Mental chronometry - uni-muenchen.de · 2018. 11. 6. · C1 C2 + P1 P2 C1 C2 P1 P2. 20 Zhuanghua...
Transcript of Mental chronometry - uni-muenchen.de · 2018. 11. 6. · C1 C2 + P1 P2 C1 C2 P1 P2. 20 Zhuanghua...
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Mental chronometry
Zhuanghua Shi (Strongway)
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2https://www.youtube.com/watch?v=fwb4aNkcofI
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Airport Check
Zhuanghua Shi, LMU, Munich3
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Bistable image
Mamassian & Goutcher, 2005, JOV5
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Naming the color of the following words
RedGreenColorGSN
YellowBlue
GreenZhuanghua Shi, LMU, Munich6
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Mental processes and Reaction time◻ Mental processes requires some time◻ Speed of process correlates with cognitive and
motoric functions◻ We can infer inner mental processes and
mechanisms by investigating response times (RT)
Mental Chronometry
Mental processes
Stimuli Responses
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Mental Chronometry
Mental chronometry is the use of response time to infer mental processes. The way for this is the manipulation of the tasks and/or of variables determining the behavior of participants in the tasks.
Mental chronometry is one of the core paradigms of experimental and cognitive psychology.
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Mental processes and Reaction time
■ It is generally assumed that mental processes is constructed with multiple modules.
■ By observing different reaction times under different conditions, processing time could be observed.
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Perception Cognition Motor response
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Mental processes and reaction time■ Assumptions and paradigm
◻ the temporal sequencing of information processing in the human brain.
◻ Manipulation of the tasks/stimuli → observe the time course of mental operation
Task 1: simple detection
Task 2: discrimination task
Detection
Detection Discrimination
Response
Response
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Main goals
■ To determine components and structure of mental processes (i.e., cognitive modules)
◻ Number of subcomponents◻ Processing time◻ Serial, parallel or cascade
Reaction time
RESPONSE
Reaction time
RESPONSESTIMULUS
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History
■ 1822 Francis Galton◻ People who reacted faster are more
intelligent than others
■ 1850 Hermann von Helmholtz◻ Simple reaction time◻ Neural transmission time ~ 30 m /s
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History■ 1868 Franciscus Donders: Subtraction method
◻ Duration of subcomponent can be measured by subtracting two tasks which only differ that component
■ 1885 J. Merkel discovered the response time is longer when a stimulus belongs to a larger set of stimuli
■ 1951 Hick further developed Hick’s law
■ 1964 E. Roth demonstrated correlation between IQ and RT
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History■ 1969 Robert Sternberg devised a
memory-scanning task, and developed the additive factor method for dividing RTs in successive stages
■ 1979 ~ Modern methods◻ Cascade model◻ Diffusion model
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Donders’ subtraction method
■ Donders (1868)The idea occurred to me to interpose into the process of the physiological time some new components of mental action. If I investigated how much this would lengthen the physiological time, this would, I judged, reveal the time required for the interposed term. (Donders, 1969, p418)
◻Assumption of ‘pure insertion’: ■ Task A has all the stages of
Task B lacks an extra process, then■ Extra process can be measured by:
RTA-RTB
RTA
RTB
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An example
■ Comparison of different tasks◻ Simple Detection◻ Choice Reaction◻ Go/No-Go
SD
SD
SD
MR
MR
MR
DIS
DIS
RS
• SD: Stimulus detection; • DIS: stimulus discrimination• RS: response selection; • MR: motor response
RT(A)
RT(B)
RT(C)
Response selection = RT(B) – RT(C)
Stimulus discrimination = RT(B) – RT(C)
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Example: letter matching (Posner)
■ Several tasks associated with recognition of a pair of letters◻ Physical match task
■ e.g. AA →same, AK→different◻ Name match task
■ e.g. Aa → Same, Ak → different◻ Rule match task (vowel/Consonant)
■ e.g. AE → same, AB → different■ Using the subtraction method the cognitive processes
associated with each of these tasks can be approximate determined.
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Posner’s letter matching studies
■ Name match: 64 ms (623 -549 ms)■ Rule match: 178 ms (801 - 623 ms)
Physical match
Name match
Rule match
AA, ee
Aa, Ee
AE, CD
549 ms
623 ms
801 ms
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Problems with the method of subtraction
■ Any potential problems?■ Transitivity problem
■ Do individually isolated durations sum up to the duration of the conditions in which they all take place?
