Looking times for A) iBEATs and B) iBREATH.

Note. Looking times for the A) iBEATs and B) iBREATH tasks. In both tasks, 9-month-old infants looked significantly longer at stimuli presented synchronously to their own physiological signals. Black dots refer to the group mean. Black bars refer to the standard error of the mean. Grey lines and colorful dots refer to individual mean looking times per condition and infant.

Results from the MEGA analysis for A) iBEATs and B) iBREATH.

Note. Plot of difference scores computed as mean synchronous looking times minus mean asynchronous looking times per individual for each age group, as well as the combined sample. Red dots refer to mean effects for the respective analysis as described above, red bars refer to 95% confidence/credible intervals. Dashed line indicates a difference of 0. For 3, 9, and 18months age groups our preregistered analysis is plotted. For the combined sample we computed alinear mixed model using lme4 for visualization purposes as results from a mixed model with a beta error distribution cannot easily be transformedback to the original scale.

Interactions between condition and age for the iBEATs MEGA-analysis.

Interactions between condition and age for the iBREATH MEGA-analysis.

Relationship between iBEATs and iBREATHusing a combined sample.

Note.Histogram with plotted line for individual performance on iBEATs and iBREATH using a beta regression. Following Maister et al. (2017), individual difference scores were computed as proportion of absolute difference between synchronous and asynchronous trials.

Effects of iBEATs on iBREATH for all age groups, as well as for interactions between iBEATs and age.

Exploratory analysis for age effect.

Note.Absolute proportional scores for A) iBEATs and B) iBREATH plotted for each age group. Red dots refer to group means, and colorful dots to individual means.

Change in absolute proportional scores across age groups for the iBEATs.

Change in absolute proportional scores across age groups for the iBREATH.

Specification Curve Analysis for the A) iBEATs and B) iBREATH task.

Note. Specification curve analysis plotting standardized beta regression coefficients (y-axis) and number of analysis (x-axis) for A) iBEATs and B) iBREATH. Number of analysis (x-axis) are ordered increasing from lowest to highest standardized beta regression coefficient. Blue color indicates a significant effect (p<. 05) for a mean synchronous preference, red color indicates a significant effect (p< .05) for a mean asynchronous preference, and grey indicates a non-significant outcome

Number of significant results for specifications for iBEATs and iBREATH

Descriptive information for number of trials completed and included

Stimuli used for A) iBEATs and B) iBREATH.

Main analysis for the 9-month-olds for iBEATs and iBREATH split by randomization.

Mean differences in A) iBEATs and B) iBREATH for the 9-month-olds.

Note. Infants with alternative randomization are highlighted in red.

Infants’ Preference Over Time in the iBEATs Paradigm for All Age Groups.

Note. Here results of paired t-tests for the iBEATs with different inclusion criteria for trials are displayed for all age groups. The left column shows a cumulative analysis in which all previous trials are included. The right column shows a 3-trial sliding window analysis in which the three preceding and 3 proceeding trials are included. Blue indicates a significant result of the paired t-test.

Infants’ Preference Over Time in the iBREATH Paradigm for All Age Groups.

Note. Here results of paired t-tests for the iBREATH with different inclusion criteria for trials are displayed for all age groups. The left column shows a cumulative analysis in which all previous trials are included. The right column shows a 3-trial sliding window analysis in which the three preceding and 3 proceeding trials are included. Blue indicates a significant result of the paired t-test.

Simulating data frames for sample sizes from 15 to 125 building up on the iBEATs data from the 9-month-olds.

Note. Results from the simulations. In A) mean effects and 95% confidence intervals are plotted for the different sample sizes. Red color indicates a significant effect, while blue indicates a non-significant result. In B) the percent of significant results are plotted with a fitted line.

Full-null model comparison for the iBEATs model.

Results for the MEGA analysis of the iBEATs data with 3-months as reference group.

Results for the MEGA analysis of the iBEATs data with 9-months as reference group.

Results for the MEGA analysis of the iBEATs data with 18-months as reference group.

Full-null model comparison for the iBREATH model.

Results for the MEGA analysis of the iBREATH data.

Results for the MEGA analysis of the iBREATH data.

Results for the MEGA analysis of the iBREATH data.

MEGA analysis for the relationship between iBEATs and iBREATH with 3-months as reference group.

MEGA analysis for the relationship between iBEATs and iBREATH with 9-months as reference group.

MEGA analysis for the relationship between iBEATs and iBREATH with 18-months as reference group.

Analytical decisions for the iBEATs.

Analytical decisions for the iBREATH.

Inference of the Specification Curve Analysis

Specification Curve Analysis for the iBEATs.

Note. Descriptive results from the specification curve analysis for the iBEATs task. Blue coloring in A) and B) refers to a significant result for a mean synchronous preference, while red color indicates to a significant result for a mean asynchronous preference (p< .05) for the specification and test. In A) standardized beta regression estimates are plotted. In B) an overview for a range of analytical choices is given. In C) analytical choices are further decomposed.

Specification Curve Analysis for the iBREATH.

Note. Descriptive results from the specification curve analysis for the iBREATH task. Blue coloring in A) and B) refers to a significant result for a mean synchronous preference, while red color indicates to a significant result for a mean asynchronous preference (p< .05) for the specification and test. In A) standardized beta regression estimates are plotted. In B) an overview for a range of analytical choices is given. In C) analytical choices are further decomposed.

Looking times for slow and fast asynchronous trials