New research suggests that cell phone separation can have serious psychological and physiological effects on iPhone users, including poor performance on cognitive tests.

Researchers from the University of Missouri-Columbia said their findings suggest that iPhone users should avoid parting with their phones during daily situations that involve a great deal of attention, such as taking tests, sitting in conferences or meetings, or completing important work assignments, as it could result in poorer cognitive performance on those tasks.

"Our findings suggest that iPhone separation can negatively impact performance on mental tasks," Russell Clayton, lead author of the study and a doctoral candidate at the MU School of Journalism and lead author of the study, said in a statement. "Additionally, the results from our study suggest that iPhones are capable of becoming an extension of our selves such that when separated, we experience a lessening of 'self' and a negative physiological state."

For the study, researchers asked iPhone users to sit at a computer cubicle in a media psychology lab. The researchers told the participants that the purpose of the experiment was to test the reliability of a new wireless blood pressure cuff. Participants completed the first word search puzzle with their iPhone in their possession and the second word search word puzzle without their iPhone in their possession or vice versa while the researchers monitored their heart rates and blood pressure levels.

While completing the first puzzle, the researchers recorded participants' heart rate and blood pressure responses. Participants then reported their levels of anxiety and how unpleasant or pleasant they felt during the word search puzzle. Next, and while in possession of their iPhones, participants were informed that their iPhones were causing "Bluetooth interference" with the wireless blood pressure cuff, and that they needed to be placed further away in the room for the remainder of the experiment. The researchers then provided the participants a second word search puzzle.

While working on the puzzle, the researchers called the participants' iPhones. After the phones finished ringing, researchers collected blood pressure and heart rate responses. Participants then reported their levels of anxiety and how unpleasant or pleasant they felt during the word search puzzle.

The researchers found a significant increase in anxiety, heart rate and blood pressure levels, and a significant decrease in puzzle performance when the participants were separated from their iPhones as compared to when iPhone users completed similar word search puzzles while in possession of their iPhones.

The findings are detailed in the Journal of Computer-Mediated Communication.