基於捷思－系統雙元訊息處理模型，當九尾數與零尾數的價格以分別、聯合與依序進行評估時，此研究藉此確認九尾數定價效果的有限性。研究一證實九尾數定價效果會出現在分別評估模式，但不會出現於聯合評估模式。研究二增加了依序評估模式並在購買預算的條件下衡量實際購買數量。結果與研究一相符，且驗證在分別評估模式時，有不同最左端數字的九尾數與零尾數之知覺價格差異大於在聯合評估模式。研究四操弄了任務複雜度且結果發現因為較高任務複雜度造成認知能力超過人們負荷時，九尾數效果將消失。

This paper, which is based on a heuristic-systematic dual-process model, identifies the boundary conditions of the nine-ending pricing effect when nine-ending and zero-ending prices are separately, jointly, and sequentially evaluated. Study 1 proves the occurrence of the nine-ending effect in separate, but not joint, evaluation conditions. Study 2 adds an extra sequential evaluation mode to Study 1 and measures actual quantitative estimations with a shopping budget. The results are consistent with those from Study 1. The results of Study 3 demonstrate that the perceived price difference between nine- and zero-ending digits with different leftmost digits is greater in the separate-evaluation mode than it is in the jointevaluation mode. In Study 4, task complexity is manipulated and the results show that no nine-ending effect is observed when cognitive capacity, which is induced by greater task complexity, exceeds the capabilities that people possess.