UC San Diego

Visuospatial cognition is fundamental to our daily lives because it includes perceiving, comprehending, and conceptualizing visuospatial relationships among objects in the world. One widely researched visuospatial cognitive task is mental rotation. Mental rotation is the process of imagining an object and performing visuospatial transformations of that object in one's mind. This dissertation will describe a series of studies that explore stimulus effects on different strategies used to accomplish a typical mental rotation task, the neural underpinnings of mental rotation, and the development of mental rotation abilities. The first 2 studies used behavioral and Functional Magnetic Resonance Imaging (FMRI) methods to probe the differences in previous adult mental rotation studies by manipulating stimulus type (unmarked cube figures, UC, or feature marked cube figures, FC) and task instruction (Mental Rotation, MR, or Feature Matching, FM). The behavioral and FMRI data indicated that task instructions and slight changes in the stimulus could induce a switch in visual processing strategies. MR and UC elicited higher slope values, right parietal lobe and MT activation; while FM and FC elicited lower slope values, more left parietal lobe, middle frontal gyrus, and fusiform gyrus activation. In Study 3, children were compared to adults using both behavioral and FMRI methods. The results indicate that children generally can perform mental rotation; however, the response times for children with high accuracy were more similar to adults than children with low accuracy. Also, children with high accuracy had similar patterns of neural activation to adults; specifically, they activated the right parietal and MT regions. Conversely, the children with low accuracy had activation similar to the adults who received FM instructions or FC stimuli and notably no MT activation. These studies present data that there are different strategies to perform a mental rotation task. Also, slight changes in the stimuli may cause a person to switch from a MR to a FM strategy