Toolmakers Flashcards
What type of tool are the oldest we have discovered?
Where/ when are they from
Lomekwian
lithic artifacts found at Lomekwi (Kenya) dated to 3.3 Ma.
Describe Lomekwian lithic artifacts
What can they be compared to
anvils, cores (about 3.4 kg) and flakes, made of basalt and phonolite, series of adjacent and superposed unidirectional flakes detached.
• Similar to the non-human primate hammer-on-anvil techniques when engage in nut cracking.
Harmand (2015) argued that these were closer to apes nut cracking tools
Based upon chronology, which hominins could have made the Lomekwian artifacts ?
Which species specifically? When and where did they exist?
Taxonomical context based on the chronology: Australopithecus and Kenyanthropus.
A. deyiremeda in Ethiopia
(3.6-3.3 Ma)
A. afarensis in
Ethiopia, Kenya and Tanzania
(3.9-2.9 Ma)
K. platyops in Kenya(3.7-3.4 Ma)
(no Homo)
Have any hominin remains been found near the site where Lomekwian tools were discovered?
Dental remains from Lomekwi (but not in association): 67 teeth, size overlaps with A. afarensis and A. deyiremeda, dated to 3.5-3.3 Ma
KNM-WT 8556
(Skinner et al., 2020)
Why is there some controversy regarding Lomekwian tools as the oldest fossils?
Some suggest Lomekwi tools are not created by hominins at all but in fact just rocks that were shaped by random surface occurrences
If not Lomekwi, where are the oldest tools found?
Lithic artefacts at Gona (Ethiopia) dated to 2.6 Ma.
Describe the oldest tools that have been found in Gona, Ethiopia?
Oldowan (2.8-1.7 Ma): chopping tools and flakes, made of quartz, quartzite or
basalt, chipped in two directions.
Which hominins could have created the oldest tools at Gona
Taxonomical context based on the chronology: early Homo and Paranthropus.
P. aethiopicus in
Ethiopia (2.7-2.2 Ma)
early Homo at 2.8 Ma in Ethiopia
(Villmoare et al., 2015)
What are the oldest cut marks found on bones?
Why is this important?
Cut-marks at Dikika (Ethiopia) dated to >3.4 Ma.
• Evidence of stone-tool-assisted consumption of meat: flesh removed from bones, percussion marks that prove access to marrow
What were the specific marks found on 3.4Ma bones in Dikika
Who could’ve made these marks?
cut-marked rib
(McPherron et al., 2010)
percussion marks on a femur shaft
(McPherron et al., 2010)
Taxonomical context based on the chronology: Australopithecus and Kenyanthropus: A. deyiremeda in Ethiopia (3.6-3.3 Ma) A. afarensis in Ethiopia, Kenya and Tanzania (3.9-2.9 Ma) K. platyops in Kenya (3.7-3.4 Ma)
Other than Dikika, what are the oldest cut marks on bones?
Cut-marks at Gona (Ethiopia) dated to 2.5 Ma.
• Evidence of stone-tool-assisted consumption of meat: carcasses eviscerated,
upper and intermediate limb bones of ungulates defleshed.
• Behaviour: primary access to the carcasses?
suggested to show no other carnivore had access to the meat before hominins (Domínguez-Rodrigo et al., 2005)
Who was at Gona who could have caused the cut marks on the bones 2.5mya
P. aethiopicus in
Ethiopia (2.7-2.2 Ma)
early Homo at 2.8 Ma in Ethiopia
(Villmoare et al., 2015)
How can we assess which areas of the brain are needed to make simple Oldowan tools?
Who did this?
recording brain activity using functional near-infrared spectroscopy as modern human participants learned to make Oldowan and Acheulian stone tools in either a verbal or nonverbal training context.
Putt, 2017
What cortical brain areas did Putt (2017) discover were necessary to make Oldowan tools?
Why is this unsurprising?
Unique cortical areas recruited during the Oldowan task include the hand representation portions of the primary sensorimotor cortex in both hemispheres. This suggests the involvement of a lateral premotor system, which is dependent on external visual input to recognize and assign significance to external objects.
This is unsurprising, as the only goal of the Oldowan task is to visually identify ideal platforms and remove flakes until the core is exhausted.
Can Oldowan tools be made without verbal teaching?
