Fig 1.
Facial resemblance manipulation.
Shape and color information of the participant’s face (left) and a face of an individual unknown to the participant (right) were blended in a 50:50 ratio to create a composite face, the Self Morph (center). Only the internal face features have been morphed. The two individuals displayed here along with their legal guardians have given permission for their photographs to be used in this figure.
Fig 2.
Overview of the experimental design.
In each test trial, participants were presented with a set of three pictures of age and gender matched morphs. The masked pictures illustrate how stimuli were presented to the participating children in the test phase. The top row demonstrates the main testing condition where the participant’s face (top row, far left) was morphed with an unknown other’s face to create the Self Morph (top row, second left). Similarly, the Familiar Morph (top row, second right) was created by blending a stranger face with a previously encountered face while the Stranger Morph (top row, far right) was a composite of two stranger faces. Crucially, participants in the control condition (bottom row) were presented with the identical stimuli sets of a participant in the main condition. Therefore control participants never encountered self-similar stimuli but instead morphs that resembled the face of that other participant (bottom row, second left) who was not personally known to the control participant. Pairs of main and control participants had been randomly yoked together. The displayed control participant is not a real person but has been created for this illustration by digitally blending multiple faces.
Fig 3.
Response distribution demonstrating 5-year-Olds’ preferred choices.
The box-and-whisker plots show children’s responses across all three stimuli types in the two experimental conditions. Only in the main condition (gray boxes, n = 48) did the Self Morph resemble the participant’s face, while for participants in the control condition (white boxes, n = 48), these stimuli resembled a control face from another, unfamiliar participant. The boxes indicate the first and fourth quartiles. The solid lines inside the boxes represent the medians. The dashed lines capture the location of extreme values, with the exception of outliers (shown as circles) that exceeded the inter-quartile distance by more than 1.5. The horizontal, red dashed line indicates the chance level (33%).