Neural mechanisms underlying sex differences in aggression could potentially explain sexual dimorphism in neuropsychiatric disorders and improve dysregulated aggressive behavior

Structural and functional biomarkers of the insula subregions predict sex differences in aggression subscales. Haixia Long,Ming Fan, Qiaojun Li, Xuhua Yang, Yujiao Huang, Xinli Xu, Ji Ma, Jie Xiao, Tianzi Jiang. Human Brain Mapping, March 15 2022. https://doi.org/10.1002/hbm.25826

Abstract: Aggression is a common and complex social behavior that is associated with violence and mental diseases. Although sex differences were observed in aggression, the neural mechanism for the effect of sex on aggression behaviors remains unclear, especially in specific subscales of aggression. In this study, we investigated the effects of sex on aggression subscales, gray matter volume (GMV), and functional connectivity (FC) of each insula subregion as well as the correlation of aggression subscales with GMV and FC. This study found that sex significantly influenced (a) physical aggression, anger, and hostility; (b) the GMV of all insula subregions; and (c) the FC of the dorsal agranular insula (dIa), dorsal dysgranular insula (dId), and ventral dysgranular and granular insula (vId_vIg). Additionally, mediation analysis revealed that the GMV of bilateral dIa mediates the association between sex and physical aggression, and left dId–left medial orbital superior frontal gyrus FC mediates the relationship between sex and anger. These findings revealed the neural mechanism underlying the sex differences in aggression subscales and the important role of the insula in aggression differences between males and females. This finding could potentially explain sexual dimorphism in neuropsychiatric disorders and improve dysregulated aggressive behavior.

4 DISCUSSION

This study mainly investigated the association between sex, structure, and function of the insula and aggression subscales. We identified significant effects of sex on physical aggression, anger and hostility. Sex also influenced the GMV and FC of insula subregions. Even more striking, the GMV of the left dIa and right dIa mediated the association between sex and physical aggression, and the left dId–left ORBsupmed FC mediated the association between sex and anger, which may reveal the underlying neural mechanism of sex differences in aggression subscales.

The observed significant effect of sex on the physical aggression is consistent with previous studies that showed males tended to take physical aggression action more than females (Archer, 2004; Gerevich et al., 2007; Harris & Knight-Bohnhoff, 1996; Kalmoe, 2015; Sadiq & Shafiq, 2020). Additionally, we also found sex difference in hostility, that is, males having higher hostility than females, which is in line with a previous finding that males showed more hostility than females in Spanish and Japanese samples (Ramirez et al., 2001). These findings indicated that physical aggression may be associated with hostility. In addition, the higher anger scores in females than in males were also similar to the results in Isanzu and Buryats (Butovskaya et al., 2020). Additionally, an fMRI experiment of facial expressions also showed higher anger recognition levels in females than in males (Dores, Barbosa, Queiros, Carvalho, & Griffiths, 2020), which indicates their emotional dysregulation.

The insula is a heterogeneous brain region and is involved in various functions, such as emotion, cognitive control, attention, memory, perception, motor, and conscious awareness (Craig, 2009; Kurth, Zilles, Fox, Laird, & Eickhoff, 2010; Menon & Uddin, 2010; Uddin, Kinnison, Pessoa, & Anderson, 2014). This study used the Human Brainnetome Atlas to divide the insula into six subregions, including a dorsal anterior insula, a ventral anterior insula, a central region, a more ventral region, and two posterior subregions (Fan et al., 2016). In brief, the dorsal anterior insula is associated with cognitive function, the ventral anterior insula is associated with social–emotional tasks, and the mid-posterior insula is related to interoception, perception, somatosensation, pain, and motor (Chang, Yarkoni, Khaw, & Sanfey, 2013; Kelly et al., 2012; Kurth, Eickhoff, et al., 2010; Kurth, Zilles, et al., 2010; Uddin, Nomi, Hebert-Seropian, Ghaziri, & Boucher, 2017). Previous studies found that males exhibited significantly larger volumes across many cortex regions, including the insula, than females (Oz et al., 2021; Wierenga et al., 2014), which indicated sex differences in cortical development. Other studies have shown that sex affected the volumes of insula subregions. A related study demonstrated that males with posttraumatic stress symptoms had a larger volume of ventral anterior insula than females with posttraumatic stress symptoms, but this difference was not significant in control subjects (Klabunde et al., 2017). Another study found the larger GMV of the posterior insula in females than in males (Lotze et al., 2019). The inconsistent results of previous studies may be associated with different contexts of subjects and different locations of the insula. Therefore, our study investigated more fine-grained insula subregions based on the Brainnetome atlas and found that males showed the larger GMV of each insula subregion than females, which was partly consistent with previous studies and revealed sex difference in brain maturation, with cortex volume decreasing more in females than males during puberty (Vijayakumar et al., 2016; Wierenga et al., 2014).