Yes
but only in the nonverbal group that the left MFG, is activated
recruitment of this network in the nonverbal condition only, suggests that learning to produce simple flakes with-out language requires increased attention to visuo-spatial demands
What brain areas are active when the Oldowan tools are being produced using verbal communication
elicits activity in the left dorsal PrG, an area that also is activated when pas-sively reading action words related to the arm
Considering the brain areas that are activated when Oldowan are made without verbal communication, what can we infer about the hominins who made them?
Oldowan tool manufacture relies on the coordination of visual attention and motor control to successfully remove simple flakes.
homologous cognitive network is probs active in chimpanzees when they crack nuts with stone tools, or even in capuchin monkeys when they strike two stones together, which can sometimes lead to unintentional flakes similar to those made by early hominins.
results of this experiment point to cognitive abilities that were more ape-like than human-like among hominin toolmakers prior to 1.8 Ma
Which brain areas are involved in making Auchelian tools?
What is interesting about the involvement of some of these areas?
Middle and superior temporal cortex (visual, auditory and sensorimotor information), precentral gyrus (visual working memory), and supplementary motor areas: importance of auditory capacities in toolmaking?
Overlap with language circuits: tool making and language shares neural substrates? (Stout et al., 2008)
What is the possible role of the auditory brain centre in Auchelian tool making?
What implications could this have had on evolutioin
Acheulian knapping requires the knapper to discriminate between knapping sounds and to assign meaning to those sounds based on how they relate to the hierarchy of goals involved in making a handaxe
Thus, the knapping of Acheulian tools may have played a role in fine-tuning this function in the superior tempo-ral gyrus, perhaps facilitating the evolution of neural connections involved in speech perception
What can we infer about the evolution of hominin auditory processing from toolmaking?
Between which taxa was there a noticable shift
the Acheulian techno-complex coincides in timing with the evolution of a derived middle ear anatomy in Homo that was more attuned to human speech frequencies.
Together, fossil and neuroarchaeological evidence now show that a major shift in hominin auditory processing occurred after Homo diverged from Australopithecus and Paranthropus and before the appearance of H. heidelbergensis
The adoption of the Acheulian toolkit by early Homo also coin-cides in time with a more unpredictable environment, an increase in brain and body size, and a more diverse diet that relied upon tool-assisted hunting and foraging of large game animals and tough, fibrous plant products. Why is this timing important
As reliable food items became scarcer in this unpredictable environment, individuals who were capable of holding multiple modes of information in mind to guide and coordinate their motor behaviours probably experienced higher RS due to their enhanced ability to produce complex tools.
this allowed these individuals and their offspring greater access to a diverse set of food resources
Based off endocasrs, which taxa are more likely to have made the tools at Lomekwi and Gona?
Paranthropus and early Homo - Australopithecus has very primitive frontal lobe
- Homo: Reorganisation may not have happened until erectus
- Paranthropus: One fossil is derived but unclear in other fossils
What are the 2 hypotheses of the emergence of human-like hand traits?
Why is it hard to make confident assumptions about hominin hand morphology?
→ before 2-3 Ma: hand use because of bipedalism (at about 6 Ma),
→ at 2-3 Ma: intensive manipulative behaviours tool use and/or nonlithic tool making
Hand fossils are rarely preserved in full - they are often composite and they could be Paranthropus or Homo or a mixture etc
How do the 2 different hypotheses for the emergence of modern hands differ in their implied evolutionary scenarios?
→ with bipedalism, no need for long and curved phalanges for climbing trees, so then became shorter (neutral/positive selection) except the thumb,
→ by product of reducing the length of toes for bipedalism (exaptation)
What is exaptation
Exaptation (co-option): trait that plays a different role than the one initially played and selected (adaptation) or that was initially nonfunctional (Gould and Vrba, 1982).
What are the important aspects of human hand morphology?
robust thumb (muscle attachments),
robust fifth digit with a unique joint to rotate it towards the thumb
What are the 3 manipulative abilities in extant humans?
precision handling (rotate and manipulate objects),
forceful precision gripping,
power squeeze gripping of cylindrical objects.
Describe the hands of the earliest hominins
Ardipithecus: hand proportions more Old World monkey-like.
Orrorin: thumb human-like (precision grip abilities), more derived than
Australopithecus
Describe the manipulative abilities of A. africanus/Prometheus (4)
robust human-like thumb,
curved phalanges,
humanlike trabecular bone pattern,
possibly forceful opposition of the thumb and fingers
Describe the manipulative abilities of afarensis (2)
capability of throwing and pounding, possibly precision grip thumb/index
Describe the manipulative abilities of sediba
long thumb, pad-to-pad opposition of the thumb and fingers (greater control and manipulation of small objects), clear combination of arboreal locomotion and tool manipulation
Which aspect of sediba’s hand morphology is an arboreal trait
long thumb
What is the likelihood of afarensis making tools based off hand biomechanics?
musculoskeletal simulation of the fifth digit based on the A. afarensis hand morphology.
