Week 2: Changing Paradigms and Neuroanatomy Flashcards
What is the scientific method?
Obervation (data) -> Explaination (theory) -> Prediction (hypothesis) -> Observation (Data) ECT
What is the logic of scientific discovery
The scientific method implies incremental refinement
Our knowledge progressively becomes a closer approximation to truth/reality.
Building up of scientific knowledge is analogous to construction of a ship that is already at sea. We must keep the parts that work while discarding the parts that do not—all the while staying afloat! (Neurath, Quine)
How do we implement falsification
Scientific knowledge is not monolithic competing theories exist!
Reject a theory after proof is found.
How are scientific theories organised?
The principles invoked by the explanation and the concepts involved in the explanation are determined by an overarching paradigm.
A paradigm provides a “template” for expressing theories.
Encompasses the set of background assumptions that provide a general frame of reference for explaining things.
Theories are not simple statements about the world
Theories are often (somewhat) complex explanations of phenomena
They explain “why” rather than merely describe “what”
What do paradigms do?
Paradigms define The kinds of questions that are asked Concepts that are used in theories Methodologies that are used Root metaphor for the discipline
Paradigms offer different perspectives
Need not be mutually exclusive
Can change over time (Kuhn, 1962)
What 3 disciplines in psychology adhere to the scientific paradigm
Behavioral
Cognitive
Biological
Psychodynamic/Humanist Dont
What did some of the earlier psychologists do?
Intersection of Physiology and Philosophy of Mind
Limits of human performance: Perception and Psychophysics
The relationship between Mind and Body
Conscious Experience
Free Will
Much of this early work was reliant on introspection
William James (Consciousness) and Wilhelm Wundt (Liked performance limits)
What is the psychodynamic paradigm?
Root Metaphor of Psychological Disorder
Conflict between conscious and unconscious mind
Key Concepts of the Id, Ego, and Superego
The Pleasure Principle vs. The Reality Principle
Psychosexual Development
Questions about how disorder arises due to psychological conflict/tension among “factions”
Studied via Clinical Case Studies and Case History
What are the strengths of the psychodynamic paradigm?
Focus on the individual and their unique history and background
Therapies emphasize self-insight and understanding
Foregrounds the role of developmental change and unconscious thought
What are the limitations of the psychodynamic paradigm?
Theories are largely untestable (and therefore unfalsifiable)
Lack of quantitative measurement and objectivity
Places undue emphasis on psychological disorder
What is the behavioural paradigm?
Root Metaphor of the Blank Slate
Our behaviors are wholly determined by our environment
Key Concepts of History of Reinforcement and Learning
Law of Effect—Behaviors that are rewarded tend to be repeated
Rejection of unobservable processes as unscientific
Questions about how contingencies pairing stimuli with reward/punishment affect subsequent behavior
Studied experimentally, often with animal subjects
What are the limitations of the behavioural paradigm?
Ambiguity concerning “reward” vs. “punishment”
Denial of mental processes
What are the strengths of the behavioural paradigm?
Strong commitment to quantitative rigor and objectivity
Development of experimental designs that test specific hypotheses
Identification of universal principles (e.g., regularities across species)
What is the Cognitive paradigm?
Root Metaphor of Computer
Inputs are processed and transformed into outputs
Key concepts of Mental Representations and Mental States
Focus on unobservable mental processes and their (observable) effects
Attention, Memory, and Decision-Making
Questions about the mental processes that give rise to behavior
Studied experimentally, often with human participants
What are the strengths of the cognitive paradigm?
Quantitative and methodological rigor inherited from Behaviorism
(Re-)Incorporation of mental processes into theorizing
Development of strong mathematical models of mental processes
What are the limitations of the cognitive paradigm?
Focus on mental “software” eclipses focus on mental “hardware”
Theories risk being too flexible (and resistant to falsification) if they are not articulated formally using mathematical models. (Overcomplex)
What is the Biological paradigm?
Root Metaphor of the Biological Machine
What are the physical bases of thought and behavior?
Key concepts of evolution, genetics, and physiological functions
Focus on identifying physiological correlates of specific behaviors/cognition
Measurement of brain activity and identification of genetic contributions to behaviors or psychological disorders
Questions about how mental processes are physically realized in the brain and how such functionality evolved Studied experimentally (humans and animals) as well as via case studies
What are the strengths of the biological paradigm?
Ties together some of the best bits of Behaviorism and Cognitivism
Can provide critical insights about underlying causes of behavior
What are the limitations of the biological paradigm?
Can be more descriptive than explanatory
Relationships among human and animal results are sometimes unclear
What is the humanist paradigm?
Root Metaphor of Growth
People have a need to realize their full potential
Key concepts of self-determination and –actualization
Focus on the life history of the individual and people’s capacity for change and self-betterment
Existentialist stance on human psychology
Questions about how people can improve
Largely case-based (individual focus)
(Triangle of needs pic) Basic needs (food water -> safety) -> psychological needs (intimate relationships -> prestige) -> Self-fulfilment (Full potential)
What are the strengths of the humanist paradigm?
Therapies are highly personalized and attuned to the individual
Addresses questions about human betterment (e.g., positive psychology)
Places the individual in a broader context
What are the limitations of the humanist paradigm?
Can be considered more of an art (or philosophy) than a science
Summary
Paradigms in science serve as ways of organizing theories (i.e., explanations), programs of research (i.e., questions people ask), as well as the methodologies used within the discipline
Psychology has five major paradigms
Cognitive paradigm is the singularly most dominant, though most of psychology is informed by cognitive, behavioral, and biological paradigms
Psychodynamic and Humanistic approaches become more prevalent in clinical contexts and applied settings
Not all of psychology’s paradigms are universally accepted as scientific!
