Which statement best describes evidence of neuroplasticity from animal studies and human learning?

• A. The brain is fixed after development.
• B. Structural changes do not relate to learning.
• C. Neuroplasticity occurs only in animals.
• D. Experience can bring structural brain changes in both animals and humans, such as cortical thickness and hippocampal changes.

Answer: (D)

Neuroplasticity is shown when the brain reshapes itself in response to experience and learning. Across animals and humans, practice and new skills lead to real structural changes, not just changes in how the brain works. Animal studies show that enriched environments or targeted training increase dendritic branching and synaptic connections in relevant brain areas. In humans, learning experiences can alter brain structure as well—for example, changes in cortical thickness in regions used for a skilled task and hippocampal changes related to navigation or memory. This cross-species evidence—that experience can bring structural brain changes in both animals and humans, including cortical thickness and hippocampal alterations—best captures what neuroplasticity research shows. The other statements contradict well-supported findings: the brain is not fixed after development, structural changes can relate to learning, and neuroplasticity occurs in both animals and humans.