Lecture 1 Flashcards
Diagram from Descartes’ Treatise of Man
- Shows the formation of inverted retinal images in the eyes, and the transmission of these images, via the nerves so as to form a single, re-inverted image (an idea) on the surface of the pineal gland.
Rene Descartes
1596-1650
Defender of Dualism.
Invented the Cartesian coordinate system (X, Y, & Z).
Father of modern philosophy.
“I think therefore I am”
The Allegory of the Cave
~380 BCE
Plato’s (429-348 BCE) Early Philosophy of Perception
A Socratic Dialogue written by Plato that involved a conversation between Socrates and Glaucon, Plato’s brother.
Morpheus’s answer to Neo in The Matrix, 1999
“What is real? How do you define real? If you’re talking about what you can feel, what you can smell, what you can taste and see, then real is simply electrical signals interpreted by your brain. This is the world that you know.”
Perception and your sense of reality are the products of evolution:
Sensory systems provide a survival advantage.
Importance of type of energy in the environment for an animal determines which senses have developed.
Human senses are limited to only certain kinds of energy in the environment.
Therefore, humans’ sense of reality is also limited.
Carl Sagan Video
Cosmos- The 4th Dimension
Key concepts
- Dimensionality
- Projections to smaller dimensions
- Experiencing larger dimensions
http://www.youtube.com/watch?v=UnURElCzGc0
The 3 basic problems of perception
What is the quantitative relationship between physical energy and sensation?
(psychophysics)
How does physical energy in the environment become transduced into neural signals within the brain?
(sensory physiology)
How are patterns of sensory stimulation interpreted as meaningful events?
(psychophysiology)
What is the quantitative relationship between physical energy and sensation?
psychophysics
How does physical energy in the environment become transduced into neural signals within the brain?
sensory physiology
How are patterns of sensory stimulation interpreted as meaningful events?
psychophysiology
psychophysics
What is the quantitative relationship between physical energy and sensation?
sensory physiology
How does physical energy in the environment become transduced into neural signals within the brain?
psychophysiology
How are patterns of sensory stimulation interpreted as meaningful events?
Dualism
The idea that the mind has an existence separate from the material world.
Mental phenomena are non-physical.
Father of modern philosophy
Rene Descartes
Materialism
The idea that only matter and energy exist.
The mind is not separate from the body.
Most psychologists are modern materialists.
Gustav Fechner:
Personal Details
Held a Medical degree.
Worked to exhaustion.
Depression.
Spent 3 years alone.
Went blind looking at the sun.
Experience a “miracle” when vision returned.
Struggled with mind-body concepts.
Had some crazy ideas.
Believed in panpsychism:
The idea that all matter has consciousness.
Wrote Nanna, or Concerning the Mental Life of Plants
Gustav Fechner
1801–1887
Invented “psychophysics” and is often considered to be the true founder of Experimental Psychology.
Struggled with the mind/body problem.
Psychophysics:
Alternate Definition
The science of defining quantitative relationships between physical and psychological (subjective) events.
Ernst Weber
1795–1878
Discovered that the smallest change in a stimulus, such as the weight of an object, that can be detected is a constant proportion of the stimulus level,
(i.e. a linear relationship).
These proportions were called Weber Fractions.
Example: Object 1 must weigh 1/40th more/less than Object 2 for the difference to be noticeable or a JND (just-noticeable difference)
Just-Noticeable Difference
An Example of a Weber Fraction.
Object 1 must weigh 1/40th more/less than Object 2 for the difference to be noticeable or a JND (just-noticeable difference).
Fechner’s law
A principle describing the relationship between stimulus magnitude and the resulting sensation magnitude, such that the magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity.
S = k log R
Example: 100 candles is 2x’s as bright as 10.
10 candles is 2x’s as bright as 1.
Stevens’ power law
- Proposed relationship between stimulus energy and perceived intensity is a power function.
Sensation = a(Intensity^b)
Chronological Summary of Laws
Weber’s Law:
As stimulus level increases or decreases, the magnitude of change must increase proportionately (linearly) to remain noticeable.
Fechner’s Law:
The magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity.
Steven’s Power Law:
Stimulus energy and perceived intensity is a power function.
