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Cross-country relationships between life expectancy, intertemporal choice and age at first birth

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Humans, like other animals, typically discount the value of delayed rewards relative to those available in the present. From an evolutionary perspective, prioritising immediate rewards is a predictable response to high local mortality rates, as is an acceleration of reproductive scheduling. In a sample of 46 countries, we explored the cross-country relationships between average life expectancy, intertemporal choice, and women's age at first birth. We find that, across countries, lower life expectancy is associated with both a smaller percentage of people willing to wait for a larger but delayed reward, as well as a younger age at first birth. These results, which hold when controlling for region and economic pressures (GDP-per capita), dovetail with findings at the individual level to suggest that life expectancy is an important ecological predictor of both intertemporal and reproductive decision-making.

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... Along these lines, recent research comparing TD between populations has shown the existence of a link between the harshness of the socio-ecological environment and the TD of the individuals. The studies of Bulley & Pepper (2017) and Lee et al. (2018) found a positive relation between the average life expectancy of a country (a [negative] proxy for the harshness of the environment) and the patience of its inhabitants, using samples of university students and young participants (online sample), respectively, from over 50 different countries. On the other hand, expanding on the seminal work of Ramos et al. (2013), Martín et al. (2019) demonstrated that members of an ethnic minority which has suffered a long history of discrimination and persecution (the Spanish Romani people or Gitanos), and generally exhibits life-history traits which are (relatively) fast, tend to discount the future to a greater degree than their neighbors from the majority population, even after the effect of the current socioeconomic status is eliminated. ...
... In this study, we test the validity of this argument by means of structural equation models with country-level data using: (i) TD behavioral data obtained from two recent surveys (Bulley & Pepper 2017; (ii) a proxy measure for the incidence of intergroup discrimination (Group Grievance Index; FSI 2018); and (iii) three proxies for the harshness of the socio-ecological conditions (life expectancy, infant mortality rate and GDP per capita). These variables were chosen because together they provide a substantial part of the environmental information essential to the development of life strategies according to LHT: how long do I expect to live, how many of my children will survive and what material resources will be available to me (del Giudice et al. 2015). ...
... The first measure (Patience FAL, Falk et al. 2018) is mainly characterized by a larger number of countries, with a more detailed TD evaluation and samples which are representative of the general population of each country. On the other hand, the second measure (Patience BP) has been employed in the first article analyzing the relationship between life expectancy and TD from a LHT perspective (Bulley & Pepper 2017) and provides comparable university student samples, with relatively consistent characteristics (similar socio-economic status and intellectual levels) which, under certain circumstances, may add control and facilitate the detection of true national or cultural differences (Gächter 2010, Herrmann et al. 2008). For the 40 countries included in both databases, the correlation between the two patience measures is 0.593 (see Table S2). ...
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An evolutionary account for the existence of individual differences in temporal discounting (i.e., the orientation to the short-vs. the long-run) establishes that harsh socio-ecological conditions lead individuals to adaptively focus on the short-run, whereas more secure environments lead to the development of more future-oriented life-history strategies. Recent studies demonstrate that countries with higher life expectancy (a [negative] proxy for environmental harshness) have more future-oriented citizens, which supports the evolutionary account. Based on the results of a related study comparing the discounting of two ethnic groups, it has been hypothesized that intergroup discrimination processes generate environmental harshness which in turn make individuals involved in these processes to discount the future heavily. In this paper, we test this hypothesis using country-level data on temporal discounting (two cross-section datasets with 76 and 52 countries), environmental harshness (life expectancy, infant mortality and GDP per capita) and intergroup discrimination (Group Grievance Index), and find strong support based on structural equation modeling. These results suggest that in societies facing intergroup discrimination processes people discount the future more, live shorter and are poorer, and infants die at a higher rate. We further show that ethnic (spatial) segregation is a powerful predictor of intergroup discrimination and, therefore, temporal discounting.
... In a recent study, Bulley & Pepper [22] reported that countries with a lower life expectancy were more likely to have a higher proportion of individuals who favour an immediate reward over a larger, delayed reward. However, while Bulley & Pepper [22] demonstrated that ecological cues to mortality may influence propensity to discount future rewards, there are methodological limitations that restrict the study's conclusions. ...
... In a recent study, Bulley & Pepper [22] reported that countries with a lower life expectancy were more likely to have a higher proportion of individuals who favour an immediate reward over a larger, delayed reward. However, while Bulley & Pepper [22] demonstrated that ecological cues to mortality may influence propensity to discount future rewards, there are methodological limitations that restrict the study's conclusions. First, Bulley & Pepper [22] measured future discounting using a single binary choice item [23]. ...
... However, while Bulley & Pepper [22] demonstrated that ecological cues to mortality may influence propensity to discount future rewards, there are methodological limitations that restrict the study's conclusions. First, Bulley & Pepper [22] measured future discounting using a single binary choice item [23]. Previous research has indicated that the likelihood an immediate reward is chosen over a larger, delayed reward depends on the length of delay, and also the difference in relative gain between the immediate and delayed reward [10]. ...
Article
How organisms discount the value of future rewards is associated with many important outcomes, and may be a central component of theories of life-history. According to life-history theories, prioritizing immediacy is indicative of an accelerated strategy (i.e. reaching reproductive maturity quickly and producing many offspring at the cost of long-term investment). Previous work extrapolating life-history theories to facultative calibration of life-history traits within individuals has theorized that cues to mortality can trigger an accelerated strategy; however, compelling evidence for this hypothesis in modern humans is lacking. We assessed whether country-level life expectancy predicts individual future discounting behaviour across multiple intertemporal choice items in a sample of 13 429 participants from 54 countries. Individuals in countries with lower life expectancy were more likely to prefer an immediate reward to one that is delayed. Individuals from countries with greater life expectancy were especially more willing to wait for a future reward when the relative gain in choosing the future reward was large and/or the delay period was short. These results suggest that cues to mortality can influence the way individuals evaluate intertemporal decisions, which in turn can inform life-history trade-offs. We also found that older (but not very old) participants were more willing to wait for a future reward when there is a greater relative gain and/or shorter delay period, consistent with theoretical models that suggest individuals are more future-orientated at middle age.
... At the same time, there is clear evidence for the existence of an effect of resources on human behavior, an effect often called the "behavioral constellation of deprivation" or conversely a "behavioral syndrome of abundance" (Amir & Jordan, 2017;Baumard, 2019;Pepper & Nettle, 2017). For example, studies have shown that people who have lower income are more present-oriented, meaning that they prefer a smaller reward today to a larger reward in the future (Bulley & Pepper, 2017;Griskevicius et al., 2011;Sunde et al., 2018). Individuals with fewer resources also tend to consume more alcohol and drugs (Droomers et al., 1999;Hanson & Chen, 2007;Hiscock et al., 2012;Pampel et al., 2010), be more violent (McCullough et al., 2013), invest less in their children's education (Gibson & Lawson, 2011;Nettle, 2008Nettle, , 2010Quinlan, 2007), take less risk in terms of variance in returns (Boon-Falleur et al., 2021), invest less in cognitive exploration and information gathering (Jacquet et al., 2018), are less trusting of others (Petersen & Aarøe, 2015), are more likely to prefer authoritarian leaders (Safra et al., 2017), and have a tight culture with many strong norms and a low tolerance of deviant behavior (as opposed to a loose culture) (Gelfand et al., 2011). ...
... As a result, we should expect that people's time preferences will be calibrated by the amount of capital they have at their disposal to fulfill their needs. Evidence supports a link between people's capital and their time preferences (Adams & White, 2009;Bulley & Pepper, 2017;Griskevicius et al., 2011;Robb et al., 2009). ...
Preprint
Life history theory is increasingly invoked in psychology as a framework for understanding differences in individual preferences. In particular, evolutionary human scientists tend to assume that, along with reproductive strategies, several behavioral traits such as cooperation and risk-taking and, in its broadest version, a range of psychological and personality traits also cluster into ‘fast’ and ‘slow’ life histories. However, the inclusion of such a wide range of traits in a life history strategy is founded on relatively little theoretical justification. Beyond environmental factors such as mortality risk, we argue that quantitative changes in resources - either embodied, physical or social - can lead to qualitative changes in people’s priorities and psychology. People use their resources to satisfy their different needs. People with access to fewer resources focus on their needs with the greatest marginal fitness benefit, while people with more resources can also afford to satisfy their needs with smaller fitness benefits. We show that, depending on the total amount of resources available, the optimal resource allocation of these resources differs, leading to the empirically observed ‘pyramid of needs’. In addition, the optimal allocation of resources shapes people’s risk and time preferences, which in turn affect a whole range of behaviors such as parenting style, cooperation, health, skill acquisition and exploration.
... Specifically, harsher ecologies tend to be associated with psychological traits such as an immediate reward orientation and a shorter time horizon (Bulley & Pepper, 2017;Griskevicius et al., 2011). One possible reason for this is that people living in harsher and unpredictable environments are less likely to reap the benefits of deferred rewards. ...
... For instance, it has been shown that women's age at first birth is younger when extrinsic mortality risks are higher (Low et al., 2008). One possible explanation for this acceleration of reproductive scheduling is that it offsets the fitness cost of high extrinsic mortality by increasing the chance of reproducing before death (Bulley & Pepper, 2017). ...
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Although humans cooperate universally, there is variability across individuals, times and cultures in the amount of resources people invest in cooperative activities. The origins of such variability are not known but recent work highlights that variations in environmental harshness may play a key role. A growing body of experimental work in evolutionary psychology suggests that humans adapt to their specific environment by calibrating their life-history strategy. In this paper, we apply structural equation models to test the association between current and childhood environmental harshness, life-history strategy and adult cooperation in two large-scale datasets (the World Values Survey and the European Values Study). The present study replicates existing research linking a harsher environment (both in adulthood and in childhood) with a modulated reproduction-maintenance trade-off and extends these findings to the domain of collective actions. Specifically, we find that a harsher environment (both in adulthood and in childhood) is associated with decreased involvement in collective action and that this association is mediated by individuals' life-history strategy.
... Many authors believe that the relations between a harsh environment and accelerated life history dynamics are mainly due to mortality rates (Belsky, Schlomer, & Ellis, 2012;Ellis, Figueredo, Brumbach, & Schlomer, 2009) 1 . The available data shows that when the local mortality rates are higher (or converselywith lower life expectancy) individuals tend to reproduce earlier in their lifetimethe findings are congruent both at the individual and population level (Bulley & Pepper, 2017;Low, Parker, Hazel, & Welch, 2013;Pink, Willführ, Voland, & Puschmann, 2020;Störmer & Lummaa, 2014). There are similar associations between mortality and fertility: individuals who experienced higher mortality rates tend to have a higher number of offspring (Bereczkei & Csanaky, 2001;Guégan, Thomas, Hochberg, de Meeus, & Renaud, 2001;Zhang & Zhang, 2005). ...
... Chisholm et al. 2005;Dunkel et al., 2015;Međedović, 2019;Sheppard et al., 2016;Webster et al., 2014), showing that a harsher, riskier, and more depriving environment is related to fast life history dynamics, marked by enhanced reproductive output, earlier reproduction, and higher number of children. Furthermore, the result is congruent with the hypothesis and empirical findings that mortality rates are the key environmental characteristics which trigger a fast life history pathway (Belsky et al., 2012;Bereczkei & Csanaky, 2001;Bulley & Pepper, 2017;Ellis et al., 2009;Guégan et al., 2001;Low et al., 2013;Pink et al., 2020;Störmer & Lummaa, 2014;Zhang & Zhang, 2005). Hence, the motivation to have the first child earlier in life could be an adaptive response to the ecology characterized by elevated mortality rates -delaying reproduction could be highly costly to fitness in a harsh environment since individuals may die before leaving descendants. ...
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One of the key life history assumptions is that mortality rates are positively associated with fast life history dynamics. Since the Covid-19 pandemic has elevated mortality rates throughout the world, we tested this assumption using reproductive motivation (desired number of children and desired age of first reproduction) as a key output measure using a repeated cross-sectional design. We assessed reproductive motivation in Serbian young adults before the pandemic started (N=362), during the pandemic-caused state of emergency (the peak of the epidemic's first wave: N=389) and after the state of emergency (i.e. after the first wave: N=430). Furthermore, in the third time-point we measured experiences during the state of emergency and additional measures of reproductive motivation (reasons for and against parenthood). Subsamples were matched by sex, education, and the sampling procedure. We found the between-group differences which are congruent with life history theory: the desired age of first reproduction was lowest after the state of emergency compared to the two previous time-points. However, there were no differences in the desired number of children. Furthermore, the analysis of the links between experiences during the epidemic and reproductive motivation yielded the results which are incongruent with life history theory - adverse experiences during the state of emergency were negatively related to the reproductive motivation. Since the findings were only partially in accordance with life history theory, we discuss possible reasons which may explain the heterogeneity of results.
... Consistent with this notion, young adults living in slums (favelas) of Rio de Janeiro were found to discount the future more heavily than age-matched Brazilian university students (41). Across 46 nations, those with greater life expectancy (proxy for better conditions) were more willing to wait for a larger but delayed reward (i.e., less presentoriented) (42). ...
Article
The present lack of sample diversity and ecological theory in psychological science fundamentally limits generalizability and obstructs scientific progress. A focus on the role of socioecology in shaping the evolution of morphology, physiology, and behavior has not yet been widely applied toward psychology. To date, evolutionary approaches to psychology have focused more on finding universals than explaining variability. However, contrasts between small-scale, kin-based rural subsistence societies and large-scale urban, market-based populations, have not been well appreciated. Nor has the variability within high-income countries, or the socioeconomic and cultural transformations affecting even the most remote tribal populations today. Elucidating the causes and effects of such broad changes on psychology and behavior is a fundamental concern of the social sciences; expanding study participants beyond students and other convenience samples is necessary to improve understanding of flexible psychological reaction norms among and within populations. Here I highlight two examples demonstrating how socioecological variability can help explain psychological trait expression: (i) the role of environmental harshness and unpredictability on shaping time preference and related traits, such as impulsivity, vigilance, and self-efficacy; and (ii) the effects of industrialization, market integration, and niche complexity on personality structure. These cases illustrate how appropriate theory can be a powerful tool to help determine choices of diverse study populations and improve the social sciences.
... p's < 0.001. Figure which may relate to life expectancy (Bulley and Pepper, 2017), unhealthy behaviors (Story et al., 2014), obesity (Amlung et al., 2016), gambling (Wiehler et al., 2015), and a range of other potentially maladaptive decision-making patterns. It is also exacerbated in various 'externalizing disorders' as well in some neurodegenerative disorders (Gleichgerrcht et al., 2010) for example bvFTD patients show increased delay-discounting, mirroring the prominent displays of impulsivity in their daily lives. ...
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Much of human life revolves around anticipating and planning for the future. It has become increasingly clear that this capacity for prospective cognition is a core adaptive function of the mind. Here, we review the role of prospection in two key functional domains: goal-directed behavior and flexible decision-making. We then survey and categorize variations in prospection, with a particular focus on functional impact in clinical psychological conditions and neurological disorders. Finally, we suggest avenues for future research into the functions of prospection and the manner in which these functions can shift toward maladaptive outcomes. In doing so, we consider the conceptualization and measurement of prospection, as well as novel approaches to its augmentation in healthy people and managing its alterations in a clinical context.
... Moreover, markers of the choice process (for example, patterns of gaze transitions, latency of attribute integration) were predictive of subject-specific individual differences in patience (see Supplementary Fig. 12 for trial by trial differences in the choice process). These markers contribute to an improved understanding of the mechanisms of intertemporal choice, which in turn could inform policy and interventions that ameliorate negative real-world outcomes [7][8][9][10][11][12][39][40][41][42][43] . ...
Article
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Intertemporal choices involve trade-offs between the value of rewards and the delay before those rewards are experienced. Canonical intertemporal choice models such as hyperbolic discounting assume that reward amount and time until delivery are integrated within each option prior to comparison1,2. An alternative view posits that intertemporal choice reflects attribute-wise processes in which amount and time attributes are compared separately3–6. Here, we use multi-attribute drift diffusion modelling (DDM) to show that attribute-wise comparison represents the choice process better than option-wise comparison for intertemporal choice in a young adult population. We find that, while accumulation rates for amount and time information are uncorrelated, the difference between those rates predicts individual differences in patience. Moreover, patient individuals incorporate amount earlier than time into the decision process. Using eye tracking, we link these modelling results to attention, showing that patience results from a rapid, attribute-wise process that prioritizes amount over time information. Thus, we find converging evidence that distinct evaluation processes for amount and time determine intertemporal financial choices. Because intertemporal decisions in the lab have been linked to failures of patience ranging from insufficient saving to addiction7–13, understanding individual differences in the choice process is important for developing more effective interventions. Amasino et al. show that when humans decide between earlier or later monetary pay-outs of smaller or larger amounts, patient choices result from processing the information about amount and time successively, focussing first on amounts to be gained.
