Development of Psych as a Science

Scientific study of cognition, brain and behaviour

Theory of knowledge

Rationalism and empiricism

Verifiable by observation

Some concepts are innate
Other knowledge derived from deductive reasoning
Mental substance (psych ideas) cannot be scientifically tested

Building onto innate concepts we already have
Eg. all birds have feathers and a penguin is a bird -----> so penguins must have feathers

Cartesian dualist principle

Mental substance has a completely different nature to physical substance
Physical substance can be studied scientifically but mental substance cannot
Thererfore we can't use science to investigate psych ideas

John Locke

No knowledge is innate
Knowledge derived from perception and experience and inductive reasoning
Mental substance (psych ideas) can be scientifically tested because it's created from the environment

Drawing general conclusions from specific observations
Eg. I saw a penguin with feathers ------> so all penguins must have feathers

Hermann von Helmholtz
Investigated speed of neural transmission with frogs leg muscle and nerve
Around 27m/s (slow)
Then moved onto humans

Theory of perception
Sensations represent physical stimuli
Relationship between physical stimulus and sensation is derived from inconscious inference
Basis of most modern psych theory

Established first experimental psych lab (in Germany)
Advocated for structuralism
Developed introspection

Theory of consiousness
Separate and analyses the components of mental experiences

Pp's observation of immediate state of consciousness changes the state of consciousness
Wundt only used introspection when stimuli given were very controlled and mental event could occur without reflection (used reaction times etc)

William James

Purpose of consciousness
Why are we conscious? How is it evoluntionarily advanatgeous?

States of consciousness are not required in the explanation of psych phenomena (rejects introspection)
Eg. behaviourism and Pavlovian conditioning

The mind and consciousness are too indefinable to be empirically tested because they cannot be observed

Investigated instrumental learning
Cat put in puzzle box and had to learn how to escape and then repeated

Similar to Pavloian conditioning but the animal has to do something
Animal learns that a specific behaviour leads to a specific response

Any behavior that is followed by pleasant consequences is likely to be repeated (Thorndike found this)
Animals learn gradually though law of effect how to escape from a puzzle and not through insight learning (shows in lack of sudden reduction in escape time)

Simplest explanation is often the most accurate
If 2 explanations are equally good, pick the simplest

Explains behaviour but not emotion

Advocated for behaviourism
Reductive stance can be applied to all human behaviour
Don't need to refer to consciousness/mental states
Psych is purely objective

Cognitive revolution
Compare human brain to computers

Neuroscience
Attempting to relate behaviour and language to physical instantiation in the brain

Many examples of pseudo-scientific ideas (psychoanalysis, phrenology etc.)
Subject is familiar and appears approachable
Often reported in the press which limits objectivity
Statistical evidence is probabilistic (not definitive)
Often proves the obvious
Lack of reproducibility (replication crisis)

Scientific or not - no hard/soft science
Employs the scientific method

Karl Popper 1959

Scientific theories can be derived from observations using inductive reasoning
These theories MUST be capable of falsification
Hypotheses developed using deductive reasoning
Hypotheses tested to determine possible falsification of the theory

Observation ----> inductive reasoning ----> theory ----deductive reasoning ----> hypothesis ---- falsification? ----> test (then back to observation and repeat)

Based on empiricism
Involves development of theories which must be able to be tested using empirical methods and falsified
Requires a systematic approach (using replication)
Single test of a theory cannot assess all possible circumstances
Parsimonious approach

Attempt to explain observed behaviour

Summarises existing empirical knowledge about the phenomen
Organises this in statements of relationships among variables
Proposes and explanation for the phenomenon
Serves as a basis for making testable predictions about behaviour

Can never prove it to be true
Can support it
The more successful replications increase the likelihood of it being true but don't prove it
BUT we can disprove it as false

Widely shared sets of guiding assumptions and research methods

Science progresses though paradigm shifts and incremental refinement of theories

Hypothetical psych factors
Psych factors which can't be observed but we infer their existence from behaviours which we assume follow from certain circumstances
Hypothetical factor which represents a cluster of related behaviours
Eg. personality and intelligence

Makes concepts in scientific theories concrete, observable, measurable events which enables replication

Using different measures for the same concept increases the likelihood that the theory is true (but can never include all possibilities)
There is no perfect operational definition for a construct so using many increases the validity??

Least representative - Henrich et al
Policy overgeneralisarions
Premature evolutionary psychology conclusions
Using Western tests

Inertia - lots of research on US pps so more research focusing on this population to address debates about this population
Neglect of culture
Preference for 'generic' conclusions in scientific communities