Tuesday, October 13, 2020

Partner dreams are not only common in persons with stable partnership (24%) but also in singles (16%); ex-partner dreams were less positive than partner dreams and quite frequent – even years after separation

Partners and ex-partners in dreams: An online survey. Michael Schredl, Naiara Cadiñanos Echevarria, Louise Saint Macary, Alexandra Francesca Weiss. International Journal of Dream Research, Vol 13, No 2 (October 2020). https://doi.org/10.11588/ijodr.2020.2.75338

Rolf Degen's take: https://twitter.com/DegenRolf/status/1315997019517972480

Abstract: Social interactions, especially with the romantic partner, are a very important part of waking life and – in line with the continuity hypothesis of dreaming – also play an important role in dreams. In total, 1695 persons (960 women, 735 men; mean age: 53.84 ± 13.99 yrs.) completed an online survey that included questions about estimating retrospectively the frequency of partner and ex-partner(s) dreams and questions about their relationship status. These estimates indicate that partner dreams are not only common in persons with stable partnership (24%) but also in singles (16%). Partnership quality was the strongest predictor of the emotional tone of partner dreams. Ex-partner dreams were less positive than partner dreams and quite frequent – even years after separation. The next step would be to collect partner and ex-partner dream reports and study the interaction between partnership and partner dreams in a longitudinal design.

The eye wants what the heart wants: Women’s preferences for male faces are associated with their preferences for personality traits

Oh, D., Grant-Villegas, N., & Todorov, A. (2020). The eye wants what the heart wants: Female face preferences are related to partner personality preferences. Journal of Experimental Psychology: Human Perception and Performance, Oct 2020. https://doi.org/10.1037/xhp0000858

Abstract: Women prefer male faces with feminine shape and masculine reflectance. Here, we investigated the conceptual correlates of this preference, showing that it might reflect women’s preferences for feminine (vs. masculine) personality in a partner. Young heterosexual women reported their preferences for personality traits in a partner and rated male faces—manipulated on masculinity/femininity—on stereotypically masculine (e.g., dominance) and feminine traits (e.g., warmth). Masculine shape and reflectance increased perceptions of masculine traits but had different effects on perceptions of feminine traits and attractiveness. While masculine shape decreased perceptions of both attractiveness and feminine traits, masculine reflectance increased perceptions of attractiveness and, to a weaker extent, perceptions of feminine traits. These findings are consistent with the idea that sex-dimorphic characteristics elicit personality trait judgments, which might in turn affect attractiveness. Importantly, participants found faces attractive to the extent that these faces elicited their preferred personality traits, regardless of gender typicality of the traits. In sum, women’s preferences for male faces are associated with their preferences for personality traits.

Famous pop songs, 1975-2017: Lyrics became darker as emotional words became less positive and more negative; swear words and sexual words tended to remain rare and to increase slightly over the decades

Blais-Rochette, C., Miranda, D., Goulet, M.-A., & Gaudreau, P. (2020). Songs as a way of listening to cultures across generations? A comparison of Canada and the United States through their famous songs from 1975 to 2017. Psychology of Aesthetics, Creativity, and the Arts, Oct 2020. https://doi.org/10.1037/aca0000347

Abstract: This study examined if there are cross-cultural and cross-generational similitudes and differences between Canada and the United States through their famous songs across 5 decades. We used the software Linguistic Inquiry and Word Count (LIWC2015; Pennebaker, Boyd, Jordan, & Blackburn, 2015a) to analyze the evolution of lyrics for songs that were nominated at the Canadian Juno Awards and the American Grammy Awards from 1975 to 2017. We targeted songs that were nominated for “bestselling single/single of the year” at the Juno and “song of the year” at the Grammy as they represent some of the most popular and respected cultural products in their respective countries. We analyzed markers of self-focus, group-focus, social connectedness, emotions (positive and negative), religion, and explicit lyrics (swearing and sexuality). Results consistently revealed more cross-cultural similarities than differences between the lyrics of Juno’s and Grammy’s songs on all our markers. However, subtle generational variations unfolded over the years. Notably, self-focus words followed different patterns in the Juno’s songs compared to the Grammy’s songs, but reached similar levels in the 2010s. Group-focus words increased in Juno’s songs but decreased in Grammy’s songs. Social connectedness words were the most present in famous songs and remained relatively stable. Song lyrics became darker as emotional words became less positive and more negative. Religious words tended to remain rare in famous songs. Swear words and sexual words tended to remain rare and to increase slightly over the decades. Findings are discussed through a Cultural × Generational perspective. 

