The document discusses reaction time and its measurement. Reaction time is defined as the time between a stimulus and the beginning of a response. It has two components: reaction time itself, which is from stimulus to initial movement, and motion time, which is the additional time to complete the movement. Reaction time can be measured using simple reaction time tasks, which involve responding as quickly as possible to a single predictable stimulus, or choice reaction time tasks, which require selecting between multiple possible responses. The document also describes factors that can influence reaction time such as age, fatigue, distraction, and stimulus modality (auditory vs. visual). It then presents data from a study that found reaction times increased with higher noise levels, lower light levels, and

1. REACTION TIME
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2. OVERVIEW
•Definition
•Reaction Time
•Motion Time
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3. Definition
Reaction time is a measure of how quickly an organism can respond to a
particular stimulus. Reaction time has been widely studied, as its practical
implications may be of great consequence, e.g. a slower than normal
reaction time while driving can have grave results. The model for
information flow within an organism can be represented in this way:
Stimulus
Receptor
Integrator
Effector
Response
More specifically, in vertebrates, information flow can be represented in this
way:
Stimulus
Sensory Neuron
Spinal Cord or Brain
Motor Neuron
(Kosinski, Robert J. 2005)
Response
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4. csm.jsm.edu
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5. Definition
• The time passing from the appearance of a
proximal stimulus to beginning of an effector
action is called Reaction Time
• The additional time to perform an appropriate
movement is called Motion or Movement time
Note :
REACTION TIME + MOTION TIME = RESPONS TIME
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6. Sciencebuddies.org
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7. Reaction Time
If person knows that a particular stimulus will occur, is prepared
for it, and knows how to react to it, the resulting reaction time is
called “Simple Reaction Time”.
The Scientist found about the RT calculation with the variable a
and b are empiric constants and variable N is number of
choices which means a logarithmic of alternative stimuli and
responses.
Prntsqn rumus hal 146
Ditulis 2 rumusnya
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8. Under optimal conditions, simple auditory, visual,
and tactile reaction times are about 0.2 second. If
conditions deteriorate, such as uncertainty about the
appearance of signal, reaction slows. And the graph
below shows that relation :
Grafik halaman 146
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9. Motion Time
• Motion time follows reaction time. Movements may be
simple, such as lifting a finger in response to a stimulus, or
quite complex such as swinging a tennis racket.
• Movement time also depends on the distance covered and
on the precision required.
• And the formula to get the Motion Time was called Fitts’
law which describe below :
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10. Reaction Time Calculation
The way to calculate the Reaction time is not just using the
mathematic calculation. But the scientist around the world try to
define the way to calculate the reaction time by modern and
simple ways such as software. And here are some ways to
calculate the reaction time :
Flicker
fusion
threshold
Simple
Reaction
Time Task
Reaction
Times with a
Word Cue and
Word
Association
Reaction Time
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11. Simple Reaction Time
Simple Reaction Time (SRT) is a test which measures simple
reaction time through delivery of a known stimulus to a known
location to elicit a known response. The only uncertainty is with
regard to when the stimulus will occur, by having a variable interval
between the trial response and the onset of the stimulus for the next
trial. As soon as the participant sees the square on the screen, they
must press the button on the press pad.
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12. Reaction Times with a Word Cue
• This method will once again calculate reaction time by
calculating the time it takes to catch a dropped ruler, but in
this method a final word cue is given, as well, after other
words are spoken that should be ignored.
1 and 2. Exactly the same as in Method 1.
3. Determine a particular word as a signal to catch the dropped ruler.
4. Use a variety of words before dropping the ruler; disregard ruler
catches on wrong word.
5. Record the number at the subject’s fingertips, i.e. distance the ruler
fell through the subject’s fingers,
6. Calculate reaction time in seconds as in #6 above
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13. Page 13

14. Reaction Time with Word Association
1 and 2: Exactly the same as in Method 1 and 2.
