Unformatted text preview: on time task there is increased RT
with the increase number of choices. Number of SR alternatives
In choice RT, increased time with increased
number of choices represents increased processing
of information at the responseselection stage.
The relationship
is curvilinear, and
is explained by
work of Hick
(1952) and
Hyman (1953)..
Hick s Law you can pick reaction time based on this formula. Hick s Law
Choice RT is linearly related to the log of the
number of stimulus options:
Choice RT = k log2 (N+1) (Y)
4
8
16 log2 (Y)
2
3
4 (2 x 2)
(2 x 2 x 2)
(2 x 2 x 2 x 2) ﬁtts laww only works with the case of reaching. this is a littl emore general than
that bu it still is a law because it just describesknow this shit for the test and yo
should be able to calculatet his on the tets bring your claculators. N = number of SR alternatives
k is a constant (usually simple RT) who invented information theoryshannon!!!!!! Hick s Law******
In information theory, log2 represents a binary
unit, or bit of information. A bit is a yes/no (1/0)
alternative.
1 bit decision = 2 alternatives (yes/no)
2 bit decision = 4 alternatives
3 bit decision = 8 alternatives
• Increases in RT are a curvilinear function of the # of
alternatives
• Increases in RT are a linear function of the # of bits
of information
• Increases in RT are a linear function of the log of the
# of alternatives 16 Hick s Law
Consider a pitcher s options..
Action Decision Pitch? Curve Loc? or inside outside Height? L H L # bits H Fast 1 bit
2 bit inside outside
L H L 3 bit H Hick s Law
Hick s law correctly predicts RT increases with
increasing choice alternatives, and predicts
size of increase.
Two caveats to Hick s law:
1. Excess familiarit...
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 Fall '08
 marcio
 Psychology, Cognitive Science, Cognitive Psychology, Alan Turing

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