Reasoning Over the Lifespan

In this chapter we discuss the changes in the brain, cognition, and reasoning in adolescents and older adults. Some of the major changes between children and adolescents include maturation of the PFC and association cortex regions, enhanced working memory, improved strategies for encoding and making inferences based on schemas in long-term memory, and better relational reasoning capability. The teenage years are complex biologically with hormonal changes and alterations in brain areas associated with reward and risk. Teenagers may tend to take greater risks in decision making based on impulsivity and on a general lack of experience that limits their ability to use gist-based representations. Adolescent brain development continues with greater cortical maturation and interconnectivity among the networks of the brain that support task-based cognitive functions. Toward the end of life people experience a variety of brain changes and cognitive declines. The brain shows signs of reduced cortical thickness along with reductions in white matter density. These reductions in brain efficiency may be especially prominent in the frontal lobes. Working memory and long-term memory functions tend to decline in older adults along with controlled attention and integration of information. There is often a general slowing in cognition and performance speed on a range of tasks. The ability to inhibit distracting information may be especially impacted. There are reports of extremely healthy agers, who are able to maintain high memory performance and cortical thickness well into their eighties. There are ongoing studies in the field to better understand how we can improve cognitive and brain health in later life by enhancing new learning and making other lifestyle adjustments.