Lab report on Fitts law and accuracy of movement PDF

Preview

Summary

Lab report on Fitts law and accuracy of movement...

Description

Fitts law and accuracy of movement Introduction Experiments on accuracy of movement help further support and prove Fitts law. Paul Fitts discovered a mathematical equation that could predict human movement to a specific target object through human mechanics and movement. He quantitively ranked the difficulty of a task through the distance of target and the width of the target which is called Index of Movement Difficulty. This showed that the higher the Index of Movement Difficulty the longer it will take to reach that target accurately. The aim of this Lab report is to see how Index of Movement Difficulty affects timing of tasks and accuracy, supporting fits law. The article ‘Explanation of Fits law in Reaching Movement based on Human Arm Dynamics’ showed that ‘the model was found to be nearly consistent with Fitts’ law’ (Takeda et al., 2019), thus

supporting fits law accuracy through using a behavioural experiment on reaching movements. Method The method of this experiment involves providing templets with 16 different conditions varying in width and amplitude. Started with the pen in the middle of the 2 targets, then start a timer as the subject taps each target 10 times whilst trying to do it as accurately as possible (inside each box) as well as fast as they can. The errors (tap outside each box) were then recorded but if there were more than 3 errors made, that condition will need to be repeated. Each condition (width and amplitude) has to be performed in a random order to make sure results are accurate.

Results

Average Movement Time (s)

1.0 0.8 0.6 f(x) = 0.05 x + 0.21 R² = 0.43

0.4 0.2 0.0 0

1

2

3

4

Index of Movement Difficulty

5

6

7

The general result of this experiments shows that, as index of movement difficulty becomes higher (harder), the average movement time is also higher (takes longer), So the more difficult the task, the longer it will take. The bigger the amplitude, the longer the average movement time will be. The bigger the width the faster the average movement time. Amplitude also affects movement time more than width as the graph is more extreme; a small change in the amplitude affects the results more extremely, as the average movement time is more affected than a change in width only subtlety changes the results of average movement time.

Discussion Overall this This experiment on accuracy helps support Fitts law through proving that as index of movement difficulty becomes higher (harder), the average movement time is also higher (takes longer). And the article ‘Explanation of Fitts’ law in Reaching Movement based on Human Arm Dynamics’. Demonstrates the relationship between movement duration and spatial endpoint error (longer the duration the more errors occurred). The results of this experiment was compared to using fits formula and showed that it was nearly identical thus showing Fits’ law is accurate and reliable. These studies shows that the higher the Index of Movement Difficulty and movement duration, the longer and less accurate (more errors) a task will be.

References: Takeda, M., Sato, T., Saito, H., Iwasaki, H., Nambu, I., & Wada, Y. (2019). Explanation of Fitts’ law in Reaching Movement based on Human Arm Dynamics. NCBI. Retrieved 1 April 2021, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6930222/....