Visual Enumeration: Subitizing and Its Nature

To examine the role of subitizing in ongoing visual enumeration processes, three experiments were conducted using saccade-continent display change technique and peripheral preview paradigm. The results shows that numerical information of up to 3 or 4 items can be quickly enumerated from an extrafovea display and be used in the following enumeration process when the display comes into fovea in the next fixation. While a valid peripheral preview facilitates enumeration speed, invalid preview information causes a penalty in both accuracy and response time. This difference only occurs for small set enumeration; for large set sizes, enumeration speed is facilitated whether information from the peripheral preview is valid or invalid. These findings suggest subitizing as part of the object perception processes. A surprising difference between two display-change conditions in which one item was either inserted in or removed from the display during a saccade to the stimulus pattern further suggests that subitizing is explained well by the object-file/visual-index theories. The nature of small and large set enumeration processes and their interaction is discussed in the last chapter.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Education

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Tai, Yu-Chi

Contributors dc:contributor

• McConkie, George W.

• Education, Educational Psychology

Language dc:language

eng

Identifier

(MiAaPQ)AAI3153438

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/79808