Adolescent and young adult daily mobility patterns were moderately to highly heritable

Individual differences in adolescent and young adult daily mobility patterns and their relationships to big five personality traits: a behavioral genetic analysis. Jordan D. Alexander et al. Journal of Research in Personality, July 29 2022, 104277. https://doi.org/10.1016/j.jrp.2022.104277

Abstract: Youth behavior changes and their relationships to personality have generally been investigated using self-report studies, which are subject to reporting biases and confounding variables. Supplementing these with objective measures, like GPS location data, and twin-based research designs, which help control for confounding genetic and environmental influences, may allow for more rigorous, causally informative research on adolescent behavior patterns. To investigate this possibility, this study aimed to (1) investigate whether behavior changes during the transition from adolescence to emerging adulthood are evident in changing mobility patterns, (2) estimate the influence of adolescent personality on mobility patterns, and (3) estimate genetic and environmental influences on mobility, personality, and the relationship between them. Twins aged Fourteen to twenty-two (N=709, 55% female) provided a baseline personality measure, the Big Five Inventory, and multiple years of smartphone GPS data from June 2016 - December 2019. Mobility, as measured by daily locations visited and distance travelled, was found via mixed effects models to increase during adolescence before declining slightly in emerging adulthood. Mobility was positively associated with Extraversion and Conscientiousness (r of 0.17 - 0.25, r of 0.10 - 0.16) and negatively with Openness (r of -0.11 - -0.13). ACE models found large genetic (A = 0.56 - 0.81) and small-moderate environmental (C of 0.12 - 0.28, E of 0.07 - 0.15) influences on mobility. A and E influences were highly shared across mobility measures (rg = 0.70, re= 0.58). Associations between mobility and personality were partially explained by mutual genetic influences (rg of -0.27 - 0.53). Results show that as autonomy increases during adolescence and emerging adulthood, we see corresponding increases in youth mobility. Furthermore, the heritability of mobility patterns and their relationship to personality demonstrate that mobility patterns are informative, psychologically meaningful behaviors worthy of continued interest in psychology.

Introduction

In many cultures, late adolescence is the first period of substantial autonomy during the lifespan. Adolescents spend less time with their parents and more time with their peers and exert far greater control over their daily lives and activities than in childhood (Steinberg & Morris, 2001). In the United States and other western countries, developmental milestones like learning to drive, beginning to work, attending college, and leaving home all take place during late adolescence and further contribute to this expansion of autonomy (Remschmidt, 1994). As adolescents grow increasingly autonomous, adolescent personality plays a greater role in their daily experiences, behavior patterns, and life experiences (Johnson et al., 2013, McAdams et al., 2013). For example, adolescent personality is predictive of engagement in social activities, academic or career aspirations, artistic expression, and interest in recreational drug use (DeYoung et al., 2008; Wrzus et al., 2013). Additionally, life events under some degree of an adolescent’s control, like school suspensions, breaking up with a romantic partner, and starting or losing a job are also significantly associated with adolescent personality (Billig et al., 1996).

As behavior patterns which emerge during adolescence, such as eating habits, exercise, substance use, and sexual decision making, are highly predictive of important health outcomes, understanding how factors like personality contribute to their development carries significant scientific and public health implications (Alberga et al., 2012, Chambers et al., 2003, Sawyer et al., 2018). Understanding how adolescents move through and engage with their environments can help scientists, clinicians, and policy makers understand risk trajectories, identify at risk individuals, and design interventions to reduce the incidence of health problems like obesity or substance use.

Psychologists have historically relied on observational, self-report-based studies to understand developmental changes in adolescent behavior patterns. Self-report surveys are efficient to administer and adaptable to a wide variety of psychological constructs; they have helped us glean important insights into how adolescents’ daily activities change and how they are influenced by factors like personality (Csikszentmihalyi et al., 2014, Wrzus et al., 2013). However, while self-report based observational studies have proven useful, they come with methodological limitations that limit our ability to draw generalizable conclusions. For instance, they do not directly measure behavior, are subject to response biases, are limited by participant self-knowledge, and are often burdensome for participants to complete (Paulus & Vazire, 2007). Additionally, observational research is prone to confounding variables which can produce spurious correlations and render interpretation particularly difficult (Grimes & Schulz, 2002).

The limitations of self-report data can in part be mitigated through additional measures which are less prone to the biases associated with self-report. Smartphone GPS data, for example, can be used to unobtrusively observe and quantify aspects of participants’ daily activities (Harari et al., 2016; Miller, 2012). Smartphone data offer standardized, objective measures of participants’ locations and movement patterns which may be useful in corroborating the findings of existing research on adolescents’ daily lives. Previous research has demonstrated that human mobility patterns can be reliably measured using GPS data (Andrade et al., 2019) and that such patterns are meaningfully related to personality and daily activities in adolescence and young adulthood. Several studies have reported relationships between daily mobility patterns and personality traits in adolescence and young adulthood (Ai et al., 2019, Alessandretti et al., 2018, Stachl et al., 2020). Additionally, mobility based measures have been used to predict adolescent psychological and health outcomes like alcohol use, affect, anxiety and depression symptoms, and sleep patterns in adolescent and college aged samples (Jacobson and Bhattacharya, 2022, Ren et al., 2022, Santani et al., 2018, Sathyanarayana et al., 2016).

However, existing research has been conducted over short time spans in relatively small samples of adolescents, and research observing mobility patterns over the course of adolescence has yet to be conducted. Hence it remains an open question how mobility patterns change during this period of growing autonomy. Such information can help inform claims about how daily life changes during adolescence and help provide further information about whether daily mobility patterns contain useful information about human behavior over longer time spans.

Such research can be further improved by using twin data, which can help us understand where individual differences in adolescents’ daily mobility patterns come from and how they are related to potential explanatory variables like personality. Twin data allows researchers to measure the extent of genetic and environmental contributions to variation in a trait or behavior. Additionally, multivariate behavioral genetic models using twin data can assess whether associations between traits result from mutual genetic or environmental influences. Hence, twin studies can help alleviate the problem of confounding variables in observational research by providing additional understanding of the nature and origins of correlational patterns: helping to parse the extent to which associations between variables are explained by genetic, shared environmental, or non-shared environmental factors (McGue et al., 2010). Twin-based analyses can thereby offer evidence for whether adolescent mobility patterns stem more from heritable traits, such as their preferences for particular activities, or from aspects of their environment, such as how many kilometers away from school they live. Furthermore, measuring the degree of overlapping genetic influences on mobility and personality can offer further insight into why mobility might be heritable, perhaps partly due to the influence of other heritable behavioral traits, like personality.

The present study thus had three primary aims. First, to assess whether changes in autonomy and daily activities which occur during adolescence and emerging adulthood are reflected in adolescent mobility patterns. Second, to investigate how changes in mobility are related to adolescent personality. Third and finally, to estimate how mobility and its relationship to personality are influenced by genetic, shared environmental, and non-shared environmental factors.