Older adults who learn a new mentally demanding skill can improve their cognitive function, according to a study conducted at University of Texas.

The other participants were then asked to participate in more familiar activities such as crossword puzzles, watch documentaries and listen to classical music. To evaluate for the possible influence of social contact, some participants were assigned to a group that included field trips and entertainment. However, the researchers found that getting involved socially, or doing crossword puzzles or Sudoku, were just not as beneficial as learning something new where one really has to put that effort in.
Source-Medindia