personality, Feb 2022. https://osf.io/dsk53

Abstract

Introduction: Males and females tend to exhibit small but reliable differences in personality traits and indices of psychopathology that are relatively stable over time and across cultures. Previous work suggests that sex differences in brain structure account for differences in domains of cognition.

Methods: We used data from the Human Connectome Project (N = 1098) to test whether sex differences in brain morphometry account for observed differences in the personality traits neuroticism and agreeableness, as well as symptoms of internalizing and externalizing psychopathology. We operationalized brain morphometry in three ways: omnibus measures (e.g., total gray matter volume), Glasser regions defined through a multi-modal parcellation approach, and Desikan regions defined by structural features of the brain.

Results: Most expected sex differences in personality, psychopathology, and brain morphometry were observed, but the statistical mediation analyses were null: sex differences in brain morphometry did not account for sex differences in personality or psychopathology.

Conclusions: Men and women tend to exhibit meaningful differences in personality and psychopathology, as well as in omnibus morphometry and regional morphometric differences as defined by the Glasser and Desikan atlases, but these morphometric differences appear unrelated to the psychological differences.


Keywords: psychopathology, morphometry, sex, five factor model, human connectome project


Monday, February 7, 2022

Examined whether math ability was significant mediator of relation between gender and math anxiety; math ability accounted for a significant amount of the variance between gender and math anxiety, mostly due to manipulation ability

Delage, V., Trudel, G., Retanal, F., & Maloney, E. A. (2021). Spatial anxiety and spatial ability: Mediators of gender differences in math anxiety. Journal of Experimental Psychology: General. Feb 2022. https://doi.org/10.1037/xge0000884

Abstract: Females tend to be more anxious than males while engaging in mathematics, which has been linked to lower math performance and higher math avoidance. A possible repercussion of this gender difference is the underrepresentation of females in STEM fields (science, technology, engineering, and math), as math competencies are an essential part of succeeding in such fields. A related, but distinct, area of research suggests that males tend to outperform females in tasks that require spatial processing (i.e., the ability to mentally visualize, rotate, and transform spatial and visual information). Interestingly, factors from the spatial processing domain (spatial ability and spatial anxiety) are important in explaining gender differences in math anxiety. Here, we examined three types of spatial anxiety and ability (imagery, navigation, and manipulation), as well as math ability, as mediators of gender differences in math anxiety. Undergraduate students (125 male; 286 female) completed assessments of their general level of anxiety, their math anxiety, and their spatial anxiety. They also completed a series of tasks measuring their mathematical skill, their spatial skills, and basic demographics. Results suggest that manipulation anxiety and ability, navigation anxiety, and math ability explained the gender difference in math anxiety, but manipulation anxiety was the strongest mediator of this relation. Conversely, all other measures did not explain the gender difference in math anxiety. These findings help us better understand the gender difference in mathematics, and this is important in reducing the gender gap in STEM fields.


Watching Videos on a Smartphone: Do Small Screens Lead To A Shallower Narrative Experience?

Watching Videos on a Smartphone: Do Small Screens Impair Narrative Transportation. Markus Appel & Christoph Mengelkamp. Media Psychology, Feb 6 2022. https://doi.org/10.1080/15213269.2021.2025109

Abstract: Smartphones are a preferred platform to access audiovisual stories. Prior theory and research suggest that using smaller screens could lead to a shallower narrative experience. In three experiments we examined the influence of screen size (smartphone vs. computer screen) on the experience of being transported into the world of the story (narrative transportation). We further examined interaction effects with manipulations meant to change transportation by means of reviews (Experiment 1, N = 120), consistency of main character information (Experiment 2, N = 139), and prior information meant to facilitate comprehension (Experiment 3, N = 129). Because our series of studies involved theoretically and practically relevant null hypotheses (i.e., screen size does not influence transportation), we added Bayes factor analyses to standard frequentist statistics. A mini meta-analysis was conducted to summarize the results. Taken together, the three experiments indicate that smaller screen size does not impair narrative transportation. Implications and future research are discussed.


