The digit ratio (2D:4D) is considered a proxy for testosterone exposure in utero; it doesn not predict economic preferences

2D:4D does not predict economic preferences: Evidence from a large, representative sample. Levent Neyse, Magnus Johannesson, Anna Dreber. Journal of Economic Behavior & Organization, Volume 185, May 2021, Pages 390-401. https://doi.org/10.1016/j.jebo.2021.02.029

Abstract: The digit ratio (2D:4D) is considered a proxy for testosterone exposure in utero, and there has been a recent surge of studies testing whether 2D:4D is associated with economic preferences. Although the results are not conclusive, previous studies have reported statistically significant correlations between 2D:4D and risk taking, altruism, positive reciprocity, negative reciprocity and trust. However, most previous studies have small sample sizes gathered from university students and there is also no consensus on the type of analysis (e.g., which hand to analyze or subgroup to focus on) or the preference elicitation method. We present results from a pre-registered large sample study testing if 2D:4D is associated with economic preferences. Data were collected in a representative sample of adults in the German Socioeconomic Panel-Innovation Sample (SOEP-IS), in a sample of about 3450 respondents (about 5 times larger than the previously largest study in this field). Using experimentally validated survey questions, we find no statistically significant association between 2D:4D and economic preferences in the largest study to this date on the topic.

Keywords: Economic behaviorPrenatal hormonesTestosteroneDigit ratio

The tendency to perceive an electoral outcome as foreseeable is positively & consistently associated with satisfaction with the outcome

Hindsight Bias and Electoral Outcomes: Satisfaction Counts More Than Winner-Loser Status. Mauro Bertolotti and Patrizia Catellani. Social CognitionVol. 39, No. 2, March 2021. https://doi.org/10.1521/soco.2021.39.2.201

Abstract: The tendency to perceive outcomes as more foreseeable once they are available is a well-known phenomenon. However, research on the cognitive and motivational factors that induce individuals to overestimate the foreseeability of an electoral outcome has yielded inconsistent findings. In three studies based on large-scale electoral surveys (ITANES, Italian National Election Studies), we argued that the tendency to perceive an electoral outcome as foreseeable is positively and consistently associated with satisfaction with the outcome. Across all studies, satisfaction with the outcome was significantly and positively associated with retrospective foreseeability, above and beyond voters’ preference for a “winning” or “losing” party. In Study 3, a measure of memory distortion of pre-electoral forecasts was included, which was only weakly associated with retrospective foreseeability, but not with satisfaction for the outcome, supporting the notion of different levels of hindsight bias associated with different cognitive and motivational factors.

It has been suggested that inequalities in personality are implicated in the intergenerational transmission of inequality

Inequality in personality over the life cycle. Miriam Gensowski, Mette Gørtz, Stefanie Schurer. Journal of Economic Behavior & Organization, Volume 184, April 2021, Pages 46-77. https://doi.org/10.1016/j.jebo.2021.01.018

Rolf Degen's take: Personality traits are similarly unequally distributed as wealth, and the former could be a cause of the latter

Chart: Steve Stewart-Williams (@SteveStuWill)

Abstract: We document gender and socioeconomic inequalities in personality over the life cycle (age 18–75), using the Big Five 2 (BFI-2) inventory linked to administrative data on a large Danish population. We estimate life-cycle profiles non-parametrically and adjust for cohort and sample-selection effects. We find that: (1) Women of all ages score more highly than men on all personality traits, including three that are positively associated with wages; (2) High-education groups score more favorably on Openness to Experience, Extraversion, Agreeableness, and Neuroticism than low-education groups, while there is no socioeconomic inequality by Conscientiousness; (3) Over the life cycle, gender and socioeconomic gaps remain constant, with two exceptions: the gender and SES gaps in Openness to Experience widen, while gender differences in Neuroticism, a trait associated with worse outcomes, diminish with age. We discuss the implications of these findings in the context of gender wage gaps, household production models, and optimal taxation.

Keywords: InequalityPersonalityBig Five-2 InventoryLife cycle dynamicsGender disadvantageSocioeconomic disadvantage

Narcissism, Machiavellianism, and psychopathy are weakly associated to creativity; the strongest links are between the traits and scientific creativity

Creativity and the Dark Triad: A Meta-Analysis. Izabela Lebud, Bernadetta Figur, Maciej Karwowski. Journal of Research in Personality, March 21 2021, 104088. https://doi.org/10.1016/j.jrp.2021.104088

Highlights

• A meta-analysis of the links between creativity and the Dark Triad of personality.

• Significant, weak relations between creativity and narcissism and Machiavellianism.

• Dark Triad is mainly related to creativity when it was measured with self-report.

• The strongest links between Dark Triad traits and scientific creativity.

Abstract: This paper presents a meta-analysis of the relationships between creativity (creative potential, activities, and achievement) and the Dark Triad of personality: narcissism, Machiavellianism, and psychopathy. Multilevel meta-analytic models demonstrated a small but significant positive association between creativity and narcissism (r = .15 [.10, .29]) and Machiavellianism (r = .06 [.02, .09]), but not with psychopathy (r = .03 [-.02, .07]). Creativity measures (self-report-vs.-performance), aspects (self-perception, creative activity, creative abilities, creative achievements), and domains (general, art, science, and everyday creativity) moderated the links with the Dark Triad. We discuss the possible mechanism of associations between Dark Triad traits and creativity and highlight future research directions.

Keywords: The Dark Triadcreativitymeta-analysispersonality

Swearing/cursing and coprophenomena are prevalent in daily life; swearing makes up around 0.5% of the daily spoken content, however, the inter-individual variability is very high

Swearing and coprophenomena – a multidimensional approach. Asne Senberg et al. Neuroscience & Biobehavioral Reviews, March 20 2022. https://doi.org/10.1016/j.neubiorev.2021.03.016

Rolf Degen's take: https://twitter.com/DegenRolf/status/1373509898823217155

Highlights

• Swearing/cursing and coprophenomena are prevalent in daily life.

• We provide a multidimensional approach to systematize swearing and coprophenomena.

• We provide a theoretical framework reasons, targets, functions/effects and influencing factors for swearing and coprolalia.

Abstract: Swearing, cursing, expletives – all these terms are used to describe the utterance of taboo words. Studies show that swearing makes up around 0.5% of the daily spoken content, however, the inter-individual variability is very high. One kind of pathologic swearing is coprolalia in Tourette syndrome (TS), which describes the involuntary outburst of taboo words. Coprolalia occurs in approximately 20-30% of all patients with TS. This review compares swearing in healthy people and coprolalia in people with TS and is the first one to develop a multidimensional framework to account for both phenomena from a similar perspective. Different research findings are embedded in one theoretical framework consisting of reasons, targets, functions/effects and influencing factors for swearing and coprolalia. Furthermore, the very limited research investigating obscene gestures and copropraxia, compulsive obscene gestures, is summarized. New research questions and gaps are brought up for swearing, obscene gestures and coprophenomena.

