The Single Image was the static presentation of the image (c) from Figure 1.
The experiment began with a verbal instruction followed by a written instruction shown in the VR environment when participants put the VR headset on. Participants were told that they would be presented with 3 types of visual stimulus and they needed to categorize the man's emotion into 7 options: "happiness", "disgust", "sadness", "surprise", "fear", "anger" and "other" from the menu below the image in VR. The previous six categories were demonstrated by researchers as the six "primary" emotions\cite{Darwin_2009}. Participants were asked to choose "other" if they thought the man's emotion in the current visual stimulus could not fall into any of the six options above (e.g., this man has a mixed emotion or his emotion cannot be recognized.) The three types of the visual stimulus were presented to participants in a random order, and participants were asked to make their choices after carefully watching the visual for at least 12 seconds (the time duration for the montage to loop twice). Participants were asked to subjectively describe their personal feelings about the stimuli after choosing the man's emotion for all of the three visual stimuli.

Result