Egocentric source monitoring errors following ...

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Collaboration inflation: Egocentric source monitoring errors following collaborative remembering Ira E. Hyman Jr. ∗ , Rebecca F. Roundhill, Kiernan M. Werner, Calvin A. Rabiroff Western Washington University, United States

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Article history: Received 22 October 2013 Received in revised form 7 April 2014 Accepted 15 April 2014 Available online xxx Keywords: Collaborative remembering Source monitoring Egocentric memory bias Social contagion in memory

a b s t r a c t Following collaborative remembering, people may adopt their partner’s contributions as their own memory. In two studies, we asked people to study partially overlapping lists of words. During collaborative remembering, dyads either worked to include all words no matter who studied them or limited recall to only words studied by both dyad members. This differential focus on source information during collaborative recall impacted performance on a later source memory test. Nonetheless we found frequent source monitoring errors that displayed an egocentric bias. People were more likely to claim their partner’s contributions as their own memories than attribute their memories to their partners. In collaborative remembering, people work to construct an agreed upon version of the past that quickly becomes each individual’s memory. © 2014 Published by Elsevier Inc on behalf of Society for Applied Research in Memory and Cognition.

1. Introduction Collaborative remembering serves a variety of purposes. Friends and families collaboratively remember to strengthen social bonds and develop a collective history (Bluck, 2003; Bluck, Alea, Habermas, & Rubin, 2005; Hirst & Manier, 2008; Hyman, 1994, 1999; Hyman & Faries, 1992; Pillemer, 1992). Students engage in collaborative remembering as they study to better master their course material. More generally, people reconstruct their individual experiences as they respond to their audience (Hirst & Echterhoff, 2012; Marsh & Tversky, 2004). Through collaborative remembering, individuals may reshape their own memories. For example, individuals may have more complete memories as a result of collaborative remembering (Blumen & Rajaram, 2008; Rajaram & Pereira-Pasarin, 2007, 2010) and may adopt the collaboratively constructed memory as their ongoing personal memory (Cuc, Ozuru, Manier, & Hirst, 2006; Hirst & Echterhoff, 2012; Hyman, 1999). In this fashion, collaborative remembering may lead to an egocentric memory bias such that people claim the collaborative memory as their personal memory during later memory tests (Hyman, 1999). When people remember collaboratively, they approach the task differently than individuals remembering in a memory experiment and these differences may impact their memories on later tasks.

∗ Corresponding author. Tel.: +1 360 650 3519; fax: +1 360 650 7305. E-mail address: [email protected] (I.E. Hyman Jr.).

Compared to individuals remembering for an experimenter, people remembering in dyads include fewer details and more interpretations, emotional reactions, and personal connections to a story (Hyman, 1994). Collaborative remembering results in retelling rather than attempts at detailed retrieval as people make their recollections interesting and entertaining (Marsh, 2007). Additionally, collaborative remembering often results in groups searching for an agreed upon version of the past (Cuc, Koppel, & Hirst, 2007; Cuc et al., 2006; Edwards & Middleton, 1986; Hyman, 1994; Hyman, Cardwell, & Roy, 2013). Thus collaborative groups frequently make fewer errors (Ekeocha & Brennan, 2008; Hyman et al., 2013; Ross, Spencer, Blatz, & Restorick, 2008). Collaborative remembering also results in collaborative inhibition such that collaborative groups remember more than individuals but less than nominal groups – the combined unique contributions of the same number of people remembering individually (Basden, Basden, Bryner, & Thomas, 1997; Rajaram & Pereira-Pasarin, 2010; Weldon & Bellinger, 1997). Since collaborative groups remember differently from individuals, there are consequences for individuals’ memories. For example, collaborative remembering provides additional study of items that people may not have remembered on their own. Thus individuals who participated in collaborative remembering provide more information on later memory tests than individuals who engaged in previous individual remembering (Rajaram & PereiraPasarin, 2010) particularly in situations that minimize collaborative retrieval disruptions (Blumen & Rajaram, 2008). In addition, collaborative groups may develop a retrieval strategy that becomes

