What are the origins of Brain and Behaviour? Chapter 1

Question 1

Define the Clinical Focus: Living with Traumatic brain Injury

Answer 1

1. Each year = 1.7mil ppl in the U.SA receive medical attention from traumatic brain injury (TBI)
   
   • TBI involves wound to the brain = from blow to head/concussion
2. Linge
   - Forcasted that ppl w TBI must cope with: no diagnosis, no planning, no rehabilitation, no hope
   
   • newer neuroscience research addresses many of these challenges

Additional notes:
In terms of traumatic brain injury
EX: concussions –> type of closed traumatic brain injury ( can be caused by multiple reasons)
○ A silent epidemic - not something talked about a lot –> many might have troubles sleeping, headaches, and live with the repercussions of TBI

*Our brain is more plastic when we’re older
§ Children and elderly (elderly tend to have TBI bc of many falls)
§ Kids = being obnoxious or doing things more dangerous
§ Teenage boys have a higher risk of living with TBI
□ Tend to engage in risks of dangerous behaviours
® EX: drunkennes behaviour

• Lots have to cope with no diagnosis ○ What we’ve lost in our brain is not going to come back EX: Brain hemorage
  : ○ Wiplash
  § At very high velocity - can hit the skull in your brain = lead to brain injury
  § Now have more understanding

Question 2

What was the brain in the 20th Century? Why study brain and behavior?

Answer 2

1. How the brain produces behaviour/human consciousness = major unanswered scientific questions
   
   • our awareness of being alive is further than other animals: the ways in which we understand the world
   • how we have our mind = directing our decisions
2. the brain = most complex organ on earth –> found in many groups of animals
   
   • almost like magic: bunch of proteins/fats that has many outstanding abilities
3. growing list of behavioural disorders can be explained/treated
   
   • can be treated by knowing the brain better
4. study of the brain leads to an understanding of diversity
   
   • using an animal to potentially know the human brain = **transitional pipeline
   • needing to understand the diversity to have treatments of what we know now
5. study of the brain = brings insights to other fields of knowledge/source of employment
   
   • AI
     
     • inspired in the way the neuro network works/wanting to mimic that constantly (although, its not perfect)
     • why is it that we haven’t gotten AI to be like humans?: the human brain = unique
     • medicine aspect: brain disorders

Question 3

What is the brain?

Answer 3

Human nervous system
1. neurons
- very unique, not a lot of cells that can send an electrical signal

2. glial cells
   : in charge of
   • maintenance/structural integrity
   • made to support neurons
   • healthy place/directive

Brain and Spinal Cord
1. CNS
- Brain and Spinal Cord
2. PNS
- all of the nerves coming in/out of the spinal cord
- organs
- all sensations that come from our receptors
1. mechanical receptors
2. chemical receptors - transduced in our system

Major structures
1. Cerebrum (forebrain)
Hemispheres
- left & right have different functions

Forebrain
- divided into the cortex

Brain Stem
- set of structures that’s in charge of keeping us alive
- damaged brain stem = issues w breathing

Neocortex
- wrinkly/very thin
- lots of surface area
- if we were to iron out = much more surface area
- more neurons inside our skull –> less space for the brain to be in

2. Cerebellum
   
   • in charge of motor coordination/balance
   • other animals use more balance than us = have bigger cerebellum
   • some are born w/o one and don’t have issues with balance
     : it is not essential/our brain can adapt to not having one

Question 4

What is the Brain and Self-Consciousness?

Answer 4

Q: Could the brain remain awake/conscious without sensory information & without the ability to move?
- our brain always remains awake, it is working constantly

1. Embodied Behavior (Conca et al.)
   
   • commands/sensory that have been studied
     EX: our motor areas are active when we tell someone to smile (there are areas of the brain that will be active)
   • the embodied behavior is parts of our brain that is involved in that
   • one of the relationships with the motor aspect and the brain
     **the movements we make/movements we perceive in others = central to our behavior
     –> we understand one another not by only listening to words but also by observing gestures/other body language
2. Mental Emptiness (Jacobson)
   
   • those who are able to meditate/achieve it report having a mental emptiness that has no thoughts
   • only happens when we are relaxed - when we’re relaxed physically, we’re relaxed mentally
   • when those who don’t see anything or feel anything = our brains start to hallucinatewill create a sensory input that that’s not there due to uncomfortability
3. Locked-in Syndrome
   
   • not able to move/communicate
   • can sometimes be mistaken as “persistent-vegetative state”
     : these are signs of not showing to be conscious
     : minimal conscious state - is what sometimes happens
     * however, ppl who have this syndrome are cognisant = can still have thoughts/emotions and still be a person
     * the brain in intact, nerve fiber pathways that produce movement = inactivated
4. Minimal Conscious State (MCS)
   
   • individual can display some behaviours such as smiling or uttering a few words = but otherwise is not conscious
   • can follow simple commands
5. Persistent vegetative state
   
   • those who are alive/show signs of wakefulness = but unable to communicate/show signs of any cognition function

