Replaying GSR data in Pro Lab

GSR data recorded in Pro Lab can be replayed synchronized with the video of the recording and eye movement data. Pro Lab will show the GSR data as a chart with the GSR signal plotted over time. You can easily navigate to specific parts of the recording and replay the entire recording or parts of it to visualize the GSR signal. 

Reviewing the GSR signal after the recording is a good practice that allows you to inspect the GSR data quality and ensure that no relevant parts of the recording contain large artifacts, such as those caused by sudden electrode movement or electrode pressure. Replaying the GSR data in Pro Lab will enable you to inspect the GSR data and detect any large artifact.

To replay GSR data in Pro Lab:

1. Click the Analyze dropdown menu in the top navigation pane. Double-click the recording you want to replay in the Recording list. Alternatively, click the Project overview tab and double-click the recording you want to replay in the Recording list. In both cases a Replay tab will open.
2. To view the GSR data chart, click the Visualizations dropdown menu to the left of the Timeline and click the GSR data chart checkbox. You can enable the Use autoscaling option to autoscale the GSR value axis to the maximum and minimum values of the GSR portion displayed on the GSR chart.
3. You can navigate in time and zoom in the GSR recording using the timeline tools and controls. The replay controls allow you to replay any part of the recording and visualize the GSR data, eye movement data and video recording over time. To locate the GSR response to a specific stimulus use the Events List located in the Events section of the tools panel. Check Stimuli Events and click the stimulus event of interest in the Events. The video recording and GSR data chart will automatically move to that time point.

You can choose to visualize either the raw GSR data as acquired from the sensor or the GSR data after applying the Tobii GSR filter. The filtered GSR data will display the GSR signal after removing the most common types of GSR artifacts: high-frequency noise and rapid-transient artifacts. However, inspecting also the raw signal is always a good practice that will allow you to detect large artifacts that otherwise may be masked once the GSR filter is applied.

The GSR data chart also shows the results of the GSR data analysis applied by Pro Lab. Pro Lab GSR analysis will detect the rapid changes in the GSR signal (skin conductance responses (SCRs)) that measure emotional arousal responses. Pro Lab GSR analysis will also classify SCRs that are caused in response to specific events, such as the onset of a stimulus (event-related skin conductance responses (ER-SCRs)). All detected SCRs and ER-SCRs due to stimulus onsets will be displayed in the GSR data chart with a marker on top of each.

To view GSR filtered data with SCR peaks and ER-SCR peaks:

1. Select the Tobii GSR filter option in the GSR data section of the tools panel. In this section, you can also select the Raw data option to visualize the raw GSR data.
2. Enable the SCR and ER-SCR options in the GSR data chart, located to the left of the Timeline. 

• Enabling SCR will show a pink marker on top of each SCR peak detected during the GSR analysis. When hovering the mouse over the symbol, a tooltip will display the SCR properties: SCR peak time, GSR level at peak, SCR amplitude and SCR half recovery time.
• Enabling ER-SCR will show a blue marker on top of each ER-SCR peak detected during the GSR analysis. When hovering the mouse over the symbol, a tooltip will display the ER-SCR properties and related event: Stimulus name associated with the ER-SCR and latency from stimulus onset to SCR onset. Note that only ER-SCR elicited after stimulus onset will be shown in replay. Detection and characteristics of ER-SCR measured as a response to custom events can be obtained in GSR metrics. It is possible that the same ER-SCR belongs to more than one stimulus onset. This can happen when a stimulus is shown for less than four seconds. In these cases, the ER-SCR peak will show one blue marker for each stimulus onset (see figure below for an example).