It found that people who complete brain training generally have an increase in their IQ by five to 10 points.
The catch is that it only works if the participants actually believe the training will have an effect on their cognition.
The study was designed by Cyrus Foroughi, a PhD candidate of George Mason University in Virginia, USA.
It involved putting two different advertisements around a student campus.
The first ads invited students to join a study whose aim was to train their brains. Therefore, this group believed the training would help their cognition.
The other ads invited students to training that would provide credits and did not mention brain training.
Once formed, both groups completed the same brain training task.
The results showed that people who believed the training would help their cognition performed five to 10 points better on an IQ test than the other group.
“We show clear evidence of placebo effects after a brief cognitive training routine that led to significant fluid intelligence gains,” said the researchers.
They argued that the "desire to become smarter may blind us to the role of placebo effects".
The study is appearing in the journal Proceedings of the National Academy of Sciences.
Last month, another study
compared outcomes from yoga and meditation with those from brain training.
The results found that both groups saw similar benefits in their verbal memory, which is the type of memory used to remember names or lists of words.
But those who practiced yoga had better improvements in visual-spatial memory, which is the type of memory used to remember locations.
"Memory training was comparable to yoga with meditation in terms of improving memory, but yoga provided a broader benefit than memory training because it also helped with mood, anxiety and coping skills," said Helen Lavretsky, the study's senior author and professor at UCLA's department of psychiatry.
Yoga improves memory better than brain training: study
The benefits of brain training games might all be all in our heads and a result of the placebo effect, suggests new research.