Despite the abundant literature on attachment processes and the development of a secure or insecure attachment orientation during childhood, it is still unclear whether adult attachment style can be changed through systematic interventions, and if so how the change process works. One way to learn more about such change is to create it, on a small scale, in the laboratory. It is already known that a person's sense of security can be momentarily changed in the laboratory (Mikulincer & Shaver, 2007a). But there is clearly a difference between very short-term and longer-term change. According to Bowlby (1982), the development of an attachment orientation in childhood is based on many encounters and interactions with caregivers, which gradually create a mental network of relatively stable expectations and concerns. Thus, it may take many episodes of security priming in a laboratory to begin to affect a young adult's attachment style in a lasting way. Here, we explore this possibility, review existing evidence from our own and other researchers’ laboratories, and discuss directions for future research.