Stress Condition

The stress condition took place in the MAT condition in the session of mental stress. In this condition, mental stress was induced by the workload of arithmetic tasks and negative feedback.19,20 Workload was created by offering limited time to solve arithmetic tasks. The duration of the trials at the four levels was 1200 ms, 3000 ms, 4000 ms, and 5000 ms, respectively. Along with the time limit in every trial, there was extra text (“delaying response text” and “speed up text”) appearing with the stimulus on the screen to distract from the actual task and to induce more pressure on the subject. Fig. 2.2 displays a model of the computer screen. Text appearing on the screen is included in Table 2.1.

After every trial, along with the feedback on the response, the accuracy of correct responses and response time also appeared as reward. Moreover, after certain trials, a psychologically threatening message appeared on the

A model of the computer screen in the stress condition

Figure 2.2 A model of the computer screen in the stress condition.

Table 2.1 Delaying response text and speed up texts to show on the screen



Level 1 (ms)

Level 2 (ms)

Level 3 (ms)

Level 4 (ms)




Keep pace

You are slowing down






Speed up text

Quick Speed up Faster Hurry up Slow poke










Table 2.2 A summary of stressful feedback messages


Trial duration (ms)

Text feedback




After every 10 trials

Look at the screen and not at the keyboard. You are not following the instructions.

You are slower in response than normal people. Be quick.

Keep accuracy level 80%.



After every 10 trials

Look at the screen and not at the keyboard. Be active in response. Sit attentively.

This is the second level and still you are not familiar with the right keys. Give correct answers.



After 10, 15, 20, 25, 30, 35, 40 trials

Don’t guess answers.

You are very sluggish in response.

You have below average performance. How will you survive with this performance in next level.



After 8, 15, 21,25, 30, 34, 37 trials

Don’t be overly smart. Don’t guess answers. Don’t leave questions unanswered.

Money is subject to your performance. Your performance has been pathetic so far.

screen as negative feedback. This message was meant to portray the external pressures a worker would face in a work environment. The details of these feedback messages are provided in Table 2.2. This approach produced a high failure rate.

Before level 4 began, the experimenter reminded the subject that there was a required minimum performance level and that the subject’s individual performance must be up to that level in order to include that subject’s data in the study. Also the honorarium amount would reduce with wrong and unattempted questions. The subject was told about the need for standard performance across all subjects to allow the data to be grouped and would be reminded to press the correct key to submit their answer. Finally, the subject was told that his/her performance was under observation. This approach induced social stress in the subject.

Control Condition

The control condition took place in the MAT condition in the control session. For the control condition, the tasks were the same and equal in difficulty as the stress condition. However, there was no time restriction and no negative feedback in terms of psychologically threatening messages. The purpose of the control condition was to compare any cerebral activation caused by the mental arithmetic aspects of the task. Feedback (“correct” or “incorrect”) would be displayed after each trial.

Recovery Condition

After the MAT condition was over, recovery time was given while the ECG and EEG details were recorded for 5 minutes. The recovery time was to find out what the changes were in terms of the signals when the subject was in the relaxed condition again.

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