In addition, we also found the mediation of bilateral dIa GMV on the association between sex and physical aggression. The dIa belongs to the anterior insula and is related to cognitive tasks, decision making, and awareness (Craig, 2009; Deen, Pitskel, & Pelphrey, 2011). The anterior insula, which is involved in the salience network, is associated with social cognition and evaluation, and is sensitive to social saliency (Achterberg et al., 2016; Achterberg et al., 2018; Cacioppo et al., 2013). In addition, prior studies found that 19% of the variance in callous-unemotional traits was explained by the GMV of the anterior insula in males, and callous-unemotional traits were related to physical aggression (Raschle et al., 2018; Wright, Hill, Pickles, & Sharp, 2019). The fMRI studies also showed an association between anterior insula and reactive aggression and motor impulsivity (Chester et al., 2014; Dambacher et al., 2015; Werhahn et al., 2020). Therefore, compared with females, males received more social salience stimuli because of greater GMVs of bilateral dIa, which led to more physical aggression.

On the other hand, this study investigated the effect of sex on the FC of insula subregions. First, we found males showing greater FC between dIa and some prefrontal and parietal cortex, such as ORBinf, ORBsupmed, PCUN, and PUT, which was similar to previous studies (Hong et al., 2014; Sie et al., 2019). Additionally, there was significantly increased dId–MTG FC, dId–ORBinf FC and dId–ORBsupmed FC in males compared with females in our study, and the core affected regions are consistent with Dai et al.'s study (Dai et al., 2018). In addition, vId_vIg showed increased FC with ORBinf.R and decreased connectivity with Cbe9.L and CUN.R in males rather than in females, while a previous study found that women have greater FC between the posterior insula and cerebellum crus I (Sie et al., 2019), which was associated with autonomic regulation (Beissner, Meissner, Bar, & Napadow, 2013). Other studies considered the insula as a whole and found significant sex differences in FC between the insula and prefrontal cortex and sensorimotor cortex, where men showed increased FC in the insula than women (Jin et al., 2019). The effect of sex on FC mainly focuses on the relationship between the insula and brain regions in the default mode network (DMN) (Buckner, Andrews-Hanna, & Schacter, 2008; Liu et al., 2010; Smith et al., 2009). Overall, compared with females, males demonstrated a stronger modulation of insula subregions in the DMN, while the modulation of vId_vIg on Cbe9 and CUN was weaker in males than in females for the compensation mechanism.

Moreover, correlation analysis and mediation analysis revealed the important role of left dId–left ORBsupmed FC in mediating the relationship between sex and anger. The dId belongs to the middle insula and is related to interoception, sensory perception, and somatosensation (Kelly et al., 2012; Kurth, Zilles, et al., 2010). The functional experiment showed that middle insula activity was associated with tolerance of anger expression (de Greck et al., 2012). Anger is a common experience during interpersonal communication, and some interpersonal conflict behaviors, such as unfair treatment and personal insults, may arouse anger (Averill, 1983; Baumeister, Stillwell, & Wotman, 1990; Gilam & Hendler, 2017). Moreover, anger is associated with emotion underregulation, and ORBsupmed is an important region of the emotion regulation network (Gilam & Hendler, 2017). Gilam et al.'s tDCS-fMRI study validated the role of the ventromedial prefrontal cortex (vmPFC) in anger regulation (Gilam et al., 2018). Another study demonstrated that mPFC activity was positively correlated with self-reported anger (Siep et al., 2019). Functional and effective connectivity analysis studies further illustrated that the FC of the mPFC and OFC was related to anger and proactive violence, and the effective connectivity among the insula, OFC and superior temporal gyrus was involved in anger processing (Eshel et al., 2021; Romero-Martinez et al., 2019; Seok & Cheong, 2019). It is interesting to note the mediation effect of FC between left dId and left ORBsupmed on the relationship between sex and anger. The negative correlation between left dId–left ORBsupmed FC and anger indicated that the greater FC the subjects had, the stronger emotional regulation they showed, leading to less anger. Therefore, males showed stronger emotion regulation and less anger than females.

