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Inside the teenage brain Lucía Magis-Weinberg Department of Experimental Psychology University College London   Contact: lucia.magis-weinberg.12@ucl.ac.uk @luciamawe

Teenage driving: a complex picture Cognitive and social development Individual personality traits Driving experience and ability Characteristics of the vehicle Roadway environment to influence driving behaviour and safety

Teenage driving: a complex picture Teens usually know they are driving in a way that is potentially dangerous Many teens define “safe driving” as being able to drive recklessly without having an accident

Health paradox of adolescence Adolescence is the healthiest period of life Peak in strength, reaction times, immune function Adolescents are smart and react quickly Overall morbidity and mortality rates increase 200 percent from childhood to late adolescence Many of the primary causes of death and disability are related to problems with control of behaviour and emotion (crashes, suicide, substance use, risky sexual behaviours)

Hallmarks of adolescence Risk-taking and novelty seeking Impulsivity Increased focus on the social context These characteristics foster the development of independence at the same time that they increase young people’s exposure to risk They involve both natural and adaptive processes

When driving with peers teens are undertaking two separate, challenging, and complex tasks Operating vehicle and attending to road and traffic Being keenly attuned to the behaviour of and interactions among peers

Risk taking behavior in adolescents is related to brain development relatively weak behavioral control functioning protracted development of prefrontal cortex high sensitivity for reward earlier development of limbic system

During adolescence brains undergo pruning and myelination becoming more efficient

Brain pruning occurs at different rates depending on the region Gogtay, 2004 Houston, Hertig & Sowell, 2015

Brain pruning occurs at different rates depending on the region Gogtay et al., 2004

From Crone and Dahl, 2012

From Crone and Dahl, 2012

From Crone and Dahl, 2012

From Crone and Dahl, 2012

From Crone and Dahl, 2012

From Crone and Dahl, 2012

imbalance Limbic regions: rewards, emotions, peers Frontal regions: cognitive control Sommerville, Jones, Casey 2010

Sensation seeking peak (~19) precedes self regulation ability peak (~24) Steinberg et al. 2017

Pattern is consistent in a large, multi-country sample Sensation seeking peak (~19) precedes self regulation ability peak (~24) Pattern is consistent in a large, multi-country sample Steinberg et al. 2017

imbalance Limbic regions: rewards, emotions, peers Frontal regions: cognitive control Sommerville, Jones, Casey 2010

Teen brain: powerful accelerator/ underdeveloped brakes

Adult brain: more balance accelerator/brakes

It is all about the context Cold cognition Absence of stress, peers, distraction, strong emotions, excitement or reward. Most teens function well, and perform similarly to adults Limbic system is not very active  frontal regions can regulate behaviour

It is all about the context Hot cognition Presence of stress, peers, distraction, strong emotions, excitement or reward. Regulatory capacity can be easily overwhelmed by strong emotion, multitasking, sleep deprivation, or substance abuse (Luciana et al. 2005) Particular risk for teen drivers: extra passengers, music, cell phones, etc. Limbic system is over active  frontal control regions struggle to regulate behaviour

Hot contexts in the lab

Teens failure to inhibit response to happy faces is paralleled by increased activity in limbic regions Figure from Blakemore & Robbins, 2012 Study: Sommerville, Jones and Casey, 2010

Teens’ and young adults’ diminished cognitive control in response to negative cues was paralleled by their decreased prefrontal activity Cohen et al. 2016

Teens make more risky decisions when watched by peers Figure from Blakemore & Robbins, 2012 Study: Chein, et al. 2011

Increased limbic activity when teens are watched by peers Figure from Blakemore & Robbins, 2012 Study: Chein, et al. 2011

Driving: cognition in a hot context Inexperience Developing cognitive abilities Impaired multitasking Impaired attention span Social influence Peers who value risky behaviour Peers who need social acceptance Riskiest teens will be the loudest Teens’ relative lack of immunity to peer pressure The teen who is driving cannot easily see the faces of the passengers: even more attention to social dynamics

Peers activate limbic system and hot cognition making cognitive control less effective Adolescents are intensely attuned to social interactions with their peers Peer interactions often make risky behaviours more likely Teens typically initiate dangerous behaviours with peers (25% of death in US are the result of activities initiated with peers during adolescence)

Peers activate limbic system and hot cognition making cognitive control less effective Teens are more prone to thrill-seeking Their quest to seem mature and to increase their autonomy can lead them to take risks Deviance increases at about age 11, peaks at around age 16 and drop off gradually over the following 10 years. Teens’ great need for social acceptance combines with inexperience in handling pressure from peers

