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16610.1177/1368430213486206Group Processes & Intergroup RelationsBetts and Hinsz
Group Processes & Intergroup Relations Article
G P I R
Group Processes & Intergroup Relations 16(6) 734–751 © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1368430213486206 gpir.sagepub.com
Strong shared representations promote schema-consistent memory errors in groups* Kevin R. Betts1 and Verlin B. Hinsz2
Abstract We created the conditions necessary for cognitive representations to develop by presenting individuals and groups with word lists consisting of items high and low in associative strength. Strong cognitive representations were found to promote more schema-consistent memory errors than weaker representations. Moreover, strong cognitive representations resulted in more of these errors for groups than individuals. Weak cognitive representations, in contrast, resulted in fewer of these errors for groups than individuals. We find that variation in the frequency of memory errors between individuals and groups is influenced by the strength of shared representations that interfere with the ability of groups to correct schema-consistent memory errors among their members. Further analyses suggest that strong shared representations also aid correct recall relative to weak shared representations. We conclude that despite general advantages of collaboration, select circumstances that allow for strong shared representations may promote schema-consistent memory errors in groups. Keywords cognitive representations, error correction, groups, memory errors, shared representations Paper received 5 December 2011; revised version accepted 16 March 2013.
In a briefing that followed the raid on Osama bin Laden’s compound in 2011, counterterrorism official (now CIA director) John Brennan reported, “there was a female who was, in fact, in the line of fire that reportedly was used as a shield to shield bin Laden from the incoming fire” (Cohen, 2011). This report was corroborated by other officials who claimed that bin Laden “certainly did use women as shields” (Cohen, 2011). Later reports from White House Press Secretary Jay Carney retracted these statements, indicating that they were inaccurate and resulted from
the “fog of combat” (Cohen, 2011). The true cause of this change in narrative is unclear, but 1
U.S. Food and Drug Administration, USA North Dakota State University, USA
2
Corresponding author: Kevin R. Betts, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA. Email:
[email protected] * The views expressed in this article do not necessarily represent the views of the U.S. Food and Drug Administration or the United States.
Betts and Hinsz it is interesting that this misinformation is consistent with stereotypes or cognitive representations held by many Americans about how Middle Eastern men treat women in this region. Citing such evidence as women’s dress codes and other traditions, many Westerners perceive Middle Eastern women as oppressed and victimized by men (Marmenout, 2011). Thus, the misinformation about a woman being used as a human shield might have resulted from a schema-consistent memory error somewhere in the reporting structure. This error could have emerged anywhere from the SEAL team that first confronted bin Laden to the national security team that observed the raid from afar. Reliance on cognitive representations should prove effective for attaining accurate judgments so long as events coincide with the elements of the representation applied. However, our introductory example demonstrates that cognitive representations do not always map on to actual events. This basic notion is also confirmed by empirical research. Tuckey and Brewer (2003) found that witnesses to mock crimes use schemas to interpret ambiguous information, and that these schemas promote memory errors that are consistent with the schema. Otgaar, Candel, Scoboria, and Merckelbach (2010) found that children produce more memory errors when recalling familiar events than when recalling unfamiliar events, ostensibly because schema are more readily activated in the former case. Additional examples can be found in domains such as education (Neuschatz, Lampinen, Preston, Hawkins, & Toglia, 2002) and religion (Galen, Wolfe, Deleeuw, & Wyngarden, 2009). Schema-consistent memory errors (also known as false positives or false memories) observed in these studies coincide with the elements of the cognitive representations applied; yet, they do not accurately coincide with actual events. Our introductory example suggests that cognitive representations exert an impact even in groups, which are generally known to be effective at correcting the memory errors of their members (Betts & Hinsz, 2010). Members of task groups often develop shared cognitive representations
735 consisting of common knowledge and beliefs (Tindale, Smith, Thomas, Filkins, & Sheffey, 1996; also see research on shared mental models, DeChurch & Mesmer-Magnus, 2010). Cognitive representations held by individuals, whether strong or weak, are known to also be held among group members, in which case they can be “shared.” Intelligence analyst teams, for example, share task-relevant concepts, perspectives, and cognitive processes about the regions, people, and information they study (Hackman, 2004; Heuer, 1999). Our example demonstrates that even highly trained counterterrorism officials working in collaboration might produce schema-consistent memory errors when they share strong cognitive representations. Cognitive representations are known to promote schema-consistent memory errors among individuals. Likewise, shared representations appear to promote schema-consistent memory errors in groups. The group memory literature provides indirect evidence for our hypothesis that shared representations might promote schema-consistent memory errors among groups. For