The size of scientific fields may impede the rise of new ideas: Fundamental progress may be stymied if quantitative growth of scientific endeavors—in number of scientists, institutes, & papers—is not balanced by focusing attention on novel ideas

Slowed canonical progress in large fields of science. Johan S. G. Chu and James A. Evans. Proceedings of the National Academy of Sciences, October 12, 2021 118 (41) e2021636118; https://doi.org/10.1073/pnas.2021636118

Significance: The size of scientific fields may impede the rise of new ideas. Examining 1.8 billion citations among 90 million papers across 241 subjects, we find a deluge of papers does not lead to turnover of central ideas in a field, but rather to ossification of canon. Scholars in fields where many papers are published annually face difficulty getting published, read, and cited unless their work references already widely cited articles. New papers containing potentially important contributions cannot garner field-wide attention through gradual processes of diffusion. These findings suggest fundamental progress may be stymied if quantitative growth of scientific endeavors—in number of scientists, institutes, and papers—is not balanced by structures fostering disruptive scholarship and focusing attention on novel ideas.

Abstract: In many academic fields, the number of papers published each year has increased significantly over time. Policy measures aim to increase the quantity of scientists, research funding, and scientific output, which is measured by the number of papers produced. These quantitative metrics determine the career trajectories of scholars and evaluations of academic departments, institutions, and nations. Whether and how these increases in the numbers of scientists and papers translate into advances in knowledge is unclear, however. Here, we first lay out a theoretical argument for why too many papers published each year in a field can lead to stagnation rather than advance. The deluge of new papers may deprive reviewers and readers the cognitive slack required to fully recognize and understand novel ideas. Competition among many new ideas may prevent the gradual accumulation of focused attention on a promising new idea. Then, we show data supporting the predictions of this theory. When the number of papers published per year in a scientific field grows large, citations flow disproportionately to already well-cited papers; the list of most-cited papers ossifies; new papers are unlikely to ever become highly cited, and when they do, it is not through a gradual, cumulative process of attention gathering; and newly published papers become unlikely to disrupt existing work. These findings suggest that the progress of large scientific fields may be slowed, trapped in existing canon. Policy measures shifting how scientific work is produced, disseminated, consumed, and rewarded may be called for to push fields into new, more fertile areas of study.

Keywords: scientific progressdurable dominanceentrepreneurial futilityscience policyscience of science

Discussion

These findings suggest troubling implications for the current direction of science. If too many papers are published in short order, new ideas cannot be carefully considered against old, and processes of cumulative advantage cannot work to select valuable innovations. The more-is-better, quantity metric-driven nature of today’s scientific enterprise may ironically retard fundamental progress in the largest scientific fields. Proliferation of journals and the blurring of journal hierarchies due to online article-level access can exacerbate this problem.

Reducing quantity may be impossible. Proscribing the number of annual publications, shuttering journals, closing research institutions, and reducing the number of scientists are hard-to-swallow policy prescriptions. Even if a scientist wholeheartedly agreed with the implications of our study, curtailing their output would be impractical given the damage to their career prospects and those of their colleagues and students, for example. Limiting article quantity without altering other incentives risks deterring the publication of novel, important new ideas in favor of low-risk, canon-centric work.

Still, some changes in how scholarship is conducted, disseminated, consumed, and rewarded may help accelerate fundamental progress in large fields of science. A clearer hierarchy of journals with the most-prestigious, highly attended outlets devoting pages to less canonically rooted work could foster disruptive scholarship and focus attention on novel ideas. Reward and promotion systems, especially at the most prestigious institutions, that eschew quantity measures and value fewer, deeper, more novel contributions could reduce the deluge of papers competing for a field’s attention while inspiring less canon-centric, more innovative work. A widely adopted measure of novelty vis a vis the canon could provide a helpful guide for evaluations of papers, grant applications, and scholars. Revamped graduate training could push future researchers to better appreciate the uncomfortable novelty of ideas less rooted in established canon. These measures, while not easy to implement across large fields, may help push scholarship off the local attractor of existing canon and toward more novel frontiers.

The current study is at the level of fields and large subfields, and one could argue that progress now occurs at lower subdisciplinary levels. To examine lower levels at scale requires more precise methods for classifying papers—perhaps using temporal citation network community detection—than are currently available. But note that the fields and subfields identified in the Web of Science correspond closely to real-world self-classifications of journals and departments. Established scholars transmit their cognitive view of the world to their students via field-centric reading lists, syllabi, and course sequences, and field boundaries are enforced through career-shaping patterns of promotion and reward.