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Please cite this article in press as: Hyman Jr., I. E., et al. Collaboration inflation: Egocentric source monitoring errors following collaborative remembering. Journal of Applied Research in Memory and Cognition (2014), http://dx.doi.org/10.1016/j.jarmac.2014.04.004

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the organization that group members use on subsequent recalls (Congleton & Rajaram, 2013). One important impact of collaborative remembering is that individuals may incorporate information from others as part of their own memory. Thus the shared version of the past that collaborative groups develop may become the memory reported by individuals on later recalls (Cuc et al., 2006). Hirst and his colleagues have argued that this is how groups develop collective history (Hirst & Echterhoff, 2012; Hirst & Manier, 2008). Additionally, people may adopt shared narratives as their personal narratives in order to be identified as part of the group (Hyman, 1999). The individual adoption of collaboratively remembered information means that collaborative remembering effectively introduces misleading postevent information (Paterson & Kemp, 2006). For example, Roediger, Meade, and Bergman (2001) found that people adopted misleading information provided by a conversation partner who was an experimental confederate. The participants not only falsely remembered misinformation but also made source monitoring errors, believing they had seen the information rather than learned it from their partner (see also Meade & Roediger, 2002). In these cases, the participants were led to believe that they and their collaborative partners studied the same material. In many real world situations, however, people know that they and their collaborative partners have not experienced the exact same events. When people witness an event they do not all have the same view, see the same aspects, or experience the entire event. When families remember, individuals frequently have limited knowledge, dispute recollections, and share only partially overlapping memories. These situations may encourage people to carefully monitor the contributions of their partners and resist adopting information. In some contexts people may work to discover what aspects of an event they all remember – a form of collaborative memory accuracy test. In other contexts people may strive to include all recalled information regardless of who recalled the information. In yet other context people may argue over past events and work to maintain their individual recollections in the face of different stories from collaborative remembering partners. In these different types of social settings people may be variously focused on the source of remembered information. A focus on source information may influence the extent to which people incorporate false information into their memories. For example, people resist misinformation after warnings in eyewitness memory studies (Echterhoff, Hirst, & Hussy, 2005; Greene, Flynn, & Loftus, 1982). Additionally, when people are instructed to attend to source information, they make fewer memory errors (Henkel, Franklin, & Johnson, 2000). Further, experimental situations that encourage the encoding of contextual information also decrease source monitoring errors in memory (Thomas & Bulevich, 2006). In two experiments, we investigated how well people tracked the source of information following collaborative remembering. Participants individually studied categorized word lists that only partially overlapped; that is, some words were studied by both individuals whereas other words were studied by only one individual (see Fig. 1). Prior to collaborative remembering, all dyads were informed that they had studied partially overlapping lists. In many respects this resembles real world situations in which people realize they have different recollections of a shared past experience. We then varied collaborative retrieval instructions. Some dyads were given inclusive instructions – recall all words regardless of who originally studied the words. The other dyads were given exclusive instructions – only recall words that were studied by both dyad members. Our instructions were designed to focus the exclusive dyads of the source of information, much as real world groups may focus on differences in who experienced various aspects of a

Within Each Category Person A: 10 words

5 words only by Person A

Person B: 10 words

5 words by BOTH

5 words only by Person B

5 words by Neither Fig. 1. Illustration of the partially overlapping word lists for each of the 6 categories.