... In a large review paper, Pepper and Nettle [47] put forward the idea that there might be a common origin to the constellation of behaviors observed in adverse environments, which is that they reflect a contextually appropriate need to favor immediate over long-term benefits. Recent studies indeed reveal that people living in adverse conditions prefer immediate rewards over delayed rewards, discount future rewards more, are more pessimistic about their future, and are more impulsive than those living in more affluent conditions [48][49][50][51][52][53]. In sum, people's living environment appears to affect the present-future trade-off, with adverse conditions promoting present-oriented behaviors, and affluent conditions promoting future-oriented behaviors. ...
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Environmental adversity is associated with a wide range of biological outcomes and behaviors that seem to fulfill a need to favor immediate over long-term benefits. Adversity is also associated with decreased investment in cooperation, which is defined as a long-term strategy. Beyond establishing the correlation between adversity and cooperation, the channel through which this relationship arises remains unclear. We propose that this relationship is mediated by a present bias at the psychological level, which is embodied in the reproduction-maintenance trade-off at the biological level. We report two pre-registered studies applying structural equation models to test this relationship on large-scale datasets (the European Values Study and the World Values Survey). The present study replicates existing research linking adverse environments (both in childhood and in adulthood) with decreased investment in adult cooperation and finds that this association is indeed mediated by variations in individuals’ reproduction-maintenance trade-off.
... Empirical studies have consistently shown that women in harsher environments have earlier first births, more births, and a greater risk of preterm delivery and lower birthweight and/or smaller infants. This is the case in both crosspopulation (Bulley & Pepper, 2017;Caudell & Quinlan, 2012;Low, Hazel, Parker, & Welch, 2008) and within-population studies, including high-income populations such as the UK, where overall mortality risk is relatively low but there is still considerable within-population variation in mortality and morbidity (Agyemang et al., 2009;Auger, Park, Gamache, Pampalon, & Daniel, 2012;Clemens & Dibben, 2017;Luo, Wilkins, & Kramer, 2006;Pearl, Braveman, & Abrams, 2001;Schempf, Strobino, & O'Campo, 2009;Virgo & Sear, 2016). ...
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We use the UK's Born in Bradford study to investigate whether women in lower‐quality environments are less likely to breastfeed. We use measures of physical environmental quality (water disinfectant by‐products (DBPs), air pollution, passive cigarette smoke, and household condition) alongside socioeconomic indicators, to explore in detail how different exposures influence breastfeeding. Drawing on evolutionary life history theory, we predict that lower environmental quality will be associated with lower odds of initiating, and higher hazards of stopping, breastfeeding. As low physical environmental quality may increase the risk of adverse birth outcomes, which may in turn affect breastfeeding chances, we also test for mediation by gestational age, birthweight, baby's head circumference and abdominal circumference. Our sample is comprised of mothers who gave birth at the Bradford Royal Infirmary in West Yorkshire between March 2007 and December 2010 for whom breastfeeding initiation data was available. Analyses were stratified by the two largest ethnic groups: White British (n=3,951) and Pakistani‐origin (n=4,411) mothers. After controlling for socioeconomic position, Pakistani‐origin mothers had lower chances of initiating, and higher chances of stopping breastfeeding with increased water DBP exposure (e.g. OR for 0.03‐0.61 vs <0.02μg/day dibromochloromethane exposure 0.70 [0.58‐0.83], HR 1.16 [0.99‐1.36]; greater air pollution exposure predicted lower chances of initiation for both ethnic groups (e.g. OR for 10μg/m3 increase in nitrogen dioxide 0.81 [0.66‐0.99] for White British mothers and 0.79 [0.67‐0.94] for Pakistani‐origin mothers) but also a reduced hazard of stopping breastfeeding for White British mothers (HR 0.65 [0.52‐0.80]); and exposure to household damp/mould predicted higher chances of breastfeeding initiation amongst White British mothers (OR 1.66 [1.11‐2.47]). We found no evidence that physical environmental quality effects on breastfeeding were mediated through birth outcomes amongst Pakistani‐origin mothers, and only weak evidence (p<0.10) amongst White British mothers (exposure to passive cigarette smoke was associated with having lower birthweight infants who were in turn less likely to be breastfed whereas greater air pollution exposure was associated with longer gestations and in turn reduced hazards of stopping breastfeeding). Overall, our findings suggest that there is differential susceptibility to environmental exposures according to ethnicity. Whilst the water DBP results for Pakistani‐origin mothers and air pollution‐initiation results for both ethnic groups support our hypothesis that mothers exhibit reduced breastfeeding in poorer‐quality environments, several physical environmental quality indicators showed null or positive associations with breastfeeding outcomes. We consider physiological explanations for our findings, and their implications for life history theory and public health policy.
... Following other recent work on differences in behavior among countries (Bulley & Pepper, 2017;Lee et al., 2018), we controlled for autocorrelation across geographically close regions (i.e., Galton's problem) in follow-up analyses by including the United Nation's geographic region classification in our models (in addition to country). All data (including trait ratings and rankings not analyzed here), analysis code, and the full specifications for each model are publicly available at https://osf.io/4sr5f/ ...
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On average, women show stronger preferences for mates with good earning capacity than men do, while men show stronger preferences for physically attractive mates than women do. Studies reporting that sex differences in mate preferences are smaller in countries with greater gender equality have been interpreted as evidence that these sex differences in mate preferences are caused by the different roles society imposes on men and women. Here, we attempted to replicate previously reported links between sex differences in mate preferences and country-level measures of gender inequality in a sample of 3,073 participants from 36 countries (data and code available at https://osf.io/4sr5f/). Although women preferred mates with good earning capacity more than men did and men preferred physically attractive mates more than women did, we found little evidence that these sex differences were smaller in countries with greater gender equality. Although one analysis suggested that the sex difference in preferences for good earning capacity was smaller in countries with greater gender equality, this effect was not significant when controlling for Galton’s problem or when correcting for multiple comparisons. Collectively, these results provide little support for the social roles account of sex differences in mate preferences.
... Indeed, as has been found in studies of theory of mind development (e.g., Shahaeian, Peterson, Slaughter, & Wellman, 2011;Wellman, Fang, Liu, Zhu, & Liu, 2006), there may still be robust cultural variations in the steps that children acquire diverse instantiations of the capacity. To this end, future research may wish to investigate the crosscultural development of other future-oriented behaviors, such as tool acquisition and subsequent use (see Suddendorf, Nielsen, & Von Gehlen, 2011), acting for future desire states (see Atance & Meltzoff, 2006), intertemporal choice (see Bulley & Pepper, 2017;Metcalf & Atance, 2011;Mischel, Shoda, & Rodriguez, 1989), deliberate practice (see Brinums, Imuta, & Suddendorf, 2017), external reminder setting (see Redshaw, Vandersee, Bulley, & Gilbert, 2018), and affective forecasting (see Gautam, Bulley, von Hippel, & Suddendorf, 2017). ...
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This study examined future‐oriented behavior in children (3–6 years; N = 193) from three diverse societies—one industrialized Western city and two small, geographically isolated communities. Children had the opportunity to prepare for two alternative versions of an immediate future event over six trials. Some 3‐year‐olds from all cultures demonstrated competence, and a majority of the oldest children from each culture prepared for both future possibilities on every trial. Although there were some cultural differences in the youngest age groups that approached ceiling performance, the overall results indicate that children across these communities become able to prepare for alternative futures during early childhood. This acquisition period is therefore not contingent on Western upbringing, and may instead indicate normal cognitive maturation.
... A recent study using survey data from more than 40 countries finds that the proportion of "impatient citizens" (i.e. those who chose the sooner-smaller reward in a single hypothetical survey question) in a country is negatively related to the country's average life expectancy, and that adding life expectancy to the equation eliminates the negative country-level relationship between impatience and age at first birth (Bulley & Pepper, 2017). The latter results, although not directly addressing causality due to the cross-sectional nature of the data, may suggest that it is environmental mortality cues (as proxied by life expectancy) that influence both short-run orientation and early-reproduction decisions. ...
