Week 3 Flashcards
larger effect size
more correlation with variables
what approach do we take to discuss human information processing?
black box approach
black box approach to human information processing
identify stimulus/input and output and assume processing takes place in between
input - processing - output
cognitive neuroscience
a field that is concerned with processing
- processing phenomena are not directly observable
can we measure processing?
hoffmans theory of consciousness created a chronometric approach
chronometric approach
measures timing between input and output
- do not need to look into brain to see how much processing occurs (use this)
- infer the amount of processing that takes place
when do many different information processing activities take place?
during the RT period
why is it crucial to have a well designed experiment?
so you can use RT a measure of processing
what can one usually infer about RT?
infer that RT is related to the amount processing of a stimulus of task
what affects RT?
- fatigue
- substances
- sugar or caffeine
- amount of sleep
how would you classify the relationship between RT and processing?
as amount of processing increases, RT will also increase (positive correlation)
simple reaction time
a task that involves reacting to one stimulus
- gives a measure of processing time
what is simple reaction time correlated with?
age
what is simple reaction time affected by?
- fatigue
- attention
- sensory (tactile and auditory) modality of the cue
where are simple reaction time tasks used in the field?
- often must be interpreted relative to norms
- individual data is better
the stages of information processing
- stimulus identification
- response selection
- response programming (translating response into motor)
parallel processing
overlapping processes
- complete tasks at the same time
serial processing
processing in sequential steps
- one task must be completed before the next
serial vs. parallel processing with regards to human information processing
- some steps can occur in parallel under certain conditions
- some steps must occur in sequence in certain conditions
stimulus identification
- first individual must perceive the stimulus (involves stimulus detection and then identification)
- stimulus must be sensed and processed
- processed until it contacts memory - there are many variables that can affect the stimulus identification stage
sensation
involves the activation of sensory receptors
sensory receptors
have a minimum amount of stimulation required to detect a stimulus
- flicker detection
what can sensation be affected by?
attention at both the behavioural and neural level
- often don’t sense things when attention is not there
perception
involves interpreting those sensations
- moving from sensation to perception is what we do
what combination and integration does perception involve?
combination and integration of numerous sources of information to form a percept
how do we move from sensation to perception in our brains?
get a ton of sensory information
what is stimulus detection affected by?
- stimulus clarity
- stimulus intensity
- stimulus sensory modality
extracting complex features
you can use complex forms of analysis to determine/predict the outcome of an action
pattern recognition in soccer
people were better at predicting for faster velocity in side-force
what happens after the stimulus is detected?
the actor must decide what response to initiate (response selection)
response selection options
- move or not to move
- move high or low
- block or cover
Choice RT
an RT task wherein the participant is presented with more than one possible stimulus and the required response is dependent on that stimulus
hicks law
the time is takes to make a response is related to the number of stimulus response alternatives
- presented an increasing number of stimulus-response pairs and measured RT
how does choice RT increase?
increases nearly a constant amount (~150 ms) where S-R alternatives are doubled
log-linear relationship
the relationship between the choice RT and the logarithm of the number of SR alternatives should be linear
bits of information
Log2(N) = a bit of infomation
what is a bit of information?
the amount of information required to reduce uncertainty by half
- least amount of binary decisions required
bit
binary digit
how many bits with 1 choice?
0 bits
how many bits with 2 choices?
1 bit
how many bits with 4 choices?
2 bits
how many bits with 8 choices
3 bits
what is the y-intercept (a) experimentally?
0 bits of information
- simple RT
what is the slope (b) experimentally?
amount of RT added when you increase bits of information by 1
practical applications of hick’s law
reduce anticipation by increasing response alternatives (prevents anticipation)
simple RT tasks (simple definition)
reacting to 1 stimulus with the same response
go/no-go tasks
reacting to 1 stimulus, and not reacting to another
choice RT tasks (simple definition)
selecting the appropriate response for a given stimulus
which task has the fastest reaction times?
simple RT tasks
which task has the slowest reaction times?
choice RT tasks
example of simple RT
raise right-hand in response to green go signal
RT= 250 ms
example of choice RT
- raise right-hand in response to green signal
- raise left-hand in response to blue go signal
RT= 300 ms
example of a go/no-go task
raise hand in response to green go signal, stop in response to red stop signal
RT= 280 ms
what processes are in a simple RT?
response programming (RP)
what processes are in a choice RT?
- stimulus identification (SI)
- response selection (RS)
- response programming (RP)
what processes are in a go/no-go RT?
- stimulus identification (SI)
- response programming
donder’s subtractive method
subtract numbers to isolate for variable
what time would you estimate for stimulus identification?
isolate for SI
go/no-go (SI, RP) - simple RT (RP) = SI
280 - 250 = 30
SI = 30 ms
what time would you estimate for response selection?
isolate for RS
choice RT (SI, RS, RP) - go/no-go (SI, RP) = RS
330 - 280 = 50
RS = 50 ms
other factors affecting response selection
features of the S-R relationship
ex. stimulus-response compatibility
stimulus-response compatibility
the mapping of the response to the action
who performed work on S-R compatibility?
fitts and seegar, 1953
simon effect
irrelevant spatial features have effects on RTR
- participants responded to auditory cues played in either left or right ear
- had to press right key when heard work right and left key when heard the word left
what did the simon effect do?
compared responses of spatially compatible trials vs. incompatible trials
- has been replicated with numerous types of trials
joint-simon effect
when two people perform the simon task, they perform similar to when performing a two-choice task (co-represent actions)
sebanz 2003 results
- participants responded faster in compatible vs non-compatible trials in the two-choice condition
- when performing the task with another person, participants showed faster responses in compatible compared to incompatible conditions (even though they were instructed ti respond to one colour)
- in individual go/no-go task, there were no differences between compatible and incompatible stimuli
what is response selection affected by?
