Tool Use, Taxonomy

Culture and Tool Use #

Primary difference between humans / other species: tools are manufactured (use tools to make tools)

understand goal
quickly learned, easily taught } step 1
Late Acheulean tools: symmetrical, bifacial → 10–20 yrs. to learn skill
human brain reached modern shape/size about 100,000 yrs. ago (reactive to increasing tool use) → evidence for handedness (characteristic flake patterns).

bulges (petalia) in left occipital, right frontal lobes not seen in great apes
split-brain experiments
lateralized nervous systems present in many animals (mollusks, sharks, fish…)
- reason: brain tissue expensive; don’t want to duplicate function. Also allows for optimization examples: pigeons detecting small objects, chimps w/ handedness → better termite catches, parrots w/ handedness in foot → string pulling At the population level, coordination / same-handedness in group helps with fast communication + escape from predators
behavior is more symmetrical in great apes vs humans –
- rather than population-level handedness (e.g. 90% RH), apes have task-dependent handedness
- apes in captivity seem to emulate human handedness more

Human ability to reason (“how” pathway) increased

Reminder: human tool use is not unique!

Chimps use stone hammers (nuts), fishing rods (termites), leaf sponges (tree holes), spears (bush babies)
New Caledonian Crow: makes fishing hooks from leaves
Octopus uses coconut shells for hunting & protection

Planning (multiple interdependent steps + motivation)
Sensori-motor coordination (precise grips, blows)
- Ethiopian Konso society: women specialize in fine motor skills + tool making

Humans: