How to recognise physiological errors
Although our senses are very powerful tools, sometimes even more sensitive than state-of-the-art scientific equipment, if not used correctly they lead us into error and return wrong answers during our evaluation sessions. For this reason, to obtain maximum performance, we must try to avoid (or mitigate) the following errors:
Adaptation error: occurs when we are subjected for a long time to a same stimulus. This leads to a decrease of sensitivity towards a stimulation. For example, when we enter an environment with a characteristic odour, after some time we no longer perceive it. People who have the habit of eating salty foods feel the need to increase gradually the amount of salt to sense the same intensity of the stimulus.
Increase or decrease error: occurs when two stimuli interact with each other providing a greater (or lesser) total intensity than the two single stimuli. For example, a fresh water solution is perceived sweeter if consumed in the presence of the smell of vanilla (increase between the senses). Similarly, sugar in coffee reduces the bitter intensity of caffeine (decrease in taste).
Threshold error: it is due to the different threshold of perception (sensitivity) that individuals have, so that two people with very different sensitivity can associate a different intensity to the same stimulus.
Pathological errors: occur when the subject has temporary or permanent physiological deficits, that make him/her unable to perceive some smells (anosmia), some flavours (ageusia), some colours (colour blindness) or other sensory stimuli.