Plasticity: In psychology, when we talk about plasticity we're referring to "brain plasticity", which refers to the ability for nerve cells to change through new experiences. The process of changing nerve cells is learning, and it was once believed that the only kind of change that could take place after childhood was related to strength in nerve cell connection, not the ability for the cells to actually change. Most psychologists now believe that nerve cells actually can continue to change and function well into adulthood. What does this mean for you? Well, it seems that the old saying is wrong - you really can teach an old dog new tricks.