What is science? How is it done? The scientific method is ...

What is science? How is it done? 

The scientific method is characterized by 

• observability 

• measurability + validity 

• replicability 

The best approach is the use of experiments 

because they allow us to rule out competing hypotheses. 

Steps in conducting a study: 

1. formulate the question 

2. formulate the hypothesis, or prediction 

3. decide on the methodology 

4. collect and analyze the data 

5. formulate conclusions and their implications 

6. disseminate the information

An example: infant object perception 

Step 1. The question: How do infants make sense of the visual world? 

Step 2. The hypothesis: Where do we start? 

“Gestalt” theory: Why does the world look the way it does? 

Methods: phenomenology and introspection

organizational principles: 

• goodness of form 

• continuity 

• simplicity 

• symmetry 

• common fate 

• figure/ground 

• the whole is greater than the sum of the parts 

What would Gestalt theory predict about infants? 

Step 3. The method: Habituation/dishabituation 

Kellman 

& Spelke 

(1983):

Step 4. Collect and analyze the data. 

chance, randomness, patterns, and statistics: is your iPod conscious?

Step 5. Draw conclusions and implications from the data: 

How do we know which Gestalt cues infants used to perceive 

object unity? 

Yes 

Yes 

Yes 

No No No 

Conclusions: Were the predictions supported?

Virtually every scientific advancement is made like this 

(incrementally). 

Step 6. Publication in a journal 

How objective is this process? 

Some concepts to draw from this example: 

• Cross-sectional vs. longitudinal methods 

• True (controlled) experiments vs. other methods 

(e.g., correlational studies, case studies, self-reports, 

naturalistic observations, interviews, 

physiological measures, etc.) 

• independent + dependent variables, random assignment, etc. 

• Sampling 

• Ethical considerations

Some of the principals, and their principles… 

The goal: personality & psychopathology 

The starting point: id 

Mechanism(s) of development: 

• biological drives & drive reduction 

• parenting (internalization) 

Contributions to developmental psychology: 

• emphasis on early experience 

• interactionist perspective 

Freud 

Key terms: 

• id, ego, superego 

• Oedipus complex (Electra for girls) 

• oral, anal, phallic, latent, genital stages 

• identification, repression, projection, 

compensation, fixation


The goal: lifespan personality development 

The starting point: a sense of trust vs. mistrust 


• crisis resolution 

• parenting initially, then individual choices 


• a lifespan perspective 

• broader than Freudian theory 

Erikson 

Key terms: 

• autonomy vs. shame & guilt 

• conscience 

• inferiority vs. competence 

• sense of identity


The goal: mental processes 

The starting point: ability to learn 


• conditioning (classical) 


• emphasis on learning 

• theory building 

Pavlov 

Key terms: 

• unconditioned stimulus >>> 

unconditioned response 

• conditioned stimulus >>> 

conditioned response


The goal: application of Pavlov’s ideas to humans 

The starting point: ability to learn (blank slate) 


• conditioning 


• emphasis on behavior 

• precise specification of operationalized 

variables and objective measurement 

Watson 

Key terms: 

• Behaviorism 

• reflexes 

• associations 

• the famous quote 

• Little Albert


The goal: apply conditioning to complex behavior 

The starting point: ability to learn (blank slate) 


• operant (and classical) conditioning 


• emphasis on interaction of individual 

with the environment 

• better specification of conditioning 

history 

Skinner 

Key terms: 

• reinforcement 

• reward 

• punishment 

• behavior modification


The goal: learning beyond conditioning 

The starting point: several kinds of learning 


• observation & imitation 


• emphasis on learning that is not 

reinforced 

• consideration of indirect effects of 

environmental characteristics (e.g., gender 

stereotyping) 

Bandura 

Key terms: 

• observational learning 

• the Bobo doll study


The goal: an evolutionary approach 

The starting point: innate instincts 


• imprinting 


• emphasis on unlearned behaviors 

• consideration of evolutionary history 

Lorenz 

Key terms: 

• ethology 

• critical period 

• sensitive period 

• innateness

A complicated social behavior thought to be biologically mediated: attachment 

Factors predisposing attachment of newborn infant to mother: 

• bias to look at motion 

• bias to attend to sounds in the frequency of the female voice 

• early preference for faces 

Factors predisposing attachment of mother to newborn infant: 

• “motherese” 

• response to social smile 

• cuteness elicits caregiving behaviors

An aside: what does it mean for something to be innate? 