There are several limitations in the present study. First, our study only included Chinese samples to avoid stratification artifacts. Previous studies have shown that cultural background may influence aggression behavior (Butovskaya et al., 2020; Hyde, 2014; Ramirez et al., 2001). Therefore, further studies in different populations are needed to clarify the effect of sex on aggression in different populations. Second, our study only investigated the effect of sex on aggression and related neural mechanisms. In fact, aggression is a very complex social behavior that is influenced by multiple factors, such as genetic or environmental factors. Thus, further studies are needed to assess the effects of other factors on aggression. Advanced studies using machine learning models are also needed to predict aggression based on images and behavior measures. Third, although the Brainnetome atlas has been validated to effectively define more fine-grained brain subregions and is consistent with other brain parcellation atlases (Fan et al., 2016), the impact of the potential interindividual variability of the insular subregions should also be investigated in further studies.

Kerala migrants who return from Saudi Arabia exhibit more conservative values regarding gender-based violence & extreme attitudes on the perpetration of physical violence against women (compared to non-migrants or other Gulf migrants)

Beyond Money: Does Migration Experience Transfer Gender Norms? Empirical Evidence from Kerala, India. George Joseph et al. World Bank Policy Research Paper 9966. Mar 2022. https://documents1.worldbank.org/curated/en/174061647271379501/pdf/Beyond-Money-Does-Migration-Experience-Transfer-Gender-Norms-Empirical-Evidence-from-Kerala-India.pdf

Abstract: This paper examines the impact of return migration from Saudi Arabia and the Gulf on the transfer of gender norms to the Indian state of Kerala. Migration to countries in the Middle East has led to significant remittance flows and economic prosperity, although the effects on social norms and attitudes remain largely unexplored. The paper finds that returning migrants from Saudi Arabia tend to exhibit conservative values regarding gender-based violence and extreme attitudes pertaining to the perpetration of physical violence against women. Compared with those who have no migration experience, the attitudes of returning migrants from Saudi Arabia toward gender-based violence were more conservative by three standard deviations, while the attitudes of those returning from the Gulf were less conservative by 0.5 standard deviation. Similarly, compared with those with no migration experience, returning migrants from Saudi Arabia were more conservative by 2.6 standard deviations regarding extreme attitudes related to gender norms, such as sexual assault, while those returning from the Gulf were less conservative by 0.7 standard deviation. These results show that migration experience can have a substantial impact on the gender attitudes of returning migrants, with potential implications for migration and gender policies in Kerala and for countries that send a large share of temporary migrants overseas for work.

Girls express more intergroup bias against boys than boys against girls: Girls widely believe “boys are bad," possibly due aversion to boys’ rough-and-tumble play, competitiveness, actual negative experiences of teasing, harassment, exclusion by boys

Enjoying Each Other’s Company: Gaining Other-Gender Friendships Promotes Positive Gender Attitudes Among Ethnically Diverse Children. May Ling D. Halim et al. Personality and Social Psychology Bulletin, February 8, 2021. https://doi.org/10.1177/0146167220984407

Abstract: Gender segregation is ubiquitous and may lead to increased bias against other-gender peers. In this study, we examined whether individual differences in friendships with other-gender children reduce gender bias, and whether these patterns vary by gender or ethnicity. Using a 1-year longitudinal design (N = 408 second graders [Mage = 7.56 years] and fourth graders [Mage = 9.48 years]), we found that, across groups, gaining more other-gender friendships over the year led to (a) increased positive cognitive-based attitudes toward the other gender and (b) increased positive and decreased negative affect when with the other gender. We also tested the reverse pattern and found support for a bidirectional link. Girls and Latinx children often showed more gender bias than did boys and European American children. Implications for promoting positive relationships between girls and boys are discussed.