It may be that progress still occurs, even though the most-cited articles remain constant. While the most-cited article in molecular biology (22) was published in 1976 and has been the most-cited article every year since 1982, one would be hard pressed to say that the field has been stagnant, for example. But recent evidence (23) suggests that much more research effort and money are now required to produce similar scientific gains—productivity is declining precipitously. Could we be missing fertile new paradigms because we are locked into overworked areas of study?

Children do not judge animals (chicken, cows, & pigs) to be appropriate food sources; 41pct of children claimed that bacon came from a plant

Children are unsuspecting meat eaters: An opportunity to address climate change. Erin R. Hahn, Meghan Gillogly, Bailey E. Bradford. Journal of Environmental Psychology, October 9 2021, 101705. https://doi.org/10.1016/j.jenvp.2021.101705

Highlights

• Children are not reliably accurate in identifying the origins of common foods.

• Forty-one percent of children claimed that bacon came from a plant.

• Children do not judge animals to be appropriate food sources.

• Most 6- and 7-year-olds classified chicken, cows, and pigs as not OK to eat.

• Children's food concepts may help to normalize environmentally-responsible diets.

Abstract: Eating a plant-based diet is one of the most effective ways people can reduce their carbon footprint. However, global consumption of meat and other animal products is increasing. Studying children's beliefs about food may shed light on the relationship between eating behaviors and climate change. Here, we examined children's knowledge of the plant and animal origins of foods, as well as children's judgments of what can be eaten, using 2 dichotomous sorting tasks. The sample consisted of 4- to 7-year-old children from the United States. We found pervasive errors in their basic food knowledge. Foods derived from animals—especially, but not exclusively meats—were among those that children understood the least well. We suggest that the results may reveal a fundamental misunderstanding in children's knowledge of animal based foods, and we discuss reasons why the origins of meat may represent a particularly challenging concept for children to grasp. We end by considering the role that children may play as agents of environmental protection.

Keywords: Sustainable dietsAnimalsMeat eatingMeat paradoxClimate changeChildren

Language offers a unique window into psychology; natural-language processing & comparative linguistics are contributing to how we understand topics as diverse as emotion, creativity, & religion

From Text to Thought: How Analyzing Language Can Advance Psychological Science. Joshua Conrad Jackson et al. Perspectives on Psychological Science, October 4, 2021. https://doi.org/10.1177/17456916211004899

Abstract: Humans have been using language for millennia but have only just begun to scratch the surface of what natural language can reveal about the mind. Here we propose that language offers a unique window into psychology. After briefly summarizing the legacy of language analyses in psychological science, we show how methodological advances have made these analyses more feasible and insightful than ever before. In particular, we describe how two forms of language analysis—natural-language processing and comparative linguistics—are contributing to how we understand topics as diverse as emotion, creativity, and religion and overcoming obstacles related to statistical power and culturally diverse samples. We summarize resources for learning both of these methods and highlight the best way to combine language analysis with more traditional psychological paradigms. Applying language analysis to large-scale and cross-cultural datasets promises to provide major breakthroughs in psychological science.

Keywords: natural-language processing, comparative linguistics, historical linguistics, psycholinguistics, cultural evolution, emotion, religion, creativity

Applying Language Analysis in Psychological Science: Three Case Studies

Psychological science still has work to do before researchers can master NLP and comparative linguistic methods. We dedicate the rest of this article to illustrating how that might happen. First, we present Figure 4, which is a visual flowchart illustrating how the language-analysis methods discussed in this article can be employed to address psychological questions. We then summarize three case studies that demonstrate how NLP and comparative linguistics can yield new insights and increase the scale and diversity of study into three psychological constructs that have been notoriously difficult to study—emotion, religion, and creativity. In these sections, we highlight research that has used language analysis to address new questions or solve long-standing debates or that has used language-analysis methods to increase the scale or cultural diversity of research in these fields. This work illustrates the utility of language analysis for asking enduring psychological questions and foreshadows the potential of these tools to address psychological constructs across social, cultural, cognitive, clinical, and developmental psychology.