After the Yellow Vests movement, the French people would largely reject a tax and dividend policy (a carbon tax whose revenues are redistributed uniformly to each adult): overestimate their net monetary losses, wrongly think that the policy is regressive

Yellow Vests, Pessimistic Beliefs, and Carbon Tax Aversion. Thomas Douenne and Adrien Fabre. American Economic Journal: Economic Policy. Feb 2022, Vol. 14, No. 1: Pages 81-110. https://pubs.aeaweb.org/doi/pdfplus/10.1257/pol.20200092

Abstract: Using a representative survey, we find that after the Yellow Vests movement, French people would largely reject a tax and dividend policy, i.e., a carbon tax whose revenues are redistributed uniformly to each adult. They overestimate their net monetary losses, wrongly think that the policy is regressive, and do not perceive it as environmentally effective. We show that changing people’s beliefs can substantially increase support. Although significant, the effects of our informational treatments on beliefs are small. Indeed, the respondents that oppose the tax tend to discard positive information about it, which is consistent with distrust, uncertainty, or motivated reasoning. (JEL D83, H23, H31, Q54, Q58)



Sunday, February 6, 2022

Semesters or Quarters? The Effect of the Academic Calendar on Postsecondary Student Outcomes

Semesters or Quarters? The Effect of the Academic Calendar on Postsecondary Student Outcomes. Valerie Bostwick, Stefanie Fischer, and Matthew Lang. American Economic Journal: Economic Policy. Feb 2022, Vol. 14, No. 1: Pages 40-80. https://pubs.aeaweb.org/doi/pdfplus/10.1257/pol.20190589

Abstract: There exists a long-standing debate in higher education on which academic calendar is optimal. Using panel data on the near universe of four-year nonprofit institutions and leveraging quasi-experimental variation in calendars across institutions and years, we show that switching from quarters to semesters negatively impacts on-time graduation rates. Event study analyses show that the negative effects persist beyond the transition. Using transcript data, we replicate this analysis at the student level and investigate possible mechanisms. Shifting to a semester: (i) lowers first-year grades, (ii) decreases the probability of enrolling in a full course load, and (iii) delays the timing of major choice. (JEL I23, I28)


Women who earned more than their male partners—thereby making them feel insecure for being the "primary breadwinner"—were 2x as likely to fake orgasms than those who didn’t make more money than their partners

Do Women Withhold Honest Sexual Communication When They Believe Their Partner’s Manhood is Threatened? Jessica A. Jordan et al. Social Psychological and Personality Science, January 31, 2022. https://doi.org/10.1177/19485506211067884

Abstract: We explored whether women who perceive that their partners’ manhood is precarious (i.e., easily threatened) censor their sexual communication to avoid further threatening their partners’ masculinity. We operationalized women’s perceptions of precarious manhood in a variety of ways: In Study 1, women who made more money than their partners were twice as likely as those who did not to fake orgasms. In Study 2, women’s higher perceptions of partners’ precarious manhood indirectly predicted faking orgasms more, lower sexual satisfaction, and lower orgasms rate through greater anxiety and less honest communication. In Study 3, women who imagined a partner whose masculinity was insecure (vs. secure) were less willing to provide honest sexual communication, via anxiety. Together, the studies demonstrate a relationship between women’s perceptions of partner insecurity, anxiety, sexual communication, and sexual satisfaction.

Keywords: faking orgasms, gender threat, orgasm, precarious manhood, sexual communication



Anti-Bisexual Bias

Gendered Anti-Bisexual Bias: Heterosexual, Bisexual, and Gay/Lesbian People’s Willingness to Date Sexual Orientation Ingroup and Outgroup Members. Mackenzie Ess,Sara E. Burke , Marianne LaFrance. Journal of Homosexuality, Feb 3 2022. https://doi.org/10.1080/00918369.2022.2030618

Abstract: Bisexual people may appear to have more potential romantic partners than people only attracted to one gender (e.g., heterosexual, gay, lesbian people). However, bisexual people’s dating choices are limited by non-bisexual people’s reluctance to date bisexual people. Studies have indicated that some heterosexual, gay, and lesbian people are reluctant to date bisexual people, particularly bisexual men. We extend current understandings of gendered anti-bisexual bias through investigating heterosexual, bisexual, gay, and lesbian people’s reported willingness to date within and outside of their sexual orientation groups. Participants (n = 1823) varying in sexual orientation completed measures regarding their willingness to engage in a romantic relationship with heterosexual, bisexual, gay, and lesbian individuals. Heterosexual and gay/lesbian people were less willing to date bisexual people than bisexual people were to date them, consistent with anti-bisexual bias rather than mere in-group preference. Preferences against dating bisexual men appeared particularly strong, even among bisexual women.

