Overview of the set-up for experiment 1 (a.) and 2 (b.).

<p>The location of the speaker and camera that recorded looking behavior are indicated by 'S', and 'C' respectively. In the dual-screen set-up in (a.), both visual speech streams were displayed on both screens (to ensure accurate timing) and one stream on each screen was masked by a dark piece of cardboard. The areas inside and surrounding the mouth are erased for display purposes only (to guarantee our actor's anonymity).</p

Proportions of time spent looking at the matching screen (PTLM) and congruence preference.

<p>Panel a. depicts the average PTLM values. Error bars reflect one standard deviation from the mean. Panel b. shows the individual PTLM values for each language, and panel c. shows the preference for English congruent stimuli over Spanish congruent stimuli (PTLM English—PTLM Spanish).</p

Proportions of time spent looking at the screen (PTL) and congruence preference.

<p>Panel a. depicts the average PTL values. Error bars reflect one standard deviation from the mean. Panel b. shows the individual congruence preference scores (PTL for congruent stimuli—PTL for incongruent stimuli), separately for English and Spanish audio.</p

Mean values at each landmark.

<p>Numbers represent the mean (μ) brain-scalp distance at each landmark in mm (± SD).</p

Components of brain-scalp distance.

<p><b>A. Enlarged axial slice through a newborn infant brain (subject FT2009, age 2 days).</b> White shows scale bar. Red letters show manually selected landmarks. <i>L</i>: Frontal pole landmark (outer boundary of cerebral cortex). <i>A</i>: Inner boundary of cranial bone marrow. <i>B</i>: Outer boundary of cranial bone marrow. <i>C</i>: Inner boundary of cutis. <i>D</i>: Outer boundary of cutis. <b>B. Enlarged axial slice through a child brain (subject CBP, age 12 years).</b> White shows scale bar. Red letters show manually selected landmarks.</p

Growth charts for brain-scalp distance.

<p>A. Mean growth chart averaged across all brain landmarks. Black line indicates best-fit growth function <i>D</i> = a * t+b where <i>D</i> is brain-scalp distance in mm (y – axis) and t is age in months (x – axis). Each blue square shows average brain-scalp distance in one subject. Fit parameters are a = 0.021, b = 8.5, <i>r²</i> = 0.15, F_1,88 = 16, p = 0.0001. B. Growth chart for Heschl's gyrus. Axis labels are the same as (A). Green squares indicate brain-scalp distance for left Heschl's gyrus in each individual subject and best-fit line; red squares indicate right Heschl's gyrus and best-fit line. Left hemisphere fit parameters are a = 0.013, b = 7.2, <i>r²</i> = 0.08, F_1,82 = 7, p = 0.01. Right hemisphere fit parameters are a = 0.014, b = 8.7, <i>r²</i> = 0.06, F_1,84 = 5, p = 0.02. C. Brain-scalp distance across age for left and right inferior frontal gyrus <i>par triangularis</i>. Left hemisphere fit parameters are a = 0.021, b = 8.75, <i>r²</i> = 0.1, F_1,87 = 10, p = 0.002. Right hemisphere fit parameters are a = 0.018, b = 10.2, <i>r²</i> = 0.07, F_1,77 = 6, p = 0.02. D. Growth chart for frontal pole landmark. Fit parameters are a = 0.010, b = 10.4, <i>r²</i> = 0.08, F_1,52 = 4, p = 0.04. E. Growth chart for occipital pole landmark. Fit parameters are a = 0.038, b = 4.7, <i>r²</i> = 0.48, F_1,86 = 80, p = 10⁻¹³. F. Growth chart for left and right parieto-occipital sulcus landmarks. Left hemisphere fit parameters are a = 0.028, b = 9.1, <i>r²</i> = 0.09, F_1,86 = 9, p = 0.004. Right hemisphere fit parameters are a = 0.029, b = 9.3, <i>r²</i> = 0.09, F_1,88 = 9, p = 0.004. G. Growth chart for vertex landmark. Fit parameters are a = 0.024, b = 9.1, <i>r²</i> = 0.10, F_1,85 = 9, p = 0.003.</p

Selection of anatomical landmarks.

<p>A. Lateral view of pial surface of left hemisphere. Color scale indicates distance between brain and scalp. Black circles indicate location of anatomical landmarks (IFG, inferior frontal gyrus <i>par triangularis</i>). B. Location of Heschl's gyrus anatomical landmark shown on axial slice. Green symbol inside white circle indicates landmark. White arrow highlights location. Yellow curve shows reconstruction of scalp surface. C. Location of inferior frontal gyrus <i>par triangularis</i> landmark on axial slice. D. Location of frontal pole landmark on axial slice. E. Location of occipital pole landmark on axial slice. F. Location of parietal landmark (superior and posterior most portion of parieto-occipital sulcus) on sagittal slice. G. Location of vertex landmark on sagittal slice.</p