Keywords: cross-group friendships, gender attitudes, intergroup contact theory, intergroup processes, gender stereotypes

Couples who pool all of their money (compared to couples who keep all or some of their money separate) experience greater relationship satisfaction and are less likely to break up; the effect is particularly strong among couples with scarce resources

Gladstone, J. J., Garbinsky, E. N., & Mogilner, C. (2022). Pooling finances and relationship satisfaction. Journal of Personality and Social Psychology, Mar 2022. https://doi.org/10.1037/pspi0000388

When couples decide to share their lives, they are simultaneously faced with the decision of how (or whether) to pool their finances. Does the way in which couples keep their money affect happiness in their relationship? Drawing on Interdependence Theory, we demonstrate across six studies (N = 38,534)—including both primary and secondary data—that couples who pool all of their money (compared to couples who keep all or some of their money separate) experience greater relationship satisfaction and are less likely to break up. Though joining bank accounts can benefit all couples, the effect is particularly strong among couples with scarce financial resources (i.e., those with low household income or who report feeling financially distressed). These findings replicate using experimental, cross-sectional, and longitudinal data sets, as well as in both individualistic and collectivist cultures.

Women responded more modestly to a compliment than men did; & responded more modestly after receiving a compliment from a same or lower status—compared to higher status—peer, but men showed no effect of relative status

Perilloux, C., & Cloud, J. M. (2022). This old thing? Responding to compliments depends on sex and relative status. Evolutionary Behavioral Sciences, 16(2), 128–137. https://doi.org/10.1037/ebs0000259

Abstract: The purpose of the current research was to explore responses to compliments based on participant sex and relative status. We predicted that women would respond more modestly to compliments than men would, and that women would respond more modestly to compliments from equal or lower status women as opposed to from higher status women, whereas men’s responses would be unaffected by status. In Study 1, participants read three vignettes in which they imagined being complimented by a same-sex peer and chose the reaction they would most likely give. Consistent with our prediction, women responded more modestly to a compliment than men did. In Study 2, we randomly assigned participants to one of three hypothetical scenarios in which they received a compliment from a member of the same sex whose relative status to them was either higher, lower, or equal, and participants entered their response in an open-ended format. Confirming our second prediction, women responded more modestly after receiving a compliment from a same or lower status—compared to higher status—peer, but men showed no effect of relative status. Our results converge with those of past research showing that women are more sensitive than men to same-sex peers perceiving them as potential competitors.

Postnatal maternal mood provides evidence for the psychic pain hypothesis; mothers’ depressive mood was sensitive to subtle signs of lower infant health

Kardum, I., Hudek-Knezevic, J., Kalebić Maglica, B., & Shackelford, T. K. (2022). Postnatal maternal mood provides evidence for the psychic pain hypothesis. Evolutionary Behavioral Sciences, 16(2), 116–127. https://doi.org/10.1037/ebs0000256

Abstract: We tested predictions derived from the psychic pain hypothesis according to which depressive symptoms after delivery signal to a mother that she is suffering or has suffered a fitness loss. The predictions were tested on a range of mild emotional states, that is, moods, which allowed us to assess whether the consequences of unfavorable maternal conditions are limited to depressive mood or include other negative and positive moods. In a longitudinal study of 150 women, we measured positive and negative moods twice: during the last trimester of pregnancy and 1–3 months after delivery. As an index of infant quality, we used the mean of Apgar scores measured at 1 and 5 min after delivery, and as an index of maternal circumstances, we used perceived family social support. Supporting the psychic pain hypothesis, after controlling for mothers’ moods before delivery, Apgar score and perceived family social support as well as their interaction predicted mothers’ negative moods after delivery, especially depressive mood and rejection. Additionally, mothers’ depressive mood was sensitive to subtle signs of lower infant health. Perceived family social support and Apgar score were weaker predictors of mothers’ positive moods after delivery. Theoretical and practical implication of these results are discussed. 

