Lecture 4b, Information Processing II (continued) Flashcards
Cost-Benefit Analysis
no anticipation: go through all three stages of information processing (the stimulus would be the trajectory of the ball)
correct anticipation: response selection has already been done by correct anticipation (so the stimulus could be something like a back swing for example)
RT BENEFIT
incorrect anticipation: with incorrect anticipation you will have to reprogram and go through all the stages causing a reaction time cost
RT COST
What can be anticipated?
event/spatial anticipation
- predicting the spatial location of a stimulus
- most related to (bypassing of) response selection
◦ e.g. anticipation location of
forehand return (can
respond very quickly and
possibly even have a
reaction of 0)
temporal anticipation
- predicting the arrival/timing of a stimulus
- related to bypassing of several processes… (2-3)
◦ e.g., anticipating the snap in
football
What happens if foreperiod is constant/predictable? (simple, choice, go/no-go RT)
what would happen to:
simple RT: may be decreased to 0 because we know a certain stimulus will appear and we know what response to select in simple RT (one stimulus, one choice)
choice RT: should remain unchanged because we still have to identify stimulus in order to respond
go/no-go RT: the answer is the same as choice RT because we have to wait for stimulus as there is uncertainty
- foreperiod is duration between warning signal and presentation of stimulus
S-R Compatibility affects response selection
the degree of “naturalness” between a stimulus and its paired response
- favourable spatial relationships (ex. simon effects)
- S-R pairings that are a result of practice, habit or experience… “if this, then that…”
S-R spatial relationships: spatially compatible pairs are responded to faster than incompatible
- RT is lower when pairings are spatially compatible
Simon Effect
- even though the spatial dimension of the stimulus is irrelevant to the task, we still see effects of spatial S-R compatibility on RT
Population Stereotypes
- other S-R mappings may not be as “natural”
◦ association of the stimulus
and response is likely
learned in population
stereotypes
◦ ex. red for stop, green for
go; clockwise for increase,
counterclockwise for
decrease - errors are made or RT increases if S-R pairing violates stereotypical relationship
Response selection and the concept of “information” as a reduction in uncertainty
- information is needed to resolve the uncertainty in response selection (i.e. among choices/alternatives).
- the single unit of information is the bit
Bit
the amount of information required to decide between two equally likely alternatives (or reduce uncertainty by half)
◦ every bit we receive reduces
the uncertainty by half
S-R alternatives affects response selection
Hick’s Law
- as the # of S-R alternatives (S-R pairs or “choices”) increases, choice RT increases
◦ as N increases, CRT
increases
recall: response selection (RS) is only involved in choice RT tasks
Hick’s Law
Using Hick’s Law we can calculate CRT if a,b & N known or calculate a & b if CRT and N known
CRT = a + b [Log2(N)]
equation of a line: y = a + bx
a = y-intercept
occurs when Log2(N) = 0
N = 2^0 = 1
y-intercept = simple RT
b = (Y2 - Y1) / (X2 - X1)
b = slope of the line
constant amount of increase in RT every time Log 2(N) increases by 1 bit
conclusion: minimise the number of options to minimise response times and errors
What factors affect response programming?
movement complexity
- # components, movement accuracy and movement duration
More time required to organize more complex movements?
YES
assume: if a set of motor commands for a movement is prepared in advance of response initiation, then movements of greater complexity should take longer to prepare
-> RT should increase as movement complexity increases
