Six other common mistakes that should be avoided
Avoid these mistakes and increase the performance of your panel
In the previous post we started describing the errors that could mislead our sensory analysis session. Here is a list of the other physiological and psychological errors that should be avoided during sensory evaluations.
Tendency towards central value: it generally occurs with inexperienced judges who tend not to use the extreme values of a scale (too low, too high).
Presentation error: occurs because the samples are evaluated differently according to their tasting order. For example, the first sample generally obtains higher values than the others, while the evaluation of the last is inevitably influenced (both psychologically and physiologically) by the first. This is why, unless there are other needs, the sensory analysis requires to randomise the samples’ sequence of presentation.
Carry-over effect: occurs during the evaluation of samples with very intense stimuli when it’s impossible to completely “reset” the stimulus before moving on to the next sample. This is the case, for instance, with spicy foods. The flavour is persistent and it will be inevitably perceived during the following evaluations.
Proximity error: occurs when two distinct attributes are evaluated in the same way (with the same intensity) because of the similarities or the mental associations that can arise between their meanings. For instance, the attributes “tender” and “juicy” in reference to a steak can be evaluated in a similar way despite being two completely different characteristics.
Mutual influence: occurs when a judge is influenced by the response of another judge, or by the judgment of the panel leader. Sensory analysis involves the use of a statistically representative number of judges during the evaluation of the products. Judges should work independently and separately otherwise the “statistical power” of the final result will be inevitably affected.
Lack of motivation: occurs when the judge attends the sessions without the right motivation. It is the most dangerous error as it transforms the judge’s precious judgment into a trivial random number similar to that of a dice roll, invalidating all the efforts made by the panel leader and the rest of the project team to perform a correct sensory analysis.