Baumard et al (2015) wrote:
Summary
Background:
Between roughly 500 BCE and 300 BCE, three distinct regions, the Yangtze and Yellow River Valleys, the Eastern Mediterranean, and the Ganges Valley, saw the emergence of highly similar religious traditions with an unprecedented emphasis on self-discipline and asceticism and with ‘‘otherworldly,’’ often moralizing, doctrines, including Buddhism, Jainism, Brahmanism, Daoism, Second Temple Judaism, and Stoicism, with later offshoots, such as Christianity, Manichaeism, and Islam. This cultural convergence, often called the ‘‘Axial Age,’’ presents a puzzle: why did this emerge at the same time as distinct moralizing religions, with highly similar features in different civilizations? The puzzle may be solved by quantitative historical evidence that demonstrates an exceptional uptake in energy capture (a proxy for general prosperity) just before the Axial Age in these three regions.

Results: Statistical modeling confirms that economic development, not political complexity or population size, accounts for the timing of the Axial Age.

Conclusions: We discussed several possible causal pathways, including the development of literacy and urban life, and put forward the idea, inspired by life history theory, that absolute affluence would have impacted human motivation and reward systems, nudging people away from short-term strategies (resource acquisition and coercive interactions) and promoting long-term strategies (self-control techniques and cooperative interactions).

Baumard et al (2015) wrote:
From the introduction:
These doctrines all emphasized the value of ‘‘personal transcendence’’ [5], that is, the notion that human existence has a purpose, distinct from material success, that lies in a moral existence and in the control of one’s own material desires, through moderation (in food, sex, ambition, etc.), asceticism (fasting, abstinence, detachment), and compassion (helping, suffering with others). This higher purpose is reflected in the constitution of the universe itself (e.g., through karma or logos). Beyond this material world lies another reality in which human existence acquires a new meaning. In this other reality, humans are not just bodies anymore. They are endowed with a soul and can survive the death of their bodily incarnation. Most importantly, in this other reality, individuals pursuing material success are doomed. Only moderation and moral behavior guarantee salvation [2].

Baumard et al (2015) wrote:
From the discussion:
Finally, the effect of affluence on religion could be understood in terms of life history theory [2], specifically focusing on the contrast between a ‘‘fast’’ strategy, with short-term investment of resources (e.g., early reproduction, more offspring, and less nurturing), and a ‘‘slow’’ strategy, with opposite characteristics [23, 27]. Shifts of strategies are known to be triggered by environmental cues, such as the harshness or unpredictability of environments; they result in lower or higher degree of cooperation [22, 24, 28] and in investment in the self [29], a phenomenon originally described by Maslow in his ‘‘pyramid of needs’’ model [30, 31]. In this life history perspective, a massive increase in prosperity and certainty during the Axial Age may have triggered a drastic change in strategies, shifting motivations away from materialistic goals (acquiring more wealth, higher social status) [23] and short-term aggressive strategies (‘‘an eye for an eye’’) [24], typical of fast life strategies, toward long-term investment in reciprocation (‘‘do unto others.’’) and in self-development (variously described as the ‘‘good life’’ or ‘‘self-actualization’’ in Maslow’s original theory).