Fig. 4. A flowchart of different language-analysis methods and the kinds of questions they are best suited to answer. Orange boxes represent methods from comparative linguistics, and gray boxes represent methods from NLP. Black boxes approximate the questions that may guide researchers toward these methods. Concepts are defined here as the meaning associated with words. This is meant as a general guide for researchers interested in language analysis, and there is some overlap in classifications. For example, word embeddings can show how language conveys moods and attitudes, and colexification can sometimes uncover evolutionary dynamics.

Emotion

Questions and debates about the nature of human emotion have existed since the earliest days of psychological science (Darwin, 1872/1998; James, 1884; Spencer, 1894; Wundt, 1897) and are relevant to psychological questions pertinent to social, clinical, and developmental psychology. Language-analysis methods have already increased the scope of this long-standing field and generated original methods of addressing old debates.

One of the most enduring debates about emotions concern whether emotions are universal, inborn categories that possess little variation around the world or are socially learned categories that vary in their experience and conceptualization across cultures (Cowen & Keltner, 2020; Ekman & Friesen, 1971; Izard, 2013; Plutchik, 1991; Lindquist et al., 2012; Mesquita et al., 2016; Russell, 2003). We recently addressed this question by means of a comparative-linguistics approach using colexifications (Jackson, Watts, et al., 2019). This analysis allowed us to increase the scale and generalizability over previous field studies of cross-cultural differences in emotion that had relied on smaller sample sizes and two-culture comparisons (Bryant & Barrett, 2008; Ekman & Friesen, 1971; Gendron et al., 2014, 2015, 2020).

In our study, we computationally aggregated thousands of word-lists and translation dictionaries into a large database named “CLICS” (https://clics.clld.org/), and we used this database to examine colexification patterns of 24 emotion concepts across 2,474 languages. We constructed networks of colexification in which nodes represented concepts (e.g., “anger”) and edges represented colexifications (instances in which people had named two concepts with the same word), and then compared emotion colexification networks across language families. In contrast to Youn and colleagues (2016), who found universal colexification patterns involving concepts such as “sun” and “sky,” we found wide cultural variation in the colexification of emotion concepts such as “love” and “fear.” In fact, clusters of emotion colexification varied more than three times as much as the clustering patterns of colors—our set of control concepts—across language families (see Fig. 5). For example, “anxiety” was perceived as similar to “fear” among Tai-Kadai languages, but was more related to “grief” in Austroasiatic languages, suggesting that speakers of these language may conceptualize anxiety differently.

Fig. 5. The colexification structure of emotion concepts for all languages (top left) and for five individual language families in Jackson and colleagues (2019) analysis of emotion. Nodes are emotion concepts, and links between concepts represent the likelihood that these concepts will be colexified in a language. Color indicates semantic community, which refers to clusters of emotions that are similar in meaning. From Jackson, J. C., Watts, J., Henry, T. R., List, J. M., Forkel, R., Mucha, P. J., Greenhill, S., Gray, R. D., & Lindquist, K. A. (2019). Emotion semantics show both cultural variation and universal structure. Science, 366(6472), 1517–1522. https://doi.org/10.1126/science.aaw8160. Reprinted with permission from AAAS.

The variability in emotion meaning that we observed was associated with the geographic proximity of language families, suggesting that the meaning of emotion may be transmitted through historical patterns of contact (e.g., warfare, trade) and common ancestry. We also found that emotions universally clustered together on the basis of their hedonic valence (whether or not they were pleasant to experience) and to a lesser extent, by their physiological activation (whether or not they involved high levels of physiological arousal), suggesting valence and physiological activation might be biologically based factors that provide “minimal” universality to the meaning of emotion. In sum, this study used an unprecedented sample of cultures to yield new insights into the structure and cultural variation of human emotion.

A different set of language-analysis studies involving NLP are improving how psychologists measure emotion and track it over time and across social networks. For example, in a study of unprecedented historical scale, Morin and Acerbi (2017) used sentiment analysis to examine English fiction from 1800 to 2000 to assess whether the expression of emotion had changed systematically over time. They found a decrease in positive (but not negative) emotions conveyed in language over history in three separate corpora of text. This change could not be explained by changing writer demographics (e.g., age and gender), vocabulary size, or genre (fiction vs. nonfiction), raising the possibility that something about emotion or its expression has itself changed over time.