Results suggest that it is the joint effect of being intoxicated in a bar that matters; ubjects systematically underestimated their magnitude, suggesting that they cannot be held fully accountable for their actions

Overconfidence, alcohol and the environment: evidence from a lab-in-the-field experiment. Long, Iain W., Matthews, Kent and Sivarajasingam, Vaseekaran. Cardiff Economics Working Papers, Cardiff University Business School. Mar 15 2022. http://orca.cardiff.ac.uk/id/eprint/148166

Abstract: Alcohol has long been known as the demon drink; an epithet owed to numerous social ills associated with it. Our lab-in-the-field experiment assesses the extent to which intoxication leads to changes in overconfidence or cognitive ability that are often linked to problematic behaviours. Results suggest that it is the joint effect of being intoxicated in a bar that matters. Subjects systematically underestimated their magnitude, suggesting that they cannot be held fully accountable for their actions.

The Economics of Content Moderation: Theory and Experimental Evidence from Hate Speech on Twitter

Jiménez Durán, Rafael, The Economics of Content Moderation: Theory and Experimental Evidence from Hate Speech on Twitter (February 25, 2022). SSRN: http://dx.doi.org/10.2139/ssrn.4044098

Abstract: Social media platforms ban users and remove posts to moderate their content. This "speech policing" remains controversial because little is known about its consequences and the costs and benefits for different individuals. I conduct two field experiments on Twitter to examine the effect of moderating hate speech on user behavior and welfare. Randomly reporting posts for violating the rules against hateful conduct increases the likelihood that Twitter removes them. Reporting does not affect the activity on the platform of the posts' authors or their likelihood of reposting hate, but it does increase the activity of those attacked by the posts. These results are consistent with a model in which content moderation is a quality decision for platforms that increases user engagement and hence advertising revenue. The second experiment shows that changing users' perceived content removal does not change their willingness to pause using social media, a measure of consumer surplus. My results imply that content moderation does not necessarily moderate users, but it marginally increases advertising revenue. It can be consistent with both profit- and welfare-maximization if out-of-platform externalities are small.

Keywords: social media, moderation, report, hate speech, experiment, welfare

JEL Classification: C93, D12, D85, D90, I31, J15, L82, L86, Z13

From 2016... Predicting Sexual Harassment From Hostile Sexism and Short-Term Mating Orientation: Relative Strength of Predictors Depends on Situational Priming of Power Versus Sex

From 2016... Predicting Sexual Harassment From Hostile Sexism and Short-Term Mating Orientation: Relative Strength of Predictors Depends on Situational Priming of Power Versus Sex. Charlotte Diehl, Jonas Rees, Gerd Bohner. Violence Against Women, December 9, 2016. https://doi.org/10.1177/1077801216678092

Abstract: Previous research has shown that short-term mating orientation (STMO) and hostile sexism (HS) selectively predict different types of sexual harassment. In a priming experiment, we studied the situational malleability of those effects. Male participants could repeatedly send sexist jokes (gender harassment), harassing remarks (unwanted sexual attention), or nonharassing messages to a (computer-simulated) female target. Before entering the laboratory, participants were unobtrusively primed with the concepts of either sexuality or power. As hypothesized, sexuality priming strengthened the link between STMO and unwanted sexual attention, whereas power priming strengthened the link between HS and gender harassment. Practical implications are discussed.