common event. Following collaborative remembering participants took individual source monitoring tests (Lindsay & Johnson, 1989; Zaragoza & Koshminder, 1989). They were asked if each word was studied by both members of the dyad, only the self, only their partner, or neither. We anticipated that individuals would experience some difficulties tracking source. Following the collaborative generation of problem solutions and stories, people experience difficulty on source tests for ideas (Barber, Franklin, Naka, & Yoshimura, 2010; Foley, Foley, Durley, & Maitner, 2006; Foley, Ratner, & House, 2002) and people often display unconscious plagiarism (Landau & Marsh, 1997; Stark & Perfect, 2007). Based on source monitoring theory, however, we anticipated that individuals in the exclusive condition would be more accurate on the source monitoring test (Johnson, Hashtroudi, & Lindsay, 1993). These individuals engaged in source monitoring during collaborative remembering and may more effectively use source information during the individual memory test (Henkel et al., 2000; Thomas & Bulevich, 2006). We were also interested in whether source misattributions would reveal a directional pattern. One goal of collaborative remembering is to construct shared narratives that individuals adopt as their own memories (Cuc et al., 2006; Hirst & Echterhoff, 2012; Hirst & Manier, 2008; Hyman, 1994, 1999). In many situations, people readily claim suggestions as their memories, such as the creation of false childhood memories (Hyman, Husband, & Billings, 1995) and in social contagion (Roediger et al., 2001). In addition, people will incorrectly claim that they performed an action that they observed someone else perform – an observation inflation effect (Lindner, Echterhoff, Davidson, & Brand, 2010; Lindner, Schain, Kopietz, & Echterhoff, 2012; Schain, Lindner, Beck, & Echterhoff, 2012). Interestingly, Lindner et al. (2010) found that even when participants were focused on source information, the observation inflation effect was not diminished – people still claimed other individual’s actions as their own. Thus we investigated if errors would show an egocentric memory bias (Greenwald, 1980; Ross & Sicoly, 1979). We studied whether participants would be more likely to misattribute their partner’s memories to themselves than their own contributions to their partners following collaborative remembering and particularly if being focused on the source of the information would influence any egocentric bias observed (Cuc et al., 2006; Hyman, 1999).

Please cite this article in press as: Hyman Jr., I. E., et al. Collaboration inflation: Egocentric source monitoring errors following collaborative remembering. Journal of Applied Research in Memory and Cognition (2014), http://dx.doi.org/10.1016/j.jarmac.2014.04.004

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2. Experiment 1 2.1. Method 2.1.1. Participants The participants were undergraduates fulfilling course research participation requirements (28 men, 34 women; Mage = 20.10, SD = 4.50). There were 14 inclusive dyads and 17 exclusive dyads. 2.1.2. Materials and procedure Dyad members individually studied 60 words presented in 2second intervals via PowerPoint on a computer screen. The words were blocked in 6 categories with 10 words in each. Dyad members were shown partially overlapping word lists (see Fig. 1). In each category 5 words were shown to both individuals, 5 words were unique to each individual, and 5 words were studied by neither dyad member and used as distracters on the source memory test. Two different study sets varied order and category subset presentation. After encoding, individuals worked on mazes for two minutes. During study and the maze task dyad members were in separate small testing rooms. Next participants moved to a table in an adjoining larger room and collaboratively recalled the words in same sex dyads. All dyads were informed that they studied partially overlapping word lists. Dyads first selected one member to serve as the scribe. Dyads were given either inclusive or exclusive recall instructions. Inclusive dyads were asked to recall all words, regardless of who originally studied the words and thus had little reason track source information. Exclusive dyads were asked to only write down the words that had been studied by both individuals. This manipulation was designed to focus participants on the source of remembered words. In both conditions, participants were informed that they had studied partially overlapping lists. Dyads were given as much time as they needed. The experimenter was present during the collaborative remembering and when dyads had passed 30 s without recalling any additional words, they were asked if they were ready to move on to the next task. Participants then individually completed a five-minute math task. In the final phase of the experiment, individuals completed a source memory test. The source memory test consisted of all 120 words. For each category, there were 5 words that both dyad members studied, 5 words that only the participant studied, 5 words that only the partner studied, and 5 words that neither dyad member studied. For each item on the source memory test, individuals identified the original source: whether the word was studied by both dyad members, only the self, only their partner, or neither dyad member. Thus the memory test combined recognition and source in a single response. 2.2. Results We first examined collaborative remembering performance and then the individual source monitoring. Collaborative remembering was examined based on the instructions – inclusive or exclusive. We expected that inclusive instructions would yield more words included in the recall than the exclusive instruction: Subjects in the exclusive condition should have rejected words when they could verify that only one individual studied the words. We then examined performance on the source monitoring test taken by the individuals. We predicted that individuals in the exclusive condition would more accurately identify source than those in the inclusive condition. We also predicted that participants would display an egocentric source monitoring bias – incorrectly attributing words studied by their partners to themselves more often than erroneously attributing self studied words to their partners.

