Trial Outcomes & Findings for Neural Correlates of the Shift in Social Buffering of Social Evaluative Threat (NCT NCT04211155)

NCT ID: NCT04211155

Last Updated: 2025-03-27

Results Overview

Area under the curve from initial (baseline) will be calculated and used in the analyses. Description = 9 saliva samples are collected during the course of the assessment. These samples are collected at (1) arrival for training purposes; T=0, (2) scan preparation; T=35 minutes, (3) entering scanner; T=55 minutes, (4) pre-TSST; T=75 minutes, (5) post-TSST; T=100 minutes, (6) pre-math alone; T=110 minutes, (7) post-math alone; T=120 minutes, (8) exiting scanner; T=130 minutes, (9) departure; T=140 minutes. Area under the curve at intercept (AUCi) is calculated using samples 2-7 with sample 2 as the intercept.

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 208 participants
• Primary outcome timeframe: 2 hours, approx
• Results posted on: 2025-03-27

Participant Flow

Note, a fourth arm, Close Friend, was removed from the study protocol in 2021 with programmatic approval and zero enrollment, and therefore has no results to report. Delays caused by the COVID-19 pandemic required this cut in order to accomplish the study aims.

Participant milestones

Measure	Primary Parent Participants will be randomly assigned to one of 3 conditions that differ by who is with them in the MRI scanner room during the stressful task: Primary Parent, Experimenter, No Social Partner. In this case, participants will complete the stressor with the Primary Parent in the MRI room.	Experimenter Participants will be randomly assigned to one of 3 conditions that differ by who is with them in the MRI scanner room during the stressful task: Primary Parent, Experimenter, No Social Partner. In this case, participants will complete the stressor with the Experimenter in the MRI room.	No Social Partner Participants will be randomly assigned to one of 3 conditions that differ by who is with them in the MRI scanner room during the stressful task: Primary Parent, Experimenter, No Social Partner. In this case, participants will complete the stressor with No Social Partner in the MRI room.
Overall Study STARTED	72	64	72
Overall Study COMPLETED	65	56	67
Overall Study NOT COMPLETED	7	8	5

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Neural Correlates of the Shift in Social Buffering of Social Evaluative Threat

Baseline characteristics by cohort

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Total n=188 Participants Total of all reporting groups
Age, Categorical <=18 years	67 Participants n=5 Participants	65 Participants n=7 Participants	56 Participants n=5 Participants	188 Participants n=4 Participants
Age, Categorical Between 18 and 65 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Age, Continuous	13.04 years STANDARD_DEVIATION 1.05 • n=5 Participants	12.95 years STANDARD_DEVIATION 1 • n=7 Participants	12.89 years STANDARD_DEVIATION 1.10 • n=5 Participants	12.96 years STANDARD_DEVIATION 1.05 • n=4 Participants
Sex: Female, Male Female	34 Participants n=5 Participants	34 Participants n=7 Participants	31 Participants n=5 Participants	99 Participants n=4 Participants
Sex: Female, Male Male	33 Participants n=5 Participants	31 Participants n=7 Participants	25 Participants n=5 Participants	89 Participants n=4 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Asian	3 Participants n=5 Participants	3 Participants n=7 Participants	5 Participants n=5 Participants	11 Participants n=4 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants	2 Participants n=4 Participants
Race (NIH/OMB) White	58 Participants n=5 Participants	55 Participants n=7 Participants	47 Participants n=5 Participants	160 Participants n=4 Participants
Race (NIH/OMB) More than one race	6 Participants n=5 Participants	6 Participants n=7 Participants	3 Participants n=5 Participants	15 Participants n=4 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants

PRIMARY outcome

Timeframe: 2 hours, approx

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Area under the curve from initial (baseline) will be calculated and used in the analyses. Description = 9 saliva samples are collected during the course of the assessment. These samples are collected at (1) arrival for training purposes; T=0, (2) scan preparation; T=35 minutes, (3) entering scanner; T=55 minutes, (4) pre-TSST; T=75 minutes, (5) post-TSST; T=100 minutes, (6) pre-math alone; T=110 minutes, (7) post-math alone; T=120 minutes, (8) exiting scanner; T=130 minutes, (9) departure; T=140 minutes. Area under the curve at intercept (AUCi) is calculated using samples 2-7 with sample 2 as the intercept.