Largest‐ever mega‐analysis: Already from age one, males show greater variability of brain structures than females, being more likely to fall in the extremes

Greater male than female variability in regional brain structure across the lifespan. Lara M Wierenga et al. Human Brain Mapping, October 12 2020. https://doi.org/10.1002/hbm.25204

Rolf Degen's take: https://twitter.com/DegenRolf/status/1315991008581169154

Abstract: For many traits, males show greater variability than females, with possible implications for understanding sex differences in health and disease. Here, the ENIGMA (Enhancing Neuro Imaging Genetics through Meta‐Analysis) Consortium presents the largest‐ever mega‐analysis of sex differences in variability of brain structure, based on international data spanning nine decades of life. Subcortical volumes, cortical surface area and cortical thickness were assessed in MRI data of 16,683 healthy individuals 1‐90 years old (47% females). We observed significant patterns of greater male than female between‐subject variance for all subcortical volumetric measures, all cortical surface area measures, and 60% of cortical thickness measures. This pattern was stable across the lifespan for 50% of the subcortical structures, 70% of the regional area measures, and nearly all regions for thickness. Our findings that these sex differences are present in childhood implicate early life genetic or gene‐environment interaction mechanisms. The findings highlight the importance of individual differences within the sexes, that may underpin sex‐specific vulnerability to disorders.


In this study, we analyzed a large lifespan sample of neuroimaging data from 16,683 participants spanning nine decades of life starting at birth. Results confirmed the hypothesis of greater male variability in brain structure (Forde et al. 2020; Ritchie et al. 2018; Wierenga et al. 20182019). Variance differences were more pronounced for subcortical volumes and regional cortical surface area than for regional cortical thickness. We also corroborated prior findings of greater male brain structural variance at both upper and lower tails of brain measures (Wierenga et al. 2018). These variance effects seem to describe a unique aspect of sex differences in the brain that does not follow the regional pattern of mean sex differences. A novel finding was that sex differences in variance appear stable across the lifespan for around 50% of subcortical volumes, 70% of cortical surface area measures and almost all cortical thickness measures. Unexpectedly, regions with significant change in variance effects across the age range showed decreasing variance differences between the sexes with increasing age. Finally, we observed greater male inter‐regional homogeneity for cortical thickness, but not for surface area or subcortical volumes, partly replicating prior results of greater within‐subject homogeneity in the male brain (Wierenga et al. 2018). Unexpectedly, subcortical regions showed stronger interregional correlation in females than in males.

Greater male variance was most pronounced in brain regions involved in planning, regulation and inhibition of motor movements (pallidum, right inferior parietal cortex and paracentral region), episodic memory (hippocampus), and multimodal sensory integration (thalamus) (Aron, Robbins, and Poldrack 2004; Burgess, Maguire, and O'Keefe 2002; Grillner et al. 2005). In addition, the early presence of sex differences in brain structural variability may be indicative of genetic effects, in line with findings in a pediatric sample (Wierenga et al. 2018). We also observed that sex differences in structural variation are either stable or may reduce in old age. Longitudinal designs are, however, needed to address the mechanisms underlying this observation.

The expression of greater male variability in both upper and lower tails of the distribution may be related to architectural and geometric constraints that are critical for a delicate balance for effective local‐global communication. For example, neurons only partly regulate their size, and the number of neural connections does not vary strongly with neocortical size across species (Stevens 1989). Although axon size and myelin can compensate firing rates in larger brains by speeding up conduction time, there is a limited energy budget to optimize both volume and conduction time (Buzsáki, Logothetis, and Singer 2013). As such, extreme brain structure (in both directions) may come at a cost. This is in line with recent findings that show that extreme neural activity patterns may induce suboptimal expressions of mental states (Northoff and Tumati 2019). Interestingly, it has been found that individuals with autism spectrum disorder show atypical patterns of brain structure and development in both the upper and lower range (Zabihi et al. 2019), suggesting a possible link between greater male variability and vulnerability for developmental disorders (see also Alnæs et al. 2019)). Together with our findings, this opens up new approaches to understanding sex biased developmental disorders, beyond group‐level mean differences.

