# Recognition of Blinks Activity Patterns during Stress Conditions Using CNN and Markovian Analysis
## 2 Experimental Protocol and Data Description  
### Experimental Procedure  
Firstly, an experiment was designed and conducted to investigate the effects of stress conditions on the human face. It included neutral tasks (used as reference) and stressors that simulate a wide range of everyday life conditions that were induced to the participants. In an attempt to cover different underlying stress types, 4 different stressors types (experimental phases) were performed, the _social exposure_, the _emotional recall_, the _mental tasks_ or _cognitive load_ and the _stressful videos presentation_ phase.  
The social exposure phase included an interview asking from the participant to describe himself/herself. It has its origin in the stress due to exposure faced by an actor when he/she is at the stage. Only for the first dataset, a second condition in the exposure phase entailed reading aloud an 85 word emotionally neutral literary passage. The reference of this phase was neutral pose (1 st and 2 nd dataset) and description of words (3 rd dataset).  
The emotion recall phase included stress elicitation by asking participants to recall and relieve a stressful event from their past life as if it was currently happening.  
The mental tasks phase included cognitive load assessment through tasks such as the modified Stroop colour-word task (SCWT) [10], requiring participants to read colour names (red, green, and blue) printed in incongruuous ink (e.g., the word RED appearing in blue ink). In the present task, difficulty was increased by asking participants to first read each word and then name the colour of the word. A second mental task used was the Paced Auditory Serial Addition Test (PASAT) [11], which is a neuropsychological test with arithmetic operations for assessing attentional processing. Another task used in this phase was the presentation of unpleasant images from the International Affective Picture System (IAPS) [12], which were used as affect generating stimuli (1 st and 2 nd dataset). Stimuli included images having stressful content such as human pain, drug abuse, violence against women and men, armed children, etc. Each image was presented for 15 s.  
The stressful videos phase included the presentation of 2-min video segments in attempting to induce low-intensity positive emotions (calming video), and stress (action scene from an adventure film, scene involving heights to participants with moderate levels of acrophobia, a burglary/home invasion while the inhabitant is inside, car accidents etc.).  
Three experiments for the stress assessment through biosignals/facial cues were conducted in total. The experimental procedure and tasks of the 1 st experiment (SRD'14 dataset) was performed for the stress assessment. A 2 nd experiment (SRD'15 dataset) was performed 2 years later. The only difference with the 1 st experiment was the removal of one task 1.3 (text reading). Parameters of the experimental procedure (for more information about the procedure please refer to [8,13]) along with the tasks description and their corresponding affective state is presented in Table 1.  
A 3 rd experiment similar to the 1 st and 2 nd experiments was performed 2 years later, retaining most of the previously used experimental tasks and changing slightly only 3 of them. Specifically, the IAPS images presentation task was replaced with the PASTAT mental task, one emotional recall task was used instead of two, adding also two neutral tasks (reading letters/numbers and a baseline description) which were considered better reference tasks in relation to the previous experiments. Moreover, the duration of most tasks were set to 2 min in order to have greater available monitoring time. The phases and tasks of the 3 rd experiment, along with the tasks description and their corresponding affective state are presented in Table 2.