The present thesis starts by exploring the possibility of eliciting involuntary autobiographical memories (ABMs) in the laboratory, as a preliminary step in studying the retrieval process of involuntary ABMs. The main aim of the thesis is to test whether involuntary AMBs (IAMs) can be successfully elicited in the lab, to assess whether cue manipulation changes the patterns of memories reported, and to compare IAMs and voluntary ABMs. We adopted the basic experimental paradigm recently developed by Schlagman & Kvavilashvili (2008) with a slight but important modification to it. A series of seven experiments were conducted and a total of 310 participants, participated in these experiments. Results of Experiments 1 indicate that instructing participants about involuntary memories increased significantly the number of involuntary memories reported. A clear increase in memories was obtained also when the interruptions were scheduled by the experimenter. These results indicate that the amount and type of involuntary memories depends strongly on the method used to elicit these memories. Three subsequent experiments (Exp, 2, 3, 4) have been devised to examine whether it is possible that by manipulating the cues in an experimental setting, different numbers of involuntary autobiographical memories are elicited, and memories have different qualities. The results of both experiments 2 and 3 confirm that pictorial cues are less effective in triggering IAMs than the verbal cues of the same items. In Experiment 4 we tested the possibility that concrete verbal material elicits more memories than abstract verbal material. The results of this study indicated that concrete verbal cues elicited more than twice as many IAMs than abstract verbal cues, showing that a clear concreteness effect was found when retrieval is involuntary. To explore the role of additional visual details and the distinctiveness of the items in a visual cue in triggering involuntary autobiographical memories, Experiment 5 was conducted. We found that the addition of visual details did not have a significant effect on the number of reported IAMs. In Experiment 6 we examined if adding a relatively specific detail to the cue would enhance the likelihood for that cue to trigger an involuntary memory. The results of this study showed that adding specific details to a cue tends to enhance the possibility to retrieve involuntary memories for personal events, although the results are not significant. To assess whether the effect of the concreteness/imageability of the cues observed in involuntary memory retrieval can be obtained in a parallel task in which autobiographical memories are obtained through voluntary retrieval we ran the last experiment (Exp 7) in the dissertation. The results of this experiment confirm the difference in effectiveness between concrete/high imagery and abstract/low imagery cues already found in Experiment 4. The results of Experiment 7 show that concrete cues are more effective in general, independently of the type of retrieval, whether involuntary or voluntary. Overall, these results indicate that involuntary memories can be elicited in a lab setting, that by manipulating the cues one manipulates also the number and characteristics of involuntary memories. In addition and unexpectedly, involuntary memories are about general and single events. This result is the opposite of what has been known from diary studies about IAMs, which have been reported as being more specific compared to voluntary memories. We offer a number of explanations of why IAMs are less specific than voluntary memories. However, being post-hoc explanations, work still needs to be done to assess them in a direct way
