Antropomotoryka nr 55.indb - Akademia Wychowania Fizycznego w ...

Probabilistic prognosis in sport kinetics
became stable and the RT A
got shorter than RT B
. At
this moment the experimenter started to show only
B-stimulus. Surprisingly enough, at first the RT B
got
longer and only later the shortening of it was observed.
This result also confirms the hypothesis that the RT depends
on probabilistic prognosis and not on stimulus
frequency (Fig. 1).
Experiment 3. The aim of this experiment was determination
of probabilistic prognosis in situation where
the frequencies are not associated with probabilities. To
the examinee there were shown series consisting of four
light stimuli: A, B, C and D. Each series consisted of all
four stimuli in random sequence. Accordingly, the overall
frequency of each of them was the same. The fragment
of such a sequence is shown in Table. 1. However, the
probability of the first stimulus in series was equal to
0.25, of the second – to 0.33, of the third – to 0.50 and
of the fourth – to 1.00. In this experiment it was shown
that the RT 1
equals to 460 ms, RT 2
– to 424 ms, RT 3
– to
351 ms and RT 4
– to 207 ms, no matter what stimulus (A,
B, C or D) it was (Fig. 2). So, this experiment has shown
that also in such a situation the main factor is not a type
of stimulus, but the probabilistic prognosis.
P B = 1.0
P A = 0.9
Reaction time [ms]
500
400
300
200
P B = 0.1
P A = 0.9
100
P B = 0.1
T 1 T 2
Figure 1. The influence of probability of occurrence of a given signal over the value of reaction time to this signal (experiment 2)
Reaction time [ms]
500
400
300
200
460
424
351
207
360 - 365
100
T I
T II
T III
T IV
T A T B T C T D
Figure 2. Reaction times to given signals grouped into Markov sequences consisting of four signals each (experiment 3)
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