Carrying out of delayed time-based tasks - self-initiated use of environmental support?

A series of quasi-experimental field studies (n(1) = 37, n(2) = 117, n(3) = 113) analyzed the impact of task characteristics and of the subjects' proc edure on the carrying out of delayed repeated time-based intentions. The pe riod covered by the tasks varied from 2 to 14 weeks. The main issue is whet her time-based "prospective memory" or memory for delayed intentions in non -deprived real-life settings is based on spontaneous self-initiated retriev al (Einstein & McDaniel, 1996) or on environmental support (Rabbit, 1996). People rely on neither spontaneous activation nor on automatically emerging cues but generally seek or design a self-initiated support system in takin g upon the delayed tasks and redefining them into a retrieval-supporting ve rsion. The rate at which tasks are carried out is significantly higher with people who seek and design support. However, the elaborating self-planning of intentions per se, without an enlargement of cues or tagging, does not improve retrieval. Although a prescribed external cue and a context-related type of dare did not improve performance, they did prevent its deteriorati on for weeks. If no such support is provided performance decreases over the period of delay, whereas response spacing and repetition frequency are of no effect. The cited alternative of spontaneaus retrieval vs. environmental ly cued task realization should be replaced by their cooperation. A related model is outlined.