Week 3 - CH 3 (3.1–3.7)
3.1 - Cognitive Psychology and Behavioural Methods
Cognitive psychology -> study of mental activity as an information-processing problem.
- Cognitive psychologists seek to identify the internal processing—the acquisition, storage,
and use of information—that underlies observable behavior.
- A basic assumption of cognitive psychology = we do not directly perceive and act in the
world. Rather, our perceptions, thoughts, and actions depend on internal
transformations or computations of information obtained by our sense organs
- we input information into the brain, something secret happens to it, and out comes our
behavior. Cognitive psychologists are detectives trying to figure out what those secrets
are.
- two key concepts underlie the cognitive approach:
- 1. Information processing depends on mental representations.
- 2. These mental representations undergo internal transformations.
Mental representations
- E.g. picture a ball -> do u think of an image, a linguistic description, or a mathematical
formula?
- Each instance is an alternative form of representing the “circular” or “spherical”
concept and depends on our visual system, our auditory system, our ability to
comprehend the spatial arrangement of a curved drawing, our ability to
comprehend language, or our ability to comprehend geometric and algebraic
relations.
- Context helps dictate which representational format is most useful. For example,
if we want to show that the ball rolls down a hill, a pictorial representation is
likely to be much more useful than an algebraic formula.
- A letter-matching task, (Michael Posner (1986) @ University of Oregon), provides a
powerful demonstration that, even with simple stimuli, the mind derives multiple
representations.
- In each trial, the participant sees two letters presented simultaneously -> task is
to evaluate whether both letters are vowels, both are consonants, or one is a
vowel and other a consonant. One button if the letters are from the same category
and another button if they are from different categories.
- One version of this experiment includes five conditions:
- physical-identity condition, the two letters are the same.
- phonetic-identity condition, the two letters have the same identity, but
one letter is a capital and the other is lowercase.
- TWO same-category conditions, in which the two letters fall into the same
category: In one, both letters are vowels; in the other, both letters are
consonants.
, - different-category condition, the two letters are from different categories
and can be either of the same type size or of different sizes.
- Participants respond fastest to the physical-identity condition, next fastest to the
phonetic-identity condition, and slowest to the same-category condition,
especially when the two letters are both consonants,, therefore we infer that
physical representations are activated first, phonetic representations next, and
category representations last.
- Independent variable (x-axis) = the manipulated variable; in above example, the
relationship between the two letters is the independent variable, defining the conditions
of the experiment (identical, same letter, both vowels, etc.).
- Dependent variable (y-axis) = the event you are evaluating; in above example, the
response time of the participant.
Internal Transformations
- Our mental representations undergo internal transformations -> consider how sensory
signals connect with stored information in memory.
- Taking action = translating perceptual representations into action representations in
order to achieve a goal.
- E.g. seeing garlic bread on table (sensation) -> perceptual representation (“that is
a garlic bread”) -> processing it, enabling on deciding on a course of action ->
taking action (going to the garlic bread and eating it).
- BUT, memory can sometimes alter our perceptions [e.g. seeing a dog -> you
either like it (because you had a cute dog when you were little) or you don’t like it
(a dog has bit you in the past) ]
Characterizing Transformational Operations
- Memory retrieval tasks draw on a number of cognitive capabilities.
- Sternberg’s task: comparing sensory information with representations that are active in
memory.
- In each trial, the participant sees a set of letters to memorize. This memory set
consists of one, two, or four letters. Then they see a single letter and must decide
whether this letter was part of the memorized set. They press a ‘yes’ or a ‘no’
button to indicate if the target was part of the memory set.
- Sternberg postulated that, to respond on this task, the participant must engage in
four primary mental operations:
- 1. Encoding: The participant must identify the visible target.
- 2. Comparing: The participant must compare the mental representation
of the target with the representations of the items in memory.
- 3. Deciding: The participant must decide whether the target matches one
of the memorized items.
- 4. Responding: The participant must respond appropriately for the
decision made in Step 3.