Other studies have also used language analysis to track faster emotional dynamics, such as measuring the emotional qualities of social-media posts (Roberts et al., 2012; Yu & Wang, 2015) and testing whether the emotions of one person are likely to rapidly spread via language throughout that person’s social network. Such studies have shown experimentally that emotional sentiment conveyed by language on social-media websites (e.g., Facebook) is more likely to make individuals who view that language express similar emotions (Kramer et al., 2014). Correlational studies find that social-media information with high emotional content is more likely to be shared than information with low emotional content (Brady et al., 2017). These studies show how affect can spread across many social-media users in a short period of time.

Religion

The science of religion has a rich legacy equal to that of the psychology of emotion; many psychological studies have addressed questions about the social value and historical development of religion. Language analysis has recently begun answering both kinds of questions with a scope and ecological validity that was not possible with traditional methods.

NLP analyses have shed light on the positive and negative ways that religion affects happiness and intergroup relations. Some social theorists view religion as a primarily positive force because it reinforces social connections and promotes well-being (Brooks, 2007). On the other hand, “New Atheism” suggests that religion has a more negative effect on psychology by narrowing people’s worldviews and homogenizing the beliefs of religious adherents (Dawkins & Ward, 2006; Hitchens, 2008). Evidence for this debate has been mixed because of methodological challenges. For example, religious people frequently report more well-being than atheists in large national surveys, but they also show more social-desirability bias (Gervais & Norenzayan, 2012), which makes their self-reports less reliable.

NLP analyses are able to overcome these social-desirability limitations and have begun to show ecologically valid evidence that religion is linked to well-being. For example, Ritter et al. (2014) conducted a sentiment analysis of 16,000 users on Twitter and found that Christians expressed more positive emotion, less negative emotion, and more social connectedness than nonreligious users. Wallace et al. (2019) conducted a creative analysis of obituaries, finding that people whose obituaries mentioned religion had lived significantly longer than people whose obituaries did not mention religion, even controlling for demographic information.

Other NLP research has called the New Atheist proposition of religious worldview homogeneity into question. For example, Watts and colleagues (2020) analyzed the explanations that Christian and nonreligious participants generated to explain a wide range of supernatural and natural phenomena and estimated the overlap of these explanations as a measure of worldview homogeneity. If religion does indeed homogenize adherents’ worldviews, one would expect that religious people’s explanations would share greater overlap than nonreligious people’s explanations. Watts and colleagues (2020) used a text analysis approach known as Jaccard distances, which was able to estimate the similarity between participants’ explanations of the world using overlapping key words, and test whether religious people offered more homogeneous explanations than did nonreligious people. Using this algorithm, the researchers found that religious people’s explanations of supernatural phenomena were more homogeneous than nonreligious people’s explanations, but their explanations of natural phenomena (e.g., the prevalence of parasites) were more diverse than were nonreligious explanations, probably because they drew on supernatural as well as scientific concepts when explaining the natural world.

Comparative linguistics has mostly contributed to questions about how religion has developed over time across cultures. Many of these analyses have focused on the “supernatural monitoring hypothesis”: that watchful and punitive gods contributed to the evolution of social groups by increasing in-group prosociality and fostering large-scale cooperation (Johnson, 2016; Norenzayan et al., 2016). This idea is nearly a century old, arguably dating back to Durkheim (1912/2008), but most tests of the hypothesis have been correlational, and there is an ongoing debate about whether societies with large-scale cooperation tend to adopt moralistic religions or societies that adopt moralistic religions tend to be more cooperative (Whitehouse et al., 2019).

Researchers using comparative-linguistics methods recently addressed these debates by focusing on the development of religion in the Pacific Islands, where linguistic analyses have mapped out cultural phylogenies that can then be repurposed for cross-cultural research (R. D. Gray et al., 2009). Using these phylogenetic trees and implementing a method known as Pagel’s discrete (Pagel, 1999), Watts and colleagues (2015) inferred the probability that ancestor cultures had high levels of political complexity (indicating large-scale cooperation), the probability that they believed in supernatural punishment, and the probability that they worshiped moralizing high gods. Their results showed partial support for both sides of the debate about religion and cooperation. Broad supernatural punishment (e.g., punishment for violating taboos) tended to precede and facilitate political complexity. However, belief in watchful and punitive high gods (e.g., the Christian God) tended to occur only when societies were already politically complex.