Keywords: swearingcursingcoprolaliacoprophenomenaTourette Syndrome

Sex differences in early experience and the development of aggression in wild chimpanzees

Sex differences in early experience and the development of aggression in wild chimpanzees. Kris H. Sabbi et al. Proceedings of the National Academy of Sciences, March 23, 2021 118 (12) e2017144118; https://doi.org/10.1073/pnas.2017144118

Significance: Chimpanzees, human’s close evolutionary relatives, are a tractable model system for understanding how physical aggression can develop in the absence of gender socialization. Here we used 13 y of behavioral data and a targeted 3-y social development study to document clear sex differences in chimpanzees’ early aggressive experiences, supporting the possibility for social experience to shape sex-typed behavior in the absence of explicitly taught gender norms. However, as young males’ own aggressive behavior provoked aggressive responses from others, experiential differences were influenced by early-emerging behavioral differences that already resembled adult patterns. By demonstrating interactions between exposure to aggression and developing behavior, our results add an important perspective to long-standing debates over the origins of gender differences in human aggression.

Abstract: Sex differences in physical aggression occur across human cultures and are thought to be influenced by active sex role reinforcement. However, sex differences in aggression also exist in our close evolutionary relatives, chimpanzees, who do not engage in active teaching, but do exhibit long juvenile periods and complex social systems that allow differential experience to shape behavior. Here we ask whether early life exposure to aggression is sexually dimorphic in wild chimpanzees and, if so, whether other aspects of early sociality contribute to this difference. Using 13 y of all-occurrence aggression data collected from the Kanyawara community of chimpanzees (2005 to 2017), we determined that young male chimpanzees were victims of aggression more often than females by between 4 and 5 (i.e., early in juvenility). Combining long-term aggression data with data from a targeted study of social development (2015 to 2017), we found that two potential risk factors for aggression—time spent near adult males and time spent away from mothers—did not differ between young males and females. Instead, the major risk factor for receiving aggression was the amount of aggression that young chimpanzees displayed, which was higher for males than females throughout the juvenile period. In multivariate models, sex did not mediate this relationship, suggesting that other chimpanzees did not target young males specifically, but instead responded to individual behavior that differed by sex. Thus, social experience differed by sex even in the absence of explicit gender socialization, but experiential differences were shaped by early-emerging sex differences in behavior.

Keywords: aggressive developmentsocial developmentfission–fusionearly social experienceexposure to aggression

Development of aggression in wild chimpanzees: Social experience differed by sex even in the absence of explicit gender socialization, but experiential differences were shaped by early-emerging sex differences in behavior

Sympathy for the underdog: people are inclined to adopt the emotional perspective of powerless (versus powerful) others

Sympathy for the underdog: people are inclined to adopt the emotional perspective of powerless (versus powerful) others. François Quesque, Alexandre Foncelle, Elodie Barat, Eric Chabanat, Yves Rossetti & Jean-Baptiste Van der Henst. Cognition and Emotion, Mar 16 2021. https://doi.org/10.1080/02699931.2021.1902282

Abstract: Upon learning of the story of Cinderella, most people spontaneously adopt the emotional perspective of this helpless young woman rather than of her older sisters who oppress her. The present research examines whether this pattern reveals a general human tendency to empathise more with the emotions of individuals with low (versus high) power. Six experiments (N = 878) examined how power influences the focus of people’s emotional attributions. Participants were presented with situations in which one character exercised power over another one and had to resolve a referential ambiguity by considering the perspective of one or the other character. Results show that participants largely privileged the emotional states of the low-power character over those of the high-power character. This effect was observed with different types of stimuli (comics and video clips), with high- and low-power roles attributed to pairs of different genders (Experiments 1–4) or same gender (Experiments 5–6). Finally, the tendency persisted – though it was reduced – when participants adopted a less passive role with respect to the characters (Experiment 3) and when power occurred in a less despotic way (Experiment 6). Results are discussed with respect to social attention and sensitivity to fairness.

KEYWORDS: Perspective-takingemotionpowermentalisingreferential ambiguity

Spending on clothing is linked to more happiness among males (less happiness among females); spending less on alcohol is linked to less happiness; less luxury has only a limited relationship with happiness

Happiness and Consumption: A Research Synthesis Using an Online Finding Archive. Ruut Veenhoven et al. SAGE Open, March 19, 2021. https://doi.org/10.1177/2158244020986239

Abstract: There is a considerable amount of research on the effect of income on happiness, but only a limited number of studies have considered how the spending of income works out on one’s happiness. In this article, we take stock of the scattered findings on the relation between consumption and happiness. We cover 379 research findings observed in 99 empirical studies. We use a new method of research synthesis, in which research findings are first described in a comparable format and then entered in an online “findings archive” (World Database of Happiness). This technique allows a condensed presentation of the many research findings, while providing readers access to the full results through hyperlinks from the text. Our systematic review reveals some unexpected findings, but does not provide a conclusive answer to the question of what patterns of consumption provide the most happiness for what type of people. Suggestions for further research are provided.

Keywords: life satisfaction, consumption, informed choice, research synthesis, findings archive

Discussion

In this article, we explored a new strand of consumer research, using a novel presentation method of “link-facilitated research synthesis.” The aim was to see what patterns of consumption produce the most happiness for what kind of people. What have we learned?

What We Know Now

Consumption is related to happiness, at least some kinds of consumption are. Although most of the correlations are small and insignificant, we did see several substantive links. When interpreted as denoting a causal effect, some findings suggest that a “Calvinist” or conservative consumption style tends to foster happiness. This appears in the findings on spending on durables and education. The observed correlation between house ownership and happiness can also be seen as a fruit of solid spending. Yet, we also found links between experience consumption and happiness.

Contrary to claims by critics of consumerism, we did not find much evidence of consumption reducing happiness. Owning a car does not seem to lower happiness. Some counter-intuitive findings reported in section “Daily Expenses and Happiness” are (a) spending on clothing is associated with greater happiness among males, but with less happiness among females; (b) high expenditure on communication is associated with less happiness; (c) the expected negative correlation between health expenditure and happiness persists when self-rated health is controlled; (d) spending less on alcohol is associated with lower happiness levels; (e) less luxury has only a limited relationship with happiness. An unexpected finding reported is section “House Ownership and Happiness” was that home ownership is most related to happiness among people with poor mental health. A suggestive finding reported in section “Car ownership and happiness” was that driving an expensive car does not go with greater happiness. All this requires further research.

What We Do Not Know Yet

The available studies on consumption and happiness do not show to what extent the correlations between consumption and happiness stem from a causal effect of consumption on happiness; only in the case of house ownership, there is some causal evidence.