What is in it for the adolescent? Mills and Blakemore, 2014

Late adolescents (18–22) in peer groups make more prudent decisions when an older (25–30) adult is present Silva et al. 2016

Adolescent decision making Contrary to popular belief, teens do not believe they are invulnerable Perceptions of many risks are fairly accurate Tend to rate their overall risk of premature death as far higher Both adolescents and adults have an optimistic bias and are overconfident in their own control over risk Teens lack understanding and have inaccurate thinking about cumulative risk Teens correctly assess the risk associated with any single car trip as relatively low Each time the teen takes an uneventful drive, their perception of riskiness goes down while perception of benefits go up

Adolescent decision making Teens believe they can handle hazardous situations are overconfident of his or her driving skills are decreasingly vigilant about safety Since the teen is also less experienced and competent at the wheel than the average adult, the optimistic bias is particularly hazardous for teen drivers

Sleep deprivation Adequate sleep is an important contributor to alertness and the capacity to focus on details, and is crucial for adequate brain development Adolescents are chronically short on sleep

Teen peak in crashes caused by falling asleep at the wheel Age distribution of drivers in fall-asleep crashes. SOURCE: Reprinted, with permission, from Pack et al., 1995. Copyright 1995 by Elsevier.

Sleep deprivation: high school students need ~9 h of sleep per night, but get between 7 and 7.5 h Biological factors Social factors Sleep needs increase and circadian rhythms change Biologically driven tendency to stay up later at night and sleep longer in the morning Less parental control Increasing academic obligations Increasing social opportunities 97% of teens have at least one electronic device in their bedroom

Sleep Adolescents stay up too late, but they are also required to wake up quite early for school Effects of sleepiness After 17 h awake (teen who woke up at 6:30 am and is socializing at 11:30), a teen’s performance is impaired to the same extent that it would be with a blood alcohol content of 0.05 percent After 24 h awake (driving back home at 6:30 am), impairment compared to blood alcohol of 0.10 percent Teens are sleepiest in the morning. Rate of fall-asleep crashes for 16 – 25 yo confirms peak of crashing between 6 and 8 in the morning (Pack et al. 1995)

Interventions Interventions need to draw on the relevance of social context of teen driving and the cognitive and social development that occur during these years Strategies that link responsible driving with attributes or rewards that teen value Monetary rewards for demonstrating responsible driving skills? Passing as series of tests?

Adolescence is a key transitional period of both vulnerability and plasticity Both cognitive and emotional, reward-processing function develop profoundly during adolescence Emotion and reward processing brain centers mature before cognitive control This imbalance has adaptive advantages but can sometimes have negative consequences in terms of risk taking behaviour Adolescents really struggle to regulate behaviour in hot contexts. Driving is a particularly dangerous hot context which combines thrill and peers. Contact: lucia.magis-weinberg.12@ucl.ac.uk @luciamawe

References Blakemore, S-J., & Mills, K.L. (2014). Is adolescence a sensitive period for sociocultural processing? Annual Review of Psychology, 65, 187- 207. Blakemore, S-J. & Robbins, T.W. (2012). Decision-making in the adolescent brain. Nature Neuroscience 15, 1184-1191. Chein, J., Albert, D., O'Brien, L., Uckert, U., & Steinberg, L. (2011). Peers influence adolescent risk-taking by heightening sensitivity to reward. Developmental Science, 14(2), F1-F10. Cohen, A., Briener, K., Steinberg., L., et al. (in press). When does an adolescent become an adult? Assessing cognitive capacity under emotional influences. Psychological Science. Gogtay N., Giedd J. N., Lusk L., Hayashi K. M., Greenstein D., Vaituzis A. C., et al. Thompson P. M. (2004). Dynamic mapping of human cortical development during childhood through early adulthood. Proceedings of the National Academy of Sciences of the United States of America, 101, 8174–8179. 10.1073/pnas.0402680101 Silva, K., Chein, J., & Steinberg, L. (2016). Adolescent Peer Groups Make More Prudent Decisions in the Presence of a Slightly Older Adult. Psychological Science. Somerville, L.H., Jones, R.M., Casey, B.J., 2010. A time of change: behavioral and neural correlates of adolescent sensitivity to appetitive and aversive environmental cues. Brain and Cogn. 72 (1), 124–133. National Research Council (US), Institute of Medicine (US), and Transportation Research Board (US) Program Committee for a Workshop on Contributions from the Behavioral and Social Sciences in Reducing and Preventing Teen Motor Crashes. Preventing Teen Motor Crashes: Contributions from the Behavioral and Social Sciences: Workshop Report. Washington (DC): National Academies Press (US); 2007. 3, Characteristics of Adolescence That Can Affect Driving. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9662/

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