Phylogenetic analyses have also shed light on the darker side of religious evolution, such as ritualized human sacrifice practices, which were common across the ancient world. According to the social-control hypothesis, ritual human sacrifice was used as a tool to help build and maintain social inequalities by demonstrating the power of leaders and instilling fear among subjugates. Yet evidence in support of this theory was based largely on individual case studies showing that higher classes often orchestrated ritual sacrifices (Carrasco, 1999; Turner & Turner, 1999). Watts and colleagues (2016) tested this prediction by examining patterns of ritual human sacrifice and social inequality across 93 Pacific societies that had been mapped onto an established language phylogeny (R. D. Gray et al., 2009). They found evidence that ritual human sacrifice often preceded, facilitated, and helped to sustain social inequalities, supporting the social-control hypothesis.

Creativity

Compared with the psychology of emotion and religion, that of creativity has a shorter history in psychology. Most psychologists agree that creativity contributes to personal feelings of self-fulfillment and societal innovation (Pratt & Jeffcutt, 2009; Wright & Walton, 2003), but the field is still exploring the best ways to measure creativity as a psychological construct. More than a dozen creativity-measurement paradigms exist in psychology. One such measure asks participants to name multiple uses for common household items such as article clips and bricks (Guilford, 1950), whereas others require participants to think of creative marketing schemes (Lucas & Nordgren, 2015) or draw an alien from another planet (Ward, 1994). In each paradigm, responses are qualitatively scored on creativity by trained research assistants. Although these tasks are themselves quite creative, the coding process can be onerous, and it can take months to obtain creativity ratings for a small behavioral study. Because these measures require custom tasks and laboratory settings, they are also rarely suitable for analyzing real-world creative behavior.

Language analysis has only recently been applied to study creativity, but NLP techniques are already advancing the measurement of creativity with paradigms that can be applied to both individuals in a small study as well as millions of people around the world. One such paradigm is “forward flow” (K. Gray et al., 2019). Forward flow asks people to free associate concepts, much like classic psychoanalysis methods. But rather than qualitatively deconstructing these free associations, forward flow uses word embeddings to quantitatively analyze the extent that present thoughts diverge from past thoughts. For example, because “dog” and “cat” are frequently used together in large corpora, “dog” → “cat” would not represent as much divergence as “dog” → “fortress,” which are less frequently used together. Forward flow correlates with higher creativity scores on validated behavioral tasks such as the multiple uses task, and creative professionals such as actors, performance majors, and entrepreneurs score highly on forward flow (K. Gray et al., 2019). Forward flow in celebrities’ social-media posts can even predict their creative achievement (K. Gray et al., 2019). Forward flow may represent a rich and low-cost measure that could help capture creativity across people and societies.

Other NLP analyses have captured creativity in terms of divergences from normative language (e.g., Kuznetsova et al., 2013). Much like an unorthodox-looking alien, unorthodox patterns of language can signal creativity. However, it can be difficult to distinguish nonnormative and creative language (e.g., “metal to the pedal,” which is a reformulation of “pedal to the metal”) from nonnormative and nonsensical language (e.g., “the metal pedal to”). Berger and Packard (2018) developed a potential solution to this problem in a study of the music industry and used this method to test how creativity related to a product’s success. Their approach first used topic modeling to develop words that frequently appeared in different genres of music. For instance, words about bodies and movement were often featured in dance songs, whereas words about women and cars were often featured in country music songs. The study next quantified each song from the sample on its typicality according to how much it used language typical of its genre. Analyzing these trends found that songs that broke from tradition and featured atypical language performed better than songs featuring more typical language, offering some evidence that people prefer creative cultural products.

Recent language-analysis studies have already made a considerable impact on the study of creativity and show the potential of NLP for capturing and quantifying variability in creativity across people and products. Although no comparative-linguistics research has examined creativity, this subfield also has great potential for examining whether creativity varies in its structure across cultures and how creativity has evolved across history. Some historical analyses suggest that creativity has been highest during periods of societal looseness—periods with less rigid social norms and more openness (Jackson, Gelfand, et al., 2019). But this research was done on American culture, and it is not clear whether these findings would generalize around the world.

Sexual differences in human cranial morphology: Is one sex more variable or one region more dimorphic?