Question 5

what is Deep Brain Stimulation (DBS)

Answer 5

1. X-ray image that shows electrodes implanted in the thalamus
   
   • structure deep in the brain near the tip of the brain stem for deep brain stimulation (DBS)
2. Can treat disorders - Parkinson Disease
   : neurodegenerative disease that targets the brain/ does not allow for movementmight experience tremors/hard to walk in big strides (motor movement disorder) –> when the area of the brain is stimulated the DBS device allows the experience of slight motor movement

• Depression
  : patients can sometimes not respond to therapy or drugsin some cases, there are a few studies that show DBS –> stimulation in the limbic system that can help w processes in general emotion
• aid recovery for TBI
• In patients, help improve motor movements

Question 6

What is Behaviour? Define Ethology

Answer 6

1. Ethology: Irenaus Eibl-Eibesfeldt
   - defines behaviour as “behavior consists of patterns in time”
   - movements, vocalizations, thinking, and changes in appearance (such as facial movements associated w smiling
   **all of these above shows signs that we’re behaving through forms of patterns in time

Question 7

What is Behaviour? Define Animal behavior

Answer 7

• varies enormously (these variations indicate diverse functions of the brain)
• produces actions that are
  1. inherited ways of responding
     EX 1: animals produce behavior w little/no previous experience
     EX 2: for these behaviours, their brains come equipped w necessary organization to produce these behaviors

**humans are complex but when we look at other animals around us, they also have complex behaviors (varies in culture)
- caused in the brain due to anatomical features - behaviors that are usually inherited, ways in which we respond to things
EX: pupils dilating - this is inherited & language (something that we learn by our communities)

2. learned; plasticity
   - animals produce learned behaviors - require experience/practice (depends on brain’s plasticity - ability to change in response to learning experience)

EX: Language - ability that we have (that can also be inherited)
**can be a mixture of both learned/inherited

3. Most behaviours consist of a mix of:
   
   1. inherited (innate;fixed) behaviours
   2. learned actions that are a part of cultural transmission (a way a person learns about a new culture by engaging/immersing themselves in the culture/ppl around them)

• involve a preorganized brain = modifiable through experience

Question 8

What is innate & learned behaviors? Examples of inherited/taught behaviors

Answer 8

1. Crossbill’s beak = specifically designed to open pine cones
   - behavior is innate (not taught)
2. Baby roof rat = must learn from its mother how to eat pine cones
   - behavior is learned
   - cultural: parents teach it to offspring

Question 9

What Are theories of Brain and Behavior?

Answer 9

• many ppl reasoned of the causes of behavior
• speculations can be classified in 3 theories
  1. mentalism
• non-material mind
• abstract, we cannot touch/influence it at all

2. dualism
   - 2 things: the mind/body are separate
   - those who are religious: can see their souls different from the brain
   - issues w this theory: no ways of testing this (unfalsifiable)
3. materialism
   - material mind; in charge of our physiology
   - able to measure physical things about the brain - related to our mind
   - something we can test/prove

Q: to what theory do contemporary brain investigators subscribe?
A: Materialist view

Question 10

What is Aristotle and Mentalism?

Answer 10

1. Mentalism
   - behavior as a function of nonmaterial mind
   - mind = responsible for behavior

• independent of the body but responsible for: consciousness, sensation, perception, attention, imagination, emotion, motivation, memory, and volition *as descriptions of behavior

2. Ancient Greece: Aristotle
   - believed the brain cooled the blood - no role in producing behavior
   **blood had no role in behavior

• ancient greek time: humoral theory of anatomy
  : blood humour, yellow, green, etc. - liquids that moves around our body that makes us sick
  **the different kinds of biles
• Psyche
  : synonym for mind = entity once proposed to be source of human behavior
  : nonmaterial entity - that governs our behavior/our essential consciousness survives our death
  **essentially, our consciousness will live on

Question 11

Define Descartes and Dualism

Answer 11

Descartes
- mind interacts w body to produce movement
works through the pineal gland at the brain’s center

• mind instructed the pineal body (lies beside fluid-filled brain cavities = ventricles) to direct fluid from them through nerves/into muscles)
  **essentially communicates to our body through the pineal gland

Dualism
- both nonmaterial mind/material body contribute to behaviour

• nonhuman animals/machines are unable to pass Descartes’ tests = bc they lack a mind
  **this was to test for the presence of the mind/ability to use language and memory to reason
• Turing test = contemporary version of Descartes’s test
  : proposed that a machine could be judged conscious if a questioner couldn’t distinguish its answers from a human’s
  (contemporary computers are able to pass the Turing test)

Mind-body problem
- difficulty of explaining interaction of a nonmaterial mind/physical brain
: there’s no way for a nonmaterial entity to influence the body = doing so requires spontaneous generation of energy - which violates the physical law of conservation of matter/energy

Question 12

What is the Dualist Hypothesis?

