Psychological Considerations in Sensory Analysis

To many, the term ‘‘psychology’’ conjures the image of a distraught patient lying on a couch, telling hermost intimate thoughts to a beardedman smoking a cigar and scribbling notes somewhere behind her. ‘‘What on earth do interpreted dreams, unhappy childhoods, and envy for certain aspects of male anatomy have to do with the sensory evaluation of dairy products?’’ you may ask. The answer is, ‘‘Not much.’’ When we talk about psychological considerations in sensory analysis, we are not calling upon the ghost of Sigmund Freud, but instead referring back to some of his predecessors and contemporaries up north in Germany: Ernst Weber, Gustav Fechner and Wilhelm Wundt. These men were all pioneers in the area of experimental psychology, a branch of psychology that does not rely upon interviews and introspection, but rather upon the experimental method. Experimental psychology, in essence, does not trust the individual to be able to accurately tell the researcher what features are most important in determining a response. Instead, through careful design and controls, experimental psychology forces the individual to demonstrate what aspects are most important and to more or less ‘‘Prove it.’’ The sub-discipline of experimental psychology known as psychophysics is of greatest relevance to sensory analysis. Fechner, while working in Weber’s lab, gave rise to psychophysics with the publication of Elemente der Psychophysik (1860). Psychophysics is the area of natural science that deals with sensory physiology andwhich strives to explain the relationship between sensory stimuli and human responses. A major focus of psychophysics is to discover the relationship between a stimulus (C) and the resulting sensation (R). In its simplest form, this expression may be expressed as a mathematical function (f ), R=f(C). Inspired by Fechner’s treatise, Wilhelm Wundt is credited with establishing the first laboratory for psychological research. The tools upon which the psychophysicist relied, and often still relies, weremeasured thresholds and direct scaling, tools that are often used today in sensory analysis. A complete discussion of psychophysics was provided by Amerine et al. (1965). Much of the early work in psychophysics was devoted to discovering how well a