Sexual differences in human cranial morphology: Is one sex more variable or one region more dimorphic? Marco Milella, Daniel Franklin, Maria Giovanna Belcastro, Andrea Cardini. The Anatomical Record, March 26 2021. https://doi.org/10.1002/ar.24626

Abstract: The quantification of cranial sexual dimorphism (CSD) among modern humans is relevant in evolutionary studies of morphological variation and in a forensic context. Despite the abundance of quantitative studies of CSD, few have specifically examined intra-sex variability. Here we quantify CSD in a geographically homogeneous sample of adult crania, which includes Italian individuals from the 19th and 20th centuries. Cranial morphology is described with 92 3D landmarks analyzed using Procrustean geometric morphometrics (PGMM). Size and shape variables are used to compare morphological variance between sexes in the whole cranium and four individual regions. The same variables, plus Procrustes form, are used to quantify average sex differences and explore classification accuracy. Our results indicate that: (a) as predicted by Wainer's rule, males present overall more variance in size and shape, albeit this is statistically significant only for total cranial size; (b) differences between sexes are dominated by size and to a lesser extent by Procrustes form; (c) shape only accounts for a minor proportion of variance; (d) the cranial base shows almost no dimorphism for shape; and (e) facial Procrustes form is the most accurate predictor of skeletal sex. Overall, this study suggests developmental factors underlying differences in CSD among cranial regions; stresses the need for population-specific models that describe craniofacial variation as the basis for models that facilitate the estimation of sex in unidentified skeletal remains; and provides one of the first confirmations of “Wainer's rule” in relation to sexual dimorphism in mammals specific to the human cranium.

Online men adopting a long-term mating strategy also displayed canines more than women adopting a long-term mating strategy; men show they can provide investment to court women which is more relevant to them than it is to men

Dependents as Signals of Mate Value: Long-term Mating Strategy Predicts Displays on Online Dating Profiles for Men. Mackenzie J. Zinck, Laura K. Weir & Maryanne L. Fisher. Evolutionary Psychological Science, Oct 8 2021. https://rd.springer.com/article/10.1007/s40806-021-00294-w

Abstract: Sexual strategies theory indicates women prefer mates who show the ability and willingness to invest in a long-term mate due to asymmetries in obligate parental care of children. Consequently, women’s potential mates must show they can provide investment – especially when women are seeking a long-term mate. Investment may be exhibited through financial and social status, and the ability to care for a mate and any resulting offspring. Men who care for children and pets (hereafter “dependents”) are perceived as high-quality mates, given that dependents signal an ability to invest; however, no studies have examined how dependents are associated with short-term and long-term mating strategies. Here, online dating profiles were used to test the predictions that an interactive effect between sex and mating strategy will predict displays of dependents, with long-term mating strategy predicting for men but not women. Moreover, this pattern should hold for all dependent types and, due to relative asymmetries in required investment, differences will be strongest regarding displays of children and least in non-canine pets. As expected, men seeking long-term mates displayed dependents more than men seeking short-term mates, but both men and women seeking long-term mates displayed dependents similarly. This pattern was driven mostly by canines. These findings indicate that men adopting a long-term mating strategy display their investment capabilities more compared to those seeking short-term mates, which may be used to signal their mate value.

Discussion

To begin, it should be noted that few women in our population declared interest in a short-term mate, which is consistent with previous work (e.g., Buss & Schmitt, 1993) as, due to differences in obligate parental investment, women tend toward a long-term mating strategy while men tend to seek short-term mates. This finding suggests that men’s mating strategies may be more flexible relative to women’s strategies. Also, it points to the need for future research on relationships, given Schacht and Borgerhoff-Mulder (2015) found that men and women reported being equally interested in short-term mating.

Displays of Dependents

We supported our predictions regarding the display of dependents as influenced by mating strategies. Men who were seeking long-term mates displayed dependents on their profiles significantly more than men seeking short-term mates. Men seeking long-term relationships may show dependents as a way of advertising their parenting abilities and willingness to provide resources, which align with women’s mate preferences (e.g., Bereczkei et al., 2010; Buss & Schmitt, 1993; Li & Kenrick, 2006). These preferences are generally stronger in women when seeking long-term relationships, as compared to women adopting short-term mating strategies, who tend to place a greater importance on physical attractiveness (Li & Kenrick, 2006, see also humor and sociability: Mehmetoglu & Määttänen, 2020) rather than resource and care provisioning (Buss & Schmitt, 1993).