We are still largely in the dark about the relationship between happiness and the use of goods and services purchased, such as in the above-mentioned case of car ownership and happiness. This aspect of consumption is intertwined with wider lifestyle and time-use issues. We can learn more about consumption’s effects on happiness using the methods of multiple moment assessments, such as the experience sampling method (ESM) or day reconstruction method (DRM; see, for example, Burger et al., 2020 on the relationship between lottery play and happiness for a study that uses multiple moment assessment).

This review focuses on what the relationship between consumption and happiness is, which is what consumers need to know to make informed decisions. This information will be more convincing if they also understand why particular kinds of consumption add or detract from happiness. Such effects are likely to differ across products, people, and situations; some will involve different psychological processes, such as need gratification, social comparison, as well as identification. For that purpose, we need studies that focus on particular products and particular consumers, as is common practice in marketing research.

Why So Many Blank Spaces?

The number of research findings on consumption and happiness is small, in particular when compared with the large body of research literature on consumer satisfaction with products and services. Another striking observation is that the few available studies are not very sophisticated: Most of the findings are cross-sectional, the columns for longitudinal and experimental studies in the tables are largely empty and the tables with specifications also show many blank spaces. Why is this the case?

We follow Stanca and Veenhoven (2015) who note that one of the reasons seems to be theoretical short-sightedness. Many mainstream economists still equate consumption with happiness in general and consumer satisfaction in particular. These economists are unaware of the above noted difference between expected and experienced utility and do not see the difference between needs and wants, nor do they know that happiness depends more on meeting the former than the latter. (Veenhoven, 2009)

Another reason is in commercial self-interest. Producers are interested in selling their products in the first place. They spend a lot of money on marketing research to get a better picture of what consumers expect will make them happy and on advertisements to influence these expectations and link to their products. Whether these products actually add to a consumer’s happiness is not the producer’s prime concern. Although there is a considerable body of research on consumer’s experienced satisfaction with products and services, there is little research on the effect of using products on satisfaction with life, not even in sectors where wider life satisfaction is evidently at stake, such as in the case of life insurances or residential care. This lack of research is part of a wider market failure. As there is limited dependable information on the long-term consequences of big consumer purchases on happiness, this could explain why there is no market competition on happiness effects and hence no product development in this direction.

The market is unlikely to solve this problem; governments and consumer unions are in a better position to press for more research on the effects of consumption on happiness. Scientists can also make a difference by informing the public about what kinds of consumption are conducive to happiness.

Lines for Further Research

How can we further expand our current body of knowledge? We have learned that more cross-sectional studies will not provide much more information. Thus, the focus should be on longitudinal studies that allow a view on changes in happiness following changes in consumption. One way to obtain follow-up data is to insert questions on consumer choice in ongoing large-scale longitudinal studies in which happiness is measured, such as the Australian HILDA, the British “Understanding Society Survey” and the German Socio-Economic Panel (GSOEP).¹⁴ Another option is to add questions on happiness to ongoing follow-up studies on consumption. One can think here of longitudinal studies on broad consumer behavior or particular kinds of consumption, such as the U.S. National Consumer Panel¹⁵ or the Quebec Longitudinal Study on Nutrition and Aging.¹⁶

The most informative research will be experimental studies, in which consumption change is induced externally and subsequent effects on inner happiness are traced, such as in the above-mentioned examples of subsidized house ownership (Rohe & Stegman, 1994) and the natural experiment with compulsory health insurance (Keng & Wu, 2014).

Next to such descriptive studies on what effects consumption exerts on happiness; we need more research on how consumption affects happiness; in other words, we need to understand the causal mechanisms involved.

Adaptation of sperm whales to open-boat whalers: Captures dropped 58pct in a few years, it appears that whales swiftly learned effective defensive behaviour

Adaptation of sperm whales to open-boat whalers: rapid social learning on a large scale? Hal Whitehead, Tim D. Smith and Luke Rendell. The Royal Society Biology Letters, Volume 17, Issue 3, Mar 17 2021. https://doi.org/10.1098/rsbl.2021.0030

Abstract: Animals can mitigate human threats, but how do they do this, and how fast can they adapt? Hunting sperm whales was a major nineteenth century industry. Analysis of data from digitized logbooks of American whalers in the North Pacific found that the rate at which whalers succeeded in harpooning (‘striking’) sighted whales fell by about 58% over the first few years of exploitation in a region. This decline cannot be explained by the earliest whalers being more competent, as their strike rates outside the North Pacific, where whaling had a longer history, were not elevated. The initial killing of particularly vulnerable individuals would not have produced the observed rapid decline in strike rate. It appears that whales swiftly learned effective defensive behaviour. Sperm whales live in kin-based social units. Our models show that social learning, in which naive social units, when confronted by whalers, learned defensive measures from grouped social units with experience, could lead to the documented rapid decline in strike rate. This rapid, large-scale adoption of new behaviour enlarges our concept of the spatio-temporal dynamics of non-human culture.

4. Discussion

While a combination of H1–H3 might produce a steep decline in strike rate, social learning of defensive measures between social units (HX) is the best-supported explanation for the rapid decline in strike rate following the first sperm whale sighting within a region. The whalers themselves wrote of defensive methods that they believed the whales were adopting, including communicating danger within the social group, fleeing—especially upwind—or attacking the whalers [17,18] (figure 1). Deep dives would also have been effective. But, perhaps the most straightforward change would be for sperm whales to cease their characteristic defensive behaviour against their most serious previous predator, the killer whale, Orcinus orca. Gathering in slow-moving groups at the surface and fighting back with jaws or flukes often works against killer whales [19,20], but will have only assisted the relatively slow-moving, surface-limited, harpoon-bearing open-boat whalers.

There are other behavioural changes that the whales may have made in response to whaling, but their impact on strike rates is less clear. There is some evidence that sperm whales formed larger groups in response to whaling [15], but this would likely have increased rather than decreased strike rates. They may have learned to avoid the whalers before the whalers detected them, but this should generally have reduced the mean detection range of the whalers and so increased the strike rate. However, if whales fleeing at long ranges made themselves more visible by blowing hard and showing their bodies forcefully, so increasing the number of sightings with groups that were not easily struck, this might have additionally decreased the strike rate.

Thus, there are learned behavioural changes that the sperm whales could have made to reduce strike rates, and some anecdotal witness that they did so. However, learning as individuals or within social units is not supported as the sole cause of the initial decline in strike rate. To achieve the observed reduction in strike rate through behavioural change, some mechanism must have allowed naive whales without the experience of whalers to receive the benefits of experience.