What is a top-down process?
Controlled conscious choice
Selection and inhibition
What is a bottom-up process?
Automatic brain response
Evolved for survival
What is Phrenology and what did it get right and wrong?
1810 – 1840
Proposed that: • Brain composed of “organs of thought” (faculties) • Bumps on the skull reflect relative development of underlying faculties
ALL COMPLETELY WRONG
but Introduced notion of
localisation of brain function.
What are the three major parts of their brains and alternate names?
Cerebrum (Hemispheres aka Forebrain)
Cerebellum (Hind brain)
Brainstem
What are the Cerebral Hemispheres divided by?
Two Hemispheres, divided by Longitudinal Fissure or Inter-Hemispheric Fissure
Does brain size matter?
No size doesn’t but composition and use does e.g. SA increase in cerebrum from gyrus and sulci.
What is the outermost layer of the cerebrum and what is it composed of?
Cerebral Cortex - Grey matter
What does the Cortex contain and function as?
Surface of the brain 2 to 4 mm thick
- Contains the cell bodies of the brain’s neurons
- Highly folded to maximize surface area. i.e. maximize amount of cortex that can fit inside skull
• White matter underneath the grey matter is all the “wiring” i.e. axons of the neurons, connecting to the spinal cord and to other areas of the cortex
What are some of the anatomical positions used for brains?
Superior / Dorsal - (Top) Anterior/Rostral - (front) Posterior/Caudal - (back) Inferior/Ventral - (Bottom) Lateral/Medial
What are the major lobes of the brain?
Primary motor cortex anterior of central sulcus, primary sensory cortex posterior used for touch, Primary visual cortex is posterior, primary auditory cortex temporal lobes.
Where is and what does the temporal lobe do?
Inferior to the Lateral Sulcus
- Primary Auditory Cortex – Perception of sound
- Language Comprehension (Wernicke’s area)
- Medial Temporal Lobe: – Limbic system amygdala and hippocampus
What is the limbic system and what it is comprised of?
Amygdala
• Fear and arousal
– Responds to threat / danger (snakes, spiders, angry/fearful faces)
– Fear / learning Phobias?
Hippocampus
• Learning and Memory
– Forming new episodic memories
– Damage causes anterograde amnesia
Where is and what does the occipital lobe do?
Sensation & Perception
- Posterior part of the brain, inferior to Parietal Lobe
- Primary Visual Cortex (V1) – All visual perception
- Higher visual areas – Different regions process shape, colour, orientation, motion
Where is and what does the frontal lobe do?
Attention & Executive Control
• Anterior to the Central Sulcus
• Executive Functions:
– reasoning, planning, problem-solving
– Inhibitory control
– Working memory
• Motor functions
– Premotor cortex – motor planning
– Primary motor cortex – execution
• Speech production (Broca’s area)
Where is and what does the parietal lobe do?
Attention & Executive Control
• Posterior to the Central Sulcus
• Primary Somatosensory Cortex
– Perception of touch
• Sense of space and locations
– Gives sense of stable world around us relative to our body position
• Spatial attention
– Directing attention and eye-movements to explore visual world
• Linking vision to action
– Represents spatial location of objects around us for guiding actions
Where is and what does the Corpus Callosum do?
Brain Laterality
- Neuron connections between the left and right hemispheres
- Allows brain communication between hemispheres
- “Split-Brain” patients – left and right hemispheres disconnected. The two hemispheres cannot communicate with each other.
Why was Phineas Gage important?
- Railway worker, Phineas Gage, accident in 1848
- Iron rod, about 1m length, went through his head
- Remained conscious during and after accident
- Damaged frontal lobes
- Died 20 years later and his skull was examined
What did John Harlow find?
Gage’s physician John Harlow reported
profound change in personality
• “The equilibrium or balance, so to speak, between his
intellectual faculties and animal propensities, seems to
have been destroyed. He is fitful, irreverent, indulging at times in the grossest profanity (which was not
previously his custom) … impatient of restraint or
advice when it conflicts with his desires …”
• Changed into a man who was “no longer
Gage”
• Important role of frontal lobe for executive
control of behaviour
Where is and what does the Broca’s Area do?
In 1861, Paul Broca described a patient who was unable to speak after damage to the left frontal lobe (Broca’s area).
What occurs when Broca’s area is damaged?
Broca’s Aphasia – Speech Production
- Speech is slow and non-fluent
- Difficulty finding appropriate words (anomia)
- Speech still carries meaning
- Comprehension is (mostly) unaffected
Where is and what does the Wernicke’s Area do?
In 1874, Carl Wernicke suggested that lesions to the left posterior temporal lobe led to deficits in language comprehension.
What occurs when Wernicke’s area is damaged?
- Unable to understand language – deficit in comprehension
- Speech is fluent with normal prosody (rhythm, intonation)
- Speech has no meaning, nonsense speech
What did Wilder Penfield do?
Stimulated the brain with electrical probes
while the patients were conscious, during
surgery for epilepsy.
1951, published maps of motor and sensory
cortices of the human brain
What is the Homunculus
- Primary Sensory cortex and Primary Motor cortex
- Brain function “mapped” by electrical stimulation
- Brain stimulation leads to sensation or movement (muscle twitch)
- Size of area on cortex determines sensitivity or fine motor control
Summary
• Functional brain anatomy
– Cortex: Frontal, temporal, parietal, occipital lobes
– Limbic system (hippocampus, amygdala), corpus callosum
• Specific functions localised to specific brain areas
– Shown by changes following brain damage or brain stimulation
– e.g. Broca’s and Wernicke’s areas – language