These results show evidence of cross-sex mind-reading. Geher (2009) posits that it is advantageous for heterosexual individuals to determine the mate preferences of potential mates and then advertise those desired features. Cross-sex mind-reading may be a form of mating intelligence, whereby one anticipates what potential mates desire, leading to more successful courtship. Geher (2009) proposes that there are different types of cross-sex mind-reading that are relevant here: men’s ability to know the short- and long-term preferences of women, and women’s ability to know the short- and long-term preferences of men. His findings largely indicate that of these four types, the most accurate form is men reading women’s long-term preferences. His reasoning is that, “given the notoriously discriminating nature of females’ choices in mate selection…coupled with strong tendencies for females to pursue long-term mating strategies…there may be particularly strong pressure on males to ‘get it right’ when it comes to long-term desires of females” (p. 344). This study’s findings align well with those of Geher (2009), as well as his explanation. That is, men may be showing dependents when seeking a long-term mate because they know that women prefer men who show these abilities in this relationship context.

Predictions regarding the between-sex comparisons were, however, not supported: men and women seeking long-term mates displayed dependents in a similar fashion. The types of investment dependents may signal regarding their carer are irrelevant to men, apart from caring abilities: qualities of a good parent are valued by men seeking long-term mates (e.g., Jackson & Kirkpatrick, 2007) to maximize return (in terms of reproductive success) of their investment (e.g., Buss & Schmitt, 1993). Consequently, women may be displaying their dependents to advertise their caring abilities to entice men into a long-term commitment (i.e., cross-sex mind-reading; Geher, 2009). This explanation is supported by Goetz (2013), who showed women seeking long-term mates were more likely to present indicators of their parenting abilities than women seeking short-term mates, and compared to men seeking any mate, in their online personal advertisements.

Displays of Dependent Types

How daters displayed their dependents varied by type (e.g., canine, feline), though our prediction was unsupported: not only did the pattern in which children, canines, and other pets were displayed differ, but the magnitude of between-group differences was similar. However, the results do paint an informative picture; different dependents have specific qualities about them that may explain our findings.

Children were among the most frequently displayed dependents by men seeking long-term mates. Such findings are logical as Kemkes (2008) showed men pictured with children are perceived as having elevated financial and social status, as well as parenting abilities. Men enjoy this elevation of perceived status as children in Canada take, on average, roughly $250,000 to raise to adulthood (Brown, 2015), and financial status is linked with social standing, thus making them an indicator of their parent’s ability to accrue and provide financial resources (on top of caring abilities). Moreover, such investment is strongly desired by women seeking long-term mates (e.g., Buss & Schmitt, 1993), which could explain these men’s propensity to display them so frequently. Children were also the most frequently displayed dependent on the profiles of women seeking long-term mates. Children require considerable care, which mothers typically provide more than fathers (e.g., while their partners performed childcare on non-workdays, fathers engaged in leisure activities 47% of this time: Kamp Dush et al., 2017), making them strong signals of a woman’s caring abilities (Kemkes, 2008). Furthermore, women are presumably most likely to display a child given 80% of separated Canadian women have primary custody of their children (Government of Canada, 2015). Therefore, women may be using children to showcase their caring abilities (as men seek qualities of a good parent in long-term mates: Buss & Schmitt, 1993), to honestly inform a prospective mate of her current familial situation, or even to signal fecundity if said dater was in her reproductive prime.

Next, on the profiles of long-term oriented men, canines (alongside children) were the most frequently displayed dependent, significantly more than men seeking short- and women seeking long-term mates. This pattern follows our between-strategy and between-sex predictions and was likely the main driver of the results for dependents in general. Some studies have suggested canines are a strong signal for a male’s investment capacity and masculinity (Gray et al., 2015; Kogan & Volsche, 2020; Mitchell & Ellis, 2013; Tifferet et al., 2013), as well as dominance-related qualities (Alba & Haslam, 2015, which is also sought by women: Buss & Schmitt, 1993). The types of investment that canines signal in a male carer (i.e., social and financial status, caring abilities) are sought more by women under long-term mating contexts than short-term ones, which could explain the inclination for long-term oriented males to display them over short-term ones. This conjecture is largely supported by Tifferet et al., (2013) who found perceived dog ownership improves men’s value as long-term mates in the eyes of women. Men adopting a long-term mating strategy also displayed canines more than women adopting a long-term mating strategy. Again, this can be interpreted as men showing they can provide investment to court women which is more relevant to them than it is to men (e.g., Buss & Schmitt, 1993).

