I didn't know that you knew I knew: Collaborative shopping practices between people with visual impairment and people with vision

It is important to support independent living for people with visual impairments (PVI). Part of this can be accomplished with individual assistive technologies. However, in this paper we emphasize the social and collaborative needs for PVI to fully integrate into society as equals. The study assesses how PVI collaborate with different types of sighted partners when shopping together. We chose to study grocery shopping because it is a critical and challenging task for PVI. We conducted field observations and in-depth interviews with five PVI and their sighted shopping partners, including spouses, caseworkers, and store-provided courtesy shoppers. We found several factors that modulated these collaborations with varying forms of common ground: 1) knowledge about how to assist PVI; 2) interpersonal knowledge resulting from common experience and interpersonal relationship history; and 3) knowledge of shopping as a practice. We discuss our findings with respect to the implications for designing collaborative interactions.