**5. Conclusion**

User-centered design of virtual environments continues to be an under-studied area with regard to both old and young users. Knowledge of human performance, and the nature of the sensory feedback that guides it, will be imperative in the successful, cost-effective design of tangible user interfaces intended for use by these populations. Recent work has shown that young adults can utilize visual information provided in virtual environments differently than both older adults and young children, and therefore more specific agegroup studies are needed. Future studies will focus on specific parameters of visual feedback, such as luminance contrast, and how the provision of such properties in virtual environments impacts the performance of the user.
