Working memory capacity (WMC) is critical in maintaining goal-directed behavior and in inhibiting task irrelevant or conflicting thoughts. Using eye tracking data, the current study developed measures to investigate users' experiences of presence. We investigated the cognitive processing mechanisms of feelings of presence by examining how users of varying WMC coordinate their attention between their actions in using external controllers for computer mediated environments, and the actions produced by their avatars in virtual environments. To rule out the possibility of participants acting out of social pressure, a well-practiced everyday task with minimal social component was used. Participants performed vegetable cutting tasks in a desktop virtual environment by controlling an avatar's arm, with no pressure (Experiment 1) versus while pressured to improve the evenness of their cuts (Experiment 2). The results showed that high WMC participants experienced higher degrees of presence, as indicated by the attention allocated to the avatar's hand and to task planning. Under performance pressure, low WMC participants became more immersed in the tasks. The mechanisms of adaptive and personalized presence in virtual world simulation training environments are discussed in light of our findings on the effects of pressure and individual differences of WMC in experiencing presence.