Wednesday, January 6, 2021

Maybe rodents regulate a ratio of protein to dietary carbohydrates in order to achieve metabolic benefits (reduced insulin levels, improved blood glucose control, and, in the long term, reduced weight & fat gain)

What does self‐selection of dietary proteins in rats tell us about protein requirements and body weight control? Patrick C. Even  Joséphine Gehring  Daniel Tomé. Obesity Reviews, January 5 2021.

Rolf Degen's take:

Summary: Omnivores are able to correctly select adequate amounts of macronutrients from natural foods as well as purified macronutrients. In the rat model, the selected protein levels are often well above the requirements estimated from the nitrogen balance. These high intake levels were initially interpreted as reflecting poor control of protein intake, but the selected levels were later found to be precisely controlled for changes in dietary protein quality and adjusted for cold, exercise, pregnancy, lactation, age, etc. and therefore met physiological requirements. Several authors have also suggested that instead of a given level of protein intake, rodents regulate a ratio of protein to dietary carbohydrates in order to achieve metabolic benefits such as reduced insulin levels, improved blood glucose control, and, in the long term, reduced weight and fat gain. The objective of this review was to analyze the most significant results of studies carried out on rats and mice since the beginning of the 20th century, to consider what these results can bring us to interpret the current causes of the obesity pandemic and to anticipate the possible consequences of policies aimed at reducing the contribution of animal proteins in the human diet.

Chimpanzees: Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males

The development of affiliative and coercive reproductive tactics in male chimpanzees. Rachna B. Reddy, Kevin E. Langergraber, Aaron A. Sandel, Linda Vigilant and John C. Mitani. Proceedings of the Royal Society B: Biological Sciences, January 6 2021.

Rolf Degen's take:

Abstract: Like many animals, adult male chimpanzees often compete for a limited number of mates. They fight other males as they strive for status that confers reproductive benefits and use aggression to coerce females to mate with them. Nevertheless, small-bodied, socially immature adolescent male chimpanzees, who cannot compete with older males for status nor intimidate females, father offspring. We investigated how they do so through a study of adolescent and young adult males at Ngogo in Kibale National Park, Uganda. Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males. Two other factors, affiliation and aggression, also influenced mating success. Specifically, the strength of affiliative bonds that males formed with females and the amount of aggression males directed toward females predicted male mating success. The effect of male aggression toward females on mating success increased as males aged, especially when they directed it toward females with whom they shared affiliative bonds. These results mirror sexual coercion in humans, which occurs most often between males and females involved in close, affiliative relationships.

4. Discussion

The results presented here suggest that adolescent male chimpanzees, who cannot effectively compete with older males nor sexually coerce adult females, employ at least two behavioural tactics to mate and reproduce. First, as reported in previous research, adolescent males appear to target adolescent, nulliparous females as mating partners; they mate with nulliparous females frequently and father their first offspring more often in adolescence than they do in adulthood [42,48]. Our findings also corroborate past research indicating that nulliparous female chimpanzees are less preferred as mating partners than are parous females. Specifically, as male chimpanzees transition from adolescence to adulthood and rise in dominance rank, they show less sexual interest in nulliparous females and target them for aggression infrequently [47]. High-ranking males also rarely father the first offspring of these females [3337,42]. Second, mating success for adolescent and young adult males was predicted by the strength of affiliative bonds that males formed with females. Male aggression, by contrast, had a relatively weak relationship with mating success, but one that strengthened as males grew older and increasingly dominant to females.

These findings increase our understanding of the nature of sexual coercion in chimpanzees. We have recently shown that adolescent and young adult males selectively direct aggression toward females with whom they form strong affiliative bonds [49]. Here, we demonstrate that aggression has a reduced effect on mating success outside of these bonds for young, adolescent males who are not yet physically mature and unlikely to dominate females [49,54,71]. Instead, mating success increases when an older adolescent or young adult male directs aggression to a female with whom he frequently affiliates and can dominate.