example, Clark, Stephenson, and Kniveton (1990) presented groups of police officers and students with a simulated police interrogation. The researchers expected that police officers would produce fewer memory errors than students due to the officers’ familiarity with similar situations; that is, familiarity and memory accuracy were presumed to be correlated. Consequently, officers could be expected to exhibit a strong shared representation about police interrogations, whereas students might exhibit a weak shared representation. Contrary to expectations, students produced fewer inaccurate speaker identifiers and memory reconstructions than police officers. From these results, it appears that if there were strong shared representations among the officers, they led the officers to produce (erroneous) memory responses that were consistent with their expectations, but not consistent with actual events during the interrogation. Other evidence for the hypothesis that shared representations might promote schema-consistent memory errors involves the memory accuracy of
736 intimate couples relative to strangers. Intimate couples may be more likely than strangers to exhibit strong shared representations due to their similarity in how they perceive the world (Buston & Emlen, 2003). In contrast, strangers should exhibit weaker shared representations. French, Garry, and Mori (2008) presented intimate couples and pairs of strangers with slightly varied versions of a film. Following the presentation of these films, participants were asked to discuss their recollections with the aid of specific questions. The researchers found that relative to strangers, intimate couples produced more memory errors. Peker and Tekcan (2009) provided similar evidence for friends relative to nonfriends in recognition of nonpresented information. These findings similarly suggest that strong shared representations might impact group memory responses. Shared representations build upon the cognitive representations of individuals, and thus similar outcomes regarding the memories of individuals and groups could result. However, we predict that strong shared representations in groups should promote more schema-consistent memory errors than strong cognitive representations do among individuals. Cognitive, social, and motivational processes are known to operate within groups and affect memory outcomes (Betts & Hinsz, 2010). For instance, strong shared representations may promote more memory errors among groups than strong cognitive representations do among individuals if memory errors consistent with the shared representation are reinforced among members (Reysen, 2007). A primary goal of the present research is to examine whether shared representations promote additional memory errors among groups relative to individuals, and if so, how. One way shared representations might promote these additional memory errors is through interference with error correction processes. An important advantage of collaboration on memory tasks is that it allows group members the opportunity to correct one another’s memory errors (Betts & Hinsz, 2010). Moreover, groups tend to exhibit a conservatism bias on memory tasks in that they are more cautious than individuals in the reporting
Group Processes & Intergroup Relations 16(6) of their potentially inaccurate memories (Larson, 2010). Individuals, in contrast, must rely on their own cognitive resources to differentiate between presented and nonpresented information. Most research indicates that groups produce fewer memory errors than individuals (e.g., Clark, Abbe, & Larson, 2006; Clark & Stephenson, 1989; Clark, Stephenson, & Rutter, 1986; Hinsz, 1990; Pritchard & Keenan, 2002; Ross, Spencer, Linardatos, Lam, & Perunovic, 2004); yet, some research instead finds that groups produce more memory errors than individuals (e.g., Alper, Buckout, Chern, Harwood, & Slimovits, 1976; Clark, Hori, Putnam, & Martin, 2000). From these inconsistent findings, we can gather that the degree to which groups correct memory errors among their members varies. The strong or weak shared representations that exist or develop within groups may partially account for this variation. As depicted in Figure 1, memory error correction within groups should follow a specific process. By understanding this process, we can see how shared representations might interfere at various points. First, at least one member of the group must perceive the erroneous memory response as incorrect. Second, the member or members must express this perception to the other group members as an attempt to correct the error. Third, this attempt at error correction must be supported or at least accepted by the other group members. If each of these conditions is met, the error will be corrected. If any of these conditions is not met, the error will remain uncorrected and will be included in the group’s consensus memory responses. Shared representations might impede error correction at any part of the aforementioned process. Brown, Tumeo, Larey, and Paulus (1998, p. 499) developed a matrix model of associative memory related to idea generation in which they described how individuals sample knowledge from their memory networks in a way that is consistent with the demands of the task. They are assumed to generate the ideas whose representations are most active, and thus most easily
Betts and Hinsz
737
An erroneous memory is suggested
The memory error is publicly identified as an error by one or more group members
Correct members are successful in convincing incorrect members to reject the memory error
Memory error is rejected
The memory error is publicly supported (or at least accepted) as accurate by the group
Correct members are unsuccessful in convincing incorrect members to reject the memory error
Memory error occurs
Memory error occurs
Figure 1. Schematic diagram for the correction of memory errors in groups.
