psychophysics anthropometrics and ergonomics
Do the “Classic” visual/motor ruler reaction time measurement study, as follows:
- Using a rule, hold it near the end (highest number) and let it hang down
- Have a participant put their hand at the bottom of the ruler and have them ready to grab the ruler (they should not be touching the ruler)
- Tell the participant that you will drop the ruler sometime within the next 5 seconds and they are to catch the ruler as fast as they can after it is dropped
- Record the level (inches or centimeters) at which they catch the ruler
Repeat multiple times (we recommend 20 times) varying the time the ruler drop within the 5 second window.
Then repeat with a different participant.
Use either the formulas or chart (to right) to convert measures to response times:
d = Â½ g t2 or
t = time (in seconds)
d = distance (in cm)
g = gravity of 980 cm/sec2 or 385.8 in/sec2
Write up your design, procedures, materials, findings and conclusions (use the scientific paper format – module 2G). Include the following:
- A simple block diagram model (no more than about 6 blocks) of the visual-motor processes involved, include both sensory and cognitive processing aspects
- Hypothesis and null hypothesis
- Independent, dependent and confounding variables
- Descriptive analysis: mean, median, mode, range and scatter plot
- Answer the following questions:
- Which participant is fastest? Is the difference significant?
- Is the data skewed? Explain this result.
- Over time, does reaction time increase, decrease or stay the same? Explain this result.