Notes on The Evolution of Psychological Science

Psychology is the scientific study of mind (private events that happen inside a person, thoughts and feelings) and behaviour (public events: things that we say and do that are observable by others).

Rene Descartes ( $(1596-1650)$ ) advocated philosophical dualism: mind and body are fundamentally different things and are not both subject to the same laws of the physical world.
Implication: the mind cannot be studied using the same techniques as those that allow us to understand the physical world, e.g. the scientific method.
Thomas Hobbes ( $(1588-1679)$ ) disagreed with dualism, advocating philosophical materialism: all mental phenomena are reducible to physical phenomena; the mind is what the brain does.
Analogy: the mind as what the display does, i.e. a picture shown on a smartphone is a product of the screen itself, not something separate.

Philosophical realism: the view that our perceptions of the physical world are a faithful copy of information from the world that enters our brain through our sensory apparatus; assumed to be an objective view of the world.
Philosophical idealism: the view that our perceptions are our brain’s best interpretation of the information that enters through sensory apparatus; assumed to be a subjective view; emphasis on interpretation.

Philosophical empiricism: all ideas/knowledge are gained empirically (through the senses/direct observation).
John Locke ( $(1632-1704)$ ) related this to tabula rasa (latin for ‘blank slate’).
Empiricism is argued to be a more effective approach for understanding the world than intuition or pure reason alone, because relying on those can be misleading.

Philosophical nativism: some knowledge is innate, or inborn, rather than acquired.
Immanuel Kant ( $(1724-1804)$ ) argued that there is some preprogrammed/hardwired knowledge everyone starts life with; not about specifics, but general concepts (e.g., space, time, causality, number).
Modern developmental psychology provides evidence that is consistent with aspects of this perspective (behaviours that don’t seem to have to be learned).

Hermann von Helmholtz ( $(1821-1894)$ ) contributed to understanding brain and behaviour, with work on vision and hearing.
He provided an early example of measuring reaction time as a method in cognitive psychology.
He calculated nerve transmission speed by measuring reaction time to stimulation of body parts at varying distances from the brain; closer distances yield faster reactions.

Wilhelm Wundt ( $(1832-1920)$ ) is associated with several firsts in psychology: first course, first lab, first textbook.
Structuralism: a reductionist approach that attempts to break down mental experiences into basic elements (analogous to the periodic table in chemistry).
The goal was that understanding basic elements would allow predictions about more complex experiences (e.g., understanding how hydrogen and oxygen relate helps understand water).

Edward Titchener ( $(1867-1927)$ ) pioneered introspection: trained participants describe their experience when exposed to stimuli (emotions, thoughts, sensations) and report contents as objectively as possible.
Examples: describing what you hear when listening to piano chords; how chords make you feel; what you perceive when viewing patterns.

Major limitation: the subjective and variable nature of conscious experience.
This contrasts with measurement and observation in other sciences, where two scientists should observe the same phenomenon (e.g., chemical reactions) in the same way.
Issues of validity (is the observation accurate?) and reliability (is it consistent?) are central and will be revisited when discussing methods.

Darwin’s Theory of Evolution produced a paradigm shift across sciences; natural selection is central.
Key idea: random mutations lead to changes in characteristics; differences in survival rates cause some traits to become more common.
Adaptations are mutations that increase survival; over long periods these traits spread through populations.

Influenced by Darwin, functionalism emphasizes studying the mind and behaviour from the perspective of purpose (the function) rather than structure (the what).
Focus on how mental/behavioural processes help us survive.

Evidence emerged that specific brain regions mediate particular aspects of behaviour/experience.
Example: damage to the back of the brain often leads to visual impairments because that region houses the visual cortex.

Introspection and related methods were discussed within the context of lectures and multimedia resources (e.g., introspection-related videos and online materials linked in slides).
Note: Links and online resources were provided in the slides for further reading on realism vs idealism, tabula rasa, and related topics.

mind vs. behaviour: private internal events vs. public observable actions.
dualism: mind and body are fundamentally different.
materialism: mental phenomena are reducible to physical processes.
realism vs idealism: objective vs subjective interpretation of perception.
empiricism: knowledge through sensory experience.
tabula rasa: blank slate at birth.
nativism: innate knowledge present at birth.
reaction time: a measure of the speed of neural transmission.
structuralism: breaking experiences into basic elements.
introspection: self-reported description of experience.
validity and reliability: measures of accuracy and consistency.
natural selection and adaptation: core mechanisms of evolution.
functionalism: focus on functions and purposes of mental processes.
localization of function: brain regions associated with specific cognitive/behavioural processes.