Fig. 2. Number of words collaboratively recalled in Experiment 1 based on who studied the words and retrieval instructions (error bars are 95% CI).

2.2.1. Collaborative remembering We investigated the level of collaborative recall based on instructions and whether the words were studied by both members of a dyad or only a single member (see Fig. 2). Using a 2 × 2 mixed model ANOVA, we found a main effect of recall instruction such that dyads given inclusive instructions recalled more words than those given exclusive instructions, F(1, 29) = 21.17, MSE = 39.33, p < .001, partial eta2 = .42, and a main effect of who studied the words such that words studied by both members of a dyad were more likely to be recalled, F(1, 29) = 4.99, MSE = 10.01, p = .033, partial eta2 = .15. These main effects were moderated by a significant interaction, F(1, 29) = 24.77, MSE = 10.01, p < .001, partial eta2 = .46. The effect of who studied the words appears to be an artifact of the interaction because the recall advantage of both individuals studying the words only appeared in the exclusive condition. Exclusive dyads followed the instructions and generally excluded words that only a single member studied making them more conservative in reporting the words that both members studied and particularly the words studied by only one individual. We also looked at the number of errors in collaborative recall. Because the words were category exemplars, intrusions were likely to occur (Deese, 1959; Roediger & McDermott, 1995). We found low overall error rates and a trend toward an effect of instructions such that inclusive instructions resulted in an average intrusion rate of 0.57 (SD = 0.76) and exclusive in an error rate of 0.18 (SD = 0.39), t(29) = 1.87, p = .07, Cohen’s d = .69. This is consistent with exclusive dyads employing more stringent criteria than inclusive dyads. In summary, instructions influenced collaborative recall suggesting that the exclusive dyads used source information to limit the words reported. 2.2.2. Individual source monitoring We first looked at overall levels of accuracy on the source monitoring test. We did this both for words that had been included in a dyad’s collaborative recall and for words not recalled. Non-recalled words included words that a dyad may have considered but which they did not include in their collaborative recall. A 2 × 2 mixed-model ANOVA revealed an effect of whether or not words were collaboratively recalled, F(1, 60) = 435.59, MSE = 98.60, p < .001, partial eta2 = .88, an effect of dyad instructions, F(1, 60) = 5.80, MSE = 188.45, p = .019, partial eta2 = .09, and no interaction, F(1, 60) = 0.94, MSE = 98.60, p = .34, partial eta2 = .02. All participants were more accurate in source monitoring for words that were collaboratively recalled. In addition, there was a moderate sized effect of instructions such that individuals who engaged in exclusive instructions were more accurate than those who followed inclusive instructions (see Fig. 3). When words were not included in the collaborative recall, participants were essentially assigning

Please cite this article in press as: Hyman Jr., I. E., et al. Collaboration inflation: Egocentric source monitoring errors following collaborative remembering. Journal of Applied Research in Memory and Cognition (2014), http://dx.doi.org/10.1016/j.jarmac.2014.04.004

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Fig. 3. Percentage of correct individual source attributions in Experiment 1 based on whether the words were included in the collaborative recall and retrieval instruction (error bars are 95% CI).

