Ostrich eggshell beads reveal 50,000-year-old social network across
Africa

Date:
December 20, 2021
Source:
Max Planck Institute for the Science of Human History
Summary:
New archeological study shows ancient connection between populations
3,000 km apart, and provides first direct link between climate
change and ancient human social behavior.



FULL STORY ========================================================================== Humans are social creatures, but little is known about when, how, and why different populations connected in the past. Answering these questions
is crucial for interpreting the biological and cultural diversity that
we see in human populations today. DNA is a powerful tool for studying
genetic interactions between populations, but it can't address any
cultural exchanges within these ancient meetings. Now, scientists from
the Max Planck Institute for the Science of Human History have turned to
an unexpected source of information -- ostrich eggshell beads -- to shed
light on ancient social networks. In a new study published in Nature, researchers Drs. Jennifer Miller and Yiming Wang report 50,000-years of population connection and isolation, driven by changing rainfall patterns,
in southern and eastern Africa.


========================================================================== Ostrich eggshell beads: a window into the past Ostrich eggshell
(OES) beads are ideal artifacts for understanding ancient social
relationships. They are the world's oldest fully manufactured ornaments, meaning that instead of relying on an item's natural size or shape,
humans completely transformed the shells to produce beads. This extensive shaping creates ample opportunities for variations in style. Because
different cultures produced beads of different styles, the prehistoric accessories provide researchers a way to trace cultural connections.

"It's like following a trail of breadcrumbs," says Miller, lead-author
of the study. "The beads are clues, scattered across time and space, just waiting to be noticed." To search for signs of population connectivity,
Miller and Wang assembled the largest ever database of ostrich eggshell
beads. It includes data from more than 1500 individual beads unearthed
from 31 sites across southern and eastern Africa, encompassing the last
50,000 years. Gathering this data was a painstakingly slow process that
took more than a decade.

Climate change and social networks in the Stone Age By comparing OES bead characteristics, such as total diameter, aperture diameter and shell
thickness, Miller and Wang found that between 50,000 and 33,000 years
ago, people in eastern and southern Africa were using nearly identical
OES beads. The finding suggests a long-distance social network spanning
more than 3,000 km once connected people in the two regions.



==========================================================================
"The result is surprising, but the pattern is clear," says Wang, co- corresponding author of the study. "Throughout the 50,000 years we
examined, this is the only time period that the bead characteristics
are the same." This eastern-southern connection at 50-33,000 years ago
is the oldest social network ever identified, and it coincides with a particularly wet period in eastern Africa. However, signs of the regional network disappear by 33,000 years ago, likely triggered by a major shift
in global climates. Around the same time that the social network breaks
down, eastern Africa experienced a dramatic reduction in precipitation
as the tropical rain belt shifted southward. This increased rain in the
large area connecting eastern and southern Africa (the Zambezi River catchment), periodically flooding riverbanks, and perhaps creating a
geographic barrier that disrupted regional social networks.

"Through this combination of paleoenvironmental proxies, climate models,
and archaeological data, we can see the connection between climate change
and cultural behavior," says Wang.

Weaving a story with beads Together, the results of this work document a 50,000-year-long story about human connections, and the dramatic climate changes that drove people apart.

The data even provides new insight into variable social strategies between eastern and southern Africa by documenting different bead-use trajectories through time. These regional responses highlight the flexibility of human behavior and show there's more than one path to our species' success.

"These tiny beads have the power to reveal big stories about our past,"
says Miller. "We encourage other researchers to build upon this database,
and continue exploring evidence for cultural connection in new regions." ========================================================================== Story Source: Materials provided by Max_Planck_Institute_for_the_Science_of_Human_History.

Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Ostrich_eggshell_beads ========================================================================== Journal Reference:
1. Jennifer M. Miller, Yiming V. Wang. Ostrich eggshell beads reveal
50,000-
year-old social network in Africa. Nature, 2021; DOI:
10.1038/s41586-021- 04227-2 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211220120634.htm

--- up 2 weeks, 2 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)