In what ways are the adolescent brain still developing and what are the consequences for teen behavior?

Question

What will be an ideal response?

Answer 1

In early adolescence, there is another overproduction of synapses, this time in the frontal lobes of the brain. Until this overproduction of synaptic connections is pruned away, it results in inefficiency of thought For instance, when children and adolescents were shown a picture of a face (for example, a sad face) and heard a word that might or might not match that expression ("happy" or "sad"), it took longer for the 11 and 12 year old participants to correctly decide whether the image and word matched than it did either younger or older participants in the study (McGivern, Andersen, Byrd, Mutter, & Reilly, 2002). The decrease in early adolescent performance was attributed to the proliferation of synapses at this age, and the increased efficiency in later adolescence was attributed to the synaptic pruning that had occurred.
The normal pruning process is complete in some areas of the brain by age 12, but in others, especially the prefrontal cortex, the process is not complete until well into adolescence or early adulthood (Blakemore & Choudhury, 2006; Giedd, 2004; Gogtay et al., 2004). Because the prefrontal cortex is the part of the brain that controls judgment and planning and regulates impulse control, the tendency of some adolescents to act on their emotions without thinking through a situation may be related to the immaturity of this system in their brain. Because the connections between the centers for reasoning and the centers for emotions, such as the amygdala, are still developing during adolescence, their emotional responses are less tempered by reasoning than will be the case in adulthood (Society for Neuroscience, 2007b).
Our understanding of the immaturity of the adolescent brain has had consequences for adolescents who are in the judicial system. In a landmark case in 2005, the Supreme Court overturned the death sentence of Christopher Simmons, who had murdered an elderly woman when he was 17. This decision effectively made it illegal to execute people who committed crimes before the age of 18. It was affected by the argument entered into evidence by the American Society for Adolescent Psychiatry that although adolescents may know right from wrong, they are less able to control their impulses, are more influenced by their peers, and are less able to think through the consequences of their actions because of the immaturity of their brain development, in particular, the prefrontal cortex, which controls these functions (Dittmann, 2005; Lehmann, 2004).
The number and type of changes that occur in adolescence may make the brain especially vulnerable to the effect of neurotoxins (such as alcohol and other drugs) during this period of development (Squeglia, Jacobus, & Tapert, 2009). For instance, use of alcohol and marijuana during adolescence has been shown to affect both the structure and the functioning of the brain. Heavy drinking is associated with impaired performance on tests of memory, attention, spatial skills, and executive functioning, and marijuana use is associated with decreased in several aspects of cognitive functioning, including learning. Furthermore, these deficits are seen in adolescents who are not currently using substances, suggesting that they are the result of long-term changes in the brain. Any cognitive deficits that result at this time in development have potential consequences for future academic, occupational, and social functioning as the adolescent moves into young adulthood.