- number of stimulus alternatives
- stimulus-response compatibility
- actions of others
which tasks occur in parallel?
- simple RT
- go/no-go
what tasks occur in series?
choice RT
simple RT number of stimulus choices?
1
simple RT number of response choices?
1
go/no-go number of stimulus choices?
2
go/no-go number of response choices?
1
choice RT number of stimuli choices?
2
choice RT number of response choices?
2
go/no-go - simple RT = ?
stimulus identification (time taken)
choice RT - go/no-go = ?
response selection (time taken to make a response)
response programming
transformation/translation of the action concept into the muscular actions that will achieve the goal (translating brain information into actions to achieve your goal)
characteristics of response programming
- sensorimotor transformations (sensory information transformed into motor action)
- events occurring in RP could be related to memory
- involves preparation of relevant motor structures to get information from brain to muscles
what is the final set of processes that allow the individual to communicate with the environment?
response programming
henry and rogers (1960) - response programming
compared the reaction time for 3 different movements
3 movements henry and rogers (1960) compared RT between
- movement A: lift finger
- movement B: lift finger and reach to ball
- movement C: lift finger and hit ball, press a button, then reach to another ball
findings from henry and rogers (1960)
- RT increased as movement complexity increases
- took longer to complete first part of movement when movement got more complex
what did henry and rogers (1960) conclude from the experiment?
- the programming of more complex movements requires more time
- involves the planning of coordinated action required to control the limb through different tasks
what makes a movement more complex?
accuracy requirement - the size of the goal
speed-accuracy tradeoffs (Fitt’s law)
take more time to program movements that require more accuracy
movement components
- the number of parts of a movement can increase the initial programming time
- the time between components is important
time between movement components
with a long pause in between movements components RTs did not increase
movement duration
how much time from beginning to end
- might be the major variable
how can we test movement duration?
have individual perform zoom movement in 3s, then 5s, then 10s
- increase response duration
does movement complexity affect RT?
yes, but movement complexity also affects RT even before selection has been made
what happens when the choice of movement is unknown?
more complex S-R relationships take longer to program
inverse kinematics
position in space trying to reach, need to solve muscle contractions and joint movements to get to that point
what do proponents of sensory-coding theory argue?
argues that we plan a point-to-point visual trajectory based on the idea that neural activation patterns in motor areas represent spatial goals in a visual reference frame
evidence for trajectory programming
measures neural response of monkey’s reaching for different targets
- neural response was higher when reaching target points in visual field
- without being able to see arm, neural response was lower
criticisms of sensory coding and reference frames
cannot thoroughly explain rapid corrections based on information from non-visual sensory sources
- can make movements more rapidly correct when touching limb to limb
motor programs
a pre-structured set of movement commands that defines the essential details of a skilled action, with minimal (or no) involvement of sensory feedback
what do motor programs specify?
- muscles to use
- sequence of muscle activations
- force, timing and duration of muscle contractions
motor programs during response programming?
motor program to achieve the action is specified
- generalized program for a movement that is stored in memory
triphastic bursts
3 burst phases during agonist triceps and antagonist biceps
storage problem
imagine if every movement was a distinct motor program - it would require much more space to store them all
degrees of freedom problem
there are too many degrees of freedom to control (to many moving parts)
criticism of motor programs
- storage problem
- degrees of freedom problems
do we need a CNS to control movements?
yes passive dynamics mimic human gait pattern
dynamical systems theory
stereotypes similarities of movement patterns are not represented in motor programs but emerge naturally due to complex mechanics
- interactions with environment and physics of body
what does the dynamical systems theory do?
solves the DoF problem, and explains expertise and freezing the right DoF
what solves the DoF problem?
dynamical systems theory
what people like the dynamical systems theory?
biomechanics and rehabilitation people
- deals with environment and leaves out complexity of human nervous system
which type of skills do you think motor program researchers use?
discrete, finer skills, closed, very start and stop, don’t involve much environment
which type of skills do you think dynamical systems theorists use?
bigger, continuous skills
which fields so motor programming originate from?
cognitive psychology
which fields do dynamical systems originate from?
- engineering
- biomechanics
- rehabilitation
what is response programming related to?
the preparation of the motor program
can responses be prepared in advance?
yes (ANTICIPATION)
what are some ways we can reduce anticipation?
- multiple types of stimuli
- reducing stimulus clarity or intensity
- varying the time of stimuli onset
what does anticipation mean in information processing?
the removal/reduction of the response selection stage
2 different types of anticipation
- temporal anticipation (WHEN)
- spatial anticipation (WHAT and WHERE)
rosenbaum (1980)
used precuing technique to determine which information is most useful for facilitating response programming
pre-cued different combinations of variables
- arm (right or left)
- extent (far or near)
- direction (up or down)
pre-cued
narrows the choices down by 1/2
RT result of pre-cueing
pre-cuing any of the variables led to a decrease in RT
decrease in RT due to precuing
- greatest reduction in RT was found for arm (150ms)
- extent of movement led to 100 ms reduction
- direction of movement was smallest reduction in RT
how can anticipation be studied?
by examining the startle response
a startling tone
shown to trigger a prepared movement at short latency
startle and brain
startle is though to act as a subcortical trigger for prepared movements
how can we figure out what response people are preparing?
by using a startle stimulus