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Humans differ greatly in their tendency to discount future events, but the reasons underlying such inter-individual differences remain poorly understood. The evolutionary framework of Life History Theory predicts that the extent to which individuals discount the future should be influenced by socio-ecological factors such as mortality risk, environmental predictability and resource scarcity. However, little empirical work has been conducted to compare the discounting behavior of human groups facing different socio-ecological conditions. In a lab-in-the-field economic experiment, we compared the delay discounting of a sample of Romani people from Southern Spain (Gitanos) with that of their non-Romani neighbors (i.e., the majority Spanish population). The Romani-Gitano population constitutes the main ethnic minority in all of Europe today and is characterized by lower socioeconomic status (SES), lower life expectancy and poorer health than the majority, along with a historical experience of discrimination and persecution. According to Life History Theory, Gitanos will tend to adopt "faster" life history strategies (e.g., earlier marriage and reproduction) as an adaptation to such ecological conditions and, therefore, should discount the future more heavily than the majority. Our results support this prediction, even after controlling for the individuals' current SES (income and education). Moreover, group-level differences explain a large share of the individual-level differences. Our data suggest that human inter-group discrimination might shape group members' time preferences through its impact on the environmental harshness and unpredictability conditions they face.
... Empirical measures of discount rates across individuals and societies indeed show a significant amount of variation, which correlates with indicators of deprivation (e.g. Bruderer Enzler et al., 2014;Green et al., 1996;Harrison et al., 2002;Tanaka et al., 2010;Wang et al., 2016), and correlations between people's tendency to discount the future and reproductive behaviours have also been documented (Bulley and Pepper, 2017). Hence, a theoretical understanding of why environments should elicit different rates of delay discounting is needed. ...
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Individuals exposed to deprivation tend to show a characteristic behavioural syndrome suggestive of a short time horizon. This pattern has traditionally been attributed to the intrinsically higher unpredictability of deprived environments, which renders waiting for long term rewards more risky (i.e. collection risks are high). In the current paper, based on a simple dynamic life history model, we show that a significant portion of individuals’ propensity to discount future rewards might have a completely distinct origin. Upon collecting a resource, individuals have the opportunity to accumulate “capital” (e.g. grow muscular tissue, build a protective shelter, buy a car, etc.), which eventually increases their productivity and/or their chances of survival. As a result, delaying the collection of a resource creates an opportunity cost in the sense that during the waiting time, the benefits otherwise generated by the increment in capital are lost. These forgone benefits are independent of collection risks and constitute waiting costs per se. Using optimal control theory we show that these costs can lead to the evolution of short time horizons even in the complete absence of collection risks. Moreover, assuming diminishing returns to capital, we show that the evolutionarily stable time horizon increases with the amount of capital already owned by individuals. When individuals possess little capital, they have a lot of room to improve their productivity and/or survival, hence they should be impatient to collect resources; that is, their time horizon should be short. On the contrary, when individuals already possess a lot of capital, the benefits of further accumulation are plateauing, hence patience becomes a more profitable strategy and individuals should lengthen their time horizon. This means that individuals get more patient as they age and that people in deprivation, who still have important productive and survival needs that can be satisfied, should have a shorter time horizon. Moreover, beyond time horizon, our model shows that people with little capital should also be more risk averse than the more privileged. Taken together, these results lead us to interpret the behavioral constellation of deprivation in a new way.
... The total fertility rate is decreasing and the average age for women who become pregnant for the first time is simultaneously rising [11]. The average age of primiparas in Poland is 27, which means it occurs at a time when the drop in fertility begins [12]. There is also a new phenomenon called voluntary childlessness, which is referred to as "a childfree lifestyle" [13,14]. ...
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Introduction : Early sexual initiation, the phenomenon of promiscuity, and voluntary childlessness are some reasons behind contraception use by women. Health-related behaviors determine the state of human health and are closely related to quality of life. The aim of the study was to analyze the manifestations of pro-health behaviors and to examine their impact on the quality of life in a group of fertile women using any form of contraception. Materials and methods : Research material was collected from August 2017 to January 2018 in the West Pomeranian Voivod-ship, from 183 women of childbearing age who had been using contraception. The questionnaire consisted of a author’s part and the WHOQOL-BREF questionnaire. Statistical analysis used descriptive and analytical methods, such as the Shapiro–Wilk test and the analysis of variance (ANOVA) test. A structure index containing a percentage was used. The results obtained were statistically analyzed using χ2 test for independent samples. The probability value of p < 0.05 was considered statistically significant. Results : Among pro-health behaviors, 80.9% of the women declared that they performed some physical activity at least once a week, 76% stated that their eating habits were correct, 47% went to a gynecologist once a year, 83.6% claimed they regularly performed preventive examinations. The better the subjective assessment of health, the higher the quality of life in the psychological domain (p < 0.001). The better the nutritional habits were assessed, the better the quality of life in the environment domain (p < 0.05). Not using stimulants had a positive impact on the quality of life in the physical health domain (p < 0.05). A rise in the frequency of follow-up visits to a gynecologist led to a rise in the quality of life in social relationships and physical health domains (p < 0.05). Conclusions : The manifestation of pro-health behaviors in women of childbearing age who use contraception has a positive influence on the quality of their lives in almost all the domains. The overriding purpose of pro-health education is to strengthen the actions of women who display healthy behaviors and, in the case of those exposed to a reduced quality of life due to unhealthy practices, conduct intervention and preventive actions while respecting the woman’s individual biopsychosocial needs.
... On the one hand, correlational studies show that a faster life-history strategy is associated with higher levels of impulsivity (Lee, DeBruine, & Jones, 2018;Mishra, Templeton, & Meadows, 2017). Similarly, experimental studies show that people who have grown up in harsh environments may be more likely to respond to resource scarcity with higher levels of impulsive behavior (Griskevicius et al., 2013;Kruger, Reischl, & Zimmerman, 2008; but see for a replication study that obtains a different result) and residents of countries with low life expectancy show less willingness to wait for a delayed reward (Bulley & Pepper, 2017). On the other hand, fast life history traits such as early maturation do not always correlate with less deliberation, exploration, or future orientation in humans (Copping, Campbell, & Muncer, 2013, 2014 or non-human animals (Royauté et al., 2018). ...
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Evolutionary social scientists have argued that impulsive behavior is adaptive in harsh and unpredictable conditions. Is this true? This paper presents a mathematical model that computes the optimal level of impulsivity in environments varying in harshness and unpredictability. We focus on information impulsivity, or choosing to act without gathering or considering information about the consequences of one's actions. We explore two notions of harshness: the mean level of resources (e.g., food) and the mean level of extrinsic events (e.g., being the victim of a random attack). We explore three notions of unpredictability: variation in resources, variation in extrinsic events, and the interruption risk (the chance that a resource becomes unavailable). We also explore interactions between harshness and unpredictability. Our general model suggests four broad conclusions. First, impulsive behavior is not always adaptive in harsh and unpredictable conditions; rather, this depends on the exact definition of harshness, unpredictability, and impulsivity. Second, impulsive behavior may be adaptive in environments in which the quality of resources is low or high, but is less likely to be adaptive when their quality is moderate. Third, impulsive behavior may be adaptive when resource encounters are likely to be interrupted. Fourth, extrinsic events have only a limited effect on whether impulsive behavior is adaptive. We discuss the implications of these findings for future research, consider several limitations, and suggest future directions.
... Foreseeing this regret, a consumer may intentionally splurge on indulgences like an expensive dinner 26,137 , and this would be incorrectly called short-sighted by those failing to understand the causal metacognitive and prospective deliberation involved 24 . In a similar vein, people may intentionally choose a smaller, sooner reward if they do not trust that they will obtain a larger, later one 138 , a fact that helps explain the steeper discounting observed amongst people living in poverty 7,133,139 and perhaps also the robust individual and cross-national associations between lower life expectancy and steeper delay discounting [140][141][142] . Even young children will modify their intertemporal choices based on their expectations of environmental reliability. ...
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Many fundamental choices in life are intertemporal: they involve trade-offs between sooner and later outcomes. In recent years there has been a surge of interest into how people make intertemporal decisions, given that such decisions are ubiquitous in everyday life and central in domains from substance use to climate change action. While it is clear that people make decisions according to rules, intuitions and habits, they also commonly deliberate over their options, thinking through potential outcomes and reflecting on their own preferences. In this Perspective, we bring to bear recent research into the higher-order capacities that underpin deliberation—particularly those that enable people to think about the future (prospection) and their own thinking (metacognition)—to shed light on intertemporal decision-making. We show how a greater appreciation for these mechanisms of deliberation promises to advance our understanding of intertemporal decision-making and unify a wide range of otherwise disparate choice phenomena.
... For example, at the biodemographic level of analysis, both within-and between-country comparisons show that women's age at first birth is lower when mortality rates are higher (Low et al. 2008). As another example, at the psychometric level, people prefer smaller immediate rewards to larger delayed rewards in countries with shorter life expectancies (Bulley and Pepper 2017). Within human societies, lower socioeconomic status (SES) is often associated with both higher mortality rates and biodemographic fast LHS indicators (e.g., Nettle 2010). ...