Keywords: BisexualitybinegativitydatinggenderLGBTQ+sexual prejudicestereotyping


Spenders were more likely to have psychopathic tendencies, but less likely to be Machiavellian; savers rated themselves as more attractive, healthy, & intelligent than spenders; spenders had more liberal political views & report higher emotional intelligence

Furnham, A., Robinson, C., & Grover, S. (2022). Spenders and savers, tightwads and spendthrifts: Individual correlates of personal ratings of being a spender or a saver. Journal of Neuroscience, Psychology, and Economics, Feb 2022. https://doi.org/10.1037/npe0000155

Abstract: There is limited literature on the causes, correlates, and consequences of being a saver (tightwad) or a spender (spendthrift). This paper reports on five studies which look at demographic, bright- and dark-side personality, money belief, and self-evaluation correlates of to what extent a person considers themselves a spender or saver. In each study, adult participants indicated their spender–saver habits on a single scale and completed a number of tests. The first study looked at trait correlates and showed savers were close-minded, conscientious, stable, extraverts. It also showed as predicted that savers were more likely to associate money with security, and not love or freedom, and claim to have better financial knowledge. The results from the second study on dark-side personality correlates indicated that spenders were more likely to have psychopathic tendencies, but less likely to be Machiavellian. The third study on personality disorder correlates of spender–saver tendencies suggested that spenders were likely to have elevated Cluster B personality disorders. The fourth study examined self-beliefs and showed savers rated themselves as more attractive, healthy, and intelligent than spenders. The fifth study, also using various self-ratings, showed spenders had more liberal political views, report higher emotional intelligence and are less likely to own their own home, while savers rated their physical health higher, and saw themselves as more entrepreneurial. Overall, the results suggest the simple saver–spender question is logically correlated with a number of individual difference variables with savers having a more positive profile. Implications and limitations are considered. 




Consumers who avoid fast food do so not because they think it is unhealthy, but because eating it causes them guilt, and resisting the "sin" gives them a sense of accomplishment

Why Do and Why Don’t People Consume Fast Food?: An Application of the Consumption Value Model. Kiwon Lee, Jonghan Hyun, Youngmi Lee. Food Quality and Preference, Feb 5 2022. https://doi.org/10.1016/j.foodqual.2022.104550

Highlights

• Regular consumers approach fast food mainly due to convenience and taste.

• Non-regular consumers feel a sense of accomplishment when not consuming fast food.

• Regular consumers may avoid fast food when they encounter food safety issues.

• Non-regular consumers may approach fast food when experiencing time pressure.

Abstract: This study explores the nature of the consumption values that differentiate regular consumers of fast food and non-regular consumers using the consumption value model. Data was collected from a total of 307 respondents via a self-administered online survey. The collected data was then classified into two groups, regular consumers (RCs, n=140) and non-regular consumers (non-RCs, n=167), based on the respondents’ self-identification as either a regular fast food consumer or a non-consumer and their fast food consumption frequency (≥ 2-3 times a week for RCs and ≤ 1 time a fortnight for non-RCs). Using factor analysis, 15 factors were extracted for the six consumption values (functional, social, emotional, conditional, epistemic, and process values). Discriminant analysis showed that 5 factors out of those 15 are influential in discriminating RCs and non-RCs. Specifically, RCs were found to consume fast food due to convenience and taste whereas non-RCs were found to avoid fast food due to the feelings of guilt when consuming fast food and the sense of accomplishment when not consuming fast food. Also, RCs and Non-RCs were found to deviate from their normal behavior when certain conditions are present (e.g., food safety issue, time pressure, stress). In all, the results of this study provide marketers a clearer understanding of the consumption values that regular consumers and non- regular consumers perceive in fast foods, further enabling the development of marketing strategies that appeal better to current and potential customers.

