Podium: Is That First Cup of Coffee Really a Pick-Me-Up? ; Extract from a Speech Given by Bristol University's Senior Lecturer in Psychology to the British Association Festival of Science
Rogers, Dr Peter, The Independent (London, England)
CAFFEINE IS the most widely and frequently consumed drug in the world. Coffee and tea account for the vast majority of this intake, estimated at about a cup of coffee's worth of caffeine consumed by every person on Earth every day. Therefore, even if caffeine has only a small effect on the health and functioning of individuals, its overall impact on human well-being is likely to be significant.
This impact will occur owing to the effects of caffeine itself and through the effects of other constituents of caffeine- containing drinks. Currently, for example, there is considerable interest in the possible beneficial effects of antioxidant compounds consumed in tea. The evidence for the beneficial effects of caffeine is mixed. The view that caffeine is a useful psychostimulant is challenged by findings showing the negative effects of short-term abstinence in regular consumers, including fatigue, headache and impaired psychomotor performance.
Why do we consume caffeine-containing drinks? One factor influencing our consumption is the recognition of their potential psychostimulant properties. Thus the coffee-drinker may choose to consume coffee at breakfast for its expected alerting effects, but may then avoid coffee late in the evening because it could lead to difficulty in getting to sleep.
However, if people are asked why they drink coffee or caffeine- containing drinks, they are likely to say that this is because they like the "taste" of the drink - people typically do not consume coffee as if it were a medicine, prepared to tolerate its taste in the expectation of a benefit. At the same time, it is fairly certain that human beings are not born with a liking for the taste of coffee or tea, because these drinks contain bitter constituents and bitterness is innately aversive. This raises the question of how people come to acquire a liking for the sensory qualities of these drinks.
An important way in which liking is modified is through the association of the taste of foods and drinks with the after-effects of eating and drinking. The most dramatic example of this is the strong and specific aversion that can develop when consumption of a food is followed by stomach pain, or vomiting. …