words to the correct source at chance levels. But even when the words were included in the collaborative recall, participants made many source attribution errors. We thus looked for an egocentric bias in source misattributions. Self-directed attribution errors included words attributed to the self alone that had actually been studied only by one’s partner or by both dyad members. Conversely, partner-directed attribution errors included words erroneously attributed to one’s partner that had been studied by the self alone or by both. Using a 2 × 2 mixed-model ANOVA, we found a main effect of direction of error, F(1, 60) = 96.92, MSE = 21.34, p < .001, partial eta2 = .62, no main effect of dyad instructions, F(1, 60) = 0.04, MSE = 23.53, p = .85, partial eta2 = .001, and no interaction, F(1, 60) = 0.06, MSE = 21.34, p = .81, partial eta2 = .001. No matter what instructions they were given, all individuals were more likely to erroneously attribute words to themselves (M = 12.24, SD = 5.49) than erroneously attribute words to their partners (M = 4.02, SD = 3.74). In this experiment, we found that exclusive dyads tracked who originally studied words and used that information to guide collaborative remembering. The individuals from exclusive dyads were also better at correctly attributing words to their original sources on the source monitoring test. Nonetheless, all individuals made frequent errors in source monitoring. These errors followed an egocentric bias: Participants more often erroneously attributed words to themselves than to their partners. One limitation of this experiment is that dyads discussed some words that were not included in their eventual collaborative recalls. Since those conversations were not recorded, no data exists for words mentioned during collaborative remembering but not included in the collaborative recall. Thus in the second experiment, the memory conversations were recorded. This allowed for a new type of word in the collaborative recall – mentioned, but not recalled.

3. Experiment 2 3.1. Method 3.1.1. Participants Participants were undergraduates fulfilling course requirements for lower-level psychology classes (32 men, 32 women; Mage = 19.52, SD = 1.56). There were 16 inclusive dyads and 16 exclusive dyads.

Fig. 4. Number of words collaboratively recalled and simply mentioned in Experiment 2 based on who studied the words and retrieval instructions (error bars are 95% CI).

3.1.2. Materials and procedure Experiment 2 was an exact replication with the addition of recording each dyad’s collaborative recall. Thus we documented words that dyads mentioned but did not include in their written recall. All participants were aware that they were being recorded and permission to record was included in the consent form. 3.2. Results As with Experiment 1, we first examined collaborative recall based on the inclusive and exclusive instructions. Since the collaborative recalls were recorded, we had additional data concerning words mentioned during the collaborative remembering but not written down as part of the agreed-upon collaborative recall. After analyzing the collaborative recall, we then evaluated the individual source monitoring performance. 3.2.1. Collaborative recall We looked at the number of words recalled and the number mentioned based on the retrieval instructions (see Fig. 4a). We found a main effect of how words were included in the collaborative recall such that overall more words were recalled than simply mentioned, F(1, 30) = 59.56, MSE = 36.50, p < .001, partial eta2 = .67, no main effect of dyad instructions, F(1, 30) = 1.64, MSE = 33.26, p = .21, partial eta2 = .05, and a significant interactions F(1, 30) = 132.82, MSE = 36.50, p < .001, partial eta2 = .82. The interaction is clearly stated. Inclusive dyads recorded almost every word considered and rarely mentioned words without including them in their recall (7 of the 16 inclusive dyads never mentioned a word without including it

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in their recall). Exclusive dyads, in contrast, more often mentioned words without recalling the words. Much of the difference in recalled and mentioned words was based on who studied the words (see Fig. 4b). For recalled words, we found a main effect of who studied the words such that words studied by both were more likely to be recalled than words studied by one person, F(1, 30) = 5.51, MSE = 6.53, p = .026, partial eta2 = .16, a main effect of instructions with inclusive instructions resulting in more recall than exclusive instructions, F(1, 30) = 58.42, MSE = 25.37, p < .001, partial eta2 = .66, and an interaction, F(1,30) = 264.06, MSE = 6.53, p < .001, partial eta2 = .57. The interaction replicates the pattern in Experiment 1: Inclusive instructions resulted in greater recall overall, particularly for words studied by one person. In addition, the advantage for words studied by both dyad members only occurred for exclusive dyads. For words mentioned but not recalled, the pattern flipped. There was a main effect of who studied the words such that words studied by one person were more likely to be mentioned without being recalled than words studied by both dyad members, F(1, 30) = 41.12, MSE = 7.77, p < .001, partial eta2 = .58. There was also a main effect of instructions with exclusive dyads mentioning more words than inclusive dyads, F(1, 30) = 101.90, MSE = 9.51, p < .001, partial eta2 = .77. In addition, there was an interaction, F(1, 30) = 38.85, MSE = 7.77, p < .001, partial eta2 = .56. The overall pattern demonstrates that the dyads with exclusive instructions were attending to and using information about source to guide collaborative recall. In contrast, the inclusive dyads essentially included all words in their collaborative recall that either member suggested. Intrusions during collaborative recall also showed that dyads differentially used source information. We found a perfect crossover interaction of dyad instructions and whether intrusions were included in the recall or mentioned without being recalled, F(1, 30) = 7.56, MSE = 0.38, p < .001, partial eta2 = .40. The inclusive dyads were more likely to include intrusions in their recall (M = 0.88, SD = 1.09) than mention the words without recalling (M = 0.19, SD = 0.54). In contrast, the exclusive dyads mentioned possible intrusions (M = 0.88, SD = 0.81) more often than they recalled intrusions (M = 0.19, SD = 0.40). Both the effects of dyad instructions and recall or mention were non-significant (Fs = 0.00). 3.2.2. Individual source monitoring For the source monitoring test, we examined how successfully the participants attributed source for recalled or mentioned words and words that were not mentioned in the collaborative recall. Since these conversations were recorded, this comparison is not an exact replication of Experiment 1. Without recording, any words that were mentioned but not recalled were included in the not recalled set of words. In this experiment, we included mentioned words with the recalled words since the dyads considered the words during collaborative recall. Using a 2 × 2 (recalled/mentioned or not recalled by dyad instructions) mixed-model ANOVA, we found a main effect of whether the words were included in the collaborative recall such that recalled and mentioned words were more likely to be correctly attributed than words that were not recalled, F(1, 62) = 559.95, MSE = 88.58, p < .001, partial eta2 = .90. There was also a main effect of dyad instructions such that individuals from the exclusive dyads were more accurate than individuals from inclusive dyads, F(1, 62) = 5.16, MSE = 131.94, p = .027, partial eta2 = .08. The effect of dyad instructions was modified by an interaction, F(1, 62) = 14.86, MSE = 88.58, p < .001, partial eta2 = .19. For words that were not included in the dyad conversations, there was no effect of dyad instructions (see Fig. 5). For the individuals from the exclusive dyads, source monitoring accuracy was further examined by comparing recalled,

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Fig. 5. Percentage of correct individual source attributions in Experiment 2 based on whether the words were included in the collaborative recall and retrieval instruction (error bars are 95% CI).

Fig. 6. Direction of source misattribution errors in Experiment 2 (error bars are 95% CI).

mentioned, and not recalled words (this comparison was not possible for the inclusive dyads since many did not have any words that were mentioned but not recalled). There was a main effect of how the words appeared in the collaborative remembering, F(1, 62) = 138.27, MSE = 176.81, p < .001, partial eta2 = .82. Tukey’s follow-up comparisons (p < .05) indicated that words that were recalled (M = 67.11, SD = 16.80) were more accurately attributed than words that were only mentioned (M = 57.55, SD = 15.48) which were more accurately attributed than words not recalled (M = 15.18, SD = 7.35). Finally we checked for an egocentric bias in source misattributions (see Fig. 6). Using a 2 × 2 (direction of source misattributions by dyad instructions) mixed-model ANOVA, we found a main effect of the direction of source misattributions such that participants more often made errors attributing words to the self than errors attributing words to the partner, F(1, 62) = 49.92, MSE = 29.34, p < .001, partial eta2 = .45. There was no overall effect of dyad instructions, F(1, 62) = 3.12, MSE = 24.52, p = .082, partial eta2 = .05, but there was a significant interaction, F(1, 62) = 7.25, MSE = 29.34, p = .009, partial eta2 = .11. The interaction reflects the finding that although the egocentric bias appeared overall, the effect was stronger for individuals from exclusive dyads. 4. Discussion and practical applications We found that dyads used source information during collaborative remembering. In particular, the exclusive dyads recalled fewer words than the inclusive dyads because they correctly rejected

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words that only one member studied. The exclusive dyads also more frequently rejected words that both members studied and words that neither studied. In the source monitoring test, individuals were able to correctly identify source to a limited extent. Individuals from exclusive dyads more accurately attributed source than individuals from inclusive dyads. Our finding that dyads with exclusive instructions used source information during collaborative remembering is consistent with other work concerning warnings and source monitoring. When warned about misleading information, participants are generally able to use that warning to limit the inclusion of misleading information in later memory tests (Echterhoff et al., 2005; Greene et al., 1982; Weingardt, Loftus, & Lindsay, 1995). People can also use source information to guide remembering when specifically instructed to do so (Henkel et al., 2000; Thomas & Bulevich, 2006). Our studies extend the effect of careful source monitoring to the product of collaborative remembering. Nonetheless, participants made frequent source attribution errors on the later individual source monitoring test, showing an egocentric memory bias. This is not the traditional egocentric memory bias in which people display better memory for self-related information (Greenwald, 1980) or remember the self differently from other individuals (Hyman & Neisser, 1992). Instead participants claimed their collaborative partners’ memories as their own more often than they attributed their memories to their partners. This egocentric source memory bias is consistent with other types of memory errors such as unconscious plagiarism (Landau & Marsh, 1997; Stark & Perfect, 2007), claiming additional credit for shared work (Ross & Sicoly, 1979), social contagion in memory (Meade & Roediger, 2002; Paterson & Kemp, 2006; Roediger et al., 2001), the creation of false childhood memories (Hyman et al., 1995), and observation inflation (Lindner et al., 2010, 2012; Schain et al., 2012). In all these examples, people claim other’s ideas, work, and memories as their own. Source monitoring theory offers possible explanations for this egocentric bias (Johnson et al., 1993). When the original sources are similar, people are more likely to make source errors. For example, people are more likely to falsely remember someone else’s actions as their own for in-group rather than out-group actors (Lindner et al., 2012) and people make few self-other confusions for a real life version of an observation inflation experiment (Rosa & Gutchess, 2011). In our experiments, the two participants engaged in the same encoding and collaborative remembering tasks. In addition, they share features since they are college students in same gender dyads. While similarity of source would lead to more attribution errors, it would not, however, predict the egocentric bias. Another aspect of source monitoring theory may nonetheless account for the egocentric bias. The participants may have lost memory for the original source information. When they considered the item on the source test, they were remembering it at that moment – it was their memory on the test regardless who studied that information originally. Thus people may adopt collaborative memories as personal memories because they are remembering the information in the current moment. Egocentric source monitoring errors may be a fundamental directional bias in memory – claiming information from others as personally experienced and personally remembered (Hyman, 1999). As people share their stories about the past, they construct a socially agreed upon version (Edwards & Middleton, 1986; Hyman, 1994; Hyman et al., 2013). Hirst and his colleagues have documented that individuals’ memories are influenced by what groups collaboratively recall and exclude (Cuc et al., 2007, 2006; Hirst & Echterhoff, 2012; Hirst & Manier, 2008; Muller & Hirst, 2010). Malleable memory systems allow socially induced changes in memories to improve social cohesion and allow individuals to update their memories (Drivdahl & Hyman, 2013; Hyman, 1999;

Newman & Lindsay, 2009). Shared collaborative memories can also improve individuals’ memories by providing an additional study opportunity (Blumen & Rajaram, 2008; Rajaram & Pereira-Pasarin, 2007). Although the updating of memories to include the product of collaborative remembering may be advantageous, this advantage is problematic in situations that demand accuracy, such as eyewitness memory (Meade & Roediger, 2002; Paterson & Kemp, 2006). We suspect there are limits to the egocentric source monitoring bias. If people are more likely to incorporate information from similar others, then they should be less likely to do so from dissimilar others (Lindner et al., 2012). In addition, Hyman (1999) suggested that when people are trying to emphasize group membership they should be more likely to update memories to reflect the collaborative remembering product. If they are less concerned about group membership, then they may be less likely to adopt the group’s recollections. There should also be situations in which people acknowledge memory disputes about a past situation and pointedly work to differentiate their recollection from someone else’s recollection. In many social situations people are aware that their memories differ from the recollections of other individuals. When families and friends share recollections, they start with slightly varying memories. We created an experimental version of this situation by having dyad partners study partially overlapping material. Nonetheless we found that even when participants were directly instructed to attend to source during collaborative remembering, they still made source monitoring errors on a later individual source memory test. People quickly claimed their collaborative partner’s recollections as their own memories exhibiting an egocentric source monitoring bias. Collaborative remembering results in an agreed-upon version of the past that becomes each individual’s memory. The practical application of this research is two-fold. In terms of autobiographical memory, people may incorporate information originally recalled by others as part of their own recollections. Through this egocentric bias in source errors, people will construct memories and thus the self from socially recalled information. An additional practical concern is that people will experience difficulties tracking the source of remembered information even in situations that emphasize careful attention to who originally saw and recalled which information. Although our exclusive dyads focused on the source of remembered information, the individuals nonetheless displayed an egocentric bias of claiming their partner’s contributions as their own memories. People quickly adopt socially shared information as their personal memories. Conflict of interest statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. References Barber, S. J., Franklin, N., Naka, M., & Yoshimura, H. (2010). Higher social intelligence can impair source memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 36, 545–551. http://dx.doi.org/10.1037/a0018406 Basden, B. H., Basden, D. R., Bryner, S., & Thomas, R. L., III. (1997). A comparison of group and individual remembering: Does collaboration disrupt retrieval strategies? Journal of Experimental Psychology: Learning, Memory, and Cognition, 23, 1176–1189. Bluck, S. (2003). Autobiographical memory: Exploring its functions in everyday life. Memory, 11, 113–123. http://dx.doi.org/10.1080/09658210244000306 Bluck, S., Alea, N., Habermas, T., & Rubin, D. C. (2005). A tale of three functions: The self-reported uses of autobiographical memory. Social Cognition, 23, 91–117. Blumen, H. M., & Rajaram, S. (2008). Influence of re-exposure and retrieval disruption during group collaboration on later individual recall. Memory, 16, 231–244. Congleton, A. R., & Rajaram, S. (2013). Collaboration changes both the content and structure of collective memory. In Paper presented at the meeting of SARMAC (Society for Applied Research in Memory and Cognition) Rotterdam, June.

Please cite this article in press as: Hyman Jr., I. E., et al. Collaboration inflation: Egocentric source monitoring errors following collaborative remembering. Journal of Applied Research in Memory and Cognition (2014), http://dx.doi.org/10.1016/j.jarmac.2014.04.004

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Please cite this article in press as: Hyman Jr., I. E., et al. Collaboration inflation: Egocentric source monitoring errors following collaborative remembering. Journal of Applied Research in Memory and Cognition (2014), http://dx.doi.org/10.1016/j.jarmac.2014.04.004