Keywords: sexual harassment, priming, motivation, computer harassment paradigm

Acute hunger does not increase unethical economic behaviour

Honestly hungry: Acute hunger does not increase unethical economic behaviour. Christian T. Elbæk/Elbaek et al. Journal of Experimental Social Psychology, Volume 101, July 2022, 104312. https://doi.org/10.1016/j.jesp.2022.104312

Abstract: Acute hunger leads to self-protective behaviour, where people keep resources to themselves. However, little is known about whether acute hunger influences individuals' inclination to engage in unethical behaviour for direct monetary gains. Past research in moral psychology has found that people are less likely to cheat for monetary than non-monetary gains. Integrating research on scarcity into the study of unethical economic behaviour, we predicted that acute hunger increases cheating for monetary gains. We further predicted that this effect is moderated by childhood socioeconomic status, trait self-control, and moral identity. We tested these predictions in a well-powered laboratory experiment where we manipulated acute physiological hunger as indexed by blood glucose levels and obtained a validated behavioural measure of cheating for direct monetary gains. Contrary to our predictions, our results show that acute physiological hunger as indexed by blood glucose levels does not increase (or decrease) the propensity to engage in unethical economic behaviour and that neither childhood socioeconomic status nor trait self-control or moral identity moderate this relationship. These findings advance scientific understanding of whether experiences of scarcity shape moral judgment and decision-making.

Keywords: Unethical economic behaviourAcute hungerBlood glucoseRelative resource scarcityMoral psychologyExperimental methods

Higher neuroticism was related to an older subjective age, whereas higher extraversion, openness, agreeableness, and conscientiousness were associated with a younger subjective age

Stephan, Y., Sutin, A. R., Kornadt, A., Canada, B., & Terracciano, A. (2022). Personality and subjective age: Evidence from six samples. Psychology and Aging, Mar 2022. https://doi.org/10.1037/pag0000678

Abstract: Subjective age is associated with health-related outcomes across adulthood. The present study examined the cross-sectional and longitudinal associations between personality traits and subjective age. Participants (N > 31,000) were from the Midlife in the United States Study (MIDUS), the Health and Retirement Study (HRS), the National Health and Aging Study (NHATS), the Wisconsin Longitudinal Study Graduate (WLSG) and Siblings (WLSS) samples, and the English Longitudinal Study of Aging (ELSA). Demographic factors, personality traits, and subjective age were assessed at baseline. Subjective age was assessed again in the MIDUS, the HRS, and the NHATS, 4 to almost 20 years later. Across the samples and a meta-analysis, higher neuroticism was related to an older subjective age, whereas higher extraversion, openness, agreeableness, and conscientiousness were associated with a younger subjective age. Self-rated health, physical activity, chronic conditions, and depressive symptoms partially mediated these relationships. There was little evidence that chronological age moderated these associations. Multilevel longitudinal analyses found similar associations with the intercept and weak evidence for an association with the slope in the opposite of the expected direction: Lower neuroticism and higher extraversion, agreeableness, and conscientiousness were related to feeling relatively older over time. The present study provides replicable evidence that personality is related to subjective age. It extends existing conceptualization of subjective age as a biopsychosocial marker of aging by showing that how old or young individuals feel partly reflects personality traits. 

Extraverts are secretly seen as bad listeners who only pretend to care about what one says; they are perceived as too good at adapting their speech to the audience

Are You Listening to Me? The Negative Link Between Extraversion and Perceived Listening. Francis J. Flynn, Hanne Collins, Julian Zlatev. Personality and Social Psychology Bulletin, March 18, 2022. https://doi.org/10.1177/01461672211072815

Abstract: Extraverts are often characterized as highly social individuals who are highly invested in their interpersonal interactions. We propose that extraverts’ interaction partners hold a different view—that extraverts are highly social, but not highly invested. Across six studies (five preregistered; N = 2,456), we find that interaction partners consistently judge more extraverted individuals to be worse listeners than less extraverted individuals. Furthermore, interaction partners assume that extraversion is positively associated with a greater ability to modify one’s self-presentation. This behavioral malleability (i.e., the “acting” component of self-monitoring) may account for the unfavorable lay belief that extraverts are not listening.

