Turns out not all social networks are created equal when it comes to their effect on our brains.

Dr. Tracy Alloway of Scotland’s University of Stirling, says her study shows using Facebook stretches our “working memory” (our short-term or recent memory), while Twitter, YouTube and text messages tend to weaken it.

Alloway studies working memory and has developed a training program to increase the performance of children – ages 11 to 14 – who are slow learners. She found:

• Keeping up-to-date with Facebook improved the children’s IQ scores
• Playing video games – especially those that require planning and strategy – and Sudoku also were beneficial
• Using Twitter, YouTube and text messaging does not engage enough of the brain to be helpful, and actually reduce attention span. (Click here for the full story on Alloway’s study.)

“On Twitter, you receive an endless stream of information, but it’s also very succinct,” Alloway said. “You don’t have to process that information.”

She noted that Facebook requires you to keep track of past actions and then plan future actions, which stretches the working memory.

They might not be doing it to improve their memory, but prospective college students are increasingly using Facebook for more than just social interaction. According to a new Kaplan Test Prep and Admissions study, more than 70% of college admissions officials have received “friend requests” from students using Facebook and MySpace.

While it’s debatable whether “friending” an admissions official gives a student an edge when applying to a given college, it’s reasonable to suggest students are using social network sites to help their chances of getting into the school of their choice.

Do you interact with students on Facebook? Let us know in the comments section below.