accessed, and then to move on to less salient representations, until finally running out of ideas. At any time during recall, and particularly once memories fitting a particular representation approach exhaustion, group members may stretch their efforts to recall information that is consistent with the representation, but not necessarily accurate. Schema-consistent errors that arise from strong cognitive representations among members might then seem worthy of validation simply because they fit the group’s shared representation. Consistent with the rightmost portion of Figure 1, these incorrect recollections may thus be supported or at least accepted as presented by the group. If a group member does recognize these as memory errors, this cognizant member may find it more difficult to find support among the other group members than when there is only a weak or no shared representation, as illustrated in the center portion of Figure 1. Believing that he or
she may not receive the support of other members, the group member may not even alert comembers to the errors—an example of a conservatism bias for error correction (Larson, 2010). By themselves, these factors reduce the likelihood that schema-consistent memory errors will be corrected; together, they greatly decrease the likelihood that errors will be rejected before inclusion in consensus memory responses of groups. The likelihood of schema-consistent errors being corrected is hypothesized to increase as the strength of the shared representation decreases. Given a weak cognitive representation, group members should rely more on their memory for specific stimuli rather than on the basis of a consistency between their memory and a given schema. Moreover, recollections by other members should be judged more on the basis of whether or not they are also remembered by comembers. When errors are detected by a group member, he or she may feel more confident about expressing this perception to comembers and
738 other group members may be more likely to consider the possibility that schema-consistent memory errors are in fact errors. As in the leftmost portion of Figure 1, erroneously identified items should be easier to diagnose and correct as a result of the weak shared representation. Our predictions are consistent with general patterns of group accentuation and attenuation observed in other work (Hinsz, Tindale, & Nagao, 2008; Hinsz, Tindale, & Vollrath, 1997). In a review of information processing in groups, Hinsz et al. (1997) described group accentuation and attenuation as the tendencies of groups to exaggerate or diminish the information-processing themes, features, or errors of similarly treated individuals. If there is an error or bias in information processing for individuals, then groups will process the information in a similar fashion but will exaggerate that error or bias (Hinsz et al., 2008; Hinsz et al., 1997; see Kerr, MacCoun, & Kramer, 1996, for qualifying conditions). Moreover, if the error or bias is not widely shared by individuals, then information processing by groups will tend to attenuate the error or bias. These group accentuation and attenuation patterns of information processing have been demonstrated on a variety of tasks (Hinsz et al., 1997) such as the overutilization of case-specific information and ignoring of base-rate information in probabilistic judgments (Hinsz et al., 2008). However, these patterns have not been examined systematically for memory errors. The Deese–Roediger–McDermott paradigm (DRM; Deese, 1959; Roediger & McDermott, 1995) provides an effective technique for manipulating strong cognitive representations among both groups and individuals. In this paradigm, lists consisting of items (bed, rest, awake, etc.) that are strongly associated with a critical nonpresented item (sleep) are presented. When memory for items in these lists is assessed, participants remember the presented items in a pattern similar to that of other list-learning memory studies, but they also generate critical items that were not presented. Participants tend to generate these schema-consistent critical nonpresented items with greater frequency than items that