Keywords: extraversion, listening, self-monitoring, sociability, interaction

Protective Role of the Internet in Depression for Europeans Aged 50+ Living Alone

The Protective Role of the Internet in Depression for Europeans Aged 50+ Living Alone. Patrícia Silva, Alice Delerue Matos, Roberto Martinez-Pecino. Social Media + Society, March 18, 2022. https://doi.org/10.1177/20563051221077675

Abstract: Depression is a significant and limiting health problem, and living alone has been identified as an essential determinant of depressive symptoms in middle-aged and older adults. This study looks at this relationship by introducing a new factor into the equation—the Internet—which has become increasingly relevant for communication and interaction. It aims to assess to what extent the use of the Internet can mitigate the association between living alone and depression in middle-aged and older adults. This study focuses on a sample of 64,260 individuals aged 50+ who are resident in Portugal, Greece, Italy, Spain, Denmark, Sweden, Austria, Belgium, France, Germany, Switzerland, Luxemburg, Poland, Czech Republic, Slovenia, Estonia, and Croatia and were surveyed in the context of the SHARE project (Survey of Health, Ageing, and Retirement in Europe), Wave 6. The results showed that living alone relates to greater odds of depression. Nevertheless, of particular relevance is that they also evidenced that the Internet has a moderating role on this relationship, revealing a protective role, since Europeans aged 50+ who live alone and are Internet users are less likely to experience depression than other older adults. The findings reinforce the importance of policies aimed at digital inclusion to benefit the mental health of older adults who live alone in Europe.

Keywords: depression, living alone, Internet, 50+ individuals, Europe

Discussion

The main goal of this study was to analyze, with a large sample, the moderating role of the Internet in the relationship between living alone and depression in Europe, after having controlled for the influence of the characteristics of the individuals frequently associated with depression.

In this research, by the previous literature, living alone positively relates to depression (Das Gupta et al., 2020; Djernes, 2006; Gyasi et al., 2020; Hu et al., 2012; D. Russell & Taylor, 2009; Stahl et al., 2017). However, Internet use by adults aged 50+ years is related to fewer depressive symptoms in Europe. This corroborates the results of previous studies (Cotten et al., 2014; Wang et al., 2019) and may reinforce the potential importance of the Internet as a means of communication (Antonucci et al., 2017; Martinez-Pecino et al., 2013; Román-García et al., 2016; C. Russell et al., 2008).

The main result of this study is that the Internet moderates the relationship between living alone and depression; that is, adults who live alone and use the Internet are less likely to experience depression than other middle-aged and older adults, confirming our hypothesis. Considering the increasing number of older adults living alone in the current society (Mudrazija et al., 2020; Reher & Requena, 2018), the result is relevant since the study focuses on a large sample and controls for variables that have traditionally been associated with depression.

One possible explanation for this outcome is that the Internet can constitute a crucial means of communication (Antonucci et al., 2017; Martinez-Pecino et al., 2011; Reis et al., 2021) with social networks of older persons living alone, which are very important for their well-being (Djundeva et al., 2019; Gyasi et al., 2020). As stated by Papacharissi (2015), all media foster communication. Thus, our results align with recent studies that suggest that, although adults living alone have less interaction with their family, through online communication, they can communicate like people who live with their family (Nakagomi et al., 2022). In this sense, the Internet can prevent depression by increasing social contact (Nakagomi et al., 2022). Furthermore, according to Szabo et al. (2019), contact with family and friends through the Internet helps older adults to maintain their sense of belonging, increase social engagement and receive social support, which can be especially important when family members are geographically distant (Szabo et al., 2019). Thus, this study also supports the literature that indicates that social media are essential for activating, strengthening, or maintaining ties (Haythornthwaite, 2002, 2005), even in contexts where older adults reside alone. It also complements the literature that states that social media are essential resources for older adults’ mental health (Bonsaksen et al., 2021; Forsman & Nordmyr, 2017).

