- Subject index
Via 100 entries, 21st Century Psychology: A Reference Handbook highlights the most important topics, issues, questions, and debates any student obtaining a degree in the field of psychology ought to have mastered for effectiveness in the 21st century. This two-volume reference resource, available both in print and online, provides an authoritative source to serve students’ research needs with more detailed information than encyclopedia entries but without the jargon, detail, or density found in a typical journal article or a research handbook chapter. Students will find chapters contained within these volumes useful as aids toward starting research for papers, presentations, or a senior thesis, assisting in deciding on areas for elective coursework or directions for graduate studies, or orienting themselves toward potential career directions in psychology.
Chapter 22: Taste
The evolution of life on this planet required organisms to sense chemicals suspended or dissolved in water for their survival. Some such chemicals were destructive and required avoidance, whereas others provided nourishment and sustenance. Single-celled organisms such as the bacterium Escherichia coli that inhabits our own digestive systems, developed multiple chemical receptors that determined whether they should approach or avoid a given situation. In the case of E. coli, for example, the direction of rotation of the flagella—whip-like appendages that propel them through their environment—is influenced by the type of chemical they encounter. Thus, chemicals important for sustenance produce a counterclockwise rotation of the flagella that facilitates a smooth and somewhat linear swimming path, whereas other, seemingly noxious chemicals induce a clockwise flagellar rotation ...