The target article concludes that, from an evolutionary life history perspective, the impact of affluent environments on slow life history strategy-relevant psychological traits (e.g., trust, future orientation, and optimism) may partly explain the modern acceleration in technological innovations. However, the article ignores one of two fundamental environmental conditions (i.e., unpredictability) and relies heavily on English GDP per capita as a measure of affluent environment but ignores the economic inequality in England. Last, the article does not explain the developments that followed the Industrial Revolution (e.g., high birth rate and pollution). We argue that life history is dynamic and that this is why English people tended to shift their slow strategies to fast strategies during the post-Industrial Revolution period. In this commentary, we raise three concerns.

First, an individual's life history strategy is shaped by physiological and psychological mechanisms (e.g., attachment; Chen Reference Chen2018), which frequently involve evaluation of external ecological conditions of the environments and the making of trade-offs in resource allocation as a consequence (Chen Reference Chen2017). Two fundamental dimensions of environmental risk have been identified as affecting life history outcomes: harshness and unpredictability (Ellis et al. Reference Ellis, Figueredo, Brumbach and Schlomer2009). The target article emphasized only one of the environmental dimensions (i.e., low levels of harshness, or affluence); it ignored predictability. It should be noted that previous work (e.g., Belsky et al. Reference Belsky, Schlomer and Ellis2012) has demonstrated that environmental predictability and harshness play different roles in life history strategies. Environmental predictability may also lead to the development of psychological traits that are related to innovation. For example, Chen and colleagues (Chen & Kruger Reference Chen and Kruger2017; Chen & Qu Reference Chen and Qu2017) found that procrastination, which was related to a high level of future discounting (Chen & Chang Reference Chen and Chang2016), was also indirectly influenced by environmental unpredictability via mediation of life history information processing. Another example is provided by a recent study that showed that adolescents who perceived their environment as predictable were more likely to develop external and internal assets (e.g., constructive use of time, commitment to learning, and positive values; Chen et al. Reference Chen, Wiium and Dimitrova2019). This evidence suggests that environmental unpredictability may be negatively related to future orientation, whereas environmental predictability may be positively related to future orientation. It is necessary, therefore, to include both harsh and unpredictable environmental conditions in any test of their unique effects on psychological traits, which were discussed in the target article.

Second, the target article argues that environmental affluence increases the absolute number and relative size of “the upper tail of human capital” (sect. 4.5, para. 2) and that upper-class English individuals have played an important role in innovation, making the entire society more open-minded and innovative. This seems to imply that high economic equality (often indexed by the Gini coefficient) in pre-industrial England represents a balanced distribution of social wealth. It should, however, be noted that the GDP per capita can capture environmental affluence, but not economic inequality. Analysis of data from 28 pre-industrial societies (Milanovic et al. Reference Milanovic, Lindert and Williamson2011) revealed that the inequality indicator was lower in the United Kingdom than in other European countries (e.g., Holland and France) during the same period. Economic inequality has been found to be related to use of fast life history strategies, such as high future discounting (Wilson & Daly Reference Wilson and Daly1997) and lack of interpersonal trust (Elgar & Aitken Reference Elgar and Aitken2010), which are the main psychological traits related to innovation, as discussed in the target article. In addition, it is possible that economic inequality might be a good indicator of both environmental harshness and unpredictability. People in societies with high income inequality may perceive the environment as more harsh than those in societies with less income inequality (Wilkinson & Pickett Reference Wilkinson and Pickett2010). Economic inequality may also be related to the unpredictability of future resources (Wilson & Daly Reference Wilson and Daly1997), and so, when considering innovation, it is necessary to recognize that economic inequality is one of the important environmental risk factors when it comes to influence on people's life history strategies.

Last, although the target article provides a good discussion of global life history strategy before and during the Industrial Revolution, it seems to ignore life history strategy after the Industrial Revolution. Why did the Industrial Revolution last only about 100 years? How did it affect social environment and individuals’ life strategies? Acceleration in technological innovations and the associated economic growth during the post-Industrial Revolution period resulted in environmental pollution (Luckin Reference Luckin2003; Thorsheim Reference Thorsheim2007), higher rates of birth (Komlos Reference Komlos1990), and an increase in economic inequality (Jackson Reference Jackson2010), which may in turn have led to adoption of fast life history strategies. Thus, life history is dynamic in nature and should be altered in response to environmental changes. The psychological mechanisms that influence life history strategies should take into account cues to environmental conditions. In evolutionary history. the potential benefits of faster strategies in harsh and unpredictable environments may have outweighed the costs, whereas the reverse would be true in more hospitable environments. Environmental pollution and resource scarcity, caused by the higher population density, might favor fast life history strategies. For example, a very recent survey of 9,360 cities in America showed that air pollution predicted crimes (Lu et al. Reference Lu, Lee, Gino and Galinsky2018). This study also demonstrated that exposure to air pollution in experimental laboratories induced unethical behaviors (Lu et al. Reference Lu, Lee, Gino and Galinsky2018). Criminal and unethical behaviors are considered fast life history strategies (Del Giudice et al. Reference Del Giudice, Gangestad, Kaplan and Buss2015).