When faced with question whether to have 20 euros (22 U.S. dollars) now or 50 euros in a month, adolescents often yield to the impulse to take the immediate reward rather than waiting for the bigger one, said a study of Max Planck Institute for Human Development on Tuesday.

Researchers at Stanford University, the Max Planck Institute for Human Development, and the University of California, Davis, have investigated why it is so difficult for adolescents to resist short-term temptations by studying the underlying brain mechanisms.

The results of their study have been published in the Proceedings of the National Academy of Sciences of the USA (PNAS).

As the researchers found out, adolescents' impatience is associated with a change in both brain structure and functioning.

The results of the study show that it was difficult for the adolescents to wait for the larger payment, because the structural connections between two key areas activated during decision making are not yet as strong in adolescents as they are in adults.

These two areas are the dorsolateral prefrontal cortex, which is activated by tasks such as planning for the future, and the striatum, which is part of the reward evaluation system.

Due to the lower connection strength, the influence of the dorsolateral prefrontal cortex on reward evaluation is relatively limited in adolescence, which is why larger but later options appear less appealing and impulsivity prevails, said the study.

"It's not that adolescents don't plan for the future at all. But when they make decisions, they focus much more on the here and now," said Wouter van den Bos, lead author of the study and researcher in the Center for Adaptive Rationality at the Max Planck Institute for Human Development in Berlin.

With increasing age, however, the connections between the two areas of the brain become stronger, and future goals come to play a more important role in making decisions.

As a result, adolescents gradually learn to curb their impatience and to take a more forward-looking approach, said the study