Outcome measures

Measure	No Social Partner n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=61 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=55 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Change in Cortisol AUCi	-0.04 (ug/dl)*minutes Standard Deviation 0.29	0.02 (ug/dl)*minutes Standard Deviation 0.12	-0.01 (ug/dl)*minutes Standard Deviation 0.06

PRIMARY outcome

Timeframe: 2 hours

Population: Originally, we intended to capture heart rate date from EKG signal collected while the participant was in the MRI. During data extraction/analysis, we were unable to reliably separate out the interfering noise caused by the MRI scanner from the EKG signal. Therefore, these data are not available to be reported. Instead, we extracted data from a pulse oximeter reading on the available subset of participants, and report that data here.

Heart rate will be derived from the EKG signal collected during periods of stress (social evaluation) and non-stress (no evaluation) during the course of the assessment. The variable, heart rate response, is a numeric output (reported in beats per minutes) from validated software (BIOPAC) which is calculated using a regression algorithm. The outcome measure will be reported as the difference between heart rate response during the period of stress and period of non-stress.

Outcome measures

Measure	No Social Partner n=25 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=29 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=30 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Change Heart Rate Response	6.09 beats per minute Standard Deviation 4.60	4.82 beats per minute Standard Deviation 11.07	4.18 beats per minute Standard Deviation 5.15

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the bilateral dorsal anterior cingulate cortex (dACC) between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the Harvard-Oxford brain atlas anterior cingulate cortex thresholded at 50% confidence and dorsal to the genu of the corpus callosum.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Dorsal Anterior Cingulate: Task-related Brain Activity (Judged Math vs. Math Alone)	0.07369 % change in BOLD signal Standard Deviation 0.04541	0.09059 % change in BOLD signal Standard Deviation 0.04055	0.1669 % change in BOLD signal Standard Deviation 0.05167

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the left anterior insula between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the Harvard-Oxford brain atlas left insula thresholded at 50% confidence and anterior to the region's midpoint.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Left Anterior Insula: Task-related Brain Activity (Judged Math vs. Math Alone)	0.06186 % change in BOLD signal Standard Deviation 0.02908	0.0807 % change in BOLD signal Standard Deviation 0.04315	0.1336 % change in BOLD signal Standard Deviation 0.02638

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the right anterior insula between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the Harvard-Oxford brain atlas right insula thresholded at 50% confidence and anterior to the region's midpoint.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Right Anterior Insula: Task-related Brain Activity (Judged Math vs. Math Alone)	0.02742 % change in BOLD signal Standard Deviation 0.04186	0.05733 % change in BOLD signal Standard Deviation 0.03973	0.09256 % change in BOLD signal Standard Deviation 0.04243

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the bilateral ventromedial prefrontal cortex (vmPFC) between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the combination of Harvard-Oxford brain atlas frontal pole, frontal medial cortex, and subcallosal cortex thresholded at 50% confidence and ventral to the genu of the corpus callosum and medial to the lateral edges of the Harvard-Oxford brain atlas frontal medial cortex.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Ventromedial Prefrontal Cortex: Task-related Brain Activity (Judged Math vs. Math Alone)	0.02742 % change in BOLD signal Standard Deviation 0.04186	0.05733 % change in BOLD signal Standard Deviation 0.03973	0.09256 % change in BOLD signal Standard Deviation 0.04243

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the left dorsolateral prefrontal cortex (left dlPFC) between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the Harvard-Oxford brain atlas left middle frontal gyrus thresholded at 50% confidence.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Left Dorsolateral Prefrontal Cortex: Task-related Brain Activity (Judged Math vs. Math Alone)	0.11 % change in BOLD signal Standard Deviation 0.03105	0.08843 % change in BOLD signal Standard Deviation 0.04333	0.1492 % change in BOLD signal Standard Deviation 0.06621

