I. First, scientists normally don’t publish an extensive list of all the activities
they do not see at a particular location. Yet this is the very information we
need to know—which behaviors were and were not observed at each site.
Second, there are many reports describing chimpanzee behaviours without
expressing how common they are; without this information, we can’t determine
whether a particular action was a transient phenomenon or a routine event
that should be considered part of its culture. Finally,researchers’ description of
potentially significant chimpanzee behaviours often lacks sufficient detail,
which makes it difficult for scientists from other spots to report the presence or
absence of the activities.
J. To tackle these problems, my colleague and I determined to take a new
approach.We asked field researchers at each site to list all the behaviours
which they suspected were local traditions. With this information, we
assembled a comprehensive list of 65 candidates for cultural behaviours.
K. Then we distributed our list to team leaders at each site. They consulted
with their colleagues and classified each behaviour regarding its occurrence or
absence in the chimpanzee community. The major brackets contained
customary behaviour (occurs in most or all of the able-bodied members of at
least one age or sex class, such as all adult males), habitual (less common
than customary but occurs repeatedly in several individuals), present
(observed at the site but not habitual), absent (never seen), and unknown.
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Questions 14-18 Instructions to follow
• Which paragraph contains the following information?
• Write the correct letter,
