Can humans be said to be perfect? — Mental load, stress, human error (2)
If we can’t avoid the mental load, it’s better to keep it under control. The first way to reduce human error is to know that humans make errors.
Subjective Measure: Questionnaire
Points to note when filling out the questionnaire
1. Organize the contents to be surveyed by category in advance and review whether the categories are independent (meaning that they do not overlap each other)
Incorrect examples: family relationships, friendships, hobbies, favourite sports, blood type
2. Use positive sentences as a basis, but do not use negative or negative expressions.
Misconception: Which of the following is not a food you don’t normally like?
3. Use the Likert scale, but keep the meaning of high and low numbers consistent.
Consistency is needed whether a small number is positive or a high number is positive. On the other hand, it is also used to deliberately change the order to screen out unfaithful respondents.
Incorrect or intended example: What do you think about the following eating habits? (Survey on Awareness of Healthy Lifestyle)
4. Psychological distance should be considered when determining steps 3, 5, and 7 of the Likert Scale.
The distance between 3 and 4 and the psychological distance between 4 and 5 are different.
5. The reliability of the survey results can be measured by confirming whether the survey respondents give consistent answers through surveys with different sentences with the same intent.
Ex) Question 1: Do you think regular exercise is beneficial to your health?
Question 13: Do you think regular participation in an exercise program is necessary to restore health?
NASA TLX (Task Load Index): A questionnaire created by NASA to simultaneously measure mental and physical load in a short time.
Body load, psychological measurement
Heart Rate Variability (HRV), electrocardiogram
- Time Domain Analysis
How to statistically process the degree of change in R-R interval during the recording time
Example) SDNN index (mean of s.d. of the normal RR interval for 5 min of 24 hrs ECG recording)
- Frequency Domain Analysis
A method of analyzing the change in R-R interval by dividing it into waveforms for each frequency band
TP(total power), VLF(very low frequency), LF, HF, norm HF, norm LF, LF/HF ratio
Electroencephalogram (EEG), electroencephalogram
Since the increase in beta wave represents an increase in excitatory tension, it is associated with an increase in cognitive load.
An increase in alpha waves is associated with a decrease in cognitive load
Galvanic Skin Resistance; GSR (skin electrical resistance)
The level of skin resistance that changes according to the degree of secretion of body fluid (electrolyte) on the skin surface is passed through a microcurrent and then the resistance value is measured (measure the level of skin resistance changed)
Peripheral Plethysmography; PPG (peripheral blood flow)
Records blood flow and heart rate by measuring the amount of infrared rays incident from the sensor absorbed or reflected by the blood (Using infra-red light to detect the red cell in the capillary of finger tip)
Eyetracking
When the pupil size increases, the cognitive load increases.
Fatigue increases with increased blinking.
As the saccade speed increases, the cognitive load increases.
Facial Movement
Attempts are being made to measure cognitive load through Facial Monitoring.
In particular, the reactions of the sympathetic and parasympathetic nerves are closely connected with the person’s psychological state, so when measuring this physiological change, an objective psychological state can be grasped.
