# Datasets for Cognitive Load Inference Using Wearable Sensors and Psychological Traits
## 3 Datasets  
### CogLoad  
In the conducted experiments, the participants solved cognitive tasks of varying difficulty: The experiments were performed in a quiet, normal-temperature room with one participant at a time. At the beginning of each session, the participants were placed in a comfortable chair in front of a computer monitor and were presented with brief information regarding the experiments. Next, a wrist device (MS band) was put on their left wrist, and the rest of the experimental session was recorded in the same chair without any restrictions regarding the participants' hand gestures. Thus, the experimental setup simulated sedentary work on a computer in an office.  
The experimental scenario consisted of Part 1 and Part 2. Part 1 was dedicated to assessing the participants' cognitive capacity and the personality type. For assessing the participants' cognitive capacity, the participants solved two N-back tasks [60], i.e., 2-back and 3-back tasks, with a three-minute rest after each of them. For assessing the personality type, the participants filled a Hexaco Personalityquestionnaire, which provided information about the participants' honesty-humility, emotionality, extraversion, agreeableness, conscientiousness, and openness to experience [61].  
In Part 2, the participants were presented with six primary tasks. For each task, three variations of a randomly selected primary cognitive-load task were presented to the participant. The variations differed in difficulty (easy, medium, and difficult) and thus in the expected cognitive load. After each of the three variations, the participants filled the NASA-TLX questionnaire to assess subjective cognitive load posed by the tasks. This questionnaire, the most common means of measuring cognitive load, contains a set of questions that, if administered immediately after the task, allows post hoc analysis of the cognitive load [25]. The questions identified by the NASA-TLX questionnaire assess mental, physical and time effort, quality of performance, effort, and frustration.  
Additionally, in parallel with the primary tasks, a secondary task was presented to fill in the participant's free cognitive resources. The secondary task contained a square starting as completely transparent in a random placement on the PC screen, and then increased in opacity. The participant's goal was to react, i.e., to click on the appearing square as soon as they noticed it. The opacity of the square when clicked was intended to be related to the participant's engagement in the primary task, since more engaged users were expected to notice the square later, when it is darker [26]. An assumption is that increased engagement corresponds to higher cognitive load put towards the primary task.  
The software, developed by [PERSON] et al. [29] in their study on psycho-physiological measures for assessing cognitive load, was used to display the primary tasks. The software displays the following tasks: Gestalt Completion test--where the participant is asked to identify incomplete drawings; Hidden Pattern test--where the participant has to decide whether a model image is hidden in other comparison images; Finding A's test--where the participant has to find the letter 'a' in presented words; Number Comparison test--where the participant has to decide whether or not two displayed numbers are the same; Pursuit test--where the participant has to visually track irregularly curved overlapping lines from numbers on the left side of a rectangle to letters on the opposite side; and Scattered X's test--where the participant has to find the letter 'x' on screens containing random letters at random placements. More details about the technical implementation can be found in [PERSON]'s thesis [20], while we present the statistical properties of the dataset in Section 4.1.