• Present at birth vs. later emergence 

• Genetic vs. environmental 

• Unlearned vs. learned 

• Culturally universal vs. culture specific 

• Species universal vs. species specific 

• Individually universal vs. specific to individuals 

• Biological vs. cultural 

• Inevitable vs. flexible 

• Central vs. peripheral 

• Modular vs. general-purpose

Genes, environment, & behavior: What causes what? 

Concordance studies: monozygotic vs. dizygotic twins, family members, & unrelated people 

Bouchard & McGue, 1981

OGOD vs. QTL 

http://www.ornl.gov/TechResources/Human_Genome/home.html

Genetic determinism = nonsense 

enzyme production 

regulation of biochemical 

reactions in cells 

Proteins 

Cellular 

metabolism 

regulation of nervous system, 

endocrine system, etc. 

Physiological 

mechanisms 

direct & indirect effects 

Genes 

Behavior 

the “environment”

How do we get from this 

Is the brain a computer? 

How does it work? 

to this? 

Brain development questions: 

1. How do neurons develop? 

2. How do they know where to go? 

3. How do they know how to interconnect? 

4. How do they know what to do?

Brain basics: I 

Neurons & networks 

Brain development phenomena: 

1. Neurogenesis & connectivity 

2. Synaptogenesis 

3. Synaptic pruning 

4. Myelination

Brain basics: II 

areal specificity 

Is the cortex equipotential? 

Brodmann’s areas

Brain basics: III 

laminar specificity

Origins of neurons

Development of connectivity: the radial unit hypothesis (Rakic) 

abbreviations: 

MZ = marginal zone 

CP = cortical plate 

SP = subplate zone 

IZ = interzone 

VZ = ventricular zone 

E = embryonic day of 

development 

RG = radial glial cell 

MN = migrating neuron 

CC = corpus callosum 

TR = thalamic radiations

Input from sensory systems 

guides brain development 

Molecular markers 

guide neural migration 

LGN = lateral geniculate nucleus 

MGN = medial geniculate nucleus

Transplant studies: evidence for equipotentiality

Synaptogenesis & synaptic pruning 

corpus 

callosum 

cortex

Continuity across prenatal & postnatal development: sleep patterns

Experience & development 

Molyneux’s question: "Suppose a man born blind, and 

now adult, and taught by his touch to distinguish 

between a cube and a sphere of the same metal, and 

nighly of the same bigness, so as to tell when he felt 

one and the other, which is the cube, which is the 

sphere. Suppose then the cube and the sphere placed 

on the table, and the blind man made to see; query: 

whether by his sight, before he touched them, he could 

distinguish and tell which is the globe, which is the 

cube?"

MM’s visual proficiency (Fine et al., 2003)

MM’s visual proficiency (Fine et al., 2003)

Orientation sensitivity in kittens (Blakemore & Cooper, 1970):

Direction sensitivity in kittens 

(Cynader & Chernenko, 1976): 

Ocular dominance and stereoblindness 

(Crawford et al., 1992): Prisms and diplopia 

in infant monkeys

Visual deprivation and face perception in humans (Le Grand et al., 2001):



Plasticity throughout the lifespan in cortical reorganization: phantom limbs 

(Ramachandran & Hirstein, 1998):

Perceptual development 

1. How do we parse the input? 

2. How do we make sense of the input? 

A description of the problem to be solved: 

The optic array (J. J. Gibson)

aerial perspective 

Pictorial information for distance 

relative & familiar size 

height in the picture plane 

T-junctions 

(interposition) 

linear perspective 

texture gradients 

transparency 

shading 

shadows

Motion information for distance 

Degree of 

relative 

motion 

Observer motion 

Optic flow 

Motion parallax

Motion information for distance 

Kinetic occlusion

Stereoscopic (binocular) information for distance

Investigating development of depth perception 

the “visual cliff”

Perceiving depth from pictorial information (Yonas)

Development of object perception: unity (Johnson)

Development of object perception: segregation (Needham)

Development of visual attention 

" " 

fovea 

(1-2°) 

Eye 

lens 

Optic nerve 

foveation 

Why is foveation necessary?

Eye movement types: 

1. Saccades 

2. Smooth pursuit 

3. Optokinetic nystagmus 

4. Vestibulo-ocular reflex 

5. Convergence 

How do infants know where to look? 