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The difference in fMRI BOLD signal intensity in the right dorsolateral prefrontal cortex (right dlPFC) between the social evaluative stress condition (judged math) and non-stress condition (math without judges). Mean group differences in signal intensity between the two math tasks were extracted from a brain region defined by the Harvard-Oxford brain atlas right middle frontal gyrus thresholded at 50% confidence.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=50 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Right Dorsolateral Prefrontal Cortex: Task-related Brain Activity (Judged Math vs. Math Alone)	0.05686 % change in BOLD signal Standard Deviation 0.04326	0.06929 % change in BOLD signal Standard Deviation 0.03735	0.1659 % change in BOLD signal Standard Deviation 0.04624

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the bilateral amygdala over a five-minute recording period. Signal intensity will also be measured using fMRI in the ventromedial prefrontal cortex (vmPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=53 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=48 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Amygdala-vmPFC Connectivity: fMRI Functional Connectivity (Speech Prep vs. Rest)	0.0225 difference in r-correlation coefficient Standard Deviation 0.1774	-0.0180 difference in r-correlation coefficient Standard Deviation 0.1709	0.0131 difference in r-correlation coefficient Standard Deviation 0.2193

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the amygdala over a five-minute recording period. Signal intensity will also be measured using fMRI in the left dorsolateral prefrontal cortex (dlPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=59 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=57 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Amygdala-left dlPFC Connectivity: fMRI Functional Connectivity (Speech Prep vs. Rest)	0.0332 difference in r-correlation coefficient Standard Deviation 0.2236	-0.0492 difference in r-correlation coefficient Standard Deviation 0.1994	-0.0263 difference in r-correlation coefficient Standard Deviation 0.2150

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the amygdala over a five-minute recording period. Signal intensity will also be measured using fMRI in the right dorsolateral prefrontal cortex (dlPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=59 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=57 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Amygdala-right dlPFC Connectivity: fMRI Functional Connectivity (Speech Prep vs. Rest)	0.0548 difference in r-correlation coefficient Standard Deviation 0.1983	0.0716 difference in r-correlation coefficient Standard Deviation 0.2268	0.1069 difference in r-correlation coefficient Standard Deviation 0.2095

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the hypothalamus over a five-minute recording period. Signal intensity will also be measured using fMRI in the bilateral ventromedial prefrontal cortex (vmPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=59 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=57 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Hypothalamus-vmPFC Connectivity: fMRI Functional Connectivity (Speech Prep vs. Rest)	0.0079 difference in r-correlation coefficient Standard Deviation 0.1514	0.0424 difference in r-correlation coefficient Standard Deviation 0.1779	0.0416 difference in r-correlation coefficient Standard Deviation 0.2032

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the hypothalamus over a five-minute recording period. Signal intensity will also be measured using fMRI in the left dorsolateral prefrontal cortex (dlPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=59 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=57 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Hypothalamus-left dlPFC Connectivity: fMRI Functional Connectivity (Speech vs. Rest)	0.0269 difference in r-correlation coefficient Standard Deviation 0.1390	-0.0068 difference in r-correlation coefficient Standard Deviation 0.1555	0.0010 difference in r-correlation coefficient Standard Deviation 0.1571

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

For each participant, signal intensity (unitless measure) will be measured using fMRI in the hypothalamus over a five-minute recording period. Signal intensity will also be measured using fMRI in the right dorsolateral prefrontal cortex (dlPFC) over the same period of time. A bivariate correlation will be conducted for these two data sets to determine functional connectivity, which will be reported as the r value of the correlation. This outcome measure will be reported as the mean difference in functional connectivity value (r, or correlation coefficient) for each buffering condition/group.

Outcome measures

Measure	No Social Partner n=59 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=57 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Hypothalamus-right dlPFC Connectivity: fMRI Functional Connectivity (Speech vs. Rest)	-0.0318 difference in r-correlation coefficient Standard Deviation 0.1179	0.0109 difference in r-correlation coefficient Standard Deviation 0.1585	0.0058 difference in r-correlation coefficient Standard Deviation 0.1425

PRIMARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

salivary Alpha Amylase is used to index autonomic/sympathetic function. 9 saliva samples are collected during the course of the assessment. These samples are collected at (1) arrival; T=0, (2) scan preparation; T=35 minutes, (3) entering scanner; T=55 minutes, (4) pre-TSST; T=75 minutes, (5) post-TSST; T=100 minutes, (6) pre-math alone; T=110 minutes, (7) post-math alone; T=120 minutes, (8) exiting scanner; T=130 minutes, (9) departure; T=140 minutes. 4 samples (3-6) are assayed for salivary alpha amylase in micrograms per milliliter (sAA). Area under the curve at intercept (AUCi) is calculated using samples 3-6 with sample 3 as the intercept.

