CHAPTER 1 Summary

• Science is an ongoing process in which scientists conduct carefully designed studies to answer questions or test hypotheses.
• Scientific hypotheses are tested in controlled experiments or in observational studies, the results of which can support or rule out a hypothesis.
• Scientific hypotheses can be supported by data but cannot be proved absolutely, as future studies may provide new findings.
• The strength of the conclusions of a scientific study depends on, among other factors, the type of study carried out and the sample size.
• Every experiment should have a control—a group that is identical in every way to the experimental group except for one factor: the independent variable.
• The independent variable in an experiment is the one being deliberately changed in the experimental group (e.g., coffee intake). The dependent variable is the measured result of the experiment (e.g., effect of coffee on memory).
• Often a control group takes a placebo, a fake treatment that mimics the experience of the experimental group.
• In epidemiological studies, a relationship between an independent variable (such as caffeine intake) and a dependent variable (such as development of Parkinson disease) does not necessarily mean one caused the other; in other words, correlation does not equal causation.
• A randomized clinical trial is one in which test participants are randomly chosen to receive either a standard treatment (or a placebo) or an experimental treatment (e.g., caffeine).
• Scientists rely on peer-reviewed scientific reports to learn about new advances in the field. Peer review helps to ensure that the scientific results are valid as well as accurately and fairly presented.
• Most of the general public relies on media reports for scientific information. Media reports are not always completely accurate in how they portray the conclusions of scientific studies.
• To understand a study properly, it is often necessary to look at how the study was designed and to analyze the data oneself.
• Scientific theories are different from everyday theories. A scientific theory has withstood the test of time and extensive testing and is supported by a significant body of evidence.

• MORE TO EXPLORE

  • HealthNewsReview.org
  • Ryan, L., et al. (2002) Caffeine reduces time-of-day effects on memory performance in older adults. Psychological Science 13:68–71.
  • Seifert, S. M., et al. (2011) Health effects of energy drinks on children, adolescents, and young adults. Pediatrics 127(3):511–528.
  • Rogers, P. J., et al. (2010) Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption. Neuropsychopharmacology 35(9):1973–1983.
  • Ross G. W., et al. (2000) Association of coffee and caffeine intake with the risk of Parkinson disease. Journal of the American Medical Association 283(20):2674–2679.