Low mobility of the joint, restrict ability to orient the ray towards the handheld object: limited possibility for sufficient grip force to make Lomekwian (large) stone tools
What is the biomechanics of Paranthropus’ hand
Derived specific pattern: robusticity pattern on distal phalanges, convergence with quadrupedal monkeys due to similar manual feeding techniques?
If we use mean of measuremetns of distal phalanxes it falls in the range of non human primates
Discuss what can be inferred from the fossils about the manual manipulative ability of early Homo hands
OH 86 (Tanzania) dated to 1.84 Ma: proximal phalanx from the fifth ray different from OH 7 modern human-like proportions.
- KNM-KP 51260 (Kenya) dated to 1.42 Ma: metacarpal, human-like morphology.
- Contemporaneity with the Acheulian technology (emergence at 1.75 Ma).
Describe the biomechanics and thumb of early Homo
Biomechanics: muscle modelling, estimation of the muscle force-generating capacity of the thumb.
• Modern human morphology of the thumb emerged about 2 Ma (thus not in Australopithecus): increased thumb opposition efficiency.
What is interesting about the Manipulative abilities in Homo floresiensis?
Why is this important for how we study tool making?
Human-like precision grip (phalanges) but similarities with Australopithecus
(wrist).
Association with Oldowan tool artefacts.
• Is bone morphology a reliable proxy?
(Tocheri et al., 2007; Larson et al., 2009)
What do the wrist bones of floresiensis contribute to the debate over the taxon’s validity
Tocheri (2007) found its wrist morphology is closer to that of apes and older hominins compared to Neanderthals and humans (Hopkin, 2007)
This suggests LB1 (floresiensis) is descended from a hominin ancestor that migrated out of Africa before the evolution of the shared, derived wrist morphology that is characteristic of modern humans, Neandertals,and their last common ancestor.
Suggests floresiensis is its own taxon and not a microencephalic H. sapiens (especially as Tocheri (2007) compared wrist to pituitary dwarf and giant, neither of which had similar changes in wrist morphology due to their condition)
Is a modern derived human wrist morphology necessary for tool making?
he association of LB1 (H. floresiensis) with direct evidence of stone flaking technology comparable to that found at Oldowan or other Lower Paleolithic sites throughout the Old World provides additional support for the hypothesis that the earliest hominins to use and make stone tools retained primitive hominin wrist morphology
What neural connections allow finger dexterity
evidence?
cortico-motoneuronal connections (direct, monosynaptic connections with motoneurons, bypassing the spinal interneurons.)
- projections to motorneurons appear in species that make independent finger movements (in primates) but are not seen in species without.
- Lesions of the corticospinal tract in the medulla leave permanent deficits that are most extreme in finger movement and manipulation.
- n man the direct projections post-natally, appearing at about 9 months. At this age dexterity begins to develop.
What are Clark’s (1968) technological modes
Mode 1: flakes - Oldowan
Mode 2: bifacial/ symmetrical tools - Acheulean
Mode 3; levallois (pre-prepared) - Mousterian
Mode 4: Blades - Aurignacian
Mode 5: hafted onto wood - Microlithic
When did mode 1, 2, and 3 appear
Mode 1: ~2.6 mya with afarensis and africanus
Mode 2: 1.7mya with habilis and ergaster
Mode 3: 160kya-40kya; associated primarily with the Neanderthals in Europe, and to the earliest anatomically modern humans in North Africa and West Asia.
Give the chronology of when different tool modes appeared
Early Stone Age/ Lower Palaeolithic:
Lomeckwian 3.3 Ma (E. Africa)
Mode 1 (Oldowan) 2.58mya E. Africa
Mode 2 (Acheulean) 1.8mya E. Africa
Middle Stone Age/ Middle Palaeolithic:
Mode 3 (Prepared cores, Levallois) 3-400 Ka E or N Africa
Upper Palaeolithic:
Mode 4 (blades, systematically
produced)
50 Ka Levant?
Late Stone Age/ Mesolithic/Post-glacial:
Mode 5 (ephemeral) 80 ka S. Africa
Mode 5 (persistent) 12 Ka Global
