Why The Big Brain?
Environment
early primates
arboreal species
creation of the precocial complex in primates
offspring clings to mother for beginning of life
more time given for early brain developement
precocial traits
Long lifespans
Small litter sizes
Developed young
Low mortality
Large body and brain size
Environmental predicability
Living at carrying capacity
Increased grasping and climbing abilities
increased hand eye coordination
increased sociality
visual sensory evolutions in primates
segregation of M and P cells
allows for different depths of vision to be processed
LGN processing both layers separately as different images
primate vision focused on depth of image and not surrounding
more advantageous in dense arboreal environments
M and K cells project to the SC
create a detailed sensory map of surroundings
useful for grasping, head movement, feeding
SC sends map to motor cortex, visual cortex and frontal cortex
blobs
Evolution #
K layers of the LGN target specialized compartments within area V1
receive input from K layers of the LGN
multilevel organization of visual and sensory cortex
primates adapted to quick and fast thinking based on visual information
primates adapted to bilateral movement and muscle coordination involving grasping
Specializations of the Primate Frontal Cortex
Ventral premotor area
sensory map of the body in brain
highly mapped forelimb and orofacial representations
Primate limbic cortex
cingulate cortex
The posterior region is connected to cortical areas with known visuospatial functions,
involved in spatial attention and memory, eye movements, and mental navigation
Posterior parahippocampal cortex
TH and TF, are found uniquely in primates
increased memory abilities
enhanced memory ability with emotional cognition as well
allows tracking of social situation
machiavellian intelligence
exhibited by simians and other primates
requires social intelligence, but does not fully require Theory of mind
use of social knowledge to manipulate others
tactical deception
Acts of deception involve other primates as objects to be manipulated, these animals have long memories and ability to retaliate, therefore deception must be more complex to be successful
learnable in social environments
based on brain size
terrestrial habitats
large populations communally living
genetic variations
developmental variations #
ecological variations
social explanations
energetic explanations
Predation risk will determine social group size
Social group will also determine how well you are defended against predation
Social group sizes alway correlate with larger brains and sparter animals
social brain hypothesis
The more social the animal and expansive their social network, the more difficult it is to maintain brain function with an insufficient diet, diet must be balanced correctly
Foraging a huge part of brain grown
More food and better food you get, better brain
Better brain, smarter animal
Smarter animal, better forager
sociality might lead to intelligence, but not vice versa
an individual’s social competitors have essentially the same intelligence as itself
cultural intellugence
large brains allow the social transmission of behaviour
Social learning has high fitness benefits, would be under strong selective forces
Vygotskyan intelligence
intrinsic cooperation
Scheherazade Hypothesis
Large brains were sexually selected in mate choice as signals of an individual’s cooperation as part of a bonded pair
hominin evolution
powered by
precocial developement
predation
group living
social competition
increased sociality
predation from terrestrial species
sexual
resources
hominin differentiation
hominin differentiation from genus pan
stone tools
larger skull size
bipedal
sagittal crest
small flat cannines
hominin differentiation from australopithicus
larger brain
small chewing teeth
smaller jaw
widening forehead
obligate long range bipedal
widely distributed across world
Biogeography #
climate change
if a stable climate changed and was the habitat for a species, they would either have to migrate or perish (neandertals)
hominin species walked out of africa across the world
created isolated pockets of hominids across the world
rapid evolution and differentiation
evolutionary leaps
climate
Cooling, drying, expansion of savannah
forces migration and adaptation
climate pulses
force extreme rapid change of hominin behavious
predation
movement into open plains with no protection
terrestrial primates living in large groups to protect themselves
Across mammals, large brain size in prey reduces predation risk–Predators prefer prey with small brains
sociality #
Imposes cognitive demands due to the need to solve environmental problems in a coordinated social environment
creates TOM and creation of empathy
living in larger groups to consolidate resources
Metabolic demands
Use of fire for cooking made food more digestible
cooperative foraging
high energy food options
innovation of cooking and food preparation
language
increases an individual’s understanding of the world
Leads to distributed cognition
neural substrate for symbolic thought
social brain structures
cerebellum #
functions
Working memory and mental rehearsal
language function
Spatial and episodic memory
event prediction
empsthy
imitation
Non-motor associative learning
planning
motor control
neocortex
function
episodic memory
Touch sensation
language processing
essentially higher functioning thought
cerebellum size correlates more strongly with foraging skill
neocortex size correlated with sociality
cerebellum and cortico-cerebellar networks are key components enabling the control,organization and comprehension of complex sequences such as language
social learning
social cognition
The capacity to infer the social purpose of the behaviours of other persons or the self
imitation
emulation
copying the form of another
learning from the results of what the subject does
action based
goal based
over imitation
copy all, refine later
high fidelity imitation only unique to humans
cumulative culture also unique to humans
joint cooperative activities
interactants are mutually responsive to one another
shared goal by all to act together
coordination of plans and intentions with understanding of roles
language
physical
respiratory
phonatory
resonatory
articulatory
lungs
diaphragm
larynx
vocal chords
nasal cavities
tongue
teeth
lips
control sound of communication
brain pathway
auditory area
wernikies area
brocas area
motor area
processing of sounds from ears
comprehension of speech
formulation of responce
sensory information for speech producton
foxp2 gene #
highly conserved protein sequences in vertebrates
development of circuits involving the neocortex, basal ganglia, and cerebellum
role in not only vocal learning, but also fine motor contro
Human variant of FOXP2 causes alteration in brain development
synaptic plasticity, axon and dendrite outgrowth, and activity in medium spiny neurons of the striatum
language pathway in brain conceptualized in two ways
FLB
FLN
physical production and creation of speech
figurative understandng and idea generation for speech
recursion
discrete infinity
Theory of mind
the ability to
Recognize that all people act on the basis of mental states or propositional attitudes (beliefs, desires, etc.)
