What this trial measures

• Quantity of locations visited as a potential indicator of social opportunity or isolationContinuous over the duration of the 6-week study

  Participants will be asked to download a geolocation app to their smartphone that tracks their physical location throughout the study. Number of locations visited is a count variable (integers), with a lower bound of zero and an upper bound to be determine by participant behavior.

• Roaming entropy as a potential indicator of social opportunity or isolationContinuous over the duration of the 6-week study

  Based on GPS data (i.e., coordinates and timestamps), roaming entropy (RE) scores are computed with RE higher for days where one visits a greater number of locations and exhibits greater uniformity in the time distribution across visited locations. A minimum RE value would be achieved by spending all day in a single location, whereas maximum RE would, theoretically, be achieved by spending an equal proportion of the day in each unique location in an environment. Possible range is 0.00 to 1.00; range in past datasets is 0.00 to 0.52.

• Left Home (Yes/No) as a potential indicator of social opportunity or isolationContinuous over the duration of the 6-week study

  This is a binary Indicator of whether the participant visited any location outside of the home cluster, defined as the location most frequently visited between 2:00 AM and 6:00 AM.

• Loneliness, Self-Report (Biweekly)Baseline/Week 0, Week 2, Week 4, and Week 6

  Four items from the National Institute of Health (NIH) Toolbox Adult Social Relationship Scales with mean responses ranging from 1 to 5. Lower scores indicate reduced loneliness.

• Loneliness, Self-Report (Day)Included in Day Reports, 3 times a week, over the 6-week RCT

  One item: "Today, I felt lonely." Mean scores range from 1 to 7 with a lower score representing less loneliness.

• Behavioral Motivational Value for Strangers-Smiling-with-Direct-GazeWeek 4

  The behavioral measure of motivational value (a.k.a., Implicit Motivational Value, or iMV) is estimated in a choice task as k values for stimulus types using a reinforcement learning (RL) paradigm and computational approaches. The task stimuli include fractals that precede the presentation of headshot photos of unfamiliar others in the same age range as study participants. Those photos show persons with one of 3 facial expressions: smiling-with-direct-gaze, smiling-with-gaze-averted, and neutral-with-gaze-averted. Participants are instructed to select their preferred fractal. Following work by Waugh et al. Computational a priori starting range: -1.5 to 1.5, with higher means representing more motivation to experience the image type (e.g., strangers-smiling-with-direct-gaze) relative to the middle category (i.e., strangers-smiling-with-gaze-averted).

• Social Connection, Open TextWeek 6

  Participants will respond to an open-ended writing prompt asking them to reflect on how socially connected (or not) they felt during the study. To index social connection, both top-down (theory-driven) dictionary-based approaches, specifically the Linguistic Inquiry Word Count (LIWC) and also bottom-up (data-driven) open-vocabulary linguistic features (words, phrases, and topics) will be used. LIWC scores represent the relative frequency of designated words within each LIWC category, ranging from 0.0 to 1.0. Higher scores represent greater frequency of the designated word category. Latent Dirichlet Allocation modeling (LDA) will be used to generate "topics" that represent data-driven linguistic features. The investigators will compute the topic distribution of each participant, ranging from 0.0 to 1.0. Higher scores represent greater frequency of the designated topic.