Triadic discrimination testing: refinement of Thurstonian and sequential sensitivity analysis approaches

Area of Science:

• Sensory Science
• Psychophysics
• Chemosensation

Background:

• Discrimination testing performance is influenced by cognitive strategies and oral environment variations.
• Understanding these factors is crucial for accurate sensory evaluation.

Purpose of the Study:

• To investigate the impact of cognitive search strategies and oral environment changes on the performance of discrimination tests.
• To evaluate the adequacy of existing models in explaining sensory discrimination.

Main Methods:

• Participants performed discrimination tasks using 3-AFC (three-alternative forced choice) and triangle test protocols with low concentration NaCl solutions and water.
• Analyzed physical signal strengths by measuring Na+ cation concentration changes in the oral environment.

Main Results:

• Higher accuracy was observed with the 3-AFC protocol compared to the triangle test, aligning with Thurstonian modeling.
• Discrimination accuracy was better for triads with one NaCl stimulus versus one water stimulus, supporting the Sequential Sensitivity Analysis Model.
• Classical two-distribution models were insufficient due to significant carry-over effects in chemical senses, suggesting a need for multi-distribution models.

Conclusions:

• Cognitive strategies and oral environment dynamics significantly impact sensory discrimination accuracy.
• Existing models require refinement to account for complex interactions and carry-over effects in taste perception.
• Inconsistent strategy use by participants introduced artifacts, highlighting the need for careful experimental design.