Method:%20Reaction%20Time%20(RT)

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Method Reaction Time (RT)

• Example
• Simple detection (, ruler, glasses)
• Liberal vs. conservative response criterion
• (speed/accuracy trade-off)
• Secondary task
• Additive method (e.g., visual degradation)

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Subtractive Method

• Task 1 simple detection task
• press key when light blue appears on the screen
• Task 2 discrimination task
• Respond to the blue light but not to the yellow
  light
• The two tasks have
• Same stimulus (blue light)
• Same response (key press)
• Only one thing different (?) discrimination vs.
  detection
• RT discrimination - RT detection the mental
  operation of having to discriminate two stimuli

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Subtractive Method

• Very simple and powerful method
• Developed by Donders in the 1800s
• Used even today (e.g., fMRI studies)
• But it has its problems
• What constitute the elemental mental operation
• It is not very flexible

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Additive Factors Method

• Developed by Sternberg (1969)
• Example memory task (as already described)
• Numbers were displayed 3 9 5 4
• Delay
• A probe 4 yes
• Number of items in each trial vary from 1 to 6
  items

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3 7 9 2
6
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9
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Another trial
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5 1
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1
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Plot - RT relative to number of items in the
list - plot separately yes and no trials
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Stages Encode target Search in WM Select
response Start response INPUT
OUTPUT Factors target visibility number of items
target probability ease of response
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Additive factors

• Assumes serial processing of stages
• Often this is not the case
• E.g., addition
• RT to decide 4 3 12 no
• RT to decide 4 3 11 no
• Because addition and multiplication are run in
  parallel
• But, does this mean a single system?

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On Method Dual task

• Tasks that tap onto the same system interfere
  with each other
• Having your room-mate talk to you when you are
  trying to remember a phone number (phonological
  code)
• No interference independent systems

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One STM .. Or many?
. . .
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Short-Term Memory for Visual and Verbal
Materials One or two stores? Approach 1 Store
maximum capacity of one type -- then see if
person can remember any of the other type.
Example

3 9 8 2 1 7 4
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4 9 3 2 6 8 7
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?
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One more time...
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7 4 1 2 3 9 8
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?
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How did you do??
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Usual Finding ZERO interference between
verbal and visual STM loads
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- different memory systems are involved in the
short term retention of objects and verbal
stimuli - This result is difficult to interpret
without reference to mental representations. -
Thus, we infer the existence multiple memory
buffers, (a type of mental representations)
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Question for thought

• If your data shows interference, can you still
  rescue the idea of independence between visual
  and verbal short-term memory?
• hint itemize step-by-step what you did, making
  sure to not skip any steps (think of it as a
  writing computer code for a a machine to compute
  the task, do not make any pragmatic assumptions
  of knowledge).

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Mental Representations 3 Levels of Analysis
(1) Computational What is the problem to be
solved? (i.e. input/output mapping of the mental
process) (2) Algorithmic How is this
calculation carried out? (3) Implementational
What is the hardware that makes these
calculations possible?
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Question for debate

• Does neuroscience (level 3) help for
  understanding psychology (i.e., how mental
  processes are carried out in level 2)?
• Yes
• Reductionism eliminativism
• cognitive neuroscience,
• No
• functionalism, Marr (think birds and planes)
• dualism

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Cognitive Psychology The study of the
structures, and processes of the mind and brain
that take in, transform, and use information.
But what do we mean by information?
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Types of Information (Mental Representations)
Sensory information - Images on our sensory
organs, coming from light of a particular
frequency that stimulates the rods and cones in
our retinas
Conscious Perception that are stored in and
manipulated by our minds (e.g., of color, sound,
etc.)
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Other types of mental representation (memories)
Procedural knowledge (knowing how) e.g. how to
throw a frisbee, swing a golf club, drive a
carIn other words, skill knowledge, or
knowledge that doesnt refer to the state of
things in the world.
Declarative knowledge (knowing that)
(1) Semantic knowledge (referred to as generic
knowledge in your textbook) refers to facts about
the world. E.g. what color is the sky?, what is
7x9?, who is the quarterback for the Ducks?
(2) Episodic knowledge knowledge about the
world that is specific to a particular time and
place. E.g. Whats the last song you heard on
the radio? What time did you wake up this
morning? Where were you last New Years Eve?
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Cognitive Psychology The study of the
structures, and processes of the mind and brain
that take in, transform, and use information.
But what do we mean by processes?