Keywords: fast foodconsumption valueconveniencetasteguilt


Positive emotions produce no or weak and highly variable increases in autonomic nervous system activity

Autonomic Nervous System Activity During Positive Emotions: A Meta-Analytic Review. Maciej Behnke et al. Emotion Review, February 4, 2022. https://doi.org/10.1177/17540739211073084

Abstract: Autonomic nervous system (ANS) activity is a fundamental component of emotional responding. It is not clear, however, whether positive emotional states are associated with differential ANS reactivity. To address this issue, we conducted a meta-analytic review of 120 articles (686 effect sizes, total N = 6,546), measuring ANS activity during 11 elicited positive emotions, namely amusement, attachment love, awe, contentment, craving, excitement, gratitude, joy, nurturant love, pride, and sexual desire. We identified a widely dispersed collection of studies. Univariate results indicated that positive emotions produce no or weak and highly variable increases in ANS reactivity. However, the limitations of work to date – which we discuss – mean that our conclusions should be treated as empirically grounded hypotheses that future research should validate.

Keywords: positive emotions, autonomic nervous system, cardiovascular activity, electrodermal activity

In this quantitative review, we aimed to inspect, evaluate, and synthesize (to the extent possible) findings from past research that measured a physiological component of positive emotions. We found the available data to be quantitatively imbalanced, with many studies focused on some positive emotions and physiological signals and few studies focused on other positive emotions and physiological signals. Furthermore, we found high variability in methods used for emotion elicitation and data collection. Recognizing that the empirical evidence might be insufficient to test some effects, we aimed to use all available empirical data and stringent criteria for multiple hypothesis testing to examine whether the currently available empirical findings allow us to conclude that positive emotions elicit ANS reactivity. We also explored whether the ANS reactivity is specific to discrete emotions (in terms of patterns and magnitudes) or—alternatively—whether similar ANS reactivity accompanies all positive emotions. Finally, we tested participant characteristics and methodological factors as moderators of the ANS reactivity to discrete positive emotions. One main and three secondary findings emerged.

Based on univariate analyses, most discrete positive emotions elicited no or weak ANS reactivity. Moreover, half of the effect sizes in ANS responses were highly inconsistent, suggesting that other significant physiological variability sources exist. We also found that similarities outweighed differences in ANS responses during positive emotions. This contrasts the literature suggesting a stronger physiological differentiation among discrete positive emotions (Kreibig, 2010Shiota et al., 2017). Finally, we found few moderating effects of study or participant characteristics. Thus, the current empirical material supports the view that positive emotions produce no or only a weak and nonspecific ANS response relative to baseline and neutral conditions (Cacioppo et al., 2000Lench et al., 2011Siegel et al., 2018).

However, we emphasize that these conclusions must be considered tentative because they are based upon imbalanced and incomplete data and one type of analysis (univariate, not multivariate). This suggests the need for more systematic research on the physiology of positive emotions that will fill existing gaps and provide material for future robust evaluation of positive emotions and ANS activity. For instance, impedance cardiography that is often applied to the study of stress and negative emotions is relatively underrepresented in the study of positive emotions. Moreover, the psychophysiological study of amusement is greatly overrepresented relative to gratitude, pride, or love. Finally, we advocate more multivariate sampling and analysis of emotional responses in positive emotions.

Positive Emotions and ANS Reactivity: The State-Of-The-Art

We based this review on the most extensive collection of available studies, which produced over 686 effect sizes derived from 6,546 participants. However, in the coding process, we observed substantial variability across this large number of studies, which resulted in the collection of a widely dispersed dataset. The studies were conducted in different settings. For instance, the laboratories used various equipment, procedures, and data cleaning and analysis techniques. Most studies examined only reactivity related to two emotions using 2-3 ANS measures with a single elicitation method. Furthermore, when coding the possible moderators, in many cases, we were unable to determine whether participants were alone during the experimental task or the experimenter stayed in the room after placing the physiological sensors. We found that only 44% of studies explicitly stated that they video recorded participants during the experiments. In this way, our meta-analysis supports the message from the recent comment on the current state of the science of positive emotion (Shiota, 2017) - although the field made incredible progress in the last decades, affective scientists are still far away from the promise of this field being fully realized. This also includes the call for more detailed reporting of procedures (e.g., were participants explicitly observed) and data use (e.g., duplicate datasets).