Answer 12

descartes
- mind lives in the pineal gland, where it directs flow of fluid through ventricles/into muscles to move the body

• pineal gland influences daily/seasonal biorhythms
  (this is what the pineal gland’s role is in behavior)

Question 13

What is the comparative Focus? Define the Speaking Brain (Part 1)

Answer 13

Robert Berwick & Noam Chomsky (2016)
- argued that among animals, only humans have evolved language bc of their unique ability to “merge” words/concepts to make infinity number of concepts

1. confronted the evolutionary theory that predicts: it’s unlikely that language appeared full-blown to modern humans

• However, this theory that animals are non-verbal/non-conscious = challenged by other researchers
  : argues that we evolved from other languages/can communicate through other ways

**Noam Chomsky suggested that it’s something in our genes

2. Language training & spontaneous vocalization
   - show that nonverbal forms of language can precede verbal language = taught in ASL to a Chimp

• taught a bonobo (chimp species thought to be even closer relative of humans than others) the symbolic language Yerkish
  **some understanding of complex speech (different calls) & gestural drifts (facial/arm gestures) to signal intent

3. Brain-blood imaging studies
   - humans and chimpanzees activate the same brain regions when they communicate

• imaging studies of the pathways in the brain show that Chimpanzees that voluntarily learn to use sounds to attract human investigators = show structural changes in these same brain regions compared to chimps that don’t use these signals

Question 14

What is the comparative focus? The Speaking Brain (Part 2)

Answer 14

Sam Roberts & Anna Roberts (2020)
- chimps communication ability = behavioural trait that allows large number of animals to live together in groups

In humans
- we can live to 100 if we wanted too - something that we wouldn’t be able to do if we didn’t have language to pass on through our society
**something that is adaptable to survive

Michael Wilson (2021)
- argues that the language-like behavior displayed by chimps is antecedent to same behaviors displayed by modern humans

Question 15

What is Darwin and Materialism? (p1)

Answer 15

• natural selection & heritable factors: way new species evolve and existing species change over time

Materialism
- the mind is material
EX: drugs and alcohol
- activates our gava receptors = which becomes more lose/disinhibited (which changes the way in which we behave)

Darwin
- pointed out the term natural selection

• when there’s changes in our DNA/some kind of genetic mutation, it can be favourable/detrimental
• species that have the resources are the one to thrive

Species
- group of organisms that can breed among themselves
EX: horses & donkeys
**different species can reproduce other species - but it depends on if they can keep reproducing

Phenotype
- physical trait or appearance
- what we can see or measure

Genotype
- all of our DNA
- comes from both parents - therefore, we have 2 genes that are coding for the same trait
EX: blue eyes vs. Brown eyes
- brown eyes are more dominant

Epigenetics
- how our behaviors/environment can cause changes that affect the way our genes work

Question 16

What is Darwin and Materialism? Natural Selection? (p2)

Answer 16

Materialism
- philosophical position: behavior can be explained as function of the Nervous system w/o recourse to the mind
**thought that this alone could fully explain behavior

Evolution by natural selection explains how?
1. new species evolve/existing species change over time

2. Differential success in reproduction of characteristics (phenotypes) = from interactions of organisms w their environment

EX: PVS
- explains how new species have evolved throughout time
- how old the earth is/how new species have come about
- traits/phenotypes that we have that can be adaptable to our environment

Question 17

What is Darwin and Materialism? Heritable factors? (p3)

Answer 17

natural selection & heritable factors
- Gregor Mendel
: heritable factors (genes) govern various physical traits displayed by the species

: members of a species w particular genetic makeup/genotype are likely to express (turn on) similar phenotypic traits
EX: if a gene/combination of genes for a specific trait (flower color) - passed onto offspring, offspring will express the same trait
**can be turned off/on depending on our environment

: Similar characteristics within/between species = usually due to similar genes
- Primates = share many of our DNA/aspects of our genes

Question 18

What is Darwin and Materialism? Define Epigenetics.(p4)

Answer 18

• interplay of genes, environment, and experience
• “Beyond genes”

Epigenetics
- study of differences in gene expression from environment/experience

• epigenetic factors don’t change genes; only influence how genes express traits inherited from parents
  : sometimes can be turned off due to chemicals in our genes that can be added

EX: twins (if they have different environments) can have different genetic makeup

• epigenetic changes = persist throughout a lifetime/cumulative effects can make dramatic differences in how genes work
  EX 1: Drugs
  : can be added to our genes/can be added to our offspring = 50% of genetic makeup will be passed on

EX 2: kids of parents that have gone through wars - tend to have behavioural issues, anemia, autoimmune disorders due to ancestors (that can be passed on)

Question 19

Can you summarize Materialism into 4 parts?

Answer 19

1. all animal species = related/& so are their brains
   **there can be commonalities to the brain
2. All species of animals are related = their behaviour must also be related
   **commonalities in the way we behave

• darwin (1872) argued that emotional expressions = similar in humans/other animals bc all animals inherited them from a common ancestor

3. brain/behaviours in complex animals (humans) evolved from simpler animals’ brains/behaviours
   **see simple ways of communicating in groups - in humans, have become more elaborate
4. Consciousness/other processes attributed to the mind = must be a product of the nervous system
   **must be a product of the nervous system = when there are changes to our anatomy = changes in characteristics/looks

Question 20

What are the Contemporary Perspectives on consciousness? What are the different perspectives on theories? Define Donald O. Hebb’s perspective.