We suggest that naive social units learned defensive measures from grouped experienced social units and adopted them. Encounters with whalers typically lasted hours, and sperm whales through their echolocation and communication systems can probably sense and coordinate behaviour over ranges of several kilometres. Other processes could have enhanced the social learning process. If groups were particularly likely to split between or within social units after an experience with whalers, and then to join other units, this will have increased the probability that a naive animal was grouped with an experienced individual during its first encounter with whalers.

Our analysis provides substantial support for rapid (less than 20% generation time, so much too fast for genetic evolution) social learning over large spatial scales. The ability of sperm whales, or potentially other species, to rapidly change behaviour in the face of a new anthropogenic threat by making use of social learning has implications for the population significance of new threats, and their assessment. Data from the earliest exposures may not generalize to later periods, and vice versa.

Increased subjective age (personal aging rate perception) increases mortality very much; biggest factors in SubjAge are physical health and expections of sex life in 10 years

PsychoAge and SubjAge: development of deep markers of psychological and subjective age using artificial intelligence. Alex Zhavoronkov et al. Aging, Volume 12, Issue 23 pp 23548—23577, December 8, 2020. https://doi.org/10.18632/aging.202344

Rolf Degen's take: Higher subjective age doubles mortality risk, and one of the top concomitants of subjective age is how satisfying people expect their sex life to be in 10 years’ time

Abstract

Aging clocks that accurately predict human age based on various biodata types are among the most important recent advances in biogerontology. Since 2016 multiple deep learning solutions have been created to interpret facial photos, omics data, and clinical blood parameters in the context of aging. Some of them have been patented to be used in commercial settings. However, psychological changes occurring throughout the human lifespan have been overlooked in the field of “deep aging clocks”.

In this paper, we present two deep learning predictors trained on social and behavioral data from Midlife in the United States (MIDUS) study: (a) PsychoAge, which predicts chronological age, and (b) SubjAge, which describes personal aging rate perception. Using 50 distinct features from the MIDUS dataset these models have achieved a mean absolute error of 6.7 years for chronological age and 7.3 years for subjective age. We also show that both PsychoAge and SubjAge are predictive of all-cause mortality risk, with SubjAge being a more significant risk factor.

Both clocks contain actionable features that can be modified using social and behavioral interventions, which enables a variety of aging-related psychology experiment designs. The features used in these clocks are interpretable by human experts and may prove to be useful in shifting personal perception of aging towards a mindset that promotes productive and healthy behaviors.

Discussion

In this article, we present two novel aging clocks created within the deep learning paradigm — PsychoAge and SubjAge. Both these clocks use the same set of 50 psychosocial features to estimate human chronological age and subjective age, respectively. These clocks showed superior performance during CV in MIDUS 1 (MAEPsychoAge= 6.70 years; MAESubjAge= 7.32 years) and were verified in two other large data sets — MIDUS 2 and MIDUS Refresher (Table 1). In terms of epsilon accuracy, PsychoAge reached a score of 0.78 in MIDUS 1, and SubjAge — 0.74.

Having trained and verified the final models, we aimed to understand how PsychoAge and SubjAge see human aging and what features they pay the most attention to. With a tandem PFI-DFS approach we ranked all features according to their relative importance. Top-5 important features in both clocks were associated with health conditions (e.g. headache frequency) and relationship status (marital status, expectations from sex life in 10 years). Less significant features greatly differ in their relative importance for SubjAge and PsychoAge predictions. For example, top-20 PsychoAge features contain only one personality trait — neuroticism. Meanwhile, the only personality traits encountered among top-20 SubjAge features are — extraversion and openness.

These three personality traits, along with conscientiousness and agreeableness form “the big five traits”, which are commonly used in practice and scientific research to describe the human mental state landscape. High neuroticism is characteristic of emotional instability and common mental disorders, such as mood disorders, anxiety, and substance use disorders. Openness and extraversion, on the other hand, are considered more balanced traits, although their abnormally low scores are also related to social phobia and agoraphobia [27]. Positive orientation, seeking warmth, social interaction, and emotional stability may play an important role in psychological aging.

We hypothesized that the human mind evolves throughout the lifespan, which results in some traits, beliefs, or priorities shifting — not always in unison or at the same speed. At certain life stages, career-related priorities may rise, while at others they may fade and be replaced by different priorities. These lifelong progressions of the psyche eventually get recognized by the neural networks we constructed to let them build an image of psychological aging.

This idea of human mind progression is described in much more detail in the review of SST by Laura Carstensen. SST suggests that younger people are more goal-oriented, interested to obtain new knowledge and skills, while older people tend to value emotionally meaningful goals more.

To identify the psychosocial features that change while a person advances from one age group to another we trained separate DNNs on MIDUS 1 samples from three age groups (25-39, 40-64, 65-75 years). First, we defined the psychological aging core — variables that remain highly important (top-25) across all age groups (Table 2). The core contained not only strictly psychological features, however. To illustrate, marital status, hypertension medication, headaches, and body mass index were among the seven core features required for accurate chronological age prediction. Interestingly, neuroticism score also belonged to the same psychological aging core, as well as seeing the community as a source of comfort. Psychological traits within the subjective aging core contained aspirations scale, extraversion, openness, positive reappraisal prevalence, and two career-related variables — effort put into work now and work expectations in 10 years. In contrast to the first psychological core, which contained few psychological traits, the subjective core consisted almost exclusively of psychological features.

This highlights an important distinction between aging per se (as judged by PsychoAge) and our perception of it (as judged by SubjAge): subjective aging is mostly dependent on internal causes.

We also explored the uniquely important features for each age group — features that emerged only in one top-25 set. Since these features were recognized as important only in these groups, it may be assumed that they shift the most markedly during the corresponding life periods. To illustrate, young adults were not the only age group who responded affirmatively to the statement “Forceful describes you well”, but rather many of these people went through a transformation that affected their forcefulness. Detecting such a change was essential for a predictor to accurately predict whether a person was at the beginning or the end of this phase of life.

On their own, DNNs are unable to tell generational and age-related changes apart or tell the difference between pro-longevity and progeroid features. Thus, the results of the feature importance analysis should always be cautiously inspected and verified in more rigorous settings. Still, feature importance analysis is a powerful tool for hypothesis generation and the verification of overall biological relevance.

While neuroticism was identified as a part of the psychological aging core, it was also a uniquely important subjective aging feature in the elderly MIDUS 1 subsample. This may be interpreted as neuroticism progressing unnoticed by an individual until old age when it starts to affect the perception of age. Previous studies identified that neuroticism tends to cause low emotional differentiation, anxiety, and depression in old people [28, 29].

Other personality traits rendered important for subjective age estimation in the elderly were optimism, being outgoing, and content with life in general. These results indicate that these might be top-priority features to focus on while developing policies aimed to involve the elderly in social life. Several studies have shown the importance of a social and productive lifestyle during aging [30, 31]. psychologically important and active events may protect against aging diseases, such as dementia [32].