The data collected so far on positive emotion is insufficient to strongly support the ANS specificity versus similarity for a wide range of positive emotions presented in our investigation. Our analyses were challenging due to a widely dispersed dataset with small numbers of studies per emotion and per ANS measure. Moreover, some comparisons and analyses were performed on a relatively small number of effect sizes. Although the field of affective science struggles to just-decide-already whether specificity or similarity of ANS emotion-related reactivity is the ground truth, with this review, we observed that the current state-of-the-art is not sufficient to address this expectation for definite conclusions. While reviewing hundreds of studies, we also observed that researchers moved quickly to asking complex questions related to functions of targeted emotion without addressing more basic questions, e.g., which ANS parameters are adequate for studying a specific positive emotion. We suggest that a return to more basic questions might advance the field of psychophysiology of emotions. It would be beneficial for the field of positive emotions to further examine ANS reactivity, in particular, to positive emotions that have not been explored yet, such as hope or schadenfreude, using multiple ANS measures. We advocate that the field of positive emotions would benefit from greater integration and uniform standards/rigor for emotion elicitation and data curation, analysis, and reports.

Do Positive Emotions Produce Robust Changes in ANS Reactivity?

We found that the set of inspected positive emotions produce no or weak increases in ANS reactivity in both SNS and PNS. Our findings are consistent with models of positive emotions that assumed that positive emotions do not generate independent sympathetic responses (Fredrickson & Levenson, 1998Fredrickson et al., 2000Fredrickson, 2013Folkman, 2008Levenson, 19881999). Moreover, we did not observe increased PNS reactivity in positive emotions, as suggested by the polyvagal theory (Porges, 2011). One explanation for these null results is that large differences across experiments might be responsible for the responding range. Figure 2 presents that even the mean effects interpreted as medium sizes had wide confidence intervals that prevented them from being significant. These findings are consistent regardless of focusing only on separate ANS measures, measures that had more than ten studies, or measures aggregated into broader categories.

Our findings match previous meta-analyses focused on happiness that concluded that happiness produces weak ANS reactivity and that this reactivity is not different from neutral conditions (Lench et al., 2011Siegel et al., 2018). Our findings do not support conclusions from qualitative reviews in which some positive emotions such as contentment and love decreased cardiovascular or electrodermal activity (Kreibig, 2010). However, more than half of the physiological responses’ directions in the qualitative review were based on fewer than three studies, suggesting that these findings were preliminary (Kreibig, 2010). With additional studies that were published over the last decade, we found support for the previously found directions of the electrodermal reactivity (increases) to positive emotions. We also found support for increased ANS activity to joy and amusement (Kreibig, 2010).

Are ANS Reactivity Patterns Specific to Particular Positive Emotions?

The main goal was to provide a quantitative review of the body of research related to ANS reactivity and positive emotions. However, we also evaluated the specificity or generality of ANS reactivity to discrete emotions. The basic expectation in this meta-analysis was that discrete positive emotions produce specific adaptive changes in physiology (Ekman & Cordaro, 2011Levenson, 2011; Panksepp & Watt, 2011; Kreibig, 2010).

We found that similarities outweighed differences in ANS responses during positive emotions. This finding is consistent with the models that view ANS reactivity to emotion as context-sensitive and not discrete-emotion-sensitive (Barrett, 20132017Quigley & Barrett, 2014). Thus, the ANS reactivity is not random but is specific and supports actions in the specific context, which could vary for the same discrete emotion (Barrett, 2006Barrett & Russell, 2015Quigley, & Barrett, 2014). Theorists suggest that multiple distinct, context-sensitive physiological responses to discrete emotion are possible, as long as both serve the same adaptive function, e.g., freezing versus fleeing from a threat in fear (Ekman, 1992).

However, the ANS reactivity is only one component of emotional responding. Thus, major judgments about the structure of emotions should be interpreted along with affective and behavioral responses and should not be based solely on any one component.

