Cognitive
Psychology
Methods and Research in
Cognitive Science
Lesson I: Introduction
module 03
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 1
What are the methods in cognition?
Introspection and armchair theorizing
– Even though widely used 100 years ago, it is not
highly regarded in modern cognitive science
– Might lead to interesting hypotheses …
– Philosophical analyses of core questions / problems
can be very helpful to clarify positions or focus
research questions
Empirical methods
– Experimental studies
– Correlational studies
– These are often combined with simulations /
mathematical models
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 2
Experimental study
Logic behind an experiment
– The experimenter controls and manipulates one
aspect of the situation (independent variable)
• E.g., retention interval in a memory task
– Everything else stays the same between conditions
– As part of the experiment, one or more behaviors
(dependent variables) are measured
• E.g., reaction time, error rates, associations
Inferring causal relationships
– Because the independent variable was manipulated
by the experimenter, changes in the dependent
variable are likely caused by the independent var.
Univers ity o f Idaho
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Introd uct ion.03. 3
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Cognitive
Psychology
Experimental study: Ebbinghaus
Role of retention interval on memory performance
– Ebbinghaus studied lists of nonsense syllables
– Dependent variable:
The main performance measure was the number of
repetitions until he could recite a list without error
– Independent variable:
Duration between first learning a list and then
relearning it (memory retention interval)
Results
– The number of repetitions for relearning increases
with increasing retention interval
Interpretation
– Information is lost according to a negatively
accelerated exponential function
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 4
Correlational study
Basic idea of a correlational study
– Two or more variables are measured
• E.g., memory span, reaction time, verbal ability, IQ
– The variables are then correlated
• Usually reported in terms of a correlation coefficient r
or as a frequency distribution and corresponding χ 2
Differences to experiment
– No control and manipulation of the relevant variables
– Problem: Other factors may influence the correlation
between the variables (third variable problem)
– Therefore less ability to infer causal relations
between variables
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 5
Correlational study:
Phonological loop and verbal ability
Language development and working memory
– Baddeley’s model of working memory assumes that
language acquisition depends on the so called
phonological loop substructure
– Phonological loop capacity can be measured by the
ability to repeat back nonsense pseudowords
Correlating pseudoword repetition and language
development in children
– In a twin study, researchers found a high correlation
between the measured capacity of the phonological
loop in children with their vocabulary development
– In addition, pseudoword repetition showed high
heritability and predicted specific language
impairments
Univers ity o f Idaho
© S teffen Werne r - 2004
Introd uct ion.03. 6
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Cognitive
Psychology
A neuropsychological experiment
Functional mapping of face processing
– Where does the brain process facial features?
Is there a special brain area devoted to this
particular visual stimulus?
Correlating visual stimulation and brain activity
– A healthy participant agrees to lie in a large Magnetic
Resonance Imaging device (MRI; large magnet)
– The person looks at a screen that presents pictures
of faces and other visual scenes in random order
– The experimenter compares the recorded brain
activity between conditions
– A small area in the right temporal lobe (face fusiform
area) shows elevated activity for faces
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 7
A neuropsychological correlational study
What causes Alzheimer’s?
– Researchers are trying desperately to find the cause
of Alzheimer’s disease
– Alzheimer’s is accompanied by severe memory loss
and problems in many cognitive tasks, like speaking,
thinking, writing, etc.
What are the causes … ?
– Post-mortem analyses and MRIs consistently show
atrophy in brains of Alzheimer patients (correlation)
– Researchers are looking for other clues that correlate
with the onset of Alzheimer’s (e.g., level of certain
peptides, different types of diets, genetic markers,
environmental causes, etc.)
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 8
A neuropsychological case study: H.M.
Different faces of memory: anterograde amnesia
– A researcher is presented with a patient (known as H.M.),
who suffers from severe anterograde amnesia since
undergoing brain surgery in 1957
– The patient can remember events leading up to the
surgery (e.g., Kennedy was president), but cannot
remember anything that happened thereafter
Does anterograde amnesia affect all new memories
– In a laboratory, the H.M. is asked to learn a simple
problem solving task (the tower of Hanoi problem)
– He is tested on this problem over and over
– Even though he cannot remember ever working on this
problem, his performance improves over time
– This shows that there are different memory systems in
H.M., some of which are less affected by amnesia
Univers ity o f Idaho
© S teffen Werne r - 2004
Introd uct ion.03. 9
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Cognitive
Psychology
Cognitive psychology: Methods
Theory is important in empirical research
Experimental research / laboratory
– Best approach to test causal relations between
independent and dependent variables
– High level of control
Psychobiological research
Self-reports, ratings, diaries
Case studies
Naturalistic observation
Computer simulations and modeling
Univers ity o f Idaho
Cognitive
Psychology
© S teffen Werne r - 2004
Introd uct ion.03. 1 0
Measures relevant to cognitive psychology
Examples of behavioral measures
– Reaction times
– Error rates
– Thinking aloud protocols
– Eye movements
– Motor movements and locomotion
Examples of classical physiological measures
– Galvanic skin response (GSR)
– Blood pressure, heart rate
Examples of neuropsychological imaging
– EEG, fMRI, PET (see module 1.05)
Univers ity o f Idaho
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Introd uct ion.03. 1 1
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