After establishing which variables are important in absolute terms, we aimed to measure the models’ response to changes in their values. Using mixed-effects linear models, we explored the monotonic trends between 50 variables, PsychoAge and SubjAge predictions (Supplementary Figure 1 and Supplementary Figure 2).

Once again, neuroticism showed unique behavior. Contrary to the other big five traits, neuroticism score was associated with higher SubjAge and lower PsychoAge. More specifically, people within the same PsychoAge group could have >5 years of SubjAge difference due to differences in neuroticism score alone. This verifies our previous conjecture that neuroticism is a key marker of subjective aging and may be used as a sensitive measure of emotional states and late-life depressive symptoms.

Other big five traits also had significantly large effects on both PsychoAge and SubjAge. For example, a person with the bottom openness score would feel 7.2 years older than their PsychoAge counterpart with the top score. In the meantime, a person with the bottom openness score would be 5.3 years younger, as measured by PsychoAge, than their SubjAge counterpart with the top score. Similar tendencies could be observed for most other personality traits, thus building a strong case for SST.

Interestingly, personal opinion on when middle age starts and ends was significantly associated with higher PsychoAge but does not affect SubjAge. We hypothesize that this is an indication of “time dilation” associated with aging. As people get older, they place “middle age” higher and higher, as if their lifetime dilates, while younger participants may have stereotypes about aging and place “middle age” lower. An excellent study on the topic of perception of age stereotypes and self-perception of aging has been written by Hummert [33].

Among the health-related features, the distinction between internal and external health locus of control is of utmost interest. Health locus of control is a set of personal beliefs and experiences that determine whether a person takes responsibility for their health (internal locus) or considers it to be outside of their power, fully dependent on external factors (external locus). Internal locus of control is associated with a problem-solving mindset, while external locus is tied to depression, anxiety, and suicidal thoughts, as well as maladaptive behaviors [34]. We demonstrated that external locus of health control is a rare feature that demonstrated a linearly positive effect on both PsychoAge and SubjAge. It was the only feature to offer no payoff in at least one aging dimension, except for “Taking prescription medications for blood pressure”. Internal control, per contra, did not display concordant linearly negative effect on. Instead, it decreased SubjAge and decreased PsychoAge, just as most other health-related variables.

While the external locus of control was a senopositive (higher values increase age predictions) feature in both aging dimensions, some features were identified as double senonegative (higher values decrease age predictions). Increasing values for the variables from the relationships category were associated with lower PsychoAge and SubjAge, thus favoring single people content with their sex life, who expected to remain sexually active in 10 years. In this case, it is difficult to conclude the cause-effect relation between psychological aging and sexuality. Is reduced libido a precondition to becoming subjectively old? Or does feeling old due to other factors make people less interested in the sexual aspect of life? Can more satisfying sex life prolong healthy longevity, or does PsychoAge simply see higher sex drive as a feature more frequently encounter in the youth? More thorough research is required to answer these questions as well as similar questions concerning other variables.

Although the effect of most variables on PsychoAge and SubjAge was shown to be discordant, the magnitude of their effects on these two measures of psychological aging is not equal. Since the target variable in the mixed-effects model is expressed in years, Table 3 can be used to approximate how a shift in a psycho-social parameter will affect PsychoAge or SubjAge, and which one of them will change more. For example, the variable “Rate health in 10 years” is a survey question that measures health expectation on a scale from 0 to 10, from worst to best. Each increment increases PsychoAge by 0.5 years but also decreases SubjAge by 1.0 years. This yields an “exchange rate” of 2 subjective years lost per 1 chronological age gained. Other features have their own exchange rates, which may be manipulated to accumulate “net profit” in both SubjAge and PsychoAge dimensions.

Other directional feature analysis methods may be more appropriate for navigating the psychological aging landscape since linear mixed effect models operate based on multiple assumptions and simplifications. More specifically, they treat all features independently and approximate the complex interrelations between PsychoAge and SubjAge that may be in place with a random intercept. Accumulated local effects or more sophisticated Shapley value analysis may handle the convoluted feature interrelations more efficiently.

To further validate PsychoAge and SubjAge we tested their prediction errors (delta) as all-cause mortality risk factors (Figure 6). SubjAge delta was proven to be a more powerful risk factor than PsychoAge. More specifically, the SubjAge delta beyond ±5 years was associated with roughly doubling or halving the mortality rate.

We also tested the 50 psychosocial markers of aging as risk factors. We identified significant mortality risks associated with certain factors among (i) health features (“Health compared to others your age”, “Rate current health”, “Shortness of breath while walking up a slight hill”), (ii) personality traits (“Conscientiousness personality trait”, “Agency personality trait”), (iii) psychological beliefs (“Live for today”, “Positive reappraisal”, “Lower aspirations”), (iv) well-being (“Satisfied with life at present”), and, (v) demographic factors (“Chronological age”) (Figure 7).

A problem frequently encountered even by psychologists is obtaining sufficiently detailed information about their patients while keeping the data collection process as short as possible to avoid survey fatigue. In this work, we propose a solution to this survey length-descriptiveness balance problem based on modern deep learning and biogerontological methods. The solution is a relatively short list of features that are both modifiable and provably important in the context of aging.

Some studies show that family history is a source of numerous highly important aging-related features [35]. For example, having long-lived parents and grandparents is strongly correlated with a longer lifespan. However, such factors are not easily modified, especially if the grandparents are no longer alive. Therefore, in this study, we have deliberately limited questions on non-modifiable historical factors to give our surveys more practical value. We demonstrated that variables related to health and closer personal relationships play a crucial role in chronological and subjective age prediction. Furthermore, images about life changes, for instance, when females or males enter middle age, demonstrate a strong predictive power. We suggest that modifying the behavior and the mindset via these variables may be a promising therapeutic concept.

The factors comprising the developed aging clocks can be used to create individual behavioral therapies that would make them feel and actually become biologically younger. For example, PsychoAge can be used to quantify the beneficial effects of daily vigorous-intensity activity on their rate of aging. SubjAge, in its turn, can be used to quantify the beneficial effects of physical activity on personal perception of age.

Focusing on such modifiable age-related features while being able to score lifestyle choices numerically offers interesting opportunities to both professional therapists and individuals seeking self-improvement. We believe that the described approach has a high potential to increase longevity conscience on a population level.

When the category of close relationships is considered, people with access to PsychoAge and SubjAge may choose to develop stronger bonds, get married, or stay married out of an egoistic incentive to prolong their healthspan. The beneficial effect of close relationships and intimacy on health was previously shown in multiple studies, and we believe that drawing people’s attention to such physical-mental health connections should not be neglected [36].