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Research by Sherman et al. (Journal of Personality and Social Psychology, 105, 873–888, 2013) has shown that, in speech during clinical-style interviews, life history strategy (LHS) was correlated with variation in the use of 16–19 word categories from the Linguistic Inquiry and Word Count program. However, links between individual difference variables and word use have been shown to vary as a function of communication context. Therefore, I sought to replicate their results using speech recorded during participants’ daily life via the Electronically Activated Recorder. I also used (1) observer ratings rather than self-ratings of the California Adult Q-Sort (CAQ) items as a measure of LHS, (2) the self-report Arizona Life History Battery (ALHB) as an additional measure of LHS, and (3) Bayesian multi-level aggregated binomial regressions as a complementary analytical technique to conventional correlations. In general, the Sherman et al. results were replicated, particularly with respective to distinctive (corrected for normativeness) LHS. People pursuing a slower distinctive LHS produced proportionately fewer swear words, sexual words, and affect words (particularly negative emotion and anger words), and more work-related words. They also produced fewer words overall. After controlling for distinctive LHS, women were more talkative than men. Associations between the ALHB and word use were weaker than those between the CAQ and word use.
... Beyond these individual-level relationships, there is new macro-level evidence connecting patience with economic development: patience seems to be a key determinant of GDP per capita, and its effect seems to arise through physical and human capital accumulation and productivity . Other macrolevel relationships include intergroup discrimination (negatively), life expectancy 3 (positively) and infant mortality (negatively) (Bulley and Pepper, 2017;Espín et al., 2019b). Recently, there is also an interest in studying the effect of in-the-classroom interventions on the consistency of inter-temporal decisions (Alan and Ertac, 2018;Lührmann et al., 2018), and the causal relationship between education and patience (Perez-Arce, 2017;Kim et al., 2018). ...
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The use of hypothetical instead of real decision-making incentives remains under debate after decades of economic experiments. Standard incentivized experiments involve substantial monetary costs due to participants' earnings and often logistic costs as well. In time preferences experiments, which involve future payments, real payments are particularly problematic. Since immediate rewards frequently have lower transaction costs than delayed rewards in experimental tasks, among other issues, (quasi)hyperbolic functional forms cannot be accurately estimated. What if hypothetical payments provide accurate data which, moreover, avoid transaction cost problems? In this paper, we test whether the use of hypothetical - versus real - payments affects the elicitation of short-term and long-term discounting in a standard multiple price list task. One-out-of-ten participants probabilistic payment schemes are also considered. We analyze data from three studies: a lab experiment in Spain, a well-powered field experiment in Nigeria, and an online extension focused on probabilistic payments. Our results indicate that paid and hypothetical time preferences are mostly the same and, therefore, that hypothetical rewards are a good alternative to real rewards. However, our data suggest that probabilistic payments are not.
... This tendency for delay discounting is near-universal in adults [148], present in non-human animals [149], and emerges early in childhood [150]. Steeper delay discounting (wherein rewards more quickly lose their subjective value with delays to their receipt) has become a prominent target for applied research, not least because of its occurrence in a range of psychopathologies [151] and associations with outcomes ranging from financial debt [152] to life expectancy [153,154]. Various lines of evidence have implicated subjective timing in the steepness of delay discounting [155,156], with some prominent models placing the subjective perception of time centre-stage as both a key neurocognitive mechanism and an essential individual-differences variable [156,157]. According to such mod-els, an individual who relatively overestimates the duration of delays would perceive future rewards as being relatively more distant, and they should therefore perceive the cost of waiting to be higher. ...
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The capacity for subjective time in humans encompasses the perception of time’s unfolding from moment to moment, as well as the ability to traverse larger temporal expanses of past- and future-oriented thought via mental time travel. Disruption in time perception can result in maladaptive outcomes—from the innocuous lapse in timing that leads to a burnt piece of toast, to the grievous miscalculation that produces a traffic accident—while disruption to mental time travel can impact core functions from planning appointments to making long-term decisions. Mounting evidence suggests that disturbances to both time perception and mental time travel are prominent in dementia syndromes. Given that such disruptions can have severe consequences for independent functioning in everyday life, here we aim to provide a comprehensive exposition of subjective timing dysfunction in dementia, with a view to informing the management of such disturbances. We consider the neurocognitive mechanisms underpinning changes to both time perception and mental time travel across different dementia disorders. Moreover, we explicate the functional implications of altered subjective timing by reference to two key and representative adaptive capacities: prospective memory and intertemporal decision-making. Overall, our review sheds light on the transdiagnostic implications of subjective timing disturbances in dementia and highlights the high variability in performance across clinical syndromes and functional domains.
... Our results therefore need to be replicated in a more diverse sample, which would include non-Western and non-industrialised societies. Note however that previous studies working with more culturally diverse groups of subjects have shown that environmental adversity (measured directly or indirectly) impacts cognition (e.g., intertemporal choice) and behaviour (social and academic behaviours) in relatively similar ways across these groups (Bulley and Pepper, 2017;Chang et al., 2019;Lee et al., 2018). ...
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An association between early life adversity and a range of coordinated behavioural responses that favour reproduction at the cost of a degraded health is often reported in humans. Recent theoretical works have proposed that perceived control—i.e., people’s belief that they are in control of external events that affect their lives—and time orientation—i.e., their tendency to live on a day-to-day basis or to plan for the future—are two closely related psychological traits mediating the associations between early life adversity, reproductive behaviours and health status. However, the empirical validity of this hypothesis remains to be demonstrated. In the present study, we examine the role of perceived control and time orientation in mediating the effects of early life adversity on a trade-off between reproductive traits (age at 1st childbirth, number of children) and health status by applying a cross-validated structural equation model frame on two large public survey datasets, the European Values Study (EVS, final N = 43,084) and the European Social Survey (ESS, final N = 31,065). Our results show that early life adversity, perceived control and time orientation are all associated with a trade-off favouring reproduction over health. However, perceived control and time orientation mediate only a small portion of the effect of early life adversity on the reproduction-health trade-off.
... Available discretionary time and energy may also be influenced by macro-level historical change. For example, due to increases in life expectancy and age at first birth (Bulley & Pepper, 2017), as well as the fact that younger adults are living at home for longer (Sironi & Billari, 2020), current living situations are more likely to lead to middleaged adults caring for both parents and children at the same time, greatly limiting their available discretionary time to engage with other members of their social networks. Furthermore, increasing financial demands over the past decades translates to increasing numbers of dual-income households; with both men and women working, there is less time and energy available for the traditionally female role of kin-keeping, particularly in light of enduring inequalities in the division of household labor (Perry-Jenkins & Gerstel, 2020). ...
Article
Empirical evidence about the development of social relationships across adulthood into late life continues to accumulate, but theoretical development has lagged behind. The Differential Investment of Resources (DIRe) model integrates these empirical advances. The model defines the investment of time and energy into social ties varying in terms of emotional closeness and kinship as the core mechanism explaining the formation and maintenance of social networks. Individual characteristics, acting as capacities, motivations, and skills, determine the amount, direction, and efficacy of the investment. The context (e.g., the living situation) affects the social opportunity structure, the amount of time and energy available, and individual characteristics. Finally, the model describes two feedback loops: (a) social capital affecting the individual’s living situation and (b) different types of ties impacting individual characteristics via social exchanges, social influences, and social evaluations. The proposed model will provide a theoretical basis for future research and hypothesis testing.
... measurements of time preferences [6,15,16,[18][19][20][21]. Details of the estimation and data sources are provided in the methods section: ...
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Time preferences are central to human decision making; therefore, a thorough understanding of their international differences is highly relevant. Previous measurements, however, vary widely in their methodology, from questions answered on the Likert scale to lottery-type questions. We show that these different measurements correlate to a large degree and that they have a common factor that can predict a broad spectrum of variables: the countries’ credit ratings, gasoline prices (as a proxy for environmental protection), equity risk premiums, and average years of school attendance. The resulting data on this time preference factor for N = 117 countries and regions will be highly useful for further research. Our aggregation method is applicable to merge cross-cultural studies that measure the same latent construct with different methodologies.
... Empirical measures of discount rates across individuals and societies indeed show a significant amount of variation, which correlates with indicators of deprivation (e.g. Bruderer Enzler, Diekmann, & Meyer, 2014;Green et al., 1996;Guillou, Grandin, & Chevallier, 2020;Harrison, Lau, & Williams, 2002;Tanaka, Camerer, & Nguyen, 2010;Wang et al., 2016), and correlations between people's tendency to discount the future and reproductive behaviors have also been documented (Bulley & Pepper, 2017). Hence, a theoretical understanding of why environments should elicit different rates of delay discounting is needed. ...