Attribute mental states or attitudes to oneself and to others
Understand that others have beliefs, desires, and intentions different from one’s own
involves mental deconstruction and reconstruction to understand ideas, surroundings, and other people
developement
0-12 months
mimicking of emotions
empathy
passive immitation
gaze processing
joint attention
15-24 months
Sensitivity to others’ intentions
Language development
Full understanding of joint attention
Deliberate imitation
pretend play
3-4 years
Distinction between mental and physical
Psychological causality
Understand beliefs and desires
Distinguish between direct experience and being told
domain specific
a robust and replicable response to stories that do require belief attribution
significantly lower response to closely matched control stories that only require representing non-mental representations
no difference among non-mental stories that do or do not demand meta-representation
Right temporoparietal junction
shift attention to unexpected stimuli
understands other peoples perspective
connected to voice processing
creativity and culture
creativity
culture
capacity to generate, and to reason with, novel suppositions or imaginary scenarios
occurence of creativity 20000 years after migration event of homo sapiens across the globe
simultaneous occurrence in every group of homo sapiens
found in art and figurative items across the world
pretend play
only occurs in humans
think and act within the scope of an original supposition or one learned from observation
vital in brainstorming and speculative thinking
The Joycean Machine
mental operating machine hypothesis
the stream of inner verbalization and imagery which radically altered the computational powers of the human brain
gave rise to the indefinite flexibility and creativity of modern human intelligence
issues
Children do not appear to have self talk until later in development, after the appearance of pretend play
not sufficient to explain the evolution of human creativity
does explain importance of language developement
Protean cognition
Random displays of human creative thought are honest displays of fitness –and thus sexually selected
sexually driven hypothesis to human cognition increase
human capacities for fine culture and art can be explained with sexual selection
determined if the subject can mentally differentiate themselves and another individual
cognitive elements
supposition generator
Experiential imagination
propositional imagination
imagery
perception
language
possible worlds generator
memory systems
definition
criteria
expression of trait must result from social learning
Phenotypic variation that results from information transmitted across generations through social learning
Variation in information must be transmitted across generations
Social learning must modify the phenotype of the learning individual for sufficient time in order to allow other individuals to observe the behavior and learn it
modification of the phenotype must generalize to similar situations (interprative)
increases social and overall fitness
benefits
More adaptive knowledge supports a larger carrying capacity
more innovation
promotes social learning in larger groups
Social learners can acquire more adaptive knowledge at a lower cost of individual and group
social cohesion
Larger groups with more adaptive knowledge create a selection pressure for an extended juvenile period
creates more knowledgeable youth
cultural brain hypothesis
adaptive knowledge
primary pressure for large brains across many taxa
locally adaptive information plausibly related to solving problems such as finding and processing food
necessary for longterm survival of a large group
cumulative cultural brain hypothesis
human pathway
autocatalytic improvement of brain size and complexity
prerequisites
High transmission fidelity
Smart ancestors
Sociality
Mating structure, low reproductive skew
leads to
innovation
often realistically led by groups of people working on same things
often falsely marked by an individuals accomplishments
collaborative by nature
often arise through mistakes or random luck
rate of innovation
determined by population size and interconnectivity of people and knowledge
factors
Sociality
transmission fidelity
Transmission variance
collective thought breeds innovation
driven by
mutliculturalism
openness
diversity of thought and experience