Outcome measures

Measure	No Social Partner n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=61 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=54 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Change in Salivary Alpha Amylase, AUCi	4.77 (micrograms per milliliter) * minutes Standard Deviation 23.26	6.76 (micrograms per milliliter) * minutes Standard Deviation 19.94	6.32 (micrograms per milliliter) * minutes Standard Deviation 41.1

SECONDARY outcome

Timeframe: 2 hours

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Self-report of stress using a Likert-type scale with 5 levels of stress felt: (1) Not At All, (2) A Little, (3) Some, (4) A Lot, (5) A Whole Lot. Level of stress was reported for 4 points during the assessment: (1) How stressed did you feel when you first arrived at the University and we were walking into the building, (2) How stressful was the period of time when you were preparing your speech and thinking about what to say?, (3) How stressful was giving the speech?, (4) How stressful was the math with judges?. Mean Stress reactivity was calculated as the mean of (2, 3, 4) minus the value at arrival (1).

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=61 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Self Report of Stress	1.74 score on a scale Standard Deviation 1.04	1.5 score on a scale Standard Deviation 1.15	1.81 score on a scale Standard Deviation 0.92

SECONDARY outcome

Timeframe: Parent report of child's general experience, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Scale on the MacArthur Health and Behavior Questionnaire, Potential Covariate, 5pt Scale (1-5), High Scores Indicate Peer Acceptance

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=60 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Peer Acceptance/Rejection	3.55 score on a scale Standard Deviation 0.42	3.54 score on a scale Standard Deviation 0.41	3.51 score on a scale Standard Deviation 0.43

SECONDARY outcome

Timeframe: Parent report of child's general experience, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Scale on the MacArthur Health and Behavior Questionnaire. Potential Covariate, 3pt scale (0,1,2), high scores indicate inhibition

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=60 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Behavioral Inhibition	0.64 score on a scale Standard Deviation 0.59	0.7 score on a scale Standard Deviation 0.51	0.69 score on a scale Standard Deviation 0.54

SECONDARY outcome

Timeframe: Parent report of child's general experience, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Higher Order Measure From the MacArthur Health and Behavior Questionnaire. Potential Covariate 3pt scale (0,1,2), high scores indicate Internalizing

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=60 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Internalizing Symptoms	0.24 score on a scale Standard Deviation 0.18	0.24 score on a scale Standard Deviation 0.2	0.25 score on a scale Standard Deviation 0.2

SECONDARY outcome

Timeframe: Parent report of child's general experience, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Higher Order Measure From the MacArthur Health and Behavior Questionnaire. Potential Covariate 3pt scale (0,1,2), high scores indicate externalizing

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=60 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Externalizing Symptoms	0.13 score on a scale Standard Deviation 0.11	0.12 score on a scale Standard Deviation 0.11	0.07 score on a scale Standard Deviation 0.08

SECONDARY outcome

Timeframe: reported at the beginning of the 2 hour session

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Participants self-report the clock time that they woke up on the day of the assessment, and the clock time when the imaging test was done. The difference between these times was calculated and reported in hours. This is only a potential covariate for cortisol, which follows a circadian rhythm.

Outcome measures

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=63 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=55 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Time Since Awakening	7.92 hours Standard Deviation 2.03	8.15 hours Standard Deviation 2.04	8.58 hours Standard Deviation 1.79

SECONDARY outcome

Timeframe: Parent report, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Parents report on gross family income on an 11-point ordinal scale: (1) Less than $15,000, (2) $15,001 to $25,000, (3) $25,001 to $35,000, (4) $35,001 to $50,000, (5) $50,001 to $75,000, (6) $75,001 to $100,000, (7) $100,001 to $125,000, (8) $125,001 to $150,000, (9) $150,001 to $175,000, (10) $175,001 to 200,000, (11) $200,001 or more.