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C1 C2 P1 P2+
C1 C2 P1 P2
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Problems with the method of subtraction
■ Pure insertion ◻ Assumption: Insertion/removal of processing stages
does not influence other processing stages (i.e. they are independent)
◻ Sub-modules should be independent and serial
■ Külpe (1893) – criticism: ◻ insertion of a new process → changes of the whole
task
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Sternberg’s additive-factor method
■ If two factors affect two different stages, then their effects on the overall RTs shouldbe additive ones.
F G H
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Sternberg’s additive-factor method
■ If one modulates F, changing its latency from RTa1 to RTa2 and one modulates G, changing its latency from RTb1 to RTb2, then the two changes can be described by:
■ Applying both manipulations:
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Sternberg’s additive-factor method
■ When two factors show an interaction effect on the RT, two factors affect at least one common processing stage F G H
H1 H2
RT G1G2
H1 H2
G1G2
H1 H2
G1G2
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Example: Sternberg Memory Scanning
■ Memory scanning: to identify if a probe item is in a memory list or not (Sternberg, 1969)
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Example: Sternberg task
■ Stimulus quality ■ set size
◻ are two additive factors
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What if we observe no interactions?
■ Manipulations affect independent processes■ or the statistics is under power?
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Example: AFM in cognitive neuroscience
■ Dehaene (1996) ◻ The organization of brain activations in number
comparison: Event-related potentials and the additive-factors method. J Cogn Neurocsci 1: 47–68.
◻ investigated a simple task of number comparison: A number is present on the monitor and subject has to compare if the number is above or below five.
◻ Factors ■ Input: Arabic digits / spell numbers (4 / four)■ Comparison: Near 5/ far from 5■ Response: dominant / non-dominant hand
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Cont.
■ Four stages processes
◻ According to AFM, a variable that affects overall reaction time by varying the time to complete one stage will be additive with the effects of factors that affect other stages.
comparisonencoding Response selection Checking error
Arabic digits/ Spelled numbers Close/Far
Non-dominant /Dominant hand
Error/Correct trials
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An example of AFM
Close/far Non-dominant/Dominant hand
Arabic / spelled numbers
EEG and fMRI studies showed these four factorsprocessed in different regions
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Does AFM make sense?
■ Partially■ No problem with ‘pure insertion’
◻ Manipulation of the duration of a processing stages
■ Comparison between one and the same type of tasks◻ Criticism of Külpe does not hold
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Problems with AFM
■ Basic assumptions◻ Factors can affect certain processing stages, while leave
other stages unaffected◻ Stages should not temporally overlap◻ Discrete serial assumption
■ Problems with the reversed inference◻ Additive effects of two factors does not necessarily mean
that two independent stages■ Independence is sufficient, but not necessary, to lead
additive effect■ If p then q → if q then p?
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Cascaded processes model■ McClelland (1979)
◻ A series of processes cascading activation from an input level to an output level. Thus it allows a given processing level to start transmitting output (activation) before it has finished processing.
time
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How is response time determined in cascade model?■ Accumulation of response unit activates in time■ All processing stages influence this activation
more or less simultaneously
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time
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Accumulation model and diffusion model
■ Accumulation models◻ Decision information accumulates over time◻ When the accumulated information reach a boundary
(e.g. threshold), a response is made.
(Smith, Ratcliff, 2004)
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Accumulation model and diffusion model
■ Those models are inspired by neural activations
(Smith, Ratcliff, 2004)
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Stochastic accumulation models
■ General concepts◻ Sensory evidence of a stimulus accumulates over time◻ Multiple competed information accrue in parallel◻ A decision is made according accumulated evidence
■ Simple response: signal detection■ Choice responses: choice among several possible outcomes
■ Models usually concern three major aspects:◻ How is decision information being accumulated?◻ When to stop?◻ What is the basis for making a decision?
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Diffusion model
■ Diffusion model is a continuous version of accumulator model.◻ Simple Response
Model for simple and Go/NoGo RT. The time-dependent information function u(t) is perturbed by white noise W(t) and accumulated. A response is emitted when the accumulated decision stage activation X(t) exceeds a criterion.
(smith, 2000)
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Diffusion model
◻ Two-choice Response
Smith, 2000
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Beyond reaction time: Speed accuracy trade-off (SAT)■ RTs typically co-vary with error rates■ Speed-accuracy trade-off function
◻ Fixed accuracy, measuring RTs (fair comparison across conditions)
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Next week
■ Hands-on RT analyses◻ Import RT data from a behavioral study◻ Summarize RT data◻ Visualize results
■ Requirement◻ Please make sure your R and Rstudio work◻ tidyverse package is installed
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