Answer 20

1. Donald O. Hebb (1949)
   - modern psychology takes for granted that behaviour/neural function = perfectly correlated; one is completely caused by the other

• fits together w his theory “how the brain produces new behaviour”
• suggests that learning is enabled by small groups of neurons forming new connections w another –> to form (cell assembly) = substrate for a memory
• essentially, cell assemblies interact
  : one cell assembly becomes connected to the other
• linking of cell assemblies = linking of memories, which to Hebb is what produces our complex behaviour (including our consciousness of our own/others’ actions).
• eliminative materialism stance

Additional notes
- models how consciousness is created (in terms of physical properties of the brain) & how plasticity happens (how it’s shaped/molded)

• mainly theoretical
• when neurons fire, they wire together
• brain & neural function = brain activity & motor activity
  : neural activity is what’s causing the behaviour/ includes our consciousness of our own/others’ actions

Question 21

What is Contemporary Perspectives on Consciousness? Define Patricia Churchland (1986) perspective.

Answer 21

• if attributes (such as consciousness, pain, & attention) can be explained by physical mechanisms = unnecessary to appeal to mental explanations
• can see brains structures being activated
• eliminative materialism perspective

Question 22

What are contemporary perspectives on consciousness? Define Giuiio Tononi (2012) perspective.

Answer 22

• integrated theory of consciousness (IIT): Phi theory
• Phi network’s waking activity produces what is experienced as consciousness
  EX: MRI; FMRI

Additional notes:
- theoretical theory

• certain kind of information that requires physical not functional, integration = which can be measured mathematically according to the phi metric
• rules out any eliminative materialism theories that deny the existence of consciousness
• characterize fundamental subjective nature of consciousness/ positing physical attributes necessary for a system to realize it

EX: requires a grouping of elements within a system - that have physical cause-effect power upon one another
**consists of feedback loops of either neural or computational = will realize consciousness

• several kinds of networks that are activated: visualize brain oxygenisation

Question 23

What are the separate realms of science and belief?

Answer 23

• ppl may question materialisms belief that only the brain is responsible for behaviour - bc they think it denies religion
• however, materialism is neutral with respect to religion

: dualism = was actually heavily influenced by Catholicism

: science = the idea of the mind, in history - did not allow scientists to ask questions of the mind
–> thought Materialism was going against religion - however, many scientists were religious

• many of the world’s major religions accept both evolution/brain’s centrality in behavior = as important scientific theories
• science is not a belief system – rather a set of procedures designed to all investigators to independently confirm answers to a question

EX: always being skeptical/closer to the truth/always having to question things **these can be theories of evolution

EX 2: creating a hypothesis, writing a study, a body of evidence, something that challenges theories/validity of the findings

Question 24

What is the evolution of brains and of behavior?

Answer 24

origins of brain cells and brains:
- our lineage can be traced by comparing genes, behaviours, and brains of a common ancestor

• we trace the evolution of the human brain and behavior by:

1. animals that first developed a NS and muscles to move (genes)
   **our lineage can be traced by comparing genes
2. How the NS grew more complex as the brain evolved to mediate complex behaviour
3. how the human brain evolved its present complexity

• humans and other apes are descended from common ancestors
  **humans are apes & other living apes are not our ancestors, however, we are related to them through a common ancestor
• human-like brain first developed = 6mill; our modern human brain = been around only for the past 200,00 years
• brain cells and brains evolved only recently

Question 25

what is a cladogram

Answer 25

• phylogenetic tree that suggests a taxonomy of organisms –> based on time sequence in which evolutionary branches arise
• read from left to right
  : most recently evolved organism (animal) / trait (muscle/neurons) = farthest from the right

**muscles - after is nerve life structures = nerve net

• some have neurons due to evolution

Question 26

What are the basic classification of life?

Answer 26

• taxonomy represents evolutionary sequence (phylogeny)
  : concerned w naming & classifying species by grouping representative organisms –> according to their common characteristics/their relationship to one another
• the broadest unit of classification = kingdom
  **subordinate groups:
• phylum
• class
• order
• family
• genus
• species
  **taxonomic hierarchy = useful in helping trace evolution of brain cells/the brain
• five known kingdoms
  1. monera (bacteria)
  2. Protista (single cells)
  3. Plantae (plants)
  4. Fungi (fungi)
  5. Animalia (animals)
  **we are part of the chordates = bc most chordates have a brain/spinal cord
• humans are called Homo sapiens sapiens = wise, wise human”
• animalia (one of the most recently evolved) contains species w muscles/nervous systems
  **muscles/nervous systems evolved together to underlie forms of movement (behavior) that distinguish members of animal kingdom
• 15 groups
  : also known as phyla of animalia
• classified according to increasing complexity of nervous system/movement
• nervous systems in recently evolved phyla (such as flatworms) –> have more complex structure
  **these organisms have head/tails –> their bodies also show both bilateral symmetry (one half of the body is a mirror image of the other half)
• segmentation (body = composed of similar organized parts)

Question 27

What is the Evolution of Nervous system in Animals?

