Date of Award

Summer 8-7-2014

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Educational Psychology and Special Education

First Advisor

Dr. Amy Lederberg

Second Advisor

Dr. Lee Branum-Martin


Theory-of-mind (ToM) is a conceptual framework used for interpreting human social activity (Astington, 2003). ToM has traditionally been conceptualized as an understanding of false belief, which is the understanding that people have different beliefs about the same object or situation and that those beliefs may not be consistent with reality. Hearing children acquire false belief between 4- and 5-years-of-age. In contrast, many deaf and hard-of-hearing (DHH) children show developmental delays in false belief, sometimes stretching into adolescence (Courtin, 2000; Jackson, 2001; Peterson & Siegel, 1995). Wellman and Liu (2004) have argued that false belief is just one step in a progression of the child’s understanding of mental states. They created and validated a five-step ToM scale that assesses a series of related understandings of mental states, beginning with the understanding of desires and ending with false belief. Peterson and Wellman (2009) found that school-age DHH children showed delays on the ToM scale. In addition, they found that DHH school-age children developed ToM in a different sequential order from hearing preschoolers. The present study examines the development of ToM in DHH and hearing preschoolers—the time period when ToM develops for hearing children. The primary goals of the present study are to compare the developmental sequence of ToM in DHH and hearing children, while also addressing the measurement properties of the scale. One hundred and eighty one children (109 hearing, 72 DHH; M age = 50 months) were tested on the 5-item ToM scale. Using confirmatory factor analysis, the results suggest that 1) DHH children are not delayed in their overall ToM compared to hearing children, but there are differences by task, 2) DHH and hearing children follow a similar sequence of ToM, and 3) the five tasks that make up the ToM scale reasonably measure a single construct within both groups.