Shared ANS reactivity to positive emotions might be related to common neural origin from a highly conserved circuit of neural structures, namely the mesolimbic pathway, often called the “reward system” (see Shiota et al., 2017 for discussion). The activation along the mesolimbic pathway has been linked to a wide range of stimuli associated with the family of positive emotions, including delicious foods (Berridge, 1996), monetary incentives (Knutson et al., 2001), babies (Glocker et al., 2009), loved ones (Bartels & Zeki, 2004), humor (Mobbs et al., 2003), and favorite music (Blood & Zatorre, 2001). It may explain the mechanism by which the discrete positive emotions share some overlapping properties that might be further differentiated depending on the conditions in which positive emotions are activated. Overlapping properties of positive emotions and continuous gradients between discrete emotion categories have been found in recent large-scale investigations (Cowen & Keltner, 2017). That study has shown that emotions were more precisely conceptualized in terms of continuous categories, rather than discrete emotions, showing smooth gradients between emotions, such as from calmness to aesthetic appreciation to awe (Cowen & Keltner, 2017).

Supporting the dimensionality of emotions, we found differences along the dimension of approach motivation (Gable & Harmon-Jones, 2010Harmon-Jones et al., 2013). Positive emotions characterized by strong approach tendencies, such as joy and excitement, were accompanied by a higher sympathetic reactivity (e.g., DBP, MAP) than low-approach positive emotions like amusement. Our investigation may serve future studies to conceptualize positive emotions in terms of physiological arousal starting from the least arousing and ending with the most arousing positive emotions, namely awe, attachment love, gratitude, nurturant love, contentment, excitement, amusement, pride, craving, sexual desire, and joy.

Are There Moderators of ANS Reactivity to Positive Emotions?

We investigated several moderators that we thought might influence physiological responsiveness to emotions, but most did not moderate the observed effects. Only in craving did we observe a significant moderating effect of the elicitation method on the physiological response. We observed that behavioral methods, namely, exposure to food, produced stronger ANS reactivity than pictures, films, and imagery. This observation indicates the advantage of using active rather than passive emotion elicitation methods. Furthermore, in line with Lench and colleagues (2011), we found that reactions to craving were stronger when the proportion of women in samples increased.

Contrary to our expectations, we found no influence of several continuous variables on physiological reactivity to positive emotions, including age, sex proportion, participant number, and study quality (Kret & De Gelder, 2012; Stevens and Hamann, 2012Mill et al., 2009Sullivan et al., 2007). Like the previous meta-analysis of Lench and colleagues (2011), we found no evidence that the participants’ age influenced the degree of emotional reactivity. However, this may be due to imbalanced age distribution (skewed young), meaning we were underpowered to detect age differences. A thorough examination of how age influences the emotional experience's intensity requires additional research with older participants. In line with previous meta-analyses, we found no sex differences in response to positive emotions (Joseph et al., 2020Siegel et al., 2018). Finally, although we found indications of publication bias for some pairs of ANS reactivity and positive emotion, we conclude that most mean effect sizes seem to be robust and unlikely to be an artifact of systematic error.

Limitations and Future Directions

First, as we emphasize throughout the paper, the conclusions we present are provisional and contingent upon current data availability. More definitive conclusions will await additional research, particularly on under-researched positive emotions and measures.

Second, in this project, we used a univariate approach to analyze the mean ANS reactivity to discrete positive emotions in a series of meta-analyses. Although available multivariate meta-analytic approaches (Riley et al., 2017) would provide a better fit to the characteristic of emotions (Kragel & LaBar, 2013Stephens et al., 2010), several factors militated against using a multivariate approach. For instance, a multivariate meta-analysis requires a correlation matrix between the ANS measures. This was not possible to obtain because only 7 out of 128 articles included in our investigation reported correlations between some ANS measures. Along similar lines, for many analyses (e.g., amusement), two or more ANS measures were never observed jointly in the same study. Moreover, a previous meta-analysis found that multivariate pattern classifiers did not provide strong evidence of a consistent multivariate pattern for any emotion category (Siegel et al., 2018). Of note, the multivariate and univariate models produce similar point estimates, but the multivariate approach usually provides more precise estimates. Thus, the benefits of a multivariate meta-analysis are small (Riley et al., 2017). The advantages of using multivariate meta-analysis of multiple outcomes are greatest when the magnitude of correlation among outcomes is large, which was not the case for most of our analyses. In conclusion, our approach can produce statistically valid results for each pair of positive emotion and ANS reactivity measures (Pustejovsky & Tipton, 2021). Future studies might collect multiple physiological measures when studying ANS reactivity to emotions (Cacioppo et al., 2000) to provide data that allows for robust multivariate analyses.

