本研究目的旨在檢證不確定效應的分流機制，所謂不確定效應的分流機制
是指：當決策者對於事件發生機率估計感到不確定時，該不確定感分別影響到決
策者對事件機率估計的調整（P機制，分流一），以及對事件後果評估的調整（U
機制，分流二）。這種不確定感經由機率調整與效益調整兩種途徑而影響決策與
選擇的偏好，稱為不確定效應的分流機制。本研究首先比較各種表現不確定性效
應之決策模型的合適性，結果得到Liou模型較其他模型更可清楚與獨立表現出
「不確定感程度」與「不確定態度」兩種心理效應，故本研究採Liou模型模擬P
機制與U機制的函數形式，以該模型之參數 與 分別作為「不確定感程度」與
「不確定態度」兩種心理效應的測量指標。本研究進而設計兩組實驗，就分流機
制特性所推導的假設分別加以驗證。該假設分別為：（1）存在不確定感程度效
應；（2）存在不確定態度的效應；（3）存在不確定分流機制；以及（4）存在
不確定感程度與不確定態度的交互作用。實驗結果顯示除了第（4）項假說祇在
實驗一得到部分支持外，其餘假說皆得到兩組實驗結果的一致支持，驗證了不確
定效應分流假說。

The present study tries to validate the dual mechanisms of
ambiguity effect in decisional
process. Dual mechanisms operate in a streamlining way when a
decision maker is uncertain
of the occurrence probability of certain events. The ambiguity
thus incurred modulates the
estimation of event probability (P-mechanism or Streamline 1)
and that of event consequence
(U-mechanism or Streamline 2). The present study then follows a
substantial revision of
Lattimore et al''s (1992) model to separate and accommodate the
effects of ''degree of
perceived ambiguity '' and ''ambiguity attitude'', which are expressed as and
respectively. The revised Liou model (1997) was then applied to
simulate the behavior of P-
and U-mechanisms under various combinations of and values.
Based on the proposed
streamlining mechanisms, two experiments were conducted to test
four hypotheses derived
from the revised model: (1) existence of the ''degree of
perceived ambiguity'' effect; (2)
existence of the ''ambiguity attitude'' effect; (3) existence of
the streamlining of dual
mechanisms; and (4) existence of the interaction effect between
''degree of perceived
ambiguity'' and ''ambiguity attitude'' variables. The experimental
results confirm that the first
three hypotheses are reliably supported in both experiments,
while the fourth hypothesis is
only partially supported in Experiment 1. The demonstrations
thus clearly complement the
single-mechanism (i. e., P or U-mechanism, but not both in a
streamlining way) explanations
in the literature.