Extracting actionable items from human biological profiles, such as transcriptomic or proteomic profiles, is an actively researched subject. The profiles associated with human psychology can also be subjected to similar workflows to devise personal behavioral therapy plans. In this study, we have demonstrated how the combination of deep learning and aging clocks can be used to create psychological surveys that promote longevity consciousness and personal improvement. These tools and methods could be applied in a wide range of research areas, including psychiatry, longevity, psychology, and psychophysiology for the greater good of society.

Inducing cognitive structure led novice consumers to experience numbness (less intense emotion); however, shifting experts away from using their cognitive structure restored their experience of emotion

Emotionally Numb: Expertise Dulls Consumer Experience. Matthew D Rocklage, Derek D Rucker, Loran F Nordgren. Journal of Consumer Research, ucab015, March 15 2021. https://doi.org/10.1093/jcr/ucab015

Abstract: Expertise provides numerous benefits. Experts process information more efficiently, remember information better, and often make better decisions. Consumers pursue expertise in domains they love and chase experiences that make them feel something. Yet, might becoming an expert carry a cost for these very feelings? Across more than 700,000 consumers and 6 million observations, developing expertise in a hedonic domain predicts consumers becoming more emotionally numb – i.e., having less intense emotion in response to their experiences. This numbness occurs across a range of domains – movies, photography, wine, and beer – and across diverse measures of emotion and expertise. It occurs in cross-sectional real-world data with certified experts, and in longitudinal real-world data that follows consumers over time and traces their emotional trajectories as they accrue expertise. Further, this numbness can be explained by the cognitive structure experts develop and apply within a domain. Experimentally inducing cognitive structure led novice consumers to experience greater numbness. However, shifting experts away from using their cognitive structure restored their experience of emotion. Thus, although consumers actively pursue expertise in domains that bring them pleasure, the present work is the first to show that this pursuit can come with a hedonic cost.

Keywords: expertise, emotion, hedonic, consumer knowledge, language, attitudes

Primate landscape genetics: A review and practical guide

Primate landscape genetics: A review and practical guide. Westphal D, Mancini AN, Baden AL. Evolutionary Anthropology, Mar 15 2021, DOI: 10.1002/evan.21891 PMID: 33720482

Abstract: Landscape genetics is an emerging field that integrates population genetics, landscape ecology, and spatial statistics to investigate how geographical and environmental features and evolutionary processes such as gene flow, genetic drift, and selection structure genetic variation at both the population and individual levels, with implications for ecology, evolution, and conservation biology. Despite being particularly well suited for primatologists, this method is currently underutilized. Here, we synthesize the current state of research on landscape genetics in primates. We begin by outlining how landscape genetics has been used to disentangle the drivers of diversity, followed by a review of how landscape genetic methods have been applied to primates. This is followed by a section highlighting special considerations when applying the methods to primates, and a practical guide to facilitate further landscape genetics studies using both existing and de novo datasets. We conclude by exploring future avenues of inquiry that could be facilitated by recent developments as well as underdeveloped applications of landscape genetics to primates.

On days when anxiously attached people perceived their partner as responsive to their sexual needs, they reported similar levels of relationship and sexual satisfaction, trust, and commitment as people lower in anxiety

Raposo, S., & Muise, A. (2021). Perceived partner sexual responsiveness buffers anxiously attached individuals’ relationship and sexual quality in daily life. Journal of Family Psychology, Mar 2021. https://doi.org/10.1037/fam0000823

Abstract: Satisfying relationships are central to health and well-being, yet the insecurities of anxiously attached people can detract from the quality of their romantic relationships. One factor associated with relationship quality is perceiving a partner as responsive to one’s needs, and responsiveness to a partner’s sexual needs might be a particularly powerful way to signal responsiveness to anxiously attached partners. In a 21-day daily experience and longitudinal study of 121 couples, we tested perceived partner sexual responsiveness as a buffer against the lower relationship quality (satisfaction, commitment, trust) and sexual satisfaction that anxiously attached people typically experience. On days when anxiously attached people perceived their partner as responsive to their sexual needs, they reported similar levels of relationship and sexual satisfaction, trust, and commitment as people lower in anxiety. Perceived partner sexual responsiveness was also important for maintaining commitment over time. Our findings suggest that perceived partner sexual responsiveness is one promising protective factor for anxiously attached partners. 

Men’s higher benevolent sexism predicted lower aggressive parenting, & women’s higher benevolent sexism predicted greater aggressive behavior toward partners, irrespective of power & relationship quality

Overall, N. C., Chang, V. T., Cross, E. J., Low, R. S. T., & Henderson, A. M. E. (2021). Sexist attitudes predict family-based aggression during a COVID-19 lockdown. Journal of Family Psychology, Mar 2021. https://doi.org/10.1037/fam0000834

Abstract: The current research examined whether men’s hostile sexism was a risk factor for family-based aggression during a nationwide COVID-19 lockdown in which families were confined to the home for 5 weeks. Parents who had reported on their sexist attitudes and aggressive behavior toward intimate partners and children prior to the COVID-19 pandemic completed assessments of aggressive behavior toward their partners and children during the lockdown (N = 362 parents of which 310 were drawn from the same family). Accounting for pre-lockdown levels of aggression, men who more strongly endorsed hostile sexism reported greater aggressive behavior toward their intimate partners and their children during the lockdown. The contextual factors that help explain these longitudinal associations differed across targets of family-based aggression. Men’s hostile sexism predicted greater aggression toward intimate partners when men experienced low power during couples’ interactions, whereas men’s hostile sexism predicted greater aggressive parenting when men reported lower partner–child relationship quality. Novel effects also emerged for benevolent sexism. Men’s higher benevolent sexism predicted lower aggressive parenting, and women’s higher benevolent sexism predicted greater aggressive behavior toward partners, irrespective of power and relationship quality. The current study provides the first longitudinal demonstration that men’s hostile sexism predicts residual changes in aggression toward both intimate partners and children. Such aggressive behavior will intensify the health, well-being, and developmental costs of the pandemic, highlighting the importance of targeting power-related gender role beliefs when screening for aggression risk and delivering therapeutic and education interventions as families face the unprecedented challenges of COVID-19.

Extraverts report higher levels of authenticity and extraverted behavior predicts increased feelings of authenticity, even by introverts

Wilt, Joshua A., Jessie Sun, Rowan Jacques-Hamilton, and Luke D. Smillie. 2021. “Why Does It Feel Authentic to Be and Act Extraverted? Exploring the Mediating Role of Positive Affect.” PsyArXiv. March 19. doi:10.31234/osf.io/7mj6g

Abstract: Extraverts report higher levels of authenticity and extraverted behavior predicts increased feelings of authenticity. Why? Across three studies, we examined positive affect as a mediator of the associations between extraversion and authenticity. In Study 1 (N = 205), we tested our mediation model at the trait level. Study 2 (N = 97) involved a ten-week lab-based experience sampling protocol, whereas Study 3 (N = 147) involved a preregistered week-long daily-life experience sampling protocol. These studies allowed us to test our mediation model at the state level. Positive affect explained moderate to very high proportions of the effects of extraversion on authenticity (Study 1 = 29%, Study 2 = 38%, Study 3 = 87%). We interpret these findings through the lens of cybernetic self-regulation, feelings-as-information, positive psychology, and humanistic perspectives, and propose that increased PA could also explain why extraversion is connected with other eudaimonic components of wellbeing.

