Coffee and Cigarettes. Coffee boosts brain speed, and cigarettes make thinking sharper and more precise. The effect in both cases does not last long., not to mention the long-term health effects. Non-smoking - coffee and donut. The combination of glucose and caffeine increases alertness. Chewing gum improves concentration, than caffeine, Really, the effect lasts only 20 minutes. Draw the lines too. If you think about the problem and draw something in parallel, it will increase concentration and enhance memory. Drink energy. They have a double effect: due to its chemical composition and as a placebo (the consumer is confident in their effectiveness). If you don't want to harm your health, just stare at the bank. This also has an effect.: Racers with Red Bull branding on cars feel stronger, faster and more desperate, because it is with these qualities that the energetic is associated. And their rivals are the opposite..