Third, we used univariate statistics, which disrupt the physiological response's continuity and treat the entire emotion manipulation as a separate piece. Although univariate methods have historically dominated the literature (see Cacioppo et al., 2000Kreibig, 2010, for the reviews), future reviews may use multivariate approach data to replicate our findings.

Fourth, during the coding, we relabeled examined emotions in many studies. However, we found no differences in effect sizes extracted from studies with the original emotion label and effect sizes extracted from studies for which we renamed the emotion label. Moreover, the conclusions that come from our literature research stress the importance of using precise terminology in emotion-related literature. The overview of existing empirical and theoretical models indicates not only a variety of discrete positive emotions but also a variety of terms used to describe them. For instance, researchers used different labels for emotions elicited by funny situations, such as amusement (Kreibig et al., 2013), happiness (Kring & Gordon, 1998), or mirth (Foster et al., 2003). The heterogeneity of labels suggests problems with discrete emotions’ construct validity and measurement invariance. Future research would benefit from a more uniform nomenclature and definitions accepted by researchers within affective science.

Fifth, most of the theoretical and empirical models conceptualize individual positive emotions without clearly addressing how different positive emotions might be interrelated (e.g., Cowen and Keltner, 2017Ekman and Cordaro, 2011Tong, 2015; Weidman & Tracy, 2020, with the exception of Kreibig, 2014; and Shiota et al., 2017). It might be useful to group discrete emotions into families or clusters based on their similarities. For instance, joy and excitement are similar emotions associated with progress in achieving one's goals, but excitement has an anticipatory response compared to joy that brings well-being and good fortune after an event (Lazarus, 1991Shiota et al., 2017Smith & Kirby, 2010). Future studies may focus on examining similarities rather than differences between positive emotions. Researchers should also balance between generalization and differentiation in studying emotions.

A sixth limitation resulted from including studies that examined physiological reactivity from baseline or neutral conditions. The results produced by these studies differ due to differences in the design of these studies. Some research used neutral movies as a baseline (e.g., De Wied et al., 2009), whereas other studies used neutral videos in the experiment (e.g., Codispoti et al., 2008). We followed the theoretical premise that both baselines and neutral conditions should be emotionally impartial. A moderation analysis showed that the type of comparison used in primary studies had no effect on the size of the physiological reactivity. These results allowed us to examine further hypotheses, but both decisions of including different types of comparison and relabeling the emotion categories may have produced bias in the results of our meta-analysis. Given the considerable increase in psychophysiological research on emotions in recent years, future meta-analytic work would provide empirical support for the emotional impartiality of baseline and neutral conditions.

Seventh, we found substantial research methodology variability in primary studies. We tested whether the study quality moderated the effect sizes by assessing the presence of exclusion criteria, manipulation check procedures, and protocols for reporting or handling artifacts and missing data. We found those three measures to be objective indicators of study quality. However, the study quality had no effect on the size of physiological reactivity. More studies that include multiple ANS measures and multiple discrete positive emotions with diverse samples are required to strengthen broad inferences about ANS responses to positive emotions. Future studies might also examine how emotions differ in ANS reactivity rather than asking whether emotions generally differ physiologically (e.g., Berntson et al., 1991Stemmler, 1992). ANS reactivity produces the optimal bodily milieu to provide physiological support for behaviors associated with discrete emotion (Levenson, 2014). This requires unique configurations of multiple physiological responses rather than a single unique physiological change (Levenson, 2014). Single ANS measures might not be sufficient, given that most physiological measures used in the emotion-related literature constitute the physiological outcome of emotion-related states, showing a one-to-many relation between the physiological measure and emotions (see Cacioppo et al., 2000Richter & Slade, 2017 for the discussion). Groups of emotions may lead to similar general activation that occurs in response to an upcoming action (Brehm, 1999; Fredrickson & Levenson, 1998; Frijda, 1987). For instance, excitement, craving, or sexual desire prepare the organism to “be ready for action,” and they produce similar sympathetic activation. However, more specific activity might be observed in targeted organs. For instance, craving might be observed in the gastrointestinal tract, sexual arousal in the genital system, and excitement in the locomotor system (Levenson, 20112014).