Participants who were exposed to a salient health threat (loud coughing after the COVID-19 epidemic started) displayed a lower level of overconfidence than did participants in the control condition

The bright side of the COVID-19 pandemic: Public coughing weakens the overconfidence bias in non-health domains. Heng Li, Yu Cao. Personality and Individual Differences, March 19 2021, 110861. https://doi.org/10.1016/j.paid.2021.110861

Abstract: The COVID-19 pandemic is a serious threat that produces harm to people around the globe. Prior work has almost exclusively focused on deconstructive consequences of the novel coronavirus, the present research reveals a bright side of the coronavirus outbreak: reduce the overconfidence bias in non-health domains. In Experiment 1, students passed by a trained confederate who was coughing loudly or not and completed a peer-comparison problem measuring their overconfidence bias. The results showed that participants, who were exposed to a salient health threat, displayed a lower level of overconfidence than did participants in the control condition. Experiment 2 recapitulated the effects of public coughing on overconfidence by using a non-student sample and an alternative measure of overconfidence. Across two field experiments, we replicated prior findings regarding sex differences for the overconfidence bias. Taken together, our research suggests that whereas the COVID-19 pandemic has undoubtedly ravaged nations and economies, the unprecedented crisis offers an opportunity for individuals to counteract their overconfidence in judgment and decision-making.

Keywords: COVID-19Disease threatOverconfidenceSex differencesRisk perceptionField experiments

People were relatively modest and self-critical about their ideas’ funniness; women rated their responses as less funny; & people showed some discernment and insight into their ideas’ funniness

If You’re Funny and You Know It: Personality, Gender, and People’s Ratings of Their Attempts at Humor. Paul J. Silvia et al. Journal of Research in Personality, March 19 2021, 104089. https://doi.org/10.1016/j.jrp.2021.104089

Rolf Degen's take: Although people consider themselves "funnier than average", they are relatively modest and self-critical about their own jokes’ funniness

Highlights

• In seven studies (n = 1,133), adults rated the funniness of their attempts at humor.

• People were relatively modest and self-critical about their ideas’ funniness.

• Extraversion and openness to experience predicted rating one’s responses as funnier.

• Women rated their responses as less funny.

• People showed some discernment and insight into their ideas’ funniness.

Abstract:  seven studies (n = 1,133), adults tried to create funny ideas and then rated the funniness of their responses, which were also independently rated by judges. In contrast to the common “funnier than average” effect found for global self-ratings, people were relatively modest and self-critical about their specific ideas. Extraversion (r = .12 [.07, .18], k =7) and openness to experience (r = .09 [.03, .15], k = 7) predicted rating one’s responses as funnier; women rated their responses as less funny (d = -.28 [-.37, -.19], k = 7). The within-person correlation between self and judge ratings was small but significant (r = .13 [.07, .19], k = 7), so people had some insight into their ideas’ funniness.

Keywords: humorcomedycreativitypersonalitygenderdiscernment

I know a dog when I see one: dogs (Canis familiaris) recognize dogs from videos

I know a dog when I see one: dogs (Canis familiaris) recognize dogs from videos. Paolo Mongillo, Carla Eatherington, Miina Lõoke & Lieta Marinelli. Animal Cognition, Mar 19 2020. https://rd.springer.com/article/10.1007/s10071-021-01470-y

Critical view... Big breakthrough in science: Dogs can recognize their own kind in videos and are baffled when a cow barks

Abstract: Several aspects of dogs’ visual and social cognition have been explored using bi-dimensional representations of other dogs. It remains unclear, however, if dogs do recognize as dogs the stimuli depicted in such representations, especially with regard to videos. To test this, 32 pet dogs took part in a cross-modal violation of expectancy experiment, during which dogs were shown videos of either a dog and that of an unfamiliar animal, paired with either the sound of a dog barking or of an unfamiliar vocalization. While stimuli were being presented, dogs paid higher attention to the exit region of the presentation area, when the visual stimulus represented a dog than when it represented an unfamiliar species. After exposure to the stimuli, dogs’ attention to different parts of the presentation area depended on the specific combination of visual and auditory stimuli. Of relevance, dogs paid less attention to the central part of the presentation area and more to the entrance area after being exposed to the barking and dog video pair, than when either was paired with an unfamiliar stimulus. These results indicate dogs were surprised by the latter pairings, not by the former, and were interested in where the barking and dog pair came from, implying recognition of the two stimuli as belonging to a conspecific. The study represents the first demonstration that dogs can recognize other conspecifics in videos.

Discussion

In this study, we employed a cross-modal, expectancy violation paradigm to assess whether dogs can recognize the species of conspecifics from videos. Dogs were presented with pairs of auditory and visual stimuli, which could be any combination of dog-related on non-dog-related vocalization and video. Dogs’ orientation towards the presentation area, as a function of the presented pair of stimuli, was analysed during two time intervals, in which different mechanisms were most likely at play.

The first interval spanned from the onset of the vocalization to the last frame in which the video of the animal crossing the screen was visible. Dogs’ orientation in this interval therefore reflected a proximate reaction to the presence of the stimuli, rather than an after-effect of the pairing.

Dogs spent almost the entire interval oriented toward the projection area. Moreover, dogs’ attention to specific regions of the projection area roughly followed the stimulus occupation of such regions. This finding is most likely a direct result of the capacity of motion stimuli to elicit orientation responses, an effect that is particularly relevant for stimuli abruptly appearing within the visual field (Hillstrom and Yantis 1994) and for stimuli depicting animate entities (Pratt et al. 2010), two features that characterised the visual stimuli that were presented in this experiment.

A breakdown analysis of dogs’ orientation to the different parts of the projection area revealed that dogs spent longer time looking at the exit area when a dog video was projected than when the unfamiliar species was projected. Therefore, dogs were more likely to visually follow the dogs’ video until it left the presentation area, than the unfamiliar species video. The finding is consistent with the notion that familiarity drives attentional responses for visual stimuli (Christie and Klein 1995). There is some direct evidence that this process also applies to dogs, in particular when presented with representations of dogs’, such as face photographs (Racca et al. 2010) or biological movement (Eatherington et al. 2019). Overall, the findings support the idea that dogs did at least perceive the dog video as a familiar stimulus.

