No abstract

Enset (Ensete ventricosum) is the traditional staple food of Sidama people who live in Rift Valley lowlands to highlands in southwest Ethiopia. Enset is drought resistant, but it matures slowly, requires substantial manure inputs from cattle, and intensive processing. Maize, introduced to Sidamaland in the mid-twentieth century, is common in midlands and lowlands. Maize matures rapidly and provides more kcal/kg than enset, but it is prone to failure in dry years and requires chemical fertilizer, which is subject to global market price fluctuations. We compare cultural ecology, productivity, failure, and resilience of enset and maize in 410 farms across four Sidama ecological zones. The risks and benefits of enset and maize are complexly associated with variable local environments. Enset offers drought-resistant produce that, with sufficient manure inputs, is adequate for subsistence in the wet highlands, but its performance is more variable elsewhere. Fertilized, maize yields larger harvests than enset, but vulnerability to rainfall and global processes create special challenges. Maize and enset appear to be in different adaptive cycle phases: maize grows quickly and maize farms rebounded from crop loss within four years. Only half of enset farms recovered within six years after crop failure, complicating farming decisions in an environment with tremendous localized variation. In general, the Sidama zone shows a pattern of regional diversity with local specialization for maize only, enset only, or mixed maize and enset cultivation. In some areas maize has become a preferred crop and food for younger people.

DHEAS patterns and age at adrenarche vary across cultures, perhaps indicating adaptive life history responses in diverse eco-cultural environments. Delayed involution of the fetal zone and DHEAS patterning may offer both cognitive protection and immune defense in high-risk, nutritionally-poor environments. Additional research in the majority world is essential to improving our understanding of the diversity of hormonal development and timing of 'switch points' in life history trajectories.

A paucity of ethnographic data exists on the Chabu hunter-gatherers of Southwestern ethiopia. multiple linguistic studies have been conducted because some believe their language is a linguistic isolate, but they are relatively 'new' to the ethnographic record. Based on six months' ethnographic fieldwork and reviews of existing literature, the paper provides an ethnographic introduction of the Chabu ecology, subsistence, settlement, demography, social organisation and contemporary issues threatening their lives and livelihoods. The paper aims to encourage new field research with the Chabu, increase the international awareness of the Chabu, and motivate some to assist with their threatened situation.

Sidama people occupy a subsistence niche partitioned between traditional enset agropastoralism and transitional maize farming. Enset production is low risk and requires multiple years for cultivation and processing. Maize farming is high risk and high yield, requiring one growing season from planting to harvest. Contrasting enset and maize farming, we examine effects of crop loss and social shocks on Sidama impulsivity. We argue that impulsivity is a psychological process that is differentially activated by environmental shocks in the stable, traditional enset regime and unstable, transitional maize regime. Using a robust psychometric model derived from Barratt impulsiveness scale items, we demonstrate two dimensions of Sidama impulsivity: careful control (CC) and acts without thinking (AWT). Both dimensions are associated with environmental shocks, but the associations are moderated by socialecological regimes. In the enset regime, effects of shocks on impulsivity are muted. However, increased impulsivity is significantly associated with shocks in the global market-dependent maize regime. Effects on CC were significant for social shocks but not crop loss, while AWT was associated with crop loss and social shocks. Results may indicate domain-specific aspects of impulsivity in response to environmental perturbation. Impulsivity may be adaptive in the context bidirectional predictive processing in active cultural niche construction. Human thought is cultural (Bloch 2012; D'Andrade 1995; Sperber and Hirchfeld 2004; Strauss and Quinn 1997). Familiar and shared ways of thinking that worked for extended periods of time-often generations-give people reliable mental models for action: How shall I greet a person of equal status? What is the appropriate response to an insult? These mental models inform predictable outcomes inferred through regular interaction with people and environments in patterned practices (Roepstorff et al. 2010). But how do people react when favored habits and familiar actions result in unexpected or undesirable outcomes? Culture change is an intrapsychic phenomenon when old perceptions of normality are replaced by new ones. We wonder, what psychological processes facilitate culture change, and when are they activated? We draw on insights from social-ecological systems, niche construction, cognitive science, psychometrics, and cultural ecology to examine impulsivity among Sidama people occupying a fragmented subsistence niche at the intersection of traditional enset and transitional maize production. Recent developments in Sidama subsistence provide a case study in culture change. Most Sidama are agropastoral farmers living in the highlands to Rift Valley lowlands in Southwest Ethiopia. People have grown enset (Ensete ventricosum [Welw.] Cheesman), a root and stem staple crop, in this region since prehistoric times (Brandt 1984, 1996). The Sidama are one of the two most enset-reliant societies of the enset complex (Brandt et al. 1997; Quinlan et al. 2014; see also Shack 1963). Meanwhile, maize (Zea m...