As prosthetic and orthotic components and devices increase in complexity, as well as expense, additional scrutiny has arisen regarding their outcomes and effectiveness. Quality research outcomes, as well as both self-reported and clinician-measured outcome measures, have never been more important. However, increased device complexity carries with it an additional factor that could confound all these vital outcome measures: what if the user shows more favorable outcomes simply because they are aware that a particular device is more advanced, regardless of its actual function? This is an example of a well-established cognitive phenomenon called Confirmation Bias, which occurs when perceptions of a stimulus are affected by an observer’s expectations about the stimulus. This project builds on our ground-breaking prior research to determine if confirmation bias can affect both user-reported outcomes and clinical movement outcomes when healthy older adults are led to believe they are using an advanced, computerized knee orthosis. Participants will take part in the five-repetition sit-to-stand activity in a baseline condition and while fitted with two knee orthoses. The orthoses will be functionally identical, but the participants will not know that. We will alter one set of orthoses to make them appear advanced and computerized. We will explain the enhanced functions to the participants and go through the process of allowing the pseudo-advanced orthosis to “learn” their knee motion so that it can “dynamically adjust” to stabilize and assist the joint. Following the presentation of the unmodified and modified KOs but before use, we will use a survey to assess opinions regarding expected function. Then, participants will complete the sit-to-stand exercise. We will measure standard clinical outcomes as well as literature-based 3D kinematics and kinetics. Following movement trials, we will repeat the survey to measure opinions regarding actual performance. We hypothesize that users will prefer the “advanced” orthosis, both before and after use. Our prior data further indicate that users will increase their preference for the pseudo-advanced orthosis after use, indicating the impact of confirmation bias in a self-reported outcome. In addition, we hypothesize that, while our previous data on walking outcomes showed no differences, these more sensitive outcomes in a different population will reveal altered performance with the “advanced” orthosis. This will indicate that confirmation bias can result in altered movement patterns, even when the orthopedic device offers no differential functional advantage. These results, pending but pilot data is successfully collected on the baseline condition, will have a positive impact because they will establish a critical need for blinding when conducting research with advanced or expensive orthopedic devices, and the need for clinician understanding of the potential impacts of cognitive biases in their patients