Article
Individuals exposed to deprivation tend to show a characteristic behavioral syndrome suggestive of a short time horizon. This pattern has traditionally been attributed to the intrinsically higher unpredictability of deprived environments, which renders waiting for long term rewards more risky (i.e. collection risks are high). In the current paper, based on a simple dynamic life history model, we show that a significant portion of individuals' propensity to discount future rewards might have a completely distinct origin. Upon collecting a resource, individuals have the opportunity to accumulate “capital” (e.g. grow muscular tissue, build a protective shelter, buy a car, etc.), which eventually increases their productivity and/or their chances of survival. As a result, delaying the collection of a resource creates an opportunity cost in the sense that during the waiting time, the benefits otherwise generated by the increment in capital are lost. These forgone benefits are independent of collection risks and constitute waiting costs per se. Using optimal control theory we show that these costs can lead to the evolution of short time horizons even in the complete absence of collection risks. Moreover, assuming diminishing returns to capital, we show that the evolutionarily stable time horizon increases with the amount of capital already owned by individuals. When individuals possess little capital, they have a lot of room to improve their productivity and/or survival, hence they should be impatient to collect resources; that is, their time horizon should be short. On the contrary, when individuals already possess a lot of capital, the benefits of further accumulation are plateauing, hence patience becomes a more profitable strategy and individuals should lengthen their time horizon. This means that individuals get more patient as they age and that people in deprivation, who still have important productive and survival needs that can be satisfied, should have a shorter time horizon. This result leads us to interpret the behavioral constellation of deprivation in a new way.
... At the proximal level, researchers have also aimed to put forward psychological mechanisms accounting for the constellation of behaviours that is associated with deprivation in humans (Pepper & Nettle, 2017). One possible explanation is that adverse environments are associated with mechanisms biasing individuals towards more immediate rewards and a shorter time horizon (Bulley & Pepper, 2017;Griskevicius et al., 2011;Simpson et al., 2012;Wu et al., 2020). Such a psychological switch would have a wide impact on a range of behaviours relying on delay gratification, including many social behaviours. ...
... Our results therefore need to be replicated in a more diverse sample which would include non-Western and non-industrialized societies. Note however that previous studies working with more culturally diverse groups of subjects have shown that environmental adversity (measured directly or indirectly) impacts cognition (e.g., intertemporal choice) and behaviour (social and academic behaviours) in relatively similar ways across these groups (Bulley & Pepper, 2017;Chang et al., 2019). ...
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An association between early life adversity and a range of coordinated behavioural responses that favour reproduction at the cost of a degraded health is often reported in humans. Recent theoretical works have proposed that perceived control-i.e., people's belief that they are in control of external events that affect their lives-and time orientation-i.e., their tendency to live on a day-today basis or to plan for the future-are two closely related psychological traits mediating the associations between early life adversity, reproductive behaviours and health status. However, the empirical validity of this hypothesis remains to be demonstrated. In the present study, we examine the role of perceived control and time orientation in mediating the effects of early life adversity on a trade-off between reproductive traits (age at 1 st childbirth, number of children) and health status by applying a cross-validated structural equation model frame on two large public survey datasets, the European Values Study (EVS, final N = 43 084) and the European Social Survey (ESS, final N = 31 065). Our results show that early life adversity, perceived control and time orientation are all associated with a trade-off favouring reproduction over health. However, perceived control and time orientation mediate only a small portion of the effect of early life adversity on the reproduction-health trade-off.
... (1) With high longevity, woman could exploit longer her fertility lifecycle even at its end, without fearing to die at early age, and to be unable to take care of her children. So, she may seek to have an additional child at the end of her fertility lifecycle for reviving her couple life (Bulley and Pepper, 2017). (2) Thanks to longevity gain, couples as well may be encouraged to have large family since they could benefit for their (aging) parents' attendance (if they are in good health) in particular from their childcare service for free (Del Boca 2002, Frini, 2014and Garcia-Moran and Kuehn, 2017. ...
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In Tunisia as in some Arab countries like in Algeria and Egypt, fertility has known, after a deep decline, a steady increase from the mid of 2000s. This paper tries to apprehend this unexpected and current demographic issue. For that aim, we revisit the classical fertility decline factors (namely education, income, mortality and contraceptive prevalence) in order to inspect if they do no longer influence fertility downward. Furthermore, we explore three new socio-economic factors likely to favor fertility rise, such as divorce, unemployment and longevity. We apply the dynamic one-step generalized method of moments (GMM) method over the period 1999-2017 on eight Tunisian regions. Findings confirm our presumption. The three new variables estimated have a positive effect on fertility. Likewise, the education- fertility interaction is no longer obvious. Family planning program appears no longer playing its role. The income effect dominated the substitution effect in favor of fertility increase. The increasing fertility trend in Tunisia seems to be caused by the sociocultural factors.
... A robust finding in both psychology and economics is that deprived individuals discount the future more than wealthier individuals do (Adams & White, 2009;Bulley & Pepper, 2017;de Wit, Flory, Acheson, McCloskey, & Manuck, 2007;Green, Myerson, Lichtman, Rosen, & Fry, 1996;Griskevicius et al., 2011;Lawrance, 1991;Robb, Simon, & Wardle, 2009). In the evolutionary psychology literature, these findings are explained by collection risks and/or waiting costs. ...
Article
Individual observations of risky behaviors present a paradox: individuals who take the most risks in terms of hazards (smoking, speeding, risky sexual behaviors) are also less likely to take risks when it comes to innovation, financial risks or entrepreneurship. Existing theories of risk-preferences do not explain these patterns. From a simple model, we argue that many decisions involving risk have a temporal dimension, and that this dimension is often the main determinant of individual choices. In many real life instances, risk taking amounts to damaging the individual's capital (whether embodied capital, financial capital, social reputation, etc.), which would affect her over a long period of time after the risky decision. In evolutionary terms, the marginal cost of this type of risky behavior depends on the relative importance of the future in the individual's fitness (e.g. her time horizon). Individuals with short time horizons will give less importance to a degradation of their capital because this degradation will be paid effectively for a shorter period of time. This approach explains patterns of behaviors observed across socio-economic groups and puts forward new approaches to prevent hazardous behaviors such as smoking.
... From a biological fitness perspective, it makes sense for these individuals not to risk delaying the satisfaction of immediate needs to invest time and energy in long-term activities whose pay-offs are likely to change unpredictably. Some empirical data appears to support this hypothesis by showing that people who have experienced environmental uncertainty or low perceived control are more likely than others to act on a day-to-day basis in various domains such as health, reproduction, social or economic decision-making (108,(116)(117)(118)(119)(120)(121)(122)(123)(124)(125). Interestingly, such a present-future trade-off clearly appears to be at play in people with BPD (18). ...
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Self-disturbance is recognized as a key symptom of Borderline Personality Disorder (BPD). Although it is the source of significant distress and significant costs to society, it is still poorly specified. In addition, current research and models on the etiology of BPD do not provide sufficient evidence or predictions about who is at risk of developing BPD and self-disturbance, and why. The aim of this review is to lay the foundations of a new model inspired by recent developments at the intersection of social cognition, behavioral ecology, and developmental biology. We argue that the sense of agency is an important dimension to consider when characterizing self-disturbances in BPD. Second, we address the poorly characterized relation between self-disturbances and adverse life conditions encountered early in life. We highlight the potential relevance of Life-History Theory—a major framework in evolutionary developmental biology—to make sense of this association. We put forward the idea that the effect of early life adversity on BPD symptomatology depends on the way individuals trade their limited resources between competing biological functions during development.
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We introduce the Preference for Earlier versus Later Income (PELI) scale, measuring patience for over 50,000 individuals from 65 countries. We focus on the relationship between age and income on patience, two variables that have been widely studied in isolation. We find that, within countries, individuals in the richest income quintile are equally patient at any age while individuals in the poorest quintile are less patient the older they are. The relationships in the other quintiles are distributed in an orderly manner between these extremes. We derive a national patience index that correlates with characteristics linked to economic development, with cultural differences associated with patience, and with alternative more complex measures of patience. We recommend adopting PELI in international surveys.