Group Processes & Intergroup Relations 16(6) were actually presented in the middle of the list. The majority of memory research utilizing the DRM paradigm has assessed individual rather than group performance. Still, a small number of studies have assessed group memory performance in a way that is informative for our purposes (e.g., Maki, Weigold, & Arellano, 2008; Takahashi, 2007; Thorley & Dewhurst, 2007, 2009). The limited available research demonstrates that groups and individuals alike tend to generate critical nonpresented items when recollecting items from DRM lists. Thus, it appears reasonable to assume that the presentation of highassociative-strength word lists promotes strong cognitive representations among both individuals and groups. It is unclear from previous literature, however, whether we can conclude that groups or individuals consistently generate a greater number of memory errors when responding to these lists. This lack of clarity is due in part to procedural differences between studies. For example, some studies require individuals to recall words alone and then again together as a group whereas other studies require collaborative group recall exclusively. Also, “nominal group” recall (i.e., the pooled recall of individuals) is sometimes assessed and not always compared directly to collaborative group recall. Moreover, turn-taking procedures have been used in some studies whereas more interactive strategies have been used in other studies. The present research does not attempt to resolve or interpret differences between these varied procedural strategies; rather, we seek to assess group performance relative to individual performance in a way that reflects natural, collaborative efforts at remembering. Unique to the present research, we tested memory responses to not only high-associativestrength lists, but also to low-associative-strength lists. This strategy allows for substantial contribution beyond previous research which has relied exclusively on high-associative-strength DRM lists. In contrast to high-associative-strength lists that promote strong cognitive representations, low-associative-strength lists might be expected to promote weak cognitive representations resulting
Betts and Hinsz in fewer memory errors among groups. Thus, the present research draws comparisons between individuals and groups responding to both lowand high-associative-strength lists. The present research was designed to test several hypotheses about the influence of strong and weak cognitive representations among individuals and groups on recall (Study 1) and recognition memory (Study 2). To summarize, we expect that (H1) participants should produce more schemaconsistent memory errors when presented with high-associative-strength lists than when presented with low-associative-strength lists. This finding is expected to result from strong cognitive representations that encourage schemaconsistent processing of information. We further expect that when a strong shared representation develops, (H2) groups should produce more schema-consistent memory errors than individuals, partially as a result of (H3) shared representations interfering with error correction processes of groups. In contrast, when a weak shared representation develops, we expect that (H4) groups will produce fewer memory errors than individuals, partially as a result of (H5) group error correction processes. In regard to correct recollections, we expect that (H6) participants should produce more correct memory responses when presented with high-associative-strength lists than when presented with low-associativestrength lists. As with schema-consistent memory errors, this finding is expected to result from schema-consistent processing of information and associated correct memory responses. Finally, we expect that (H7) groups should remember more presented information than individuals regardless of the strength of their shared representation. Although not a focus of the present research, this prediction is based on a consistent finding within the group memory literature (Betts & Hinsz, 2010; Hinsz, 1990).