Finally, other pets—this variable mainly comprised of cats—were displayed infrequently. Men’s hesitancy to display them may in part be explained through the findings of Mitchell and Ellis (2013): men show awareness of Western perceptions of feline-ownership being more feminine, which has negative social connotations for men and may not be a trait that women seek in a potential mate (Kogan & Volsche, 2020). Moreover, if non-canine pets are weak signals of their carer’s investment capacity (as they require minimal investment), neither sex would be inclined to display them to attract a mate, which could also explain the lack of difference regarding the between-sex comparison.

Future Work and Limitations

Future work could continue to use SST to predict human behavior in naturalistic settings such as online dating profiles. Such contexts are important as they allow researchers to examine behavior that is difficult to manipulate in the laboratory and findings are more generalizable to the public (Leichsenring, 2004). Because mating motivates human behavior and cognition (Jones et al., 2013; Miller & Maner, 2011), which develop through evolutionary forces (Buss & Schmitt, 1993), understanding how humans show that they are a valuable mate can further our understanding of the underlying drives for these processes.

As an immediate next step, future research could explore whether daters who show dependents are more successful in attracting a mate. This could be done by analyzing the number of profile-clicks or time spent observing a profile by prospective mates. Such findings could support the idea that dependents are honest signals of their carer’s investment capacity if sex- and mating strategy-specific differences are found. Additionally, to support (or weaken) the argument regarding pets as signals of caring abilities, whether people with pets make better parents should be examined.

This study was also conducted during the COVID-19 pandemic. Though one would think this level of environmental danger could influence human mating strategies (e.g., mate selection criteria become relaxed during times of increased species mortality; Reeve et al., 2016), we do not think this played a role in our findings as sampling occurred after a sharp decrease in viral presence, resulting in restrictions on social movements being relaxed (Nova Scotia’s weekly percent positivity per 100,000 population was between 0.0 and 0.2, rest of Canada between 0.8 and 1.1; see Public Health Agency of Canada, 2021). However, we procured two other samples in the late fall of 2020 which saw a resurgence of cases and intend to collect more samples as the pandemic continues. We hope to use these data to analyze whether a global pandemic influences how men (and women) display their investment capacity (i.e., via dependents) in an online mating context.

There are two main limitations of this study. First, daters were assumed to adopt a certain mating strategy according to their intent for online dating. Though online presences permit an opportunity for deceitful self-representation, dishonest advertisement decreases as the probability of meeting increases in mating contexts (Finkel et al., 2012; Gibbs et al., 2006; Guadagno et al., 2012). Overall, it was assumed daters were relatively honest in their profile construction as their indicated reasons for being on the platform implied a future meeting with a prospective mate. Haselton et al., (2005) showed that women, more than men, report previous long-term mates misconstrued their mating intentions to coerce a sexual encounter. If this was the case in this study, we would have incorrectly categorized men adopting a short-term mating strategy as adopting a long-term mating strategy which could have produced artificial (or hidden) differences between groups if these men were or were not displaying dependents. For a more accurate understanding of a dater’s true intentions, daters could be assessed using the Sociosexual Orientation Inventory (for example, see Jackson & Kirkpatrick, 2007) to determine whether daters leaned toward short-term or long-term mating, before recording their profile’s content. Overall, using SST to predict how people display their mate value on dating profiles is a valuable avenue of exploration, given individuals are seeking mating arrangements which reflect the need for physical encounters.

Second, the age of daters was left unrestricted. Age influences mating behaviour as it correlates with fertility (Conroy-Beam & Buss, 2019): with an increase in age, women’s fecundity decreases more sharply than men’s reproductive potential (Hill & Hurtado, 1991). Consequently, motives for mating change with age as well (McWilliams & Barrett, 2012): older women report seeking younger companions who can provide an active social life—rather than resources—and feel obliged to be a caretaker in later life. Men also seek out younger mates with caregiving abilities. Therefore, how these motives influence how middle- and later-aged individuals present their mate value in mating arenas deserves future consideration. For example, an extension of the current work may entail examining how daters in their reproductive prime, as well as those pre- and post-reproductive prime, display their dependents on an online dating platform.