Are three-sample tasks less sensitive than two-sample tasks? Memory effects in the testing of taste discrimination

Area of Science:

• Sensory science
• Psychophysics

Background:

• Discrimination protocols are crucial for sensory evaluation.
• Three-stimulus protocols are sometimes less sensitive than two-stimulus protocols.
• Understanding factors affecting sensitivity is key to improving methods.

Purpose of the Study:

• To investigate why three-stimulus discrimination protocols are less sensitive than two-stimulus protocols.
• To differentiate the effects of memory decay and memory interference in sensory tests.
• To compare the sensitivity of various discrimination protocols.

Main Methods:

• Two experiments were conducted using purified water and low NaCl solutions.
• Experiment 1 compared three protocols (same-different, same-different with rinse, same-different with delay).
• Experiment 2 compared four protocols (same-different, two-rinse same-different, triangle, duo same-different) to isolate decay and interference effects.

Main Results:

• Increased time delay in Experiment 1 led to decreased d' values, suggesting memory decay impacts sensitivity.
• Experiment 2 revealed a substantial effect of memory interference.
• Memory decay appears to be a significant factor in the reduced sensitivity of three-stimulus tests.

Conclusions:

• Memory decay and memory interference contribute to the lower sensitivity of three-stimulus discrimination protocols.
• Further research is needed to quantify the relative contributions of memory decay and interference.
• Findings suggest optimizing protocols to mitigate these memory effects for more accurate sensory evaluation.