Response time models of delta plots with negative-going slopes

Area of Science:

• Cognitive Psychology
• Psychophysics
• Computational Neuroscience

Background:

• Delta plots (DPs) visually compare reaction time (RT) quantiles across conditions.
• Decreasing delta plots (nDPs) indicate experimental effects are larger at lower quantiles, a pattern seen in areas like Simon effects.
• nDPs are intriguing as they imply greater RT variability in the faster condition, challenging standard RT models.

Purpose of the Study:

• To analyze five classes of latency mechanisms consistent with nDPs.
• To discuss the implications of these analyses for interpreting DPs.
• To propose a more fruitful approach to RT model comparison.

Main Methods:

• Described and analyzed five established latency mechanisms: exhaustive processing, correlated stages, mixture models, cascade models, and parallel channels.
• Examined the consistency of these models with nDP patterns.
• Discussed the interpretational limits of DPs.

Main Results:

• Five classes of latency models were identified as consistent with nDPs.
• The analysis highlights that DPs alone do not typically imply a specific processing model.
• A greater variability in RT for the faster condition is a key implication of nDPs.

Conclusions:

• DPs are generally insufficient for inferring specific processing models.
• It is more productive to start with a quantitative model and compare its predicted DP to empirical data.
• Understanding nDPs requires considering models that accommodate increased variability in faster conditions.