- Sternberg realized that the reaction time data could distinguish between these
two alternatives:
3.1 - Cognitive Psychology and Behavioural Methods
Cognitive psychology -> study of mental activity as an information-processing problem.
- Cognitive psychologists seek to identify the internal processing—the acquisition, storage,
and use of information—that underlies observable behavior.
- A basic assumption of cognitive psychology = we do not directly perceive and act in the
world. Rather, our perceptions, thoughts, and actions depend on internal
transformations or computations of information obtained by our sense organs
- we input information into the brain, something secret happens to it, and out comes our
behavior. Cognitive psychologists are detectives trying to figure out what those secrets
are.
- two key concepts underlie the cognitive approach:
- 1. Information processing depends on mental representations.
- 2. These mental representations undergo internal transformations.
Mental representations
- E.g. picture a ball -> do u think of an image, a linguistic description, or a mathematical
formula?
- Each instance is an alternative form of representing the “circular” or “spherical”
concept and depends on our visual system, our auditory system, our ability to
comprehend the spatial arrangement of a curved drawing, our ability to
comprehend language, or our ability to comprehend geometric and algebraic
relations.
- Context helps dictate which representational format is most useful. For example,
if we want to show that the ball rolls down a hill, a pictorial representation is
likely to be much more useful than an algebraic formula.
- A letter-matching task, (Michael Posner (1986) @ University of Oregon), provides a
powerful demonstration that, even with simple stimuli, the mind derives multiple
representations.
- In each trial, the participant sees two letters presented simultaneously -> task is
to evaluate whether both letters are vowels, both are consonants, or one is a
vowel and other a consonant. One button if the letters are from the same category
and another button if they are from different categories.
- One version of this experiment includes five conditions:
- physical-identity condition, the two letters are the same.
- phonetic-identity condition, the two letters have the same identity, but
one letter is a capital and the other is lowercase.
- TWO same-category conditions, in which the two letters fall into the same
category: In one, both letters are vowels; in the other, both letters are
consonants.
, - different-category condition, the two letters are from different categories
and can be either of the same type size or of different sizes.
- Participants respond fastest to the physical-identity condition, next fastest to the
phonetic-identity condition, and slowest to the same-category condition,
especially when the two letters are both consonants,, therefore we infer that
physical representations are activated first, phonetic representations next, and
category representations last.
- Independent variable (x-axis) = the manipulated variable; in above example, the
relationship between the two letters is the independent variable, defining the conditions
of the experiment (identical, same letter, both vowels, etc.).
- Dependent variable (y-axis) = the event you are evaluating; in above example, the
response time of the participant.
Internal Transformations
- Our mental representations undergo internal transformations -> consider how sensory
signals connect with stored information in memory.
- Taking action = translating perceptual representations into action representations in
order to achieve a goal.
- E.g. seeing garlic bread on table (sensation) -> perceptual representation (“that is
a garlic bread”) -> processing it, enabling on deciding on a course of action ->
taking action (going to the garlic bread and eating it).
- BUT, memory can sometimes alter our perceptions [e.g. seeing a dog -> you
either like it (because you had a cute dog when you were little) or you don’t like it
(a dog has bit you in the past) ]
Characterizing Transformational Operations
- Memory retrieval tasks draw on a number of cognitive capabilities.
- Sternberg’s task: comparing sensory information with representations that are active in
memory.
- In each trial, the participant sees a set of letters to memorize. This memory set
consists of one, two, or four letters. Then they see a single letter and must decide
whether this letter was part of the memorized set. They press a ‘yes’ or a ‘no’
button to indicate if the target was part of the memory set.
- Sternberg postulated that, to respond on this task, the participant must engage in
four primary mental operations:
- 1. Encoding: The participant must identify the visible target.
- 2. Comparing: The participant must compare the mental representation
of the target with the representations of the items in memory.
- 3. Deciding: The participant must decide whether the target matches one
of the memorized items.
- 4. Responding: The participant must respond appropriately for the
decision made in Step 3.
- Sternberg realized that the reaction time data could distinguish between these
two alternatives:
