The Amazon is a unique place. Bolivia is a country with its own identity. And the Tsimane culture of Bolivia has stood out, in a recent study published in the Journal of Personality and Social Psychology, as an exception to the standard measures of personality traits, hitherto considered universal personality traits.
The regular five dimensions of personality are openness, conscientiousness, extraversion, agreeableness and neuroticism —also known as the “Big Five.”
Earlier research has found strong support for the Big Five traits in more developed countries and across quite a few cultures. However these researchers of this study found a different set of personality markers—the Tsimane “Big Two”—socially beneficial behavior, also known as prosociality, and industriousness. These Big Two combine elements of the traditional Big Five, and represent unique aspects of a highly social society like the Tsimane culture.
“Similar to the conscientiousness portion of the Big Five, several traits that bundle together among the Tsimane included efficiency, perseverance and thoroughness. These traits reflect the industriousness of a society of subsistence farmers,” said the study’s lead author, Michael Gurven, PhD, of the University of California, Santa Barbara. “However, other industrious traits included being energetic, relaxed and helpful. In small-scale societies, individuals have fewer choices for social or sexual partners and limited domains of opportunities for cultural success and proficiency. This may require abilities that link aspects of different traits, resulting in a trait structure other than the Big Five.”
The Tsimane, who are forager-farmers, live in communities ranging from 30 to 500 people spread across approximately 90 villages. Since the mid-20th century, they have come into greater contact with the modern world but death rates remain very high [almost 20 percent of babies born never reach age 5] and the fertility rate is very high [approximately nine births per woman], the study said. Most Tsimane are not formally educated [only about 25 percent are literate]. Some 40 percent speak Spanish in addition to their native language. They reside in extended family clusters that share food and labour. They have very limited contact with outsiders unless absolutely necessary, according to the authors.
Researchers translated a standard questionnaire that assesses the Big Five personality traits into the Tsimane language. Between January 2009 and December 2010, they interviewed 632 adults from 28 villages. They also conducted a another study between March 2011 and January 2012 to understand the reliability of the model when answered by peers. They asked 430 Tsimane adults, including 66 people from the first study, to evaluate their spouse’s personality. The second study revealed that the subject’s personality as reported by his or her spouse also did not fit with the Big Five traits.
The researchers controlled for education level, Spanish fluency, gender and age. Previous research has suggested that formal schooling and greater interaction with others, such as when villagers venture to markets in other towns, can lead to more abstract reflection and may be one reason why the Big Five replicates in most places, according to the authors. However, there were no significant differences between the less educated, Tsimane-only speakers and the more educated bilingual participants.
Michael Gurven, who led the research, suggested personality researchers should expand beyond the limited scope of more Western, industrialised and educated populations. “The lifestyle and ecology typical of hunter–gatherers and horticulturalists are the crucible that shaped much of human psychology and behaviour,” he said. “Despite its popularity, there is no good theory that explains why the Big Five takes the form it does, or why it is so commonly observed. Rather than just point out a case study where the Big Five fails, our goal should be to better understand the factors that shape personality more generally.”
The study was part of the University of California-Santa Barbara’s and University of New Mexico’s Tsimane Health and Life History Project, co-directed by Gurven and study co-author Hillard Kaplan, PhD, of the University of New Mexico, and was funded by the National Institute on Aging.