Study 1 Method Participants. Undergraduate students (N = 130) drawn from lower level psychology courses at
739 North Dakota State University (NDSU) received course credit in exchange for their participation. Experimenters were upper level undergraduate and graduate students trained to follow a script. Due to a computer malfunction, data from three groups were lost. The final sample presented here includes values for 121 participants (65 male, 56 female; 30 three-person groups, 31 individuals). Word lists. Participants were presented with a series of word lists. Half of these lists consisted of items high in associative strength from previously used Deese–Roediger–McDermott (DRM) lists (Roediger & McDermott, 1995). The other half of these lists consisted of items low in associative strength based on word-association norms from the Word Association Thesaurus (Kiss, Armstrong, Milroy, & Piper, 1973). The Word Association Thesaurus provides empirical data based on the associative responses of participants to stimulus words. Low-associative-strength lists in the current research consisted of items that were only weakly associated to a target word (i.e., the critical nonpresented item). Words were considered weakly associated when they were spontaneously elicited by 5% or fewer participants in response to the related target word. Each list, regardless of associative strength, consisted of 15 words. Each 15-word list was then sequentially combined with one other 15-word list of the same associative strength to form a 30-word list. Ten 30-word lists were prerecorded at a rate of 1.5 seconds per word spoken by an adult female. Sample highand low-associative-strength lists are presented in Table 1. Recall task. Participants followed a “word list presentation–arithmetic task–recall generation” sequence through 10 repetitions. Participants were presented with one 30-word list at a time, either high or low in associative strength in alternating order (i.e., high, low, high, etc.). Order of list presentation was identical for all participants. Following each word list, participants were given 2 minutes to complete as many simple arithmetic problems as they could, with the intention of
Group Processes & Intergroup Relations 16(6)
740 Table 1. Sample set of 15-word lists. High-associative-strength lists Soft Window Hard Door Light Glass Pillow Pane Plush Shade Loud Ledge Cotton Sill Fur House Touch Open Fluffy Curtain Feather Frame Furry View Downy Breeze Kitten Sash Skin Screen Tender Shutter Low-associative-strength lists Bread Music Brown Symphony Biscuit Radio Crispy Activity Baker Tune Grain Note Poverty Beat Stale Serenade Jam Recital Toast Violin Wheat Encore Fresh Tempo Energy Culture Slice Lesson Oven Sound Food Soul
Chair Table Sit Legs Seat Couch Desk Recliner Sofa Wood Cushion Swivel Stool Sitting Rocking Bench
Cold Hot Snow Warm Winter Ice Wet Frigid Chilly Heat Weather Freeze Air Shiver Arctic Frost
Mountain Hill Valley Climb Summit Top Molehill Peak Plain Glacier Goat Bike Climber Range Steep Ski
Anger Mad Fear Hate Rage Temper Fury Ire Wrath Happy Fight Hatred Mean Calm Emotion Enrage
Foot Ankle Knee Talon Sandals Size Sock Blister Toes Heel Paw Dance Crush Sore Tickle Hop
Spider Insect Bug Creature Fly Horrible Repulsive Pest Crawling Wings Beetle Creepy Moth Scared Feeler Hairy
Slow Walk Delay Movement Donkey Brisk Gradual Careful Reflex Quiet Sloth Meander Swift Hesitant Idle Progress
High Roof Above Tower Jump Sky Loft Building Reach Soaring Elevation Orbit Ceiling Flight Dome Tall
Note. Critical nonpresented items for each list are underlined.
reducing accuracy of memory for list items. If a cognitive representation or shared representation develops, it should be more easily observed in delayed recall because memory should be more strongly influenced by a schematic understanding of the lists. All participants were asked to work alone when solving these arithmetic problems. Participant recall of the items presented in these word lists was then tested. Participants were asked to write down with paper and pencil all words that they recalled from the presented lists, trying to be as accurate as possible. Groups were asked to discuss items recalled by group members
and to achieve consensus on whether or not to include these items in their recall. Following each list and set of arithmetic problems, participants were presented with a new pair of lists until they were presented with and tested on all ten 30-word lists. Procedure. Upon arrival at the laboratory, participants were welcomed, randomly assigned to a group or individual condition, and seated in one of three rooms designed to comfortably accommodate groups or individuals. Each group was seated in a separate room. Individuals were seated
Betts and Hinsz with one or two other participants in order to control for social facilitation effects (cf. Hartwick & Nagao, 1990). Group members were instructed to work together unless instructed otherwise, and individuals were instructed to work alone. After basic information was given regarding the experiment, audio- and video-recording equipment was turned on and participants were informed of this. Participants then followed the abovementioned “word list presentation–arithmetic task–recall generation” sequence until all five high-associative-strength lists and all five low-associativestrength lists were presented and recalled.