This study also observed the influence of the traditional determinants associated with depression, controlled in the analyses. Thus, we could observe that in Europe, as underlined in the research literature, depression is influenced by a set of sociodemographic, economic, and health characteristics. In fact, as in other studies, increasing age (Weyerer et al., 2013) and being female (Calvó-Perxas et al., 2016; Conde-Sala et al., 2019; Ylli et al., 2016; Zunzunegui et al., 2007) are positively related to depression. However, increased education reduces the chances of depressive symptoms, which also corroborates the results of other studies (Calvó-Perxas et al., 2016; Kok et al., 2012; Portellano-Ortiz et al., 2018; Ylli et al., 2016). Depression has also been associated with financial difficulties (Calvó-Perxas et al., 2016; Conde-Sala et al., 2019; Portellano-Ortiz et al., 2018; Ylli et al., 2016) and increased chronic diseases and functional limitations (Calvó-Perxas et al., 2016; Conde-Sala et al., 2019; Djernes, 2006; Huang et al., 2010; Portellano-Ortiz et al., 2018; Weyerer et al., 2013; Ylli et al., 2016).

Our results reinforce the possibility that Internet use may decrease the effect of social inequalities concerning depression in older adults (Mu et al., 2021). This is in line with research that has concluded that socio-economic characteristics contribute to disparities in depression at an older age. Using this technology can decrease this disparity, contributing to the mental health of middle-aged and older individuals (Mu et al., 2021).

This study has several limitations. The main one is that a single item was used to measure overall Internet use. Nevertheless, a yes/no response to whether someone regularly uses the Internet has frequently been used to assess Internet use by seniors (Cotten et al., 2012, 2014; Hogeboom et al., 2010; König & Seifert, 2020; König et al., 2018; Silva et al., 2017). Nonetheless, considering that the impact of the Internet in the social sphere depends on the type of activities conducted online (Chen, 2013; Hampton et al., 2009; Zhao, 2006), future studies need to consider the impact that different uses of the Internet may have on depression. It is also important to remember that Wave 6 of the SHARE project was collected in 2015. SHARE Wave 7 was dedicated to life stories, and data collection of Wave 8 was interrupted due to the COVID-19 pandemic. Since there is still evidence worldwide about the existence of a high percentage of older people who do not use the Internet (König et al., 2018; Silva et al., 2017) also of those who live alone (Mudrazija et al., 2020; Reher & Requena, 2018) and those who suffer depression (Castro-Costa et al., 2007; Conde-Sala et al., 2019), the findings of this study are entirely relevant to today’s society. Also, these issues are gaining increasing relevance in the current era marked by the COVID-19 pandemic, where recommendations for self-isolation emerge (García-Portilla et al., 2021). Since seniors are considered high risk under COVID-19, and their deaths are more common, they can accumulate stress and fear (Hui et al., 2020). The COVID-19 outbreak and associated physical distancing measures altered the social world for most older adults, but people who live alone may have been disproportionately affected (Fingerman et al., 2021). Due to the COVID-19 pandemic, social isolation of the older population has intensified mental health concerns about anxiety, depression (García-Portilla et al., 2021; Sepúlveda-Loyola et al., 2020; WHO, 2020), and even suicides (Rana, 2020; Sher, 2020). As noticed by some authors, the outbreak of COVID-19 will have a long-term and profound impact on older adults’ health (Wu, 2020). Thus, attention should be paid to adults who may struggle to maintain social contacts in light of physical distancing guidelines and overcome the challenges brought by this complex environment. The outcomes of this study precisely show the need to promote Internet use to face depression among older adults living alone.

Despite the above limitations, this study contributes to the open debate about the relation between Internet use and mental health where literature shows unclear outcomes and mixed evidence of the connection between the use of the Internet, well-being, and depression (Barbosa Neves et al., 2019; Hülür & Macdonald, 2020; P. Nie et al., 2017; Quintana et al., 2018; Sum et al., 2008). Studies are often criticized due to small samples and lack of consistency in measurement, and the need to control for co-variables (Cotten et al., 2012; Hargittai et al., 2019; Hülür & Macdonald, 2020; Meshi et al., 2020). In this regard, we contribute with a large sample of 64,260 individuals of different European countries and controlling for the influence of co-variables, frequently associated with depression, to evidence the moderating role of the Internet in the relationship between living alone and depression in middle-aged and older adults, and show the importance of this technology in preventing and combating depression in those who live alone. Thus, this study has important implications for a society with an increasing number of older people who live alone. It points to the need to develop policies that address the e-inclusion of these individuals to improve their mental health.