| The aim of this dissertation was to explain why some people are indecisive, in the broadest sense of the term. First, a behavioral definition of indecisiveness was synthesized from the range of conceptions of indecision and indecisiveness found across different literatures. Indecisive behaviors were derived from the synthesized definition and used to develop a multi-dimensional, behavioral self-report scale. The scale was designed to capture the breadth of indecisive behaviors, without a priori attributing to them any causes. In three studies, the scale was developed, refined, validated, and used to test distinct mechanisms underlying indecisiveness.;In Study 1 (N = 369), the initial scale was developed. Four types of indecisiveness were hypothesized to exist at distinct phases in the decision-making process: (1) before commitment, (2) before enacting the commitment, (3) before completing the commitment, and (4) after fulfilling the commitment. Analysis suggested that indecisiveness was multidimensional, but consisted of: (1) decision evasion, (2) prolonged latency, (3) waiting, and (4) changing commitments.;Indecisiveness was conceptually refined and reconceived as manifesting itself in three core behaviors: (1) prolonged latency, (2) not-deciding, and (3) changing decisions. The scale was refined accordingly, and other behaviors associated with indecisiveness, such as decision evasion and waiting, were considered to be proximal behavioral contributors.;In Study 2 (N = 169), the multi-dimensionality and multi-determination of the refined indecisiveness scale were confirmed. The core indecisiveness behaviors were predicted by specific patterns of proximal behavioral contributors and four of the Big Five personality traits. The refined scale's validity was established using two other measures of indecisiveness, information processing style, and a double-disjunct task.;In Study 3 (N = 390), the scale was further refined and administered to a demographically broader sample. The multi-dimensionality and multi-determination of indecisiveness were again supported. Nine facets of the HEXACO (Ashton & Lee, 2007) model of personality contributed to indecisiveness through seven mechanisms: (1) worry, (2) low self-confidence, (3) dependence, (4) high standards, (5) escapist impulsivity, (6) careless impulsivity, and (7) concern for others. The scale's validity was further established using peer report, a status quo bias task, and an optimistic bias task. |
