https://scitechdaily.com/evolving-intelligence-how-chimpanzees-master-tools-well-into-adulthood/

Chimpanzees continue to learn and hone
their skills well into adulthood, a
capacity that might be essential for the
evolution of complex and varied tool use,
according to a study publishing today
(May 7th) in the open-access journal
PLOS Biology by Mathieu Malherbe of the
Institute of Cognitive Sciences, France
and colleagues.

Humans have the capacity to continue
learning throughout our entire lifespan.
It has been hypothesized that this
ability is responsible for the
extraordinary flexibility with which
humans use tools, a key factor in the
evolution of human cognition and culture.

In this study, Malherbe and colleagues
investigated whether chimpanzees share
this feature by examining how chimps
develop tool techniques as they age. The
authors observed 70 wild chimps of
various ages using sticks to retrieve
food via video recordings collected over
several years at Taï National Park,
Côte d’Ivoire.

As they aged, the chimps became more
skilled at employing suitable finger
grips to handle the sticks.

These motor skills became fully
functional by the age of six, but the
chimps continued to hone their
techniques well into adulthood. Certain
advanced skills, such as using sticks
to extract insects from hard-to-reach
places or adjusting grip to suit
different tasks, weren’t fully
developed until age 15.

This suggests that these skills aren’t
just a matter of physical development,
but also of learning capacities for new
technological skills continuing into
adulthood.
...
The authors add, “In wild chimpanzees,
the intricacies of tool use learning
continue into adulthood. This pattern
supports ideas that large brains across
hominids allow continued learning through
the first two decades of life.”
...


<https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002609>

Protracted development of stick tool use
skills extends into adulthood in wild
western chimpanzees

Abstract
Tool use is considered a driving force
behind the evolution of brain expansion
and prolonged juvenile dependency in the
hominin lineage. However, it remains rare
across animals, possibly due to inherent
constraints related to manual dexterity
and cognitive abilities. In our study, we
investigated the ontogeny of tool use in
chimpanzees (Pan troglodytes), a species
known for its extensive and flexible tool
use behavior. We observed 70 wild
chimpanzees across all ages and analyzed
1,460 stick use events filmed in the Taï
National Park, Côte d’Ivoire during the
chimpanzee attempts to retrieve
high-nutrient, but difficult-to-access,
foods. We found that chimpanzees
increasingly utilized hand grips
employing more than 1 independent digit
as they matured. Such hand grips emerged
at the age of 2, became predominant and
fully functional at the age of 6, and
ubiquitous at the age of 15, enhancing
task accuracy. Adults adjusted their
hand grip based on the specific task at
hand, favoring power grips for pounding
actions and intermediate grips that
combine power and precision, for others.
Highly protracted development of suitable
actions to acquire hidden (i.e., larvae)
compared to non-hidden (i.e., nut kernel)
food was evident, with adult skill levels
achieved only after 15 years, suggesting
a pronounced cognitive learning component
to task success. The prolonged time
required for cognitive assimilation
compared to neuromotor control points to
selection pressure favoring the retention
of learning capacities into adulthood.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)