These results complement prior research that indicates aggression, mating and reproduction are linked in chimpanzees [28,30,31] and clarify the role that affiliation plays in creating those linkages. Specifically, sexual coercion is more effective when adolescent and young adult males have affiliative bonds with the females they attack. One reason may be that females suffer higher costs if they refuse to mate with males with whom they frequently affiliate compared to males with whom they rarely affiliate [12]. The nature of these costs remains to be explored. Nor is it clear whether and how affiliative relationships with males benefit female chimpanzees. It is important to note that our findings are consistent with patterns of intersexual aggression in other species where males are highly aggressive to females with whom they share bonds. This includes hamadryas baboons (Papio hamadryas), where females live in one-male groups, and most social activity is directed by the single males in these groups, i.e. ‘leader males’. After being attacked by their leader male, hamadryas females appear fearful and follow him even more closely than they had previously [72]. In our own species too, many women are subject to frequent sexual coercion by their male partners, but often remain in such relationships for reasons that vary widely [73].

Scant data exist about the proximate psychological mechanisms that underlie male aggression and female compliance in chimpanzees. However, investigating these proximate mechanisms may provide information about how bonds that affect paternity in chimpanzees might lead to a human-like social system [74]. One interpretation consistent with our preliminary observations is that male aggression toward their social partners is motivated by sexual possessiveness (e.g. [73]), and that females have a psychologically distinct experience when attacked by a male with whom they have an affiliative bond. For example, adolescent and young adult males make direct attacks on male peers infrequently, but when they do so, it is when another male mates or attempts to mate with one of their female social partners [49]. Anecdotally, when female chimpanzees received aggression from an adult male who did not have a strong affiliative bond with them, they often just screamed and ran away. Females receiving similar aggression from males with whom they shared strong affiliative relationships, however, react in an entirely different way. When attacked, these females remain in place, lunge toward their male partners while clutching their arms, rocking back and forth, and screaming repeatedly until making choking sounds.

Our study has several limitations. First, we cannot evaluate the relative impacts of affiliation and aggression on adolescent male paternity success. Only seven males in this study have reproduced thus far, siring 15 offspring, creating a small sample to make strong inferences. Our preliminary findings based on this small sample suggest that males who affiliate with and direct aggression to specific females gain a reproductive advantage with those females, but additional data are clearly needed. As these data accumulate, evaluating the effects of affiliation and aggression on male reproduction will be complicated because additional factors that we have not considered will require examination. For instance, we are likely to have underestimated the importance of sexual coercion, as it may act to ensure mating exclusivity as well as increasing a male's ability to mate with a specific female [12]. In this context, aggression is often used to initiate consortships in chimpanzees, where males lead females away from other community members and mate with them exclusively for several days (e.g. [21]). The challenge of maintaining exclusivity is not uniform. It may be relatively easy for high-ranking males because fewer males will challenge them to mate, or easier to accomplish with nulliparas, who are not preferred mating partners [47]. Second, we conducted this study over a relatively short period spanning two years, which covered only a single reproductive cycle for most females. Additional research is required to determine whether affiliative bonds between males and females endure and whether the patterns of aggressive and affiliative behaviour between bonded pairs persist and impact male reproduction over the long term (e.g. [30,37]). Determining whether such long-term relationships exist and how they impact male mating and reproductive success will improve our understanding of male chimpanzee development and the functional consequences of their behaviour.

Our findings also provide insights into the evolution of human pair bonds. Although the mechanisms that ensure paternity certainty in our species are diverse, including intimate partner violence [7375] and larger cultural structures (e.g. religion: [76,77]), our finding that affiliative bonds between males and females appear entwined with sexual coercion in one of our two closest living relatives suggests that this aspect of intersexual relationships may be embedded deeply in our past.

Previous research suggests that choice causes an illusion of control—that it makes people feel more likely to achieve preferable outcomes, even when they are selecting among options that are functionally identical

Does Choice Cause an Illusion of Control? Joowon Klusowski, Deborah A. Small, Joseph P. Simmons. Psychological Science, January 5, 2021.

Abstract: Previous research suggests that choice causes an illusion of control—that it makes people feel more likely to achieve preferable outcomes, even when they are selecting among options that are functionally identical (e.g., lottery tickets with an identical chance of winning). This research has been widely accepted as evidence that choice can have significant welfare effects, even when it confers no actual control. In this article, we report the results of 17 experiments that examined whether choice truly causes an illusion of control (N = 10,825 online and laboratory participants). We found that choice rarely makes people feel more likely to achieve preferable outcomes—unless it makes the preferable outcomes actually more likely—and when it does, it is not because choice causes an illusion but because choice reflects some participants’ preexisting (illusory) beliefs that the functionally identical options are not identical. Overall, choice does not seem to cause an illusion of control.