Results Preliminary analyses. Preliminary analyses revealed an unexpected pattern of results from one lowassociative-strength list. One sublist consisted of items associated to the critical nonpresented item “king,” including throne, chess, eagle, generous, captain, audience, cruel, leader, anarchy, tyrant, dragon, martyr, conquer, crown, and royalty. The other sublist consisted of items associated to the critical nonpresented item “thief,” including steal, apprehend, stealth, honest, elusive, dishonest, lock, lawyer, bandit, wanted, arrest, arson, caught, crook, and grab. The number of memory errors (i.e., false positives) for this list (M = 2.90, SD = 2.34) significantly differed from the average number of memory errors produced for other low-associative-strength lists (M = 2.31, SD = 1.50), t(60) = 2.98, p < .01, Cohen’s d = .30, but did not significantly differ from the average number of memory errors produced for high-associative-strength lists (M = 2.70, SD = 1.08), t(60) = 0.83, p = .41. Moreover, a significant list main effect was revealed for the number of memory errors among the five lowassociative-strength lists when this list was included, F(4, 240) = 5.12, p = .001, ηp2 = .08. Indeed, this list resulted in the second highest number of memory errors for any list, allowing us to conclude that these items were too strongly related to one another to be considered a lowassociative-strength list. Consequently, data from this list is not included in the present analyses;
741 the pattern of results is similar but weaker if this list’s data are included. To allow for symmetry, we selected one highassociative-strength list for removal from analyses as well. Ensuring a conservative test of the hypotheses, we removed the list that resulted in the highest number of memory errors. One sublist consisted of items associated to the critical nonpresented item “needle,” including thread, pin, eye, sewing, sharp, point, prick, thimble, haystack, thorn, hurt, injection, syringe, cloth, and knitting. The other sublist consisted of items associated to the critical nonpresented item “sleep,” including bed, rest, awake, tired, dream, wake, snooze, blanket, doze, slumber, snore, nap, peace, yawn, and drowsy. Following deletion of the one high- and one low-associative-strength lists, the present analyses are based on group and individual recall of four high-associative-strength lists and four low-associative-strength lists. Responses to arithmetic problems were analyzed to ensure that all participants were distracted following the presentation of each word list. On average, participants completed 24.38 problems (SD = 6.23) within the allotted 2 minutes. Participants were also very accurate, responding correctly to 92.81% (SD = 0.06) of the problems they attempted. These results indicate that participants were engaged with the arithmetic tasks. Moreover, there were no differences between the participants in the individual or group conditions for the number of problems attempted, t(119) = 0.13, p > .05, or the proportion answered correctly, t(119) = 0.30, p > .05. Primary analyses. In line with Hypothesis 1, results indicate that across group and individual conditions, participants generated more critical nonpresented items for high-associative-strength lists (M = 4.69 out of eight possible, SD = 1.64) than for low-associative-strength lists (M = 1.21, SD = 1.08), F(1, 59) = 355.96, p < .001, ηp2 = .86. Moreover, there was a significant interaction between group or individual condition and the associative strength of the lists, F(1, 59) = 5.12, p < .05, ηp2 = .08. In line with Hypothesis 2, groups generated more of the eight possible
Group Processes & Intergroup Relations 16(6)
742 12 6
10
5.07 Recall of Crical 5 Nonpresented Items 4.32
4
2 1
8 Individuals
3
All Recall Memory 10.67 Errors 8.58 8.7 8.45
Groups
Individuals
6
Groups
4
1.26 1.17
2
0 Low Strength
High Strength
0
Low Strength
High Strength
Figure 2. Individual and group recall of critical nonpresented items for low- and high-associativestrength lists.
