Signals available in NoldusHub v1.8

1. Baseline conductivity is the measured conductivity from which transient peak responses are removed. Conductivity is expressed in microSiemens (µS)
2. Average peak rate and heart rate are expressed as the (average) number of peaks/beats per minute (min^-1)
3. The raw PPG signal is a normalized, unitless light absorption measure. It reflects the size of expansion/constriction of small blood vessels induced local blood pressure fluctuation due to the beating of the heart. 
4. Inter-beat intervals, i.e. the intervals between two subsequent heart beats, are expressed in milliseconds (msec)
   

Supported Tobii Pro remote eyetrackers are listed here.

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1. Fixation values are calculated from the raw gaze values obtained from the device. Normalized gaze values ranging from 0-1 indicate that a participant was watching the screen. Note that gaze x and y values outside the 0-1 range can be produced by some devices when participants watch besides the screen. Fixation x and y calculations can therefore also be below 0 or above 1. NoldusHub does not recode such values to NaN values.
2. Movement state can be "Saccade", i.e. moving, "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1. Fixation values are calculated from the raw gaze values obtained from the device. Normalized gaze values ranging from 0-1 indicate that a participant was watching the screen. Note that gaze x and y values outside the 0-1 range can be produced by some devices when participants watch besides the screen. Fixation x and y calculations can therefore also be below 0 or above 1. NoldusHub does not recode such values to NaN values.
   
2. Movement state can be "Saccade", i.e. moving, "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1. Fixation values are calculated from the raw gaze values obtained from the device. Normalized gaze values ranging from 0-1 indicate that a participant was watching the screen. Note that gaze x and y values outside the 0-1 range can be produced by some devices when participants watch besides the screen. Fixation x and y calculations can therefore also be below 0 or above 1. NoldusHub does not recode such values to NaN values.
   
2. Movement state can be "Saccade", i.e. moving, "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

Facial Expressions are "Insights": signals that are derived by applying an algorith to one or more measured signals. To qualify as an insight, the algorithm used should be validated scientifically to produce a signal that reflects a psychologically meaningful factor. In the case of Facial Expressions, the measured signal is a Face video of the participant. The algorithm is a set of video processing routines that quantify facial motor action unit responses and recipees to estimate emotional expressions based on those responses according to the Facial Action Coding System.

Facial Expression signals available in NoldusHub:

1. relative expression intensities are normalized values: minimum = 0, maximum = 1

Cogntive Workload is an "Insight": a psychologically meaningful factor that is estimated from measured physical and physiological signals. The Cognitive Workload insight is obtained from measured pupil sizes and environmental light intensity, using a scientifically validated algorithm.

Cognitive Workload signals available in NoldusHub v1.7:

1. relative Cognitive Load and Cognitive Load Conficence intensities are normalized values: minimum = 0, maximum = 1
2. pupil size caused by the pupillary light reflex is the theoretically contribution of light to the overall pupil diameter. Hence, the remainder (Pupil diameter - Pupil diameter by light reflex) is the pupil dilatation (mm) explained by cognitive processes.
3. Brightness (0-255) values are averaged pixel brightnesses of all pixels in the stimulus presentation screen (with the eyetracker bar placed below the screen).