Below is an example summary of this reading selection:
The article indicates that fluid intelligence, the core ingredient in what we call IQ, may be enhanced through practicing the N-back game, a game that requires players to remember where a symbol was presented or what sound was presented one or more times before. However, continual practice is required for long-term effects to remain, and motivation to continue playing may be difficult to maintain.
Your summary will differ from this one in the way it is written, but it should include roughly the same information.