Number of children (N_final) included, having met successful calibration and sufficient number of valid trials, by age group.

<p>Number of children (N_final) included, having met successful calibration and sufficient number of valid trials, by age group.</p

Descriptive data for maternal anxiety (STAI) and depression (BDI) symptoms.

<p>Descriptive data for maternal anxiety (STAI) and depression (BDI) symptoms.</p

Number of valid test trials and mean values of dwell times for each age group and stimulus condition.

<p>Number of valid test trials and mean values of dwell times for each age group and stimulus condition.</p

Early development of attention to threat-related facial expressions - Fig 1

<p>Attention dwell times at 5 to 12 months (top) and 36 months (bottom) of age. The scatterplots show dwell times from individual participants for happy vs. fearful faces (left) and happy vs. angry faces (right). Values above the grey diagonal lines indicate a bias for fearful (left) or angry (right) faces.</p

Individual trajectories of RSA uncorrected and corrected for respiration (both tidal volume and respiration rate) across the three episodes of the first Still-Face Test (n = 23).

<p>Individual trajectories of RSA uncorrected and corrected for respiration (both tidal volume and respiration rate) across the three episodes of the first Still-Face Test (n = 23).</p

Means ± standard deviations of respiration-uncorrected and respiration-corrected RSA indices, respiration measures, and HR for Still-Face Test episodes.

<p><i>Note:</i> HR = heart rate; V_T = tidal volume; RSA = respiratory sinus arrhythmia; T_TOT = total respiratory cycle time; HR = heart rate; RSA/V_T = RSA normalized by V_T; c = adjusted for T_TOT; logRSA = logarithm(RSA+1); logRSA/V_T = logarithm(RSA/V_T)+1.</p

ANOVA time effects (<i>df</i> = 4,60 or 2,44) and paired <i>t</i>-tests (<i>df</i> = 15 or 22) measuring reduction in additional respiration-uncorrected and corrected RSA indices during Still-Face Test 1 and 2.

<p><i>Note:</i> V_T = tidal volume; RSA = respiratory sinus arrhythmia; T_TOT = total respiratory cycle time; HR = heart rate; RSA/V_T = RSA normalized by V_T; c = adjusted for total respiratory cycle time; logRSA = logarithm(RSA+1); logRSA/V_T = logarithm(RSA/V_T)+1.</p><p><i>p</i>-level of both tests Bonferroni-adjusted for all indices.</p

Overview of the Still-Face Paradigm.

<p>Overview of the Still-Face Paradigm.</p

Overall ANOVA time effects (df = 4,66 or 2,44) for changes in physiological parameters across Still-Face Tests and paired t-tests (df = 15 or 22) testing changes from Play to Still-Face episodes 1 and 2.

<p><i>Note</i>: P = Play episode; SF1 = Still-Face episode 1; SF2 = Still-Face episode 2; T_TOT = total respiratory cycle time; V_T = tidal volume; RSA = respiratory sinus arrhythmia; logRSA/V_Tc = logarithm of RSA normalized by V_T (logarithm(RSA/V_T)+1), adjusted for T_TOT; HR = heart rate.</p>†<p><i>p</i>-level of both <i>t</i>-tests for each index are Bonferroni-adjusted in this subgroup.</p

RSA, respiration, and heart rate across Still-Face Test episodes controlled for physical activity: Linear mixed model overall <i>F</i> tests (<i>df</i> = 2 or 4, 50.0 to 67.7), time-varying covariate activity effect <i>F</i>-tests (<i>df</i> = 1, 25.7 to 77.8) and <i>t</i>-tests (<i>df</i> = 52.4 to 77.7) testing changes from Play to Still-Face episode 1 and 2.

<p><i>Note:</i> V_T = tidal volume; RSA = respiratory sinus arrhythmia; T_TOT = total respiratory cycle time; HR = heart rate; RSA/V_T = RSA normalized by V_T; c = adjusted.</p><p>for total respiratory cycle time; logRSA = logarithm(RSA+1); logRSA/V_T = logarithm(RSA/V_T)+1.</p