A framework of spatial thought and language proposed by Chatterjee (2008) was extended to organize measures of spatial tasks (Uttal, Meadow, Tipton, Hand, Alden, Warren, & Newcombe, 2013). Uttal et al. posited that people reason about space based on recognizing and manipulating objects; dimensions of object features (intrinsic vs. extrinsic) and object movement (static vs. dynamic). Thus, Uttal et al. proposed four types spatial of spatial processes: Spatial visualization (intrinsic-static); spatial perception (extrinsic-static); mental rotation (intrinsic-dynamic); and spatial orientation (extrinsicdynamic). Each type of spatial process involves a particular focus of spatial thought, language, and task on the object proper (spatial visualization), its locative relations (spatial perception), manner of motion (mental rotation), or path of motion (spatial orientation). Undergraduates (N = 304) completed 14 spatial tasks identified by Uttal et al. (2013) as measures of the four spatial types. Participants also completed a visual search task that was hypothesized to involve spatial processes. Measurement models of the four-factor theory of spatial reasoning were tested. The four-factor model provided a good fit to the spatial ability measures and thus supported the proposed model. Although men performed better than women on most of the spatial measures, the model of spatial reasoning implied by the typology fit the data for both men and women. For visual search, a two-factor model of easy and difficult visual search fit the observed data. However, structural models relating all four spatial types to visual search did not converge, presumably because there were multiple unmeasured relations between visual search performance and the 14 spatial tasks. I would like to thank everyone who in some small way, sought to support the completion of this dissertation. I am who I am today because of you. I also acknowledge the gifted teaching and administrative staff at Carleton University. Thank-you for every effort you have made as professors and administrators. In particular, I would like to acknowledge the excellent administrative support I have received from Mme Etelle Bourassa. Etelle, your care and attention to detail has been greatly appreciated. To my family and friends, thank-you is just not enough. Without your support I am not sure I would have embarked on this journey, or been able to complete it. First to my wife, Deborah, to say that you were supportive and encouraging is an understatement. Your belief in me knew no end, through my fear of ever finishing, to your abiding patience and feedback in our many discussions about spatial reasoning, you were always there for me. Your encouragement is what kept me going and I look forward to everything the future has in store for us. To my children: Tom, Raeanna, Will, Ioan, Nick, Scott, and Alysha. Each of you have grown up in a learning environment to be the successful young women and men you are today. I hope that you will always be committed to lifelong learning-it will ...