Figure 3. All individual and group recall memory errors (including critical nonpresented items) for lowand high-associative-strength lists.
critical nonpresented items (M = 5.07, SD = 1.89) than individuals (M = 4.32, SD = 1.28) for high-associative-strength lists, t(59) = 1.81, p < .05 (one-tailed), d = .46. In contrast and failing to support Hypothesis 4, groups generated a similar number of critical nonpresented items (M = 1.17, SD = 1.18) as individuals (M = 1.26, SD = 1.00) for lowassociative-strength lists, t(59) = 0.33, p > .05. This pattern of relationships for the recall of critical nonpresented items is depicted in Figure 2. Although critical nonpresented items are particularly likely to arise in the “recall” of participants presented with semantically associated lists (Roediger & McDermott, 1995), other noncritical, nonpresented items arose in this study as well. Moreover, like critical nonpresented items, nearly all of these errors tended to be associated with the schema activated by presented items. When these noncritical nonpresented items are combined with critical nonpresented items for analysis, very similar patterns to those observed for critical nonpresented items alone are revealed. Groups generated more memory errors (critical and noncritical nonpresented items) for highassociative-strength lists (M = 10.67, SD = 4.40) than for low-associative-strength lists (M = 8.70, SD = 4.59), t(29) = 3.54, p < .01, d = .44. In contrast, individuals generated approximately the same number of memory errors for high-associative-strength lists (M = 8.45, SD = 4.02) and low-associative-strength lists (M = 8.58, SD =
7.05), t(30) = 0.16, p > .05. Moreover, there was a significant interaction between group or individual condition and the associative strength of the lists for these memory errors, F(1, 59) = 4.37, p < .05, ηp2 = .07. Groups generated more memory errors (M = 10.67, SD = 4.40) than individuals (M = 8.45, SD = 4.02) for high-associativestrength lists, t(59) = 2.05, p < .05, d = .53. Further, individuals (M = 8.58, SD = 7.05) generated approximately the same quantity of memory errors as groups (M = 8.70, SD = 4.59) for lowassociative-strength lists, t(59) = 0.08, p > .05. These patterns of relationships for all memory errors are depicted in Figure 3. Further analyses using the audio and video recordings were conducted to test Hypotheses 3 and 5 concerning error correction processes. Recall that part of the rationale provided for Hypotheses 2 and 4 was that groups would be better able to correct the memory errors of their members for low-associative-strength lists than for high-associative-strength lists. Hypothesis 3 states that when the associative strength of lists is high, and thus shared representations are strong, groups should have difficulty correcting memory errors among their members. Hypothesis 5 proposes that groups should be better able to correct the memory errors of their members when the associative strength of lists is low, and shared representations are weak. Assessment of memory errors introduced among group members during
Betts and Hinsz discussion relative to final consensus group recall allows for direct tests of these hypotheses. Scoring of memory error correction among group members in discussion was conducted by the first author and an undergraduate research assistant. The research assistant was trained by the first author in a specific manner. First, the assistant observed the first author score an example video for memory errors that arose during discussion. Errors recorded included both critical and noncritical nonpresented items. Any time a group member suggested that an item was presented despite it not actually having been presented, an error was recorded. Second, the assistant scored another video in the same manner under the supervision of the first author. Third, the assistant demonstrated his understanding of the scoring process verbally. All videos were scored twice, once by the first author and once by the research assistant. Differences in scoring were resolved by reviewing portions of the recording in question and mutually determining who was correct. This dual check on the accuracy of the scoring made it especially unlikely that any memory errors would be missed. One additional group was excluded from these analyses due to a recording malfunction, leaving 29 groups for the present analyses. During group discussion, significantly more critical nonpresented items (i.e., preidentified target words) were recalled for high-associativestrength lists (M = 5.31, SD = 2.02) than for low-associative-strength lists (M = 1.41, SD = 1.15), t(28) = 12.85, p < .001, d = 2.37. This finding remained when considering all memory errors which consisted primarily of semantic associates to items within the target list. Groups generated significantly more nonpresented items during discussion for high-associativestrength lists (M = 13.59, SD = 4.88) than for low-associative-strength lists (M = 11.14, SD = 5.40), t(28) = 2.40, p < .05, d = .48. These results follow closely to the pattern observed for final consensus responses in that high-associativestrength lists promