Cog Ch2 - The Neural Basis for
For Exam 1 Chapter 2: 25-30; 33-36;
-cognitive psychologists rely on multiple findings: response times, error rates, and questionnaire responses.
-No one source of data more important than others; all contribute to fabric of evidence that allows us to test our
-reliance on many pieces of evidence and diverse pieces of evidence, important aspect of research on cognition;
-crucial for the "inference to best explanation" that is at the methodological core of our field.
-One form of evidence, need s its own presentation:
-evidence concerning brain functioning that makes cognition possible.
-begin w/ ex involving some bizarre symptoms that can result from brain damage;
-use ex to illustrate what we can learn about the mind by studying brain, and learn about the brain
by studying the mind.
-Ex will, highlight fact: each part of the brain has its own specialized function,
- Behaviors, thoughts, and feelings almost invariably depend on coordinated action of many regions.
-to consider some basic brain anatomy, and examine some of metostudy functioning of brain's
-will inspect the tissue altosee, understand, visual world that surrounds us.
Capgras Syndrome: An Initial Example
-human brain extraordinarily complex organ which the functioning of the whole dependent on many interconnected
-damage virtually anywhere produce specific-and sometimes highly disruptive- symptoms.
-symptoms often tragic for afflicted persons and families, but can be source of insight into how brain functions.
-Consider disordCapgras syndrome
-disorder rare on its own, but seems to be one of accompaniments to Alzheimer's syndrome,
-sometimes observed among the elderly
-disorder can result from various injuries to brain
-Someone w/ Capgras syndrome fully able to recognize people in their world- husband/wife , parents, friends-but
-utterly convinced these people not who they appear to be.
- the afflicted person insists the real individual , has been kidnapped (or worse).
-person now on scene, isn't the genuine article; instead, must be a well-trained, well-disguised
-Imagine living with this disorder.
-turn to someone you know extremely well- say, "You look x, sound like x, and act like x, But I can tell that
you're not x. WHO ARE YOU?"
-Often a person w/ Capgras insists slight differences btwn impostor and person theyve replaced-
-subtle changes in personality or tiny changes in appearance.
-no one else detects these (nonexistent) differences, compounding bewilderment experienced by Capgras
sufferer. -feelings spiral upward, w/ patient developing paranoid suspicions about why a loved one has been replaced and
no one seems to acknowledge replacement.
-extreme cases Capgras sufferer may be led to desperate steps, in some instances murdering supposed impostor
in an attempt to end the charade and relocate "genuine" character.
-one case, Capgras patient convinced his father had been replaced by robot , decapitated him in order
to look for batteries and microfilm in his head
-What is going on here?
- answer, according to some lies in fact = facial recognition involves two separate systems in brain
-one leads to cognitive appraisal ("I know what my father looks like, and I can perceive that you
closely resemble him")
-other to more global, somewhat emotional appraisal ("You look familiar to me, also trigger warm
response in me").
-concordance of two appraisals leads to the certainty of recognition ("You
obviously are my father").
-Capgras syndrome, the latter (emotional) processing disrupted, leading to intellectual
identification w/o familiarity response
-"You resemble my father but trigger no sense of familiarity, so you must be
The Neural Basis for Capgras Syndrome
- crucial step examining hypothesis about Capgras syndrome = examine brains of people w/ disorder.
-examination is made possible by neuroimaging techniques,
-allow researchers to take high-quality, three-dimensional "pictures" of living brains, w/o disturbing
the brains' owners.
-what do techniques tell us about Capgras syndrome
-One form comes from PET scans
- tell great deal about the structure of brain-incld abnormalities in brain tissue
-PET scans suggest link between Capgras syndrome and abnormalities in several brain areas
-One site of damage = temporal lobe, particularly on right side of the head.
-damage probably disrupts circuits involving amygdala, which -seems to serve as "emotional
evaluator;' helping organism detect stimuli associated w/ threat or danger.
- amygdala important for detecting positive stimuli- indicators of safety or available rewards.
- Seems likely amygdala, "evaluator;' essential for making judgment of "you look familiar to me and
trigger a warm emotional feeling" -one half of our two-systems hypothesis.
-Patients w/ Capgras syndrome also have brain abnormalities in frontal lobe, specifically in the right prefrontal cortex.
What is area's normal function:'
- turn to fMRI, allows us to track moment-by-moment activity levels in different sites in a living brain.
-allows answers to such questions as: When a person is reading, which regions are particularly active
or same for listening to music .
-can draw conclusions about brain areas function is.
-important hint about Capgras syndrome from fMRI scans of patients suffering from schizophrenia
-reveals diminished activity in patients' frontal lobes whenever experiencing hallucinations.
- plausible interpretation = diminished activity reflects decreased ability to distinguish internal
events (thoughts ) from external ones (voices), or distinguish imagined events from real ones.
-How is this relevant ?
- damage to frontal lobe, Capgras patients may be less able to keep track of what is real and what is not, what is
plausible and what is not.
-result = weird beliefs can emerge unchecked, including delusions
What Do We Learn From Capgras Syndrome?
-several lines of evidence supportaccount of Capgras syndrome
-Some evidence comes from psychology laboratory onfirms suggestion recognition ordinarily has two
separate parts: one on factual knowledge, one "emotional" tied to warm sense of familiarity
-additionally , mentioned some of neuroscience evidence
-(1) where damage is located in Capgras patients,
-(2) likely functions of brain sites when they're not damaged. -evidence fits well w/ hypothesis:
- damage to amygdala likely tobe reason Capgras patients experience no sense of familiarity when look
at faces they know quite well.
- damage to prefrontal cortex, helps understand why Capgras patients, when experience lack of
familiarity, offer crazy hypotheses about their skewed perception.
-understanding of Capgras syndrome depends on combination of evidence drawn from cognitive psychology and
-use both perspectives to test (and, confirm) hypothesis offered.
-just as perspectives can illuminate Capgras syndrome, both can be illuminated by syndrome
-can use Capgras syndrome to illuminate broader issues about nature of brain and mind.
-Ex- Capgras syndrome suggests amygdala plays a crucial role supporting feeling of familiarity.
-Other evidence suggests amygdala plays central part helping people remember emotional events
of their lives
-other evidence indicates : amygdala plays a role in decision-making esp decisions that rest on emotional
evaluations of one's options.
- tell us a lot about various functions that make cognition possible and our theorizing needs to include
broadly useful "emotional evaluator;' involved in many cognitive processes.
-Capgras syndrome tells emotional evaluator works in fashion separate from our evaluation of factual
-providing way to think about occasions which someone's evaluation of facts points toward
one conclusion, while emotional evaluation points toward different conclusion.
-great value as we seek to understand processes that support ordinary remembering
or decision making.
-Cases like Capgras syndrome just as valuable helping understand how brain functions in normal people- when all neural
-ex considers what syndrome teaches about how parts of brain work together for simplest achievement.
-ex order to recognize your father, one part needs to store factual memory of your fathers appearance
-Another part responsible for analyzing visual input received when looking at a face.
- Another area: job of comparing now-analyzed input to factual information provided from memory,