Many people cannot start their day without first having a cup of coffee or tea.These drinks help them think clearly and feel more awake.This is because of caffeine,which helps to give a jump start to the nervous system.Now,a report says it may also boost long-term memory. Mike Yassa is a neurobiology professor.He and other researchers wanted to know if caffeine could improve a person's memory.He explains,"After you learn anything,it takes some time for that memory to strengthen.And over the first 24 hours is actually where most of   the forgetting happens.So that is where we wanted to intervene with caffeine and see if we can help reduce this forgetting." They took 160 caffeine-free people and showed them pictures of everyday objects. These people were asked if the objects could be found inside the house, or outdoors.Then some of the subjects were given a caffeine pill.The others were given a placebo--a pill containing nothing. 24 hours later,the subjects were shown the exact same images from the day before.They were also shown images with slight differences,and some completely new images. Both groups correctly identified the exact same and completely new pictures.But those who took the caffeine pill were better at spottingthe pictures that were slightly different. Professor Yassa says their answers helped to show the effects of caffeine on memory. And  we find that if they are on caffeine they are much more likely to make the right decision." The amount of caffeine the researchers used in the study was similar to one cup of strong coffee.The researchers did not see any improvement to memory from smaller doses of caffeine or when it was given an hour before viewing the images. What is the focus of the text?
Caffeine can make people addicted. Caffeine can make people energetic. Caffeine can improve long--term memory. Caffeine can make people feel comfortable.