Otemon Gakuin University
Summary  The present study investigated the differences in the attributes of episodes that participants remembered between recalled words and non-recalled ones in incidental free recall. Participants were asked to judge whether an episode came to mind when each target word was presented in the orienting task phase, followed by an unexpected free recall and rating phases. In the rating phase, they were asked to rate the degree of three attributes, vividness, pleasantness, and nostalgia, for each episode. Positive correlations among the three attributes were observed for episodes of recalled words, whereas for episodes of non-recalled words, they were not. These results showed strong relationships among the attributes of episodes that were determinants of the effectiveness of autobiographical elaboration on incidental recall regarding distinctiveness.
Elaboration in memory refers to adding more information to a target’s trace (Jacoby & Craik, 1979). The newly added information could be of many types, some of which, but not all, lead to effective elaboration. Thus, effective elaboration could lead to better recall, and the quality of the added information determines the effectiveness of elaboration. Toyota (1984) reviewed the research on elaboration in memory and indicated the contrast be­tween the two types of elaboration. Semantic elaboration refers to the addition of semantic information stored in semantic memory and autobiographical elaboration stored in episodic memory. The distinction between semantic and episodic memory is based on Tulving’s (1972) proposal. Autobiographical elaboration was first proposed by Warren, Chattin et al. (1983). Each target was presented to the participant and asked to rate how long it had been since its last visual contact with the object indicated by each target on a temporal category scale (e.g., minutes, hours, day, week, month, year), followed by a free recall test. The found “recency effect,” namely target words rated in temporally recency position (e.g., minutes, hours), were recalled more often than those in temporally primacy position (e.g., month, year). They also showed that target words with visual contact were recalled more often than were those with no visual contact. When the participants remembered the visual contact with the object indicated by the target word, they added autobiographical information, namely, personal epi­sodes. Therefore, they elaborated on each target word using their episodes.
Toyota (1989) also replicated the “recency effect” using Kanjimaterials in Ex.1. He fo­cuses on the determinants of the effectiveness of autobiographical elaboration in Ex. 2 to 4. In the orienting task of Ex.2, participants were asked to rate the number of episodes that came to mind for each target word, followed by an incidental free recall test. The targets rated as eliciting many episodes were recalled more often than those that did not. This result showed that the number of episodes elicited by a target word determined the effectiveness of autobiographical elaboration. Ex.3 investigated whether the pleasantness of an episode determined the effectiveness of autobiographical elaboration. The targets rated as eliciting pleasant episodes were recalled more often than those that did not. This result showed that the pleasantness of an episode elicited by a target word was the determinant of the effectiveness of autobiographical elaboration. In the orienting task of Ex. 4, participants were asked to rate the vividness of an episode that came to mind for each target word, followed by an incidental free recall test. The targets rated to elicit vivid epi­sodes were recalled more often than those that were dull. This result showed that the vividness of an episode elicited by a target word was the determinant of the effectiveness of autobiographical elaboration. Episodes, including any person (social memories), became more vivid than those not involving any person (non-so­cial memories). Toyota (2012) investigated the difference in recall performance between target words associated with social memories and those associated with non-social memo­ries. The results showed that targets with social memories were recalled more often than those with non-social memories.
According to Hunt (2006), distinctiveness is a critical memory factor. This result was interpreted in terms of distinctiveness. Namely, episodes with social memo­ries made targets more distinctive than those with non-social memo­ries. Therefore, the person’s information in an episode determines the effectiveness of autobi­ographical elaboration. McDonough and Gallo (2008) used the distinctive heuristic (Schacter et al. 1999) to explain that autobiographical elaboration reduces false recognition. “This heuristic is used when one correctly rejects an item as having been studied in a tar­get source because that item does not bring to mind detailed recollections that would be ex­pected if it had been studied in that source”(p1430). Specifically, autobiographical elaboration makes the target distinctive by adding personal episodes. Thus, the target’s degree of distinc­tiveness determines the effectiveness of autobiographical elaboration.
Although some attributes in an episode were identified as determinants of the autobio­graphical elaboration’s effectiveness, the relationships among these attributes, such as pleasantness and vividness, were not clarified (Toyota, 1989). Cheung et al. (2018) has focused on nostalgia in autobiographical memory functions and stressed the uniqueness of its positive effect compared to rumination and counterfactual thinking. Nostalgia is also assumed to be a critical attribute of effective autobiographical elabora­tion. If so, targets with episodes involving nostalgia would be recalled more often than those without nostalgia.
The present study examined the relationships among these attrib­utes, pleasantness, vividness, and nostalgia, using correlations between each pair attrib­ute to induce strong relationships. As an episode with strong relationships among attrib­utes would be more distinctive than those with weak relationships, the former episode would be an effective cue for retrieving the target associated with it. Thus, targets with strong relationships among attributes are recalled more than those with weak relationships. The present study also used Cronbach’s alpha to index the strong relationships among attributes.
It was predicted that positive correlations among rating scores of these attributes and higher alpha were observed in recalled targets. Nevertheless, those correlations and alpha were not in non-recalled targets. The purpose of the present study is to examine this prediction.
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