Keywords: choice, illusion of control, open data, open materials, preregistered

Across 17 studies, we found no evidence that choice causes an illusion of control. Choice rarely made people feel more likely to achieve preferable outcomes when all options were functionally identical, whether we used different outcome measures (Studies 1–3), made the process visual (Study 4), varied the levels of uncertainty (Studies 5–7), or increased the subjectivity of the outcome evaluations (Studies 8 and 9). Choice had such effects only when it conferred actual control (Studies 10 and 11). In the rare cases in which choosers felt more likely to achieve preferable outcomes (Studies 12–15), choice seemed to reflect people’s preexisting beliefs rather than cause an illusion (Studies 16 and 17).

Our findings that a purported effect of choice results from an alternative account shares similarities with other reinvestigations of classic findings. Specifically, Chen and Risen (2010) showed that what looks like a choice-driven attitude change via cognitive-dissonance reduction in fact occurs because the choice is used to select people with different attitudes in the first place. Similarly, Tong, Feiler, and Ivantsova (2018) showed that what appears as choice-driven overoptimism via motivated reasoning emerges because choice reveals options that people already overestimate. Likewise, we revisited the highly influential and widely accepted phenomenon that choice causes an illusion of control. We found that such patterns rarely occur in cleanly designed experiments, and when they do, they are due to the choice reflecting people’s preexisting beliefs rather than causing an illusion. Together, this line of work suggests that some purported effects of choice may be due to the choice acting as a selection mechanism—among either different participants or different options—rather than as a cause of such effects.

Despite our attempts to provide a comprehensive investigation, multiple questions remain.

First, our research does not address what might moderate the difference between the nonsignificant (Studies 1–11) and the significant (Studies 12–15) effects of choice. One possibility is that the probability estimates used in the latter studies are more sensitive than the other measures. In fact, our result from Study 15, which directly compared the probability estimates and multiple-choice measures, seems consistent with this conjecture. However, the nonsignificant coefficients in Studies 1 to 9 do not have a consistently positive sign, which is not what one would expect if the measures were merely less sensitive. Moreover, Studies 10 and 11 directly show that these measures were sensitive enough to respond when the choice made the preferable outcomes actually more likely. Another possibility is that evaluating multiple options in Studies 12 to 15 makes people more likely to develop normatively incorrect beliefs and hence more likely to show patterns that appear consistent with a choice-driven illusion of control. When one evaluates multiple options, there is a greater number of ways to express normatively incorrect beliefs (vs. only one way to express the normatively correct belief) than when one evaluates a single option, which might facilitate such beliefs. However, our results from Studies 12 to 14 indicate that the number of evaluated options does not always moderate the effect of choice. Although our research did not address these puzzling discrepancies, subsequent research could examine what may explain them.

Second, we do not know what led a subset of participants to demonstrate preexisting illusions, even when we explicitly informed them that all options have identical prospects (Studies 16 and 17). It is possible that certain individuals were prone to forming these beliefs because of past experiences, superstitious thinking, or distrust, but our research did not address what causes these beliefs or whether they are generalizable to people outside of our samples (Harris & Osman, 2012Risen, 2016Sharpe, Adair, & Roese, 1992). Future research could examine what individual or situational factors can lead people to develop such beliefs in the face of instructions that contradict them.

Third, our research focused on choice and thus did not address other factors that might truly cause an illusion of control. Previous research suggests additional factors that might cause an illusion of control (e.g., competition, familiarity, active involvement; Langer, 1975Martinez et al., 2009). Although our research suggests that choice is unlikely to cause an illusion of control itself, it is possible that these other factors could.

In conclusion, past research suggests that choice can be powerful even without conferring actual control because it creates an illusion of control. Our research suggests a more sober perspective on the value of choice: Choice simply enables people to get what they want.

Empathy for joy recruits a broader prefrontal network than empathy for sadness; prefrontal cortex activation during both types of empathy was positively predicted by working memory capacity

Taiwo, Z., Bezdek, M., Mirabito, G., & Light, S. N. (2021). Empathy for joy recruits a broader prefrontal network than empathy for sadness and is predicted by executive functioning. Neuropsychology, 35(1), 90–102.

Rolf Degen's take:

Abstract: Empathy encompasses the ability to contemplate and vicariously share in the emotional life of others, and is critical for social interaction, and may enhance subjective happiness.