Development of saccades 

(Johnson & Johnson, 2000): 

2-month-old 

4-month-old


1. Saccades 





Recording smooth pursuit in infants


1. Saccades 





Development of smooth pursuit (Aslin, 1981): 

Development of saccades 

(Johnson & Johnson, 2000): 

2-month-old 

4-month-old

Visual development as a model system for cortical development 

Felleman and Van Essen (1991)

Schiller’s (1985) model: 

Mark Johnson’s (1990) model: 

neonate 

2- to 4-month-old

Cognitive development: Piaget’s theory 

It’s a stage theory: 

• qualitative differences between stages 

• invariant sequence 

• early structures --> later stages 

• internal coherence of stages 

• periods of transition: disequilibrium 

Jean Piaget (1896-1980) 

• décalages are a challenge to the theory 

It’s a constructivist theory 

It’s an interactionist theory

“Genetic epistemology:” focus on 

• intelligence 

• adaptation 

• organization 

• assimilation & accommodation

Methods: 

• interviews 

• observations 

Periods of development: 

• sensorimotor 

• preoperational 

• concrete operational 

• formal operational

The sensorimotor period: development of mental representations and 

transition from egocentric to allocentric spatial reasoning 

Stages 1-2: initially “out of sight, out of mind,” then recognition memory 

Stage 3: beginnings of active search. For example: 

• reconstruction of an invisible whole from a visible fraction 

• visual accommodation to rapid movements 

• removal of obstacles preventing perception 

Stage 4: perseverative (A not B) error 

Stage 5: multiple visible displacements 

Stage 6: full object permanence

Stage 3: early object concepts 

Reconstruction of an invisible whole 

Visual accommodation to rapid movements 

Stages 4-6: transition to mature object concepts 

Experimenter 

A 

B 

Infant

Success at the A not B task depends on: 

• age 

• delay between hiding and search 

Experimenter 

A 

B 

• distinctiveness of hiding locations 

Infant 

• distance between hiding locations, 

and presence of other hiding locations 

• brain maturation (Adele Diamond) 

A 

Experimenter 

Infant 

B 

• search history (Linda Smith, Esther Thelen)

The preoperational and concrete operational periods: 

The transition to logical thinking 

Initial difficulties: 

• egocentrism 

experimenter 

child 

ego view

• centration 

Number 

Conservation 

tasks

Cognitive development: Information-processing theory 

Contrasts with Piagetian theory: 

• continuous development, rather than stagelike 

• focus is on process, not product 

• careful consideration of task characteristics

An example: memory 

What determines whether something is remembered? 

Response 

motor control 

motivation 

All-pervasive: 

Input 

Sense 

organ 

attention 

motivation 

receptor maturity 

Iconic 

storage 

Production 

Short-term 

(working) 

memory 

retrieval 

Long-term 

memory 

maturity of 

neurophysiological 

structures 

rehearsal & 

practice 

task interference 

encoding 

consolidation 

knowledge base 

strategy use

What changes? I: The brain

What changes? II: Basic cognitive function

What changes? III: Strategy use

Addition strategies (Siegler)

Locomotion strategies (Adolph)

What changes? IV: General knowledge 

For example: 

• scripts, other content domains 

• metamemory 

• planning 

• analogical reasoning

Cognitive development: Core knowledge theory 

Defining characteristics: 

• focus on areas important to human survival (evolutionary theory) 

(e.g., object perception, face perception, understanding others, language) 

• domain specificity 

• genes create a tool for each job 

speech perception 

theory of mind 

language 

memory 

attachment 

face perception 

object perception

Cognitive development: Sociocultural theories 

Principles: 

• children are inherently social creatures shaped by culture & context 

• cognitive development relies on culturally-defined systems 

(e.g., language, writing, mathematics, moral values) 

• cognitive development is guided by adults and peers 

A mental activity appears “on two planes. 

It appears first between people as an 

intermental category, and then within the 

child as an intramental category.” (italics 

added) 

Lev Vygotsky (1896-1934)

The zone of proximal development “is the distance between the actual developmental level as 

determined by independent problem solving and the level of potential development as 

determined through problem solving under adult guidance or in collaboration with more 

capable peers.” (Vygotsky, 1935) 

potential level 

actual level 

ZPD

Vygotsky vs. Piaget 

Focus on individual and 

cultural differences 

Cognitive development driven by 

sociocultural interaction: 

• instruction dependent 

• guided by others 

Focus on cognitive universals 

Cognitive development driven by 

individual construction: 

• stage dependent 

• experimentation 

Thought = language (Whorf) 

• once language develops, 

thought is linguistically mediated 

Thought is independent of language 

• cognition precedes language 

• language is a subset of cognitive skills

What is science? How is it done? The scientific method is ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?