Although most results showed stable sex differences with increasing age, half of the subcortical regions and a quarter of the cortical surface area measures showed decreasing sex differences in variance. What stands out is that in all these regions, sex differences in variance were largest in young compared to older age. This is indicative of early mechanisms being involved. Furthermore, for subcortical regions, the patterns showed larger volumetric increases in females then in males. For surface area, interaction effects showed mostly stable variance across age in females, but decreases in variability in males. The observation that there were no significant quadratic interactions makes it unlikely that pubertal hormones may affect greater male variance. Yet, the decrease in male variance in older age, may be indicative of environmental effects later in life. Alternative explanation may be the larger number of clinical or even death rates in males that may lead to some sex difference in survival (Chen et al. 2008; Ryan et al. 1997).

Factors underlying or influencing sex differences in the brain may include sex chromosomes, sex steroids (both perinatal or pubertal), and the neural embedding of social influences during the life span (Dawson, Ashman, and Carver 2000). Although we could not directly test these mechanisms, our findings of greater male variance, that are mostly stable across age, together with the greater male inter‐regional homogeneity for cortical thickness are most in line with the single X‐chromosome expression in males compared to the mosaic pattern of X‐inactivation in females (Arnold 2012). Whereas female brain tissue shows two variants of X‐linked genes, males only show one. This mechanism may lead to increased male vulnerability, as is also seen for a number of rare X‐linked genetic mutations (Chen et al. 2008; Craig, Haworth, and Plomin 2009; Johnson, Carothers, and Deary 2009; Reinhold and Engqvist 2013; Ryan et al. 1997). None of the other sex effects mentioned above predict these specific inter and intra‐individual sex differences in brain patterns. Future studies are, however, needed to directly test these different mechanisms. Furthermore, the observation that greater male homogeneity was only observed in cortical thickness, but not cortical surface area or subcortical volumes, may speculatively indicate that X‐chromosome related genetic mechanisms may have the largest effect on cortical thickness measures.

This paper has several strengths including its sample size, the age range spanning nine decades, the inclusion of different structural measures (subcortical volumes and cortical surface area and thickness) and the investigation of variance effects. These points are important, as most observed mean sex differences in the brain are modest in size (Joel and Fausto‐Sterling 2016). We were able to analyze data from a far larger sample than those included in recent meta‐analyses of mean sex differences (Marwha et al. 2017; Ruigrok et al. 2014; Tan et al. 2016), and a very wide age range covering childhood, adolescence, adulthood and senescence. The results of this study may have important implications for studies on mean sex differences in brain structure, as analyses in such studies typically assume that group variances are equal, which the present study shows might not be tenable. This can be particularly problematic for studies with small sample sizes (Rousselet et al. 2017).

The current study has some limitations. First, the multi‐site sample was heterogeneous and specific samples were recruited in different ways, not always representative of the entire population. Furthermore, although structural measures may be quite stable across different scanners, the large number of sites may increase the variance in observed MRI measures, but this would be unlikely to be systematically biased with respect to age or sex. In addition, variance effects may change in non‐linear ways across the age‐range. This may be particularly apparent for surface area and subcortical volume measures, as these showed pronounced non‐linear developmental patterns through childhood and adolescence (Tamnes et al. 2017; Wierenga et al. 2018). Also, the imbalanced number of subjects across the age range may have diminished variability effects in the older part of the age range. The present study has a cross‐sectional design. Future studies including longitudinal data are warranted to further explore the lifespan dynamics of sex differences in variability in the brain. Last, one caveat may be the effect of movement on data quality and morphometric measures. As males have been shown to move more than females in the scanner (Pardoe, Kucharsky Hiess, and Kuzniecky 2016), this may have resulted in slight under estimations of brain volume and thickness measures for males (Reuter et al. 2015). Although quality control was conducted at each site using the standardized ENIGMA cortical and subcortical quality control protocols (http://enigma.ini.usc.edu/protocols/imaging-protocols/), which involve a combination of statistical outlier detection and visual quality checks and a similar number of males and females had partially missing data (52.4% males), we cannot exclude the possibility that in‐scanner subject movement may have affected the results. Nevertheless, we do not think this can explain our finding of greater male variance in brain morphometry measures, as this was seen at both the upper and lower ends of the distributions.

