The target detection paradigm was based on the odd-one-out principle (Fig. 4 for schematic illustration). In the first task subjects were asked to identify the odd-one-out on a display of four human faces, which was either an adult face (target) out of three infant faces (distractors) or an infant target out of three adult distractors, as fast and accurate as possible. The BS of the infant faces was parametrically manipulated (see also6 for the procedure). The same odd-one-out procedure was repeated in the baseline task, in which task geometric shapes (triangles, squares, or circles) were used (Supplementary Material and Methods for detailed information). The first paradigm was 16.4 minutes long and the baseline task was 6.4 minutes long.Figure 4Illustration of the target detection paradigm with example images. The three picture of babies stand for the distractors here (photographs of either 3 adult faces or 3 infant faces were shown; the 3 infant faces had the same amount of BS [higher, unmanipulated or lower BS]). The adult picture on the left stand for target here, which could be either an adult or infant face of higher, unmanipulated or lower BS. The task was to identify the target that did not fit to the other pictures via button press.