Fig 1.
Structure of an experimental session.
This figure illustrates a single experimental session, including the acclimatisation phase, trial order, and post-test activity. It also shows the three phases of a trial (i.e., baseline, stimulus presentation, and recuperation), with durations.
Fig 2.
Examples of images from the experimental stimuli.
Screenshot exemplars show the distress stimuli (left) and neutral stimuli (right), with permission.
Fig 3.
Shown are the thermal camera (lower right), video camera (middle right), laptop, the temperature and humidity logger (behind the laptop), stop watch, and chairs for the child and caregiver. The thermal camera was positioned after the child was seated at a distance of 1-1.3 metres. This figure was reproduced from a photograph of the real setup using AI.
Fig 4.
The four facial regions of interest (ROIs).
The name and shape of each ROI, as well as its location on the face, are shown.
Fig 5.
Facial expressions of some participants.
Concern is shown by a girl in the unfamiliar distress condition (e.g., brow furrowed, open mouth) (top left panel); discomfort is shown by a boy in the familiar distress condition (e.g., avoiding look, hand in mouth) (top right panel); and amusement and happiness by a girl in the familiar distress condition (i.e., mouth smiling and cheeks raised) (bottom left panel). All photos are included with parental permission.
Fig 6.
Self-directed behaviours and pointing.
Examples of self-directed behaviours and simultaneous pointing (all three panels) shown by a boy in the familiar distress condition – with permission.
Table 1.
Variables entered into the respective models.
Fig 7.
Nose bridge temperature change from baseline 80 seconds after stimulus onset.
Temperature change is shown as a function of familiarity of the model and condition (distress or neutral). The bars across the boxes are medians; crosses represent means. Dots represent outlier data that are outside 1.5x the interquartile range (IQR), up and down.
Fig 8.
Nose bridge temperature change from baseline at 200 seconds after stimulus onset.
Change in temperature is shown as a function of sex of the participant and condition (distress and neutral). Bars across the boxes are medians; crosses represent means. Dots represent outlier data that are outside the 1.5x the IQR, up and down.
Fig 9.
Nose tip temperature change from baseline at 200 seconds after stimulus onset.
Temperature change is shown as a function of the age (yo = years old) of the participant and familiarity of the model (left) and as a function of the age of the participant and valence of the stimulus (right). Bars across the boxes are medians; crosses represent means. Dots represent outlier data that are outside the 1.5 times the IQR, up and down.