Brain damage robbed a patient of the ability to put himself in other people's shoes — and the ability to recognize that failure

Anosognosia for Theory of Mind deficits: a single case study and a review of the literature. alentina Pacella et al. Neuropsychologia, October 13 2020, 107641. https://doi.org/10.1016/j.neuropsychologia.2020.107641

Rolf Degen's take: 


• Anosognosia after TBI can be selective for Theory of Mind deficits.

•Theory of Mind deficits are not secondary to executive functions impairment.

• The limbic, monitoring and attentional systems play a role in anosognosia.

Abstract: Being aware of one’s own ability to interact socially is crucial to everyday life. After a brain injury, patients may lose their capacity to understand others’ intentions and beliefs, that is, the Theory of Mind (ToM). To date, the debate on the association between ToM and other cognitive deficits (in particular executive functions and behavioural disorders) remains open and data regarding awareness of ToM deficits are meagre. By means of an ad-hoc neuropsychological battery of tests, we report on a patient who suffers from ToM deficits and is not aware of these disorders, although aware of his other symptoms. The study is accompanied by a review of the literature (PRISMA guidelines) demonstrating that ToM deficits are independent from executive functions. Furthermore, an advanced lesion analysis including tractography was executed. The results indicate that: i) ToM deficits can be specific and independent from other cognitive symptoms; ii) unawareness may be specific for ToM impairment and not involve other disorders and iii) the medial structures of the limbic, monitoring and attentional systems may be involved in anosognosia for ToM impairment.

Keywords: AnosognosiaTheory of MindDTIAwarenessFrontal Lesion

Maybe we evolved (genetically or culturally) to be insensitive to efficacy when donating because people tend not to reward efficacy but well-defined and highly observable behaviours

An evolutionary explanation for ineffective altruism. Bethany Burum, Martin A. Nowak & Moshe Hoffman. Nature Human Behaviour, Oct 12 2020. https://www.nature.com/articles/s41562-020-00950-4

Abstract: We donate billions to charities each year, yet much of our giving is ineffective. Why are we motivated to give but not to give effectively? Building on evolutionary game theory, we argue that donors evolved (genetically or culturally) to be insensitive to efficacy because people tend not to reward efficacy, as social rewards tend to depend on well-defined and highly observable behaviours. We present five experiments testing key predictions of this account that are difficult to reconcile with alternative accounts based on cognitive or emotional limitations. Namely, we show that donors are more sensitive to efficacy when helping (1) themselves or (2) their families. Moreover, (3) social rewarders don’t condition on efficacy or other difficult-to-observe behaviours (4, 5), such as the amount donated.

When men have more bargaining power (e.g., higher earnings), they manage to attend opera, ballet and other dance performances, which are more frequently attended by women than by men, less frequently

Battle of the ballet household decisions on arts consumption. Caterina Adelaide Mauri & Alexander Friedrich Wolf. Journal of Cultural Economics, Oct 9 2020. https://link.springer.com/article/10.1007/s10824-020-09395-z

Rolf Degen's take: https://twitter.com/DegenRolf/status/1315896750230700032

Abstract: Women and men differ in their tastes for the performing arts. Gender differences have been shown to persist after accounting for socioeconomic factors. This paper uses this difference to shed light on how decisions on arts consumption are made in households. Based on relatively recent theoretical developments in the literature on household decision-making, we use three different so-called distribution factors to show for the first time that the relative bargaining power of spouses affects their arts consumption. Using a sample from the US Current Population Survey, which includes data on the frequency of visits to cultural activities, we regress attendance on a range of socioeconomic variables using a count data model. The distribution factors consistently affect attendance by men at events such as the opera, ballet and other dance performances, which are more frequently attended by women than by men. We conclude that when men have more bargaining power, they tend to attend such events less frequently.