PSYC 213 Lecture Notes - Lecture 4: Synesthesia, Optical Illusion, Visual Perception
16 May 2018
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Lecture 004 - 01/18/2018
Visual perception: Physiology and awareness
Last class:
• Functional specialization: different areas of the brain support different functions
o Localization
o Modularity and phrenology
• Opposition to functional specialization
o Franz & Lashley
o Mental processes relate to the activity of the brain as a whole, and not as
individual parts
• Mind - Brain link
o Interactionism: the mind and brain are separate entities that interact and
influence each other
o Epiphenomenalism: mental events are caused by physical events
o Parallelism: the mind & brain are two aspects of the same reality
o Isomorphism: the correspondence between the mind & brain is structural
• Animal models
• Human psychophysiological experiments
• Neuropsychology cases: split brain patients
• Neuroimaging techniques
o EEG: good temporal resolution
o PET: good spatial resolution
• MEG/EEG: brain activity at the level of the millisecond
• PET/ fMRI: brain activity at the level of the millimeter
• Brain stimulation: TMS is a procedure in which brain activity is influenced by
magnetic field, either increasing or decreasing the brain’s electrical signals →
results in behavioral changes
• DBS (deep brain stimulation): implant tiny electrodes in the brain to send a weak
and constant electrical current to targeted regions of the brain & it reduces
symptoms in cases like depression & Parkinson’s but the mechanisms are not
known
This class:
• Sensations & perceptions
• Physiology of visual perception
o How information travels from the eyes to the brain
• Perception with and without awareness:
o conscious and unconscious processes
• Visual illusions
o Visual perception is constructive and relies on assumptions
find more resources at oneclass.com
find more resources at oneclass.com
• Sensation comes before perception
• Stimulus energy: light, sound, smell >
sensory receptor: eyes, ears, nose > neural
impulses > brain: visual, auditory, olfactory
areas
• Perception follows when brain translates
neural impulses into something meaningful
• Synaesthesia: stimulation of one sense simultaneously produces another
sensation in a different modality → Ie: grapheme-color
synesthesia (seeing certain numbers/ letters as certain colors)
• Sound - color synesthesia → when listening to a sound/
song this produces colors
• The causes for synesthesia are not clear but there are
genetic reasons or neural: synesthesia is due to the cross wiring
between sensory areas in the brain
• 40% of synesthetes have a family member that has synesthesia
• Vision is our dominant sense
• McGurk effect: speech sound ‘ba’ is simultaneously presented w/ visual speech
sound ‘fa’ is heard as fa → this is a multisensory illusion (= a change in auditory
perception from visual input)
• It demonstrates 2 concepts: the integration of sensory info & the power of visual
input (it overrides audio input)
• Are professional musicians more resistant towards the McGurk effect?
o Musicians are better than non-musicians at recognizing audio phonemes
(sounds) when there was a mismatched visual signal
• Conclusion: musicians showed no significant McGurk effect (because they are
skilled in auditory processing, tend to focus on auditory signal)
• Common misunderstanding: when we see, there is an input into the eye
• This is called the extramission belief → when we see, there is a ray that exits the
eye onto an object (false belief, dates from ancient Greece)
• Study: they asked participants how does vision work? (using computer graphics,
verbal descriptions, verbal reports) → results: the majority favored a view of
vision that had some variant of extramission belief that was found for all ways of
testing
• Tested the effects of education intervention:
o Reading on how vision works → many people still held in extramission
beliefs
o Reading on how audition works: still extramission
o No reading (control group): still extramission
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Interactionism: the mind and brain are separate entities that interact and influence each other: epiphenomenalism: mental events are caused by physical events, parallelism: the mind & brain are two aspects of the same reality. This class: sensations & perceptions, physiology of visual perception, how information travels from the eyes to the brain, perception with and without awareness, conscious and unconscious processes, visual illusions, visual perception is constructive and relies on assumptions. Stimulus energy: light, sound, smell > sensory receptor: eyes, ears, nose > neural impulses > brain: visual, auditory, olfactory areas neural impulses into something meaningful. Perception follows when brain translates: synaesthesia: stimulation of one sense simultaneously produces another sensation in a different modality ie: grapheme-color synesthesia (seeing certain numbers/ letters as certain colors) Sound - color synesthesia when listening to a sound/ song this produces colors genetic reasons or neural: synesthesia is due to the cross wiring.