Evidence that dogs did recognise the dog-related stimuli as belonging to a dog, however, comes from the analysis of attention patterns after the stimuli had disappeared. In this time interval, dogs spent less time oriented towards the central part of the presentation area when a bark was followed by the appearance of a dog video, than when any of such two stimuli was paired with an unfamiliar counterpart. In accordance with the violation of expectancy paradigm, longer looking at the main projection area reflected a surprised reaction to the pairing of an unfamiliar-species stimulus with a dog stimulus. Analogous interpretations of longer looking times have been found in studies in dogs (Adachi et al. 2007) and other species including cats (Takagi et al. 2019), horses (Lampe and Andre 2012; Nakamura et al. 2018), crows (Kondo et al. 2012) and lions (Gilfillan et al. 2016). Therefore, this result clearly indicates that dogs perceived the appearance of the dog video as an expected consequence of the barking, implying they had appropriately recognized both stimuli as belonging to a dog. Following presentation of dog stimuli, dogs also spent longer time looking at the entrance region of the presentation area, than when either dog stimulus was paired with an unfamiliar-species stimulus. No such effect was observed for attention to the exit region. Although the reason for this pattern of results is not immediately clear, we believe the result is further indication that dogs retained the pair of dog stimuli as coherently representing a dog; in this sense, dogs may have been interested in where the animal came from, especially since nothing indicated the presence of such animal before its sudden appearance. The lack of differences in attention to the exit region, on the other hand, could reflect a relatively low need to monitor an animal who was moving away from the observer.

When both stimuli belonged to an unfamiliar species, the pattern of dogs’ attention to the presentation area was less clear-cut than those observed when presented with dog stimuli. On the one hand, attention to the central part of the presentation area when non-dog stimuli were paired was not different than that observed when dog stimuli were paired. The similarity in reaction may suggest dogs considered the appearance of the unfamiliar individual as a plausible consequence of the unfamiliar vocalization, much as they considered the appearance of the dog an unsurprising consequence of the bark. Unsurprised reactions to pairs of unfamiliar stimuli in an expectancy violation test have also been reported before (e.g. Adachi et al. 2007). As already discussed for the pair of dog stimuli, the high amount of attention paid to the entrance region could indicate the interest in where an unknown (but plausible) type of animal came from. On the other hand, dogs’ attention to the central part of the presentation area after non-dog stimuli pairs were presented was also not lower than when a dog/non-dog stimuli pair was presented. A possible explanation is that dogs’ attention patterns after being exposed to the two unfamiliar stimuli was driven by the interest in such novel stimuli, rather than by a violated expectation. Indeed, different studies showed neophilic reactions by dogs (e.g. Kaulfuß and Mills 2008; Racca et al. 2010). Of particular relevance, as it deals with visual preference, the study by Racca and collaborators (2010) showed that while dogs pay preferential attention to familiar rather than novel images of dogs, the opposite is true for other classes of stimuli, including images of objects or of human faces. Along this reasoning, hearing a novel auditory stimulus drove attention to the entrance region, and seeing a novel visual stimulus drove attention to both the entrance and central region (the latter being predominantly occupied when the stimulus became fully visible).

One question arising from our results whether dogs showed a different response to the pairing of the bark and dog video merely because they were familiar with both stimuli, without implying classification of the stimuli as belonging to a dog. The literature provides some indications that this may not be the case. For instance, Gergely and collaborators (2019) showed that dogs exposed to a conspecific vocalization pay more attention to pictures of dogs than of humans, a species dogs were highly familiar with. Moreover, a recent functional neuroimaging study revealed greater activation of visual cortical areas in dogs, when exposed to videos of conspecific faces than when exposed to human faces, suggesting the existence of species-specific processing mechanisms (Bunford et al. 2020). Taken together, these findings suggest dogs do possess the ability to visually discriminate dogs from another familiar species. Whether such ability is the result of exposure alone or is aided by a predisposition is impossible to state by the results of the present or of other studies in dogs. Findings in humans indicate that experience builds on top of predispositions in determining one’s ability to identify motion features as belonging to a conspecific (reviewed by Hirai and Senju 2020). A thorough understanding of if and how the same factors impact on dogs’ ability to recognize other animals would require further experiments, which are currently ongoing in our laboratory.

Few other studies have attempted to demonstrate dogs’ ability to recognize the species of other conspecifics in figurative representations, providing suggestive though not conclusive evidence (Autier-Dérian et al. 2013; Gergely et al. 2019). The present findings differ in important ways from all previous attempts. First, in all other studies, the stimuli depicted animal heads, whereas our stimuli represented lateral views of the animal’s whole body. Our findings imply that a detailed frontal view of the head is not a necessary stimulus for dogs to recognize a conspecific, at least if motion information is available. Indeed, a crucial difference between the present and earlier studies was that we presented videos rather than still images, allowing us to incorporate information about movement. Our own laboratory showed dogs are attracted by the motion of a laterally walking dog (Eatherington et al. 2019) and studies in other species highlight how motion cues alone can be used for the recognition of conspecifics (Jitsumori et al. 1999; Nunes et al. 2020). Thus, the presence of motion information in our experiment may have played a role in allowing dogs to appropriately identify the conspecific’s video. The abovementioned studies indicate that morphology, independently from motion, can also be individually sufficient to the aims of recognition (Jitsumori et al. 1999; Nunes et al. 2020). However, these studies only depicted heads, a stimulus that is rich in features useful to the aims of recognition, even to the level of the individual. Our findings indicate that even more limited morphological details provided by a lateral, whole body view, paired with motion information may be sufficient for dogs to recognize a conspecific.

Finally, research on dog visual cognition has used the cross-modal and expectancy violation paradigms; for instance, similar paradigms have been successfully used to demonstrate dogs’ recognition of humans’ identity or sex (Adachi et al. 2007; Ratcliffe et al. 2014), or expectations about conspecifics’ body size (Taylor et al. 2011). However, to the best of our knowledge, this method had never been used in dogs with videos and some methodological considerations seem useful at this stage. First, while videos were projected, dogs spent most of their time oriented towards the presentation area, indicating the stimuli were able to attract the dogs’ attention (at least from a behavioural standpoint), a crucial and often problematic aspect of research on visual cognition. Second, even after the stimulus disappeared, dogs remained oriented towards the presentation area for a significant portion of the allowed 30 s—suggesting maintenance of interest in what had been projected. Third, the analysis of dogs’ orientation across subsequent presentations suggests limited habituation through the first two trials, but a significant decrement starting from the third trial. Overall, these results indicate the method is suitable to study dogs’ spontaneous cross-modal processing of auditory and animated visual stimuli, and that dogs can be presented with up to two presentations before their attention starts to decline.