Objective: While a few theoretical models propose that executive function may play a role in empathy, it is unknown how variation in executive function, and underlying variation in key large-scale brain network nodes, such as the dorsolateral prefrontal cortex node within the executive control network—or the medial prefrontal cortex (PFC) node within the mentalizing/theory of mind network—may account for individual differences in empathy capacity.

Method: The relationship between individual differences in executive capacity—parsed into working memory, inhibition, and cognitive flexibility subdomains—and magnitude of activity in a priori identified PFC subregions during a functional MRI-based ecologically valid empathy induction paradigm, was investigated. Empathic happiness (i.e., vicarious joy) and empathic concern (i.e., vicarious sadness) in response to the life circumstances of actual people were measured at separate time points as brain functional MRI was obtained. Participants also completed executive-heavy clinical neuropsychological tasks outside of the scanner.

Results: Frontopolar PFC was activated across both types of empathy. However, empathic happiness related to engagement of a much broader network of prefrontal cortex subregions relative to empathic concern: spawning frontopolar, dorsolateral, and medial aspects. PFC activation during both types of empathy was positively predicted by working memory capacity.

Conclusion: Activation in core aspects of the working memory-executive control network, and core happiness-related aspects of the mentalizing brain network (i.e., medial PFC and precuneus) predicted greater empathy capacity.

Documenting individual differences in the propensity to hold attitudes with certainty

DeMarree, K. G., Petty, R. E., Briñol, P., & Xia, J. (2020). Documenting individual differences in the propensity to hold attitudes with certainty. Journal of Personality and Social Psychology, 119(6), 1239–1265.

Abstract: The certainty with which people hold their attitudes is an important consideration because attitudes held with certainty better predict judgment and behavior than attitudes held with doubt. However, little is known about whether people’s assessments of their certainty reflect a disposition to hold attitudes with confidence. Adapting methods used to document individual differences in people’s attitudes, the present research demonstrates that the certainty with which people hold any given attitude is in part a reflection of a relatively stable disposition. Across 5 studies and 6 samples (total N = 106,050), we demonstrate dispositional variability in attitude certainty and show that it is related to but distinct from confidence in other judgmental domains. We also demonstrate that dispositional attitude certainty may be useful in predicting certainty in newly formed evaluations (Study 3) and an important consequence of certainty—attitude-behavior correspondence (as indicated by reports of behavioral intentions and recent behavior; Study 4 and Student Sample in Study 5). Furthermore, we demonstrate that dispositional attitude certainty is relatively stable over time (Study 5). Results are discussed with respect to potential mechanisms and boundary conditions relating to dispositional attitude certainty, the implications of these individual differences for attitudes and persuasion, as well as the potential origins of dispositional attitude certainty.

Women reported slightly more openness to uncommitted sexual relationships during the peri-ovulatory session, but significant differences were restricted only to women who exhibited the luteinizing hormone surge

Variation in sociosexuality across natural menstrual cycles: Associations with ovarian hormones and cycle phase. Urszula M. Marcinkowska et al. Evolution and Human Behavior, Volume 42, Issue 1, January 2021, Pages 35-42.

Abstract: The psychological construct of sociosexuality—one's sexual openness or propensity to engage in uncommitted sexual relationships—has been broadly examined within numerous cultures and mating contexts. Although there is some evidence suggesting that components of sociosexuality, namely behavior, desire and attitude, change within-person, relatively little research has investigated potential sources of such variation. The aim of our study was to explore if the individual components of sociosexuality change across the menstrual cycle, either as a function of cycle phase or ovarian hormones. One hundred and two naturally cycling women, both single and in a committed relationships, completed questions from the the SOI-R (Sociosexuality Revised) questionnaire three times during a menstrual cycle, scheduled to coincide with their early follicular, peri-ovulatory, and luteal phases. Women provided saliva samples and performed luteinizing hormone tests to distinguish between ovulatory and anovulatory cycles. Women reported slightly more openness to uncommitted sexual relationships during the peri-ovulatory session, but significant differences were restricted only to women who exhibited the luteinizing hormone surge. Ovarian hormone concentrations within cycles significantly predicted SOI Attitude and Desire scores, with estradiol positively related, and progesterone negatively related to openness to uncommitted sexuality. These effects were generally modest in size. The results of this study suggest that sociosexuality can vary within short periods of time, such as a single menstrual cycle.

Keywords: SociosexualitySOI-RMenstrual cycleLH testsEstradiolProgesteronePeri-ovulatory shifts