Eighth, most of the ANS variables included in our meta-analysis are blends of SNS and PNS activation (e.g., HR). The measures more specifically related to PNS or SNS measures (e.g., RSA or PEP) were not broadly assessed across the positive emotions. Thus, we could not fully address whether positive emotions produce pure SNS or PNS activity but rather the co-product of one of the two systems.

Nineth, we believe that our meta-analysis opened the discussion for methodological issues in the psychophysiology of emotions that would be worth testing empirically. For instance, for moderators, we focused on the length of the time interval used to calculate the physiological levels for baselines and emotion manipulations. Although we did not find effects of the time interval on mean ANS reactivity to positive emotions, we believe that comparing different time intervals of the same physiological measure is problematic. Similarly, researchers usually used the same time intervals to present the reactivity of all ANS measures despite differences across the family of ANS variables. Thus, scientists tended to sacrifice the specificity of particular ANS measures for the sake of a uniform data analysis strategy.

Saturday, February 5, 2022

Women perceived greater competitive tendencies in their fellow females when resources were plenty, rather than scarce

Bradshaw, H. K., Krems, J. A., & Hill, S. E. (2022). Resource availability differentially influences women’s perceptions of same- (versus cross-) sex others’ competitiveness. Evolutionary Behavioral Sciences, Feb 2022. https://doi.org/10.1037/ebs0000289

Abstract: Across four studies, the current research tested the prediction that women would perceive greater competitive tendencies in same- (vs. cross-) sex others when resources were scarce. Contrary to predictions, results found evidence that women perceived more competitive tendencies in same- (vs. cross-) sex targets when resources were abundant. Study 1 demonstrated that women (but not men) perceived greater competition within groups of female same-sex targets (vs. groups of male same-sex targets and groups of cross-sex targets) residing in ecologies where resources were widely available; no such pattern emerged when judging competition within groups residing in ecologies where resources were scarce. In Study 2, women (but not men) who held relatively low levels of resource scarcity beliefs (i.e., those who believed resources were relatively abundant) attributed greater competitive tendencies to same-sex targets than cross-sex targets. Study 3 showed that enacting a resource abundance (but not a scarcity) mindset led women to expect same-sex targets to behave more competitively toward them than cross-sex targets; this effect, however, did not replicate in Study 4. With the exception of Study 4, these data suggest that, contrary to intuition—and our predictions—women perceive same-sex others to be more competitive than cross-sex others when resources are abundant.


Do restaurant customers who receive an unreasonably low bill bring it to the server’s attention? A field experiment on dishonesty

Do restaurant customers who receive an unreasonably low bill bring it to the server’s attention? A field experiment on dishonesty. Yossef Tobol, Erez Siniver, Gideon Yaniv. Journal of Economic Psychology, February 4 2022, 102491. https://doi.org/10.1016/j.joep.2022.102491

Abstract: Inspired by Azar et al., 2013, Azar et al., 2015 study of customers’ tendency to return excessive change in a restaurant, the present paper reports the results of a field experiment destined to examine restaurant customers’ honesty in a different real-life situation where customers receive an unreasonably low bill. To ensure that customers noticed the error in the bill, the experiment was restricted to single customers who ordered two items only (e.g., coffee and a toasted sandwich), presenting them with a bill from which one item, either the more or the less expensive one, was omitted. A majority of customers (169 out of 278) failed to bring the error to the server’s attention. Several factors appeared to have a large effect on the decision of whether to report the bill error. Female customers reported the error in the bill much more often than male customers, customers whose more expensive item was omitted from the bill reported the error twice as often than customers whose less expensive item was omitted, repeated customers (presumably) reported the error much more often than one-time customers and customers who paid with a credit card reported the error much more often than customers who paid in cash. We also consider the possibility that the means of payment is a choice variable determined by the decision of whether or not to bring the error in the bill to the server’s attention.

Keywords: Field ExperimentRestaurant CustomersBill ErrorDishonest Behavior

Check also A field experiment on dishonesty: A registered replication of Azar et al. (2013). Jakub ProchÙ„zka, Yulia Fedoseev, Petr Houdek. Journal of Behavioral and Experimental Economics, September 2020, 101617. https://www.bipartisanalliance.com/2020/09/replication-of-azar-et-al-2013-70-of.html