3. Say a stimulus word as a signal to catch the dropped ruler. Do
not predetermine the stimulus word. The subject will catch the
ruler with any word as a cue. This time, however, the subject 3
must also respond with a word. Keep a record of catches that
do no count because of the lack of a word association.
4. Subject responds with a word and catches the ruler while
responding. If unable to make a word association, the catch
does not count.
5. Record the number at the subject’s fingertips, i.e. distance the
ruler fell through the subject’s fingers.
6. Calculate reaction time in seconds as before.
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15. The flicker fusion threshold
The flicker fusion threshold (or flicker fusion rate) is a
concept in the psychophysics of vision. It is defined as the
frequency at which an intermittent light stimulus appears to
be completely steady to the average human observer.
Flicker fusion threshold is related to persistence of vision.
Although flicker can be detected for many waveforms
representing time-variant fluctuations of intensity, it is
conventionally, and most easily, studied in terms of
sinusoidal modulation of intensity
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16. Factor Of Reaction Time
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•
•
•
•
•
•
Many factors have been shown to affect reaction
times, including :
age,
gender,
physical fitness,
fatigue,
distraction,
personality type,
whether the stimulus type (auditory or visual)
alcohol,
(Marieb, Elaine N., Exercise 22 Human Reflex Physiology)
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17. STUDY CASE
Pak ergo, selain sebagai pembawa gerobak
sampah, beliau juga seorang supir tembak. Ada tiga
jenis mobil yang dia gunakan. Ketiga mobil tersebut
memiliki keadaan lingkungan yang berupa
kebisingan, temperatur, dan pencahayaan yang
berbeda. Seorang Mahasiswa teknik industri ingin
meneliti apakah lingkungan fisik berpengaruh
terhadap waktu reaksi, Berikut merupakan tabel
penelitiannya dalam menghitung waktu reaksi
dengan metode Simple reaction time dan choice
reaction time :
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18. Faktor Lingkungan Fisik
Waktu rata-rata Hasil
Waktu Reaksi
Faktor Lingkungan Fisik
Waktu rata-rata Hasil
Waktu Reaksi
Mobil A (40 dB)
Mobil A (40 dB)
Kebisingan
279.3333
Mobil A (80 lux)
Mobil B (400 lux)
384.6667
Mobil A (18
celcius)
697.3333
Mobil B (25
celcius)
Mobil C (32
celcius)
Simple reaction Time
Pencahayaan
543.6667
459.5
Mobil B (400 lux)
656.5
Mobil C (900 lux)
Mobil A (18
celcius)
329.3333
Mobil C (900 lux)
Temperature
279.3333
543.6667
Mobil A (80 lux)
711.6667
Mobil B (70 dB)
Mobil C (100dB)
499
Mobil C (100dB)
Pencahayaan
Mobil B (70 dB)
Kebisingan
463.6667
866
810
Mobil B (25
celcius)
785
Mobil C (32
celcius)
Temperature
800
573
858
Choice reaction Time
Tentukan kesimpulan dari hasil tabel diatas!
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19. Jawaban
Jadi Kesimpulan dari tabel hasil pengamatan diatas adalah :
1. Faktor kebisingan
Dari kedua tes yaitu SRT dan CRT menunjukkan bahwa
kebisingan berpengaruh dalam reaction time, semakin
kebisingan meningkat maka waktu reaksi dari operator
semakin lambat.
2. Faktor pencahayaan
Dari kedua tes yaitu SRT dan CRT menunjukkan bahwa
pencahayaan berpengaruh dalam reaction time, cahaya
semakin terang maka waktu reaksi dari operator semakin
lambat.
3. Faktor temperatur
Dari kedua tes yaitu SRT dan CRT menunjukkan bahwa
temperatur berpengaruh dalam reaction time, semakin suhu
ruangan meningkat (diatas suhu normal) maka waktu reaksi
dari operator semakin lambat.
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