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Humans differ greatly in their tendency to discount future events, but the reasons underlying such inter-in-dividual differences remain poorly understood. Based on the evolutionary framework of Life History Theory, influential models predict that the extent to which individuals discount the future should be influenced by socio-ecological factors such as mortality risk, environmental predictability and resource scarcity. However, little empirical work has been conducted to compare the discounting behavior of human groups facing different socio-ecological conditions. In a lab-in-the-field economic experiment, we compared the delay discounting of a sample of Romani people from Southern Spain (Gitanos) with that of their non-Romani neighbors (i.e., the majority Spanish population). Romani populations constitutes the main ethnic minority in all of Europe todayand is characterized by lower socio-economic status (SES), lower life expectancy and poorer health than themajority, along with a historical experience of discrimination and persecution. According to those Life History Theory models, Gitanos will tend to adopt “faster” life history strategies (e.g., earlier marriage and reproduction) as an adaptation to such ecological conditions and, therefore, should discount the future more heavily than the majority. Our results support this prediction, even after controlling for the individuals' current SES (income and education). Moreover, group-level differences explain a large share of the individual-level differences. Our data suggest that human inter-group discrimination might shape group members' time preferences through its impact on the environmental harshness and unpredictability conditions they face.
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Humans considerably vary in the degree to which they rely on their peers to make decisions. Why? Theoretical models predict that environmental risks shift the cost-benefit trade-off associated with the exploitation of others' behaviours (public information), yet this idea has received little empirical support. Using computational analyses of behaviour and multivariate decoding of electroencephalographic activity, we test the hypothesis that perceived vulnerability to extrinsic morbidity risks impacts susceptibility to social influence, and investigate whether and how this covariation is reflected in the brain. Data collected from 261 participants tested online revealed that perceived vulnerability to extrinsic morbidity risks is positively associated with susceptibility to follow peers' opinion in the context of a standard face evaluation task. We found similar results on 17 participants tested in the laboratory, and showed that the sensitivity of EEG signals to public information correlates with the participants' degree of vulnerability. We further demonstrated that the combination of perceived vulnerability to extrinsic morbidity with decoding sensitivities better predicted social influence scores than each variable taken in isolation. These findings suggest that susceptibility to social influence is partly calibrated by perceived environmental risks, possibly via a tuning of neural mechanisms involved in the processing of public information.
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Humans frequently create mental models of the future, allowing outcomes to be inferred in advance of their occurrence. Recent evidence suggests that imagining positive future events reduces delay discounting (the devaluation of reward with time until its receipt), while imagining negative future events may increase it. Here, using a sample of 297 participants, we experimentally assess the effects of cued episodic simulation of positive and negative future scenarios on decision-making in the context of both delay discounting (monetary choice questionnaire) and risk-taking (balloon-analogue risk task). Participants discounted the future less when cued to imagine positive and negative future scenarios than they did when cued to engage in control neutral imagery. There were no effects of experimental condition on risk-taking. Thus, although these results replicate previous findings suggesting episodic future simulation can reduce delay discounting, they indicate that this effect is not dependent on the valence of the thoughts, and does not generalise to all other forms of “impulsive” decision-making. We discuss various interpretations of these results, and suggest avenues for further research on the role of prospection in decision-making.
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Many evolutionary models explain why we cooperate with non-kin, but few explain why cooperative behaviour and trust vary. Here, we introduce a model of cooperation as a signal of time preferences, which addresses this variability. At equilibrium in our model (i) future-oriented individuals are more motivated to cooperate, (ii) future-oriented populations have access to a wider range of cooperative opportunities, and (iii) spontaneous and inconspicuous cooperation reveal stronger preference for the future, and therefore inspire more trust. Our theory sheds light on the variability of cooperative behaviour and trust. Since affluence tends to align with time preferences, results (i) and (ii) explain why cooperation is often associated with affluence, in surveys and field studies. Time preferences also explain why we trust others based on proxies for impulsivity, and, following result (iii), why uncalculating, subtle and one-shot cooperators are deemed particularly trustworthy. Time preferences provide a powerful and parsimonious explanatory lens, through which we can better understand the variability of trust and cooperation.
Chapter
The idea of this chapter is to identify and make use of findings in nature that have a specific relevance for purchasing and supply management. Most of the findings are observed or studied with wild animals such as in birds, wolves, fish, fireflies, bush crickets, chimpanzees, capuchin monkeys, and prairie voles. All of the research that I studied and cited is confirmed to fulfil ethical standards for the care of animals. Beyond learnings from animal behaviour, this chapter discusses characteristic elements of the human brain and concludes on cognition. Also here, all ethical standards are fulfilled. Learnings include findings on memory, memorizing, distraction, the wish for completion of incomplete tasks and pure task orientation. Furthermore, the relevance of contextual information to behaviour in purchasing and supply management tasks is explained. This has implications for observing and understanding the business partner. Other studied aspects are communication and reciprocal expectations. The decisive moment in purchasing is the supplier selection, which is brought into focus, while the understanding of buyer–supplier relationships on different personal levels, structures of trust and help are playing a crucial role for success. Staying healthy in buyer–supplier relationships, consequences of a good breakfast before negotiations and other physiological effects are analyzed. One further aspect is to develop a deeper understanding of cultures and here especially the culture of the business partner and again reciprocal effects on the culture of the discussed business itself. Before concluding, the chapter points out on tricks of our brain that is relevant to purchasing success.
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The degree to which individuals prefer smaller sooner versus larger delayed rewards serves as a powerful predictor of their impulsivity towards a number of different kinds of rewards. Here we test the limits of its predictive ability within a variety of cognitive and social domains. Across several large samples of subjects, individuals who prefer smaller more immediate rewards (steeper discounters) are less reflective (or more impulsive) in their choices, preferences, and beliefs. First, steeper discounters used more automatic, less controlled choice strategies, giving more intuitive but incorrect responses on the Cognitive Reflection Test (replicating previous findings); employing a suboptimal probability matching heuristic for a one-shot gamble (rather than maximizing their probability of reward); and relying less on optimal planning in a two-stage reinforcement learning task. Second, steeper discounters preferred to consume information that was less complex and multi-faceted, as suggested by their self-reported Need for Cognitive Closure, their use of short-form social media (i.e., Twitter), and their preferred news sources (in particular, whether or not they preferred National Public Radio over other news sources). Third, steeper discounters had interpersonal and religious beliefs that are associated with reduced epistemic complexity: they were more likely to believe that the behavior of others could be explained by fixed rather than dynamic factors, and they believed more strongly in God and in the afterlife. Together these findings provide evidence for a link between individual differences in temporal discounting for monetary rewards and preferences for the path of least resistance (less reflective and/or more automatic modes of processing) across a variety of domains.
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The degree to which individuals prefer smaller sooner versus larger delayed rewards serves as a powerful predictor of their impulsivity towards a number of different kinds of rewards. Here we test the limits of its predictive ability within a variety of cognitive and social domains. Across several large samples of subjects, individuals who prefer smaller more immediate rewards (steeper discounters) are less reflective (or more impulsive) in their choices, preferences, and beliefs. First, steeper discounters used more automatic, less controlled choice strategies, giving more intuitive but incorrect responses on the Cognitive Reflection Test (replicating previous findings); employing a suboptimal probability matching heuristic for a one-shot gamble (rather than maximizing their probability of reward); and relying less on optimal planning in a two-stage reinforcement learning task. Second, steeper discounters preferred to consume information that was less complex and multi-faceted, as suggested by their self-reported Need for Cognitive Closure, their use of short-form social media (i.e., Twitter), and their preferred news sources (in particular, whether or not they preferred National Public Radio over other news sources). Third, steeper discounters had interpersonal and religious beliefs that are associated with reduced epistemic complexity: they were more likely to believe that the behavior of others could be explained by fixed rather than dynamic factors, and they believed more strongly in God and in the afterlife. Together these findings provide evidence for a link between individual differences in temporal discounting for monetary rewards and preferences for the path of least resistance (less reflective and/or more automatic modes of processing) across a variety of domains.
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Socioeconomic differences in behaviour are pervasive and well documented, but their causes are not yet well understood. Here, we make the case that there is a cluster of behaviours associated with lower socioeconomic status, which we call the behavioural constellation of deprivation. We propose that the relatively limited control associated with lower socioeconomic status curtails the extent to which people can expect to realise deferred rewards, leading to more present-oriented behaviour in a range of domains. We illustrate this idea using the specific factor of extrinsic mortality risk, an important factor in evolutionary theoretical models. We emphasise the idea that the present-oriented behaviours of the constellation are a contextually appropriate response to structural and ecological factors, rather than pathology or a failure of willpower. We highlight some principles from evolutionary theoretical models that can deepen our understanding of how socioeconomic inequalities can become amplified and embedded. These principles are that: 1) Small initial disparities can lead to larger eventual inequalities, 2) Feed-back loops can operate to embed early life circumstances, 3) Constraints can breed further constraints, and 4) Feed-back loops can operate over generations. We discuss some of the mechanisms by which socioeconomic status may influence behaviour. We then review how the contextually appropriate response perspective that we have outlined fits with other findings about control and temporal discounting. Finally, we discuss the implications of this interpretation for research and policy.