Answer 27

• the animal nervous system evolved along these general steps:

1. Neurons & muscles
   - brain cells/muscles evolved together = enabling animals to move
   - neurons/muscles have their origins in single-cell animals (such as amoeba) that developed many ways of moving about
   **these are traits that became more specialized in multicellular animals
2. Nerve net
   - NS representative of evolutionarily older phyla (such as jellyfishes/sea anemones) = are very simple

• consists of a diffuse nerve net, which has no structure that resembles a brain/spinal cord
  **however consists of neurons that receive sensory information/connects directly to other neurons that move muscles
• if you imagine the brain/spinal cord removed in a body
• the human PNS is similar of the nerve net in phylogenetically simpler animals

3. Bilateral symmetry
   - in more complex animals (such as flatworms) = NS is more organized/features bilateral symmetry

• the NS on one side of the animal mirrors that on the other side

**the human NS is also bilaterally symmetrical - however, does not have two sets of hearts/liver etc.

4. Segmentation
   - body of an animal (such as earthworm) consists of series of similar muscular segments

• its NS has similar repeating segments
  **the human spinal cord/brain displays segmentation –> the vertebrae contain similar repeating NS segments of the spinal cord

5. Ganglia
   - in still more evolved invertebrate phyla including: (clams, snails, octopuses) = cluster of neurons called “ganglia”
   : this resembles primitive brains / function somewhat like them (primitive brains) - bc they are command centers

• in some phyla –> encephalization (having the ganglia in the head) = is distinctive
  EX: insects’ ganglia are sufficiently large to merit (deserve) the term brain

**sophisticated neurons working together for a specific function

6. spinal cord
   - in highly evolved chordates (these are animals that have both brain/spinal cord) = a single NS pathway connects brain w sensory receptors/muscles

• chordates get their name from notochord: a flexible rod that runs the length of the back
  **in humans = notochord is present in only embryo; by birth - bony vertebrae encases the spinal cord

7. brain
   - the chordate phylum (of which amphibians, reptiles, birds/mammals) are class members

• displays greatest degree of encephalization: a true brain
• humans have the largest brain relative to body size - but many chordates have large brains
• the brain of each chordate species displays specializations related to distinctive behaviors of that species

**developed that way due to evolution

Question 28

What is a chordate brain?

Answer 28

cladogram
- phylum chordata (amphibians, reptiles, birds/mammals) = display greatest degree of encephalization –> chordates have a true brain

• of all chordates, humans have the largest brain relative to body size
• the brains of representative chordate species have many structures in common –> illustrating singe basic brain plan
  :the brain stem tends to have subcortical structures, etc.
  –> genetically, we have a simple way of making a brain
• wide variation exists among the NS systems of chordates –> but common to all = basic structural pattern of bilateral symmetry, segmentation, and spinal cord/brain encased in cartilage/bone
• evolved limbs/new forms of locomotion (their brains became larger)
  EX: all chordates have a brainstem **but birds/mammals have a larger forebrain
• evolution of more complex behavior in chordates = related to evolution of the cerebrum/cerebellum

: their increasing size/complexity in various classes of chordates (figure 1-8)
: these increases accommodate new behaviors (including new forms of locomotion in land, complex movements of mouth/hands for eating, improved learning ability/highly organized social behavior)

Question 29

What is the brain evolution?

Answer 29

• increase in brain size in chordates = related to new forms of locomotion/movement
• all chordates have a brain stem - but birds/mammals have large forebrain/cerebellum
  –> the cerebrum/cerebellum are small/smooth in earliest evolved classes (fish, amphibians, and reptiles)

**birds/mammals can have a larger cerebellum & forebrain compared to brainstem
: have more motor control for balance than we do

• increased size/folding = pronounced in primates –> animals w large brains relative to their body size
  ** we have more wrinkles and surface area, which allows us to have more cortex
  –> however, dolphins do have more wrinkles than we do (although we have more neurons)
• this accommodates complex movements (including manipulation) of the mouth/hands for eating, improved learning ability, and highly organized social behavior
  : ability to talk depends on motor movements - not able to talk as well (our tongue/muscles)

Question 30

what is the evolution of the human brain and behaviour?

