A new study conducted by researchers from the University of East London suggests that the stimulating effect of drinking morning coffee could all be in the mind.

The researchers they conducted a number of exercises to test the reaction times, mood and mental performance of the volunteers and found that while those who drank caffeinated coffee did not show any boost in reaction times, those who drank decaffeinated coffee thinking they were drinking caffeinated one, showed improved performance.
“The findings suggest the expectation of having consumed caffeine confers an enhancement on sustained attention that is at least comparable, and perhaps superior to, the effects of caffeine”, the researcher wrote in their report.
Source-Medindia