Categories are often defined by rules regarding their features. These rules may be intensely complex yet, despite the complexity of these rules, we are often able to learn them with sufficient practice. A possible explanation for how we arrive at consistent category judgments despite these difficulties would be that we may define these complex categories such as chairs, tables, or stairs by understanding the simpler rules defined by potential interactions with these objects. This concept, called grounding, allows for the learning and transfer of complex categorization rules if said rules are capable of being expressed in a more simple fashion by virtue of meaningful physical interactions. The present experiment tested this hypothesis by having participants engage in either a Rule Based (RB) or Information Integration (II) categorization task with instructions to engage with the stimuli in either a non-interactive or interactive fashion. If participants were capable of grounding the categories, which were defined in the II task with a complex visual rule, to a simpler interactive rule, then participants with interactive instructions should outperform participants with non-interactive instructions. Results indicated that physical interaction with stimuli had a marginally beneficial effect on category learning, but this effect seemed most prevalent in participants were engaged in an II task.

Dexterous manipulation is a representative task that involves sensorimotor integration underlying a fine control of movements. Over the past 30 years, research has provided significant insight, including the control mechanisms of force coordination during manipulation tasks. Successful dexterous manipulation is thought to rely on the ability to integrate the sense of digit position with motor commands responsible for generating digit forces and placement. However, the mechanisms underlying the phenomenon of digit position-force coordination are not well understood. This dissertation addresses this question through three experiments that are based on psychophysics and object lifting tasks. It was found in psychophysics tasks that sensed relative digit position was accurately reproduced when sensorimotor transformations occurred with larger vertical fingertip separations, within the same hand, and at the same hand posture. The results from a follow-up experiment conducted in the same digit position-matching task while generating forces in different directions reveal a biased relative digit position toward the direction of force production. Specifically, subjects reproduced the thumb CoP higher than the index finger CoP when vertical digit forces were directed upward and downward, respectively, and vice versa. It was also found in lifting tasks that the ability to discriminate the relative digit position prior to lifting an object and modulate digit forces to minimize object roll as a function of digit position are robust regardless of whether motor commands for positioning the digits on the object are involved. These results indicate that the erroneous sensorimotor transformations of relative digit position reported here must be compensated during dexterous manipulation by other mechanisms, e.g., visual feedback of fingertip position. Furthermore, predicted sensory consequences derived from the efference copy of voluntary motor commands to generate vertical digit forces may override haptic sensory feedback for the estimation of relative digit position. Lastly, the sensorimotor transformations from haptic feedback to digit force modulation to position appear to be facilitated by motor commands for active digit placement in manipulation.

Educators and therapists must unify and formulate new strategies to address the academic and social needs of a newly emerging at risk demographic, "the forgotten middle." Currently, a paradigm shift within educative music therapy, human development study, and educational psychology, suggests that curriculums need to integrate alternative methods into their framework, change the definition of at-risk, and recognize math aptitude and social competency as predictors of a student's ability to gain upward mobility and self-sufficiency. Musical interaction, although considered a secondary measure within educational forums, is a viable means to address the socio-emotional and academic needs of students. In order to substantiate the need for educators to integrate educative music therapy and social competency programs into standard curriculums, the researcher conducted a study using 23 students from a beginning high school guitar class and 4 students from a high school after-school program. These students participated in a ten-week study involving educative music therapy, social competency, and math aptitude. Participants completed the math fluency and math calculations sections of the Wechsler's Individual Achievement Test version 3, along with a questionnaire examining the participants' beliefs about the influence of music on math aptitude and social competency. Although the pre- and post-test results show no statistically significant difference between educative music therapy and math aptitude, the results from the questionnaires administered suggest that students perceive that social competency and musical interaction augment academic and social performance.