Answer 30

humans - members of the primate order
- humans/chimps share a common ancestor that lived 5 mil to 10 million years ago
–> about 400 primate species

**part of subcategory of mammals such as apes, old world monkeys, new world monkeys, tarsiers, and lemurs)

• hominids evolved between 5/10 million years ago (primates that walk upright - in our lineage)

: walk upright/includes all forms of humans (living & extinct)

: enhanced depth perception – highly developed visual sense/hand movements
-**excellent color vision (w eyes positioned at the front of the face to enhance depth perception)
**use highly developed visual sense to deftly guide their hand movements

**larger brains

Question 31

define the representative of the primate order

Answer 31

slide cladogram – illustrates hypothetical relationships among members of the primate order

• humans = members of great ape family

: brain size increases across the groupings –> w humans having the largest brain of all primates = Hominins

: humans are the most related to chimps as common ancestors **we have the same genes as chimps

• Primates’ brain size = related to their unique behavioral traits
  EX: use of tools - one way to communicate to others
  **tend to have more complex behaviors than others

Question 32

What is an Australopithecus: Our distant Ancestor?

Answer 32

Australopithecus species = meaning “ape”

• Australian Raymond Dart coined Australopithecus in naming the skull of a child
  –> found among fossilized remains from a limestone quarry near Taung, South Africa (1942)

EX: Lucy - best remains that we have in terms of Hominide
- much smaller in size, but can stand the way we can

Question 33

What is the First Humans?

Answer 33

• skull of 1st animal to be genus Homo (human) = found by Mary/Louis Leakey in Olduvai Gorge in Tanzania (1964)

1. Leakeys named the species = Homo-habilis (handy human) –> signify that its members were toolmakers

• earliest member of genus Homo (found in Ethiopia)
  : fossil = jaw/teeth smaller than any Australopithecus species (but characteristic to humans)

: their brain was slightly larger than that of Australopithecus

2. 1st humans who spread beyond Africa migrated into Europe/Asia = Homo erectus (upright human)

• homo erectus 1st showed up in the fossil record about 1.6 mill years ago
  : its brain was bigger than that of any hominid –> overlapping in size the measurements of present-day human brains

Question 34

What were the increases in Hominin brain size?

Answer 34

• the brain of Australopithecus = same size as that of living nonhuman apes
• succeeding members of the human lineage display a steady increase in brain size
• tools made by H. erectus = more sophisticated than those made by H. habilis

**improved tool use was enabled by their larger brain

• small subspecies of H. erectus (3ft tall) = Homo floresiensis lived up to about 13, 000 years ago

**only one hominid species exist

Question 35

What are Human Origins?

Answer 35

Figure 1-13 (go back to slides)
- shows the human lineage & lineage of extinct Australopithecus arose from common ancestor = 4mill ago

EX: Lucy - who was close to the common ancestor with H. erectus

• ancestor of human lineage Homo probably –> hominin similar to A. africanus

Question 36

What are the ratios of brain to body size in common mammals?

Answer 36

Harry Jerison:
- index that compares ratio of brain size to body size across species

• as body size increases = brain size increases in 2/3rds the increase in body weight
• assumes that even if you know little about an animals behaviour –> its brain size could provide some clues to its behavioural complexity
  **idea is that species who have larger brains = must exhibit more complex behavior
• developed a quantitative measure = encephalization quotient (EQ)

: Fig 1-14
–> plots expected brain-body size ratio of a number of animal species in relation to a trend line with an EQ of 1

–> some species are below the line = their brain size is smaller than expected of an animal of that size

–> species above the line = their brain size is larger than would be expected for an animal of that size

**the modern human brain has the largest size relative to body weight

EX: an elephant’s brain = large bc of the body (in terms of ratio of body weight/brain size)
–> elephants are very smart (morn the dead/do things in celebration of their life)
–> dolphins are smarter than us due to their brain size

Question 37

What does it mean to Compare EQs?

Answer 37

Estimating relative brain-body size
- jerison (1973) provides estimate of comparative brain size
**however, body size and brain size can vary independently

figure 1-15
- some apes (gorillas) = specialized in having large bodies
- humans = specialized in having large brains

• developed quantitative measure of brain size –> to allow comparisons among different species (EQ)
• EQs of some familiar mammals ranked at top of chart –> members of primate lineage ranked at bottom

**intelligence = widespread among animals

EX: dolphins - mammals but not primates (have one of the largest encephalization)

Question 38

Define counting and measuring brain cells.

Answer 38

• another way to estimate behavioral capacity of a brain
  EX: the roundworm (Caenorhabditis elegans)
• has 959 cells (305 are neurons)
• 30% of cells are NS
• Blue whale (weighing as 200 tons) has brain weighing 15,000g (33Ibs)
  **less than 0.01% = NS
• based on EQs – C. elegans (w 1/3) of its body made up of brain cells = have more complex behavioral repertoire (full supply of what you can do) than a blue whale w 0.01% of its body made up of brain cells

Suzana Herculano-Houzel (2019)
- devised method of dissolving/dissociating brain cells
- counting them using a counting machine = Neurons’ packing density

EX: 2 similar-sized brains could consist of either diffusely distributed large neurons or closely packed small neurons

–> using brain cell counts: a blue whale has 30 bill neurons which is more than 302 neurons of C. elegans

** these are numbers that provide a better explanation of their behaviours than relative size measures

Question 39

what is the comparative focus? The Elephant’s brain.