Outcome measures

Measure	No Social Partner n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=64 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Pretax Family Income. Potential Covariate	9 scores on a scale Standard Deviation 2.1	8 scores on a scale Standard Deviation 2.2	8 scores on a scale Standard Deviation 2.1

SECONDARY outcome

Timeframe: Parent report, collected over 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Parents report education level for both parents on a 6-point ordinal scale: (1) Less than high school degree, (2) High school or GED, (3) Associate degree, college academia program, (4) Bachelor's degree, (5) Master's degree, (6) Professional and/or Doctorate degree. Average of parents' education is calculated and reported.

Outcome measures

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Parental Average Education Level. Potential Covariate	4.5 scores on a scale Standard Deviation 0.69	4.5 scores on a scale Standard Deviation 0.83	4.5 scores on a scale Standard Deviation 0.86

SECONDARY outcome

Timeframe: Youth report, at start of 2 hour session

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Youth report on whether they consumed caffeine or nicotine in the 1-2 hours prior to the assessment. Coded as no=0, yes=1. Used as a potential covariate for heart rate and neuroendocrine measures.

Outcome measures

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Caffeine or Nicotine Within 1 Hour of Testing. Potential Covariate	0 score on a scale Standard Deviation 0	0 score on a scale Standard Deviation 0	0 score on a scale Standard Deviation 0

SECONDARY outcome

Timeframe: Youth report at the beginning of the 2 hour session

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

The Granger score (ordinal, modeled continuously) is a score based on work by Doug Granger of medications that can affect activity of the HPA axis, weighted by significance of potential impact (Granger, Hibel, Fortunato, & Kapelewski, 2009). Each medication taken is given a score of 0, 1, or 2, and all medication scores for a participant is summed, resulting in scores from 0 to infinity. Lower scores are less likely to influence cortisol. Potential Covariate

Outcome measures

Measure	No Social Partner n=66 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=63 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Granger Score	0.03 score on a scale Standard Deviation 0.25	0.19 score on a scale Standard Deviation 0.59	0.11 score on a scale Standard Deviation 0.41

SECONDARY outcome

Timeframe: Youth report, collected over course of 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Network of Relationships Inventory (NRI) reported by youth for their primary parent on how much they experience various emotions or incidents (e.g. How much free time do you spend with this person?), reported on a 5-point scale: (1) Little or None, (2) Somewhat, (3) Very Much, (4) Extremely Much, (5) The Most. Mean scores calculated from all positive attachment items, range 1-5. Potential Covariate.

Outcome measures

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Quality of Relationship With Primary Parent, BSV Positive Attachment Scale	3.25 scores on a scale Standard Deviation 0.69	3.12 scores on a scale Standard Deviation 0.78	3.15 scores on a scale Standard Deviation 0.74

SECONDARY outcome

Timeframe: Youth reported, collected over course of 30 minutes

Population: 188 participants were completed, with 67 Alone, 65 Parent, and 56 Experimenter. For each outcomes, all available analyzable data were included in results, sometimes resulting in lower n.

Network of Relationships Inventory (NRI) reported by youth for their close friend on how much they experience various emotions or incidents (e.g. How much free time do you spend with this person?), reported on a 5-point scale: (1) Little or None, (2) Somewhat, (3) Very Much, (4) Extremely Much, (5) The Most. Mean scores calculated from all positive attachment items, ranging 1-5. Potential Covariate.

Outcome measures

Measure	No Social Partner n=67 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Primary Parent n=65 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.	Experimenter n=56 Participants Participants will be randomly assigned to one of 4 conditions that differ by who is with them in the MRI scanner room: Primary Parent, Close Friend, Experimenter, No Social Partner. Questionnaires: The participant will complete questionnaires, including ones on pubertal development and quality of relations with parents and friends. MRI: Within 2 weeks of the first study visit, the participant will return to the University where they will undergo MRI.
Quality of Relationship With Close Friend, BSV Positive Attachment Scale	3.36 scores on a scale Standard Deviation 0.7	3.37 scores on a scale Standard Deviation 0.75	3.43 scores on a scale Standard Deviation 0.66

Adverse Events

No Social Partner

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Primary Parent

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Experimenter

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Bonny Donzella

University of Minnesota

Phone: 6126244351

Email: donzella@umn.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place