Assumptions and Methods in Cognitive Neuropsychology
Caitlin Turkiewicz and Darrick Chow
What is cognitive neuropsychology
o Not concerned with treatments; can’t differentiate good treatments from bad
o About mind, but looking at the brain as a lens about understanding mind
o Cognitive psychology is about the brain
o PALPA – assesses language disorders
The case of AC
o Lesions in both hemispheres, history of cardiovascular difficulties
o Lost ability to write anything but name and address
o Could copy things, but not pictures
o Had difficulty with perceptual properties (eg: how many legs an animal had)
Semantic information is not all or none
Different parts of brain; processed differently (modular)
What are the pieces that make up ‘mind’? How do they talk to each other?
Modularity
o Fodor’s theory on modules (assumptions, not data)
Hardwired: specific and localized
Not all modules have all of the characteristics
Not assembled: not made up of smaller sub-processes (minimum size for that
particular process)
Informationally encapsulated: not penetrable from other kinds of information,
eg: representation of a word in terms of its spelling semantic knowledge
doesn’t directly affect the unit (but can indirectly affect it)
Look up what a ‘precis’ is
Assumptions of Cognitive Neuropsychology
o These assumptions are required for neuropsychologists to conduct research
Functional modularity: input modular system and central system (not
functionally modular), the modular systems are the easiest to study and thus
the ones we aught to pay attention to [what is in the mind]
Anatomical Modularity – must exist in one specific area of the brain, not
multiple area, a simplifying assumption
Uniformity of Functional Architecture Across People – like a flow chart (the
boxes of arrows of it), if not true, won’t be able to generalize across people
(note that he doesn’t assume it’s uniform across anatomical architecture)
If false – if two people have very different results, cognitive professors
would know something was amiss (eg: reading nonwords faster than
words)
Subtractivity – assume that brain damage can only subtract modules, not
introduce new ones (possible for patients to cope and use their normal
architecture abnormally, but uncommon)
o A question about Oliver Sacks will be on the quiz, google the crap out of him
o The definition of ‘harbinger’ will be on the quiz for a bonus point
o Ronald Fisher father of anova, made a major impact
Inferences from Data to Theory
o Use data to support or refute a theory
o 3 types of data abrain damaged person can provide
Associations
o Could have different modules, but both might be affected
o Associations are not as important as disassociation
Eg: impairment on one task but not another
Dissociations
o Might not be good evidence
One task might be harder for another
Implausible, so not a serious issue
Double dissociations
o The holy grail, best data you can have
o Rare to find perfect performance on one task and impairment on another
o May have double dissociations in the same patient
Misunderstanding
o Nothing wrong with post-hoc analyseses, as long as leads to something new
All science is originally post-hoc
o Cogneuropsychologists don’t think their theories are the only correct idea; welcome to
suggestions
Syndromes
o An argument by association: if I have X, then I must have U
Fine theories, but weak if someone does not have U, there goes the theory
Other Concerns with Cognitive Neuropsychology
o Need more than one patient with that pattern (over the years)
o Theories are too powerful: attempt to explain everything that is possible, however, they
are just trying to explain all observed data
Looking at groups of patients can get different results slides, prof
Gave vs. have need to know ‘have’ to know how to pronounce it