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Cultural, ecological, familial and physiological factors consistently influence fertility behaviours, however, the proximate psychological mechanisms underlying fertility decisions in humans are poorly understood. Understanding the psychological mechanisms underlying human fertility may illuminate the final processes by which some of these known predictors have their influence. To date, research into the psychological mechanisms underlying fertility has been fragmented. Aspects of reproductive psychology have been examined by researchers in a range of fields, but the findings have not been systematically integrated in one review. We provide such a review, examining current theories and research on psychological mechanisms of fertility. We examine the methods and populations used in the research, as well as the disciplines and theoretical perspectives from which the work has come. Much of the work that has been done to date is methodologically limited to examining correlations between ecological, social and economic factors and fertility. We propose, and support with examples, the use of experimental methods to differentiate causal factors from correlates. We also discuss weaknesses in the experimental research, including limited work with non-WEIRD (western, educated, industrialized, rich and democratic) populations.
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We present results from the first large-scale international survey on time preference, conducted in 53 countries. All countries exhibit hyperbolic discounting patterns, i.e., the immediate future is discounted more than far future. We also observe higher heterogeneity for shorter time horizons, consistent with the pattern reviewed by Frederick, Loewenstein, and O’Donoghue (2002). Cultural factors as captured by the Hofstede cultural dimensions (Hofstede, 1991) contribute significantly to the variation of time discounting, even after controlling for economic factors, such as GDP, inflation rate and growth rate. In particular, higher levels of Uncertainty Avoidance are associated with stronger hyperbolic discounting, whereas higher degrees of Individualism and Long Term Orientation predict stronger tendency to wait for larger payoffs. We also find the waiting tendency is correlated with innovation, environmental protection, crediting rating, and body mass index at country level after controlling for county wealth. These results help us to enhance the understanding of differences across financial markets and economic behavior worldwide.
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Intertemporal choices are ubiquitous: people often have to choose between outcomes realized at different times. Although it is generally believed that people have stable tendencies toward being impulsive or patient, an emerging body of evidence indicates that intertemporal choice is malleable and can be profoundly influenced by context. How the choice is framed, or the state of the decision-maker at the time of choice, can induce a shift in preference. Framing effects are underpinned by allocation of attention to choice attributes, reference dependence, and time construal. Incidental affective states and prospection also influence intertemporal choice. We advocate that intertemporal choice models account for these context effects, and encourage the use of this knowledge to nudge people toward making more advantageous choices.
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We present results from a large-scale international survey on risk preferences conducted in 53 countries. In all countries, we find, on average, an attitude of risk aversion in gains and of risk seeking in losses. The degree of risk aversion shows significant cross-country differences. Moreover, risk attitudes in our sample depend not only on economic conditions but also on cultural factors, as measured by the Hofstede dimensions individualism and uncertainty avoidance. The data may also serve as an interesting starting point for further research on cultural differences in behavioral economics.
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Evolutionarily-based theories predict that people should adopt a faster life history strategy when their mortality risk is high. However, this raises the question of what cues evolved psychological mechanisms rely on when forming their estimates of personal mortality risk. In a sample of 600 North Americans, we examined associations between ideal or actual reproductive timing and two possible cues to mortality risk: 1) the total number of people a person knew who had died (death exposure); and 2) the number of those people to whom they felt close (bereavement). We also took a measure of financial future discounting, in order to establish whether experiences of death or bereavement are associated with a more general shortening of time horizons. We found that a greater number of bereavements were robustly associated with a lower ideal age at first birth, or an increased hazard of an actual first birth at any given age and with steeper future discounting. We did not find significant associations between any of these outcomes and overall death exposure. This suggests that the deaths of people with whom one is close may be a more salient cue for the calibration of reproductive and financial time horizons than the deaths of more distant acquaintances.
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We compared Future Discounting (FD, preference for smaller, sooner rewards over larger, later ones) by 160 Brazilian youth (1630years old; 71 women and 89 men). University students and slum-dwelling (favela) youth were compared. Participants completed a monetary FD task, a scale of youngsters view of their neighborhood, and self-reported exposure to violence (EV). Favela youth discounted the future more than students; favela men more than women. However, university women discounted more than men, an unexpected result. Predicted differences in the participants view of their neighborhood between the two groups were observed. The interaction context x EV scores was a significant predictor of FD. These youth have apparently adjusted trade-offs between the short and long term in a context-sensitive, adaptive manner.
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We construct a simple growth model where agents with uncertain survival choose schooling time, life-cycle consumption and the number of children. We show that rising longevity reduces fertility but raises saving, schooling time and the growth rate at a diminishing rate. Cross-section analyses using data from 76 countries support these propositions: life expectancy has a significant positive effect on the saving rate, secondary school enrollment and growth but a significant negative effect on fertility. Through sensitivity analyses, the effect on the saving rate is inconclusive, while the effects on the other variables are robust and consistent. These estimated effects are decreasing in life expectancy.
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— The existence of parasitic constraints on the evolution of life-history traits in free-living organisms has been demonstrated in several plant and animal species. However, the association between different diseases and human traits is virtually unknown. We conducted a comparative analysis on a global scale to test whether the diversity of human diseases, some of them responsible for high incidences of morbidity and mortality, were associated with host life-history characteristics. After controlling for direct confounding effects exerted by historical, spatial, economic, and population patterns and their interactions, our findings show that human fertility increases with the diversity and structure of disease types. Thus, disease control may not only lower the costs associated with morbidity, but could also contribute directly or indirectly to reductions in human population growth.
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Life history theory aims to explain the relationship between life events, recognizing that the fertility and growth schedules of organisms are dependent on environmental conditions and an organism’s ability to extract resources from its environment. Using models from life history theory, we predict life expectancy to be positively correlated with educational investments and negatively correlated with adolescent reproduction and total fertility rates. Analyses of UN data from 193 countries support these predictions and demonstrate that, although variation is evident across world regions, strong interactions exist among life expectancy, reproductive investments, and educational attainment, and these relationships occur independently of economic pressures and disease burdens. The interactions are strongest, however, in countries with a life expectancy of ≥60years as these countries tend to have stable economies and a limited HIV/AIDS burden. These findings suggest that policies aimed at influencing education and reproductive decisions should consider environmental characteristics that drive people’s expectations about their longevity. KeywordsDemographic factors-Educational status-Fertility-Life cycle-Mortality-Reproductive behaviors
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Impulsivity and sexual sensation seeking were examined as personality correlates of high risk sexual behaviour — unprotected sex with multiple partners — in samples of heterosexual (n=112) and homosexual (n=104) men. Among heterosexuals, both personality variables were associated with frequency of unprotected sex but only sexual sensation seeking was associated with number of sex partners. Sexual sensation seeking also mediated the association between use of drugs other than alcohol and number of sex partners. Among homosexuals, no personality or substance use variables predicted high risk sexual behaviour. Implications of the findings for the study of determinants of sexual risk-taking are discussed.
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There has been discussion over the extent to which delay discounting – as prototypically shown by a preference for a smaller-sooner sum of money over a larger-later sum – measures the same kind of impulsive preferences that drive non-financial behavior. To address this issue, a dataset was analyzed containing 42,863 participants’ responses to a single delay-discounting choice, along with self-report behaviors that can be considered as impulsive. Choice of a smaller-sooner sum was associated with several demographics: younger age, lower income, and lower education; and impulsive behaviors: earlier age of first sexual activity and recent relationship infidelity, smoking, and higher body mass index. These findings suggest that at least an aspect of delay discounting preference is associated with a general trait influencing other forms of impulsivity, and therefore that high delay discounting is another form of impulsive behavior.
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A unified approach is developed for the evolutionary structure of mammalian life histories; it blends together three basic components (individual growth or production rate as a function of body size, natural selection on age of maturity, and stable demography) to predict both the powers and the intercepts of the scaling allometry of life history variables to adult size. The theory also predicts the signs (+, -) of the correlations between life history variables when body size is held constant. Finally, the approach allows us to eliminate body size to predict the dimensionless relationships between the life history variables themselves.
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There is great variation in the age at which females of different mammalian species first breed. Recent comparative analyses have focused on the relationship between age at first reproduction and body size, but differences in patterns of mortality experienced by natural populations are expected to have major effects on selection for age at first reproduction. Here we show that the age at which females first reproduce is strongly correlated with expectation of life at birth, after the effects of body size have been removed, within and among species of mammals living in natural populations.