Answer 39

Suzana Herculano-Houzel and her colleagues (2014)
- the neurona count of an African elephant’s brain shows 3x many neurons as the human brain

• 97.5% reside in the elephant’s cerebellum –> requisite to controlling the trunk’s sensory and motor abilities

: most are in the cerebellum –> area associated w motor behavior
: number of neurons in the elephant cerebrum –> area associated w cognitive processes (equivalent to chimps)
**neuron count suggests that apes/elephants have equivalent cognitive abilities

• cognitive abilities of humans are best explained by the sheer number of cerebral neurons = which exceed number found in all other species
  **behavior of modern humans is complex – bc of large brain size w large number of densely packed neurons

Question 40

What is the evolution of complexity in the cortex?

Answer 40

brain cell connections
- brains become larger by addition of neurons

• addition of neurons adds disproportionately more connections between those neurons

figure 1-16
- shows one view of how the complexity of the brain evolves as neurons are added

1st column
- uses different colors to illustrate functions of neurons

• most of the cerebrum of a smaller brain (bottom) - such as that of a fish = devoted to primary senses/movement

: has neurons for vision, hearing, touch, olfaction, and movement
*vision = visual pathways in primates not only guide locomotion (movement) –> but also guide control of the arm/hand for reaching

topographic view
- first column shows how the brain might change w addition of neurons

• each color represents a function: vision, touch, or hearing
  **gray shading represents new areas associated w new functions of the different regions

**functional areas
- areas that control vision, hearing, touch,olfaction, and movement

connectome view
- second column of how connections might change as neurons are added –> as topographic regions separare/become larger

**connections through which each of these regions influences each other

** the first brain evolved from more simpler types of brain structures

Question 41

Why did the hominin brain become more complex? Define the primate lifestyle influences.

Answer 41

• leading hypotheses about how humans got their unique brains

: primate lifestyle influences
1. Robert Dunbar (1998)
- social group size correlated w brain complexity

• his conclusion: average group size of 150 favored by modern humans = explains their large brains

EX: his evidence = hunter-gather groups/average group size of contemporary institutions (company in military)/ the number of people we gossip about

** able to see animals who have social groups have larger brains

2. Katherine Milton (2003)
   - primate fruit foraging

• documented the relationship between fruit foraging and larger brains –> by examining the feeding behavior & brain size of 2 South American (New World) monkeys of same body size

**different diets

EX: spider monkeys obtain 3 quarters of their nutrients from fruit / have brain 2x large as that of a howler monkey = which has less than half its nutrients from fruit

• fruit harvesting required food sensory skill = such as color vision to see it
• good motor skills to reach/manipulate it
• good spatial skills to find it
• good memory to return to it
• having friends to help find it / ward off competitors

**same skills useful for obtaining temporary/perishable types of food obtained through
- scavenging
- hunting
- gathering

3. Fonseca-Azevedo and Herculano-Houzel (2012)
   - cooking food: suggested that this is a unique contribution to the hominid brain development

EX 1: gorillas have to spend 8 hours each day foraging for vegetation/eating it
–> chimps/early hominids w varied diet could support more neurons bc they spend most of their waking time foraging

EX 2: the use of fire by H. erectus / later hominids allowed for cooking
–> predigests food/maximizes caloric gain to point that much less time need to be devoted to foraging

• cooking food makes it easier to eat
  : fosters genetic mutations associated w marked size reductions in individual muscle fibers in face/entire masticatory muscles in hominids

Question 42

Why did the Hominin Brain become more complex? Define rate/altered maturation.

Answer 42

• suggests that altered heterochronicity accounts for large human brain/other distinctive human features
• heterochronicity = “different times”
  : study of processes that regulate onset/end-of-life stages/ their developmental speed/duration

**the differences in how our body develops
- most mammals are self-sufficient: they can stand up –> some things we can’t do
–> also an increase in demands of taking care of the young = why our brains can be smarter for this reason

• during neoteny –> juvenile features of predecessors become adult features of descendants

: bc of neoteny, also led adults w proportionally larger bodies/larger skulls to house larger brains
EX: baby chimps head = similar to shape of an adult human’s head than to an adult chimps head

**neoteny = common in the animal world

EX: penguins = flightless birds = neotenic adult birds
- social animals/very smart & have good memory

EX: domesticated dogs = neotenic wolves
- vary tame/have larger brains and are smart

**many anatomical features link us w juvenile stages of other primates
- we have small faces
- vaulted cranium
- upright posture
- hair on head/pubic areas

• human adults also retain some behaviors of primate infants
  : including play, exploration/intense interest in novelty/learning
  **brain processes that support learning = retained in adulthood

Question 43

Why does the Hominin brain become more complex? Define climate change and the evolving hominid brain.

Answer 43

climate change and the evolving hominid brain
- climate changes driven many physical changes in hominids
–> this ranges from the brain changes to emergence of human culture = radiator hypothesis
**Dean Falk

Radiator Hypothesis
- larger engine
- larger radiator to cool it down
- reasoned that if the brain’s radiator, circulating blood adapted into more effective cooling system = brain size could increase

• brain cooling = important due to brain’s metabolic activity generates lots of heat/at risk for overheating under conditions of
  exercise/heat stress

: unlike australopith skulls –> homo skulls contain holes which cranial blood vessels pass
**holes suggest that compared to earlier hominids –> homo species have more widely dispersed blood flow from brain = have greatly enhanced brain cooling
**compared to other species

• many species had to be driven out to where they lived due to climate changes/devastated old environments –> which led to new ones
  **new hominid species appeared after this
• fossil records show that in drier eastern regions apes evolves into upright hominids = due to selective environmental pressures that formed their new home

Question 44

Why did the hominin brain become more complex? Define the human genome.

Answer 44

• apes/modern humans have 96% of genes in common
• each of the genes have small differences = making it difficult to determine what each difference contributes
• a different approach to understanding origins of hominid genome = ask whether new genes appeared or old genes disappeared in hominids

Levchenko
- human-specific gene = SARGP2
: gene active when cerebrum = developing

• plays role in determining number of neurons that compose cerebrum
• gene mutated, producing duplicate copies in human genome (3x over the course of human evolution)
• what is more adapted will be passed on
• the human genome allows us to be more and more

Question 45

What is the modern human brain size, intelligence, and culture?

Answer 45

1. the evolutionary approach
   - makes brain-behavior comparisons between different species
   : tried to tie individual intelligence to gross brain size – not accurate

• special care attends extension of evolutionary principles –> to physical comparisons within species
  **especially biological comparisons within/among groups of modern humans

**why a lot of ppl have tried to use “larger brains are better”

EX: thought that women were not as intelligent as men bc females have smaller brains than men (mostly)
–> however, more women have more cross comparisons **meaning we have more connections in our brain

**the number of neurons we have in a species doesn’t necessarily reflect intelligence in a person

Question 46

What is the significance of human brain size comparisons? Define Problems with correlating brain size

Answer 46

problems w correlating brain size & intelligence
- difficulty in measuring brain size
- always have to consider volume or weight –> body mass and measurement

• human brain varies in weight from 1000g to more than 2000g
  **but people always vary in body mass
• individual differences in brains
  : body weight, gender, age, nutrition, disease or injury, stress, neurological disorders, plasticity (adaptability in organism and its enviro)
• sometimes differences are numerous/complex–> can have smaller brains due to early famines in life or larger people likely having larger brain than smaller people bc they have larger muscle mass to control
  **neurological diseases/disorders – associated w aging accelerate age-related decreases in the brain
• brain injuries
• stress
  -IBS
  -FASD, ASD

**can be overwritten by plasticity/brain size

Question 47

What is the significance of human brain size comparisons? what are measurements of intelligence?

Answer 47

1. species-typical behavior
   - behavior displayed by all members of a species

EX: Lamprey eels
- don’t have limbs/can’t walk vs salamanders have limbs/can walk

**difference in brain size between the 2 species can be correlated with this trait

**when comparing behavior within species –> usually comparing how well one individual performs a certain task in relation to others of the same species
EX: how well one salamander walks vs how well another salamander walks

2. General Factor intelligence (Spearman’s g)
   - carried out various tests used to rate intelligence in humans

• found a + correlation among tests / suggested that a single common factor explained them
• named it spearmans g = for general intelligence factor
  **however, g varies
• many factors unrelated to inherent ability EX: interest level, training, motivation, health –> influence performance on a task

3. Flynn Effect
   - when IQ tests were given to young adults of one generation and given to the next generation
   **next generation increased this by 25 points

• suggested that human g increased = thus young adults fall in superior category relative to their grandparents
• not due to similar increase in brain size –> more likely education/other life experiences explain the flynn effect
• cristalised intelligence = tend to have lots of knowledge

**different ways of assessing cognitive functioning: working memory/visualizing, etc

4. Multiple intelligences
   - howard gardner (2006)
   - proposed that humans have number of intelligences (verbal, musical, math, social,etc)

• each type of intelligence dependent on function of particular brain region/regions

Question 48

What is the significance of human culture?

Answer 48

culture
- learned behaviors passed from generation to generation through teaching/experience
- enabled by our large brain
**ways of interpreting the world bc we are flexible

• cultural elements, ideas, behaviors/styles that spread from person to person (memes) –> can be studied within evolutionary framework

: most forms of math/many of our skills in using mechanical device/digital devices have more recent origins

: computer programming languages
–> early H. sapiens brains did not evolve to select smartphone apps, memes, or imagine traveling to distant planets

** the things the human brain did evolve to contained elements for adapting more sophisticated skills

Memes & evolution
- propose that the individual differences in brain structure –> favor development of certain memes
- once developed = exert selective pressures on further brain development

EX: individual brain structures may have favored tool use in some individual –> tool use proved beneficial that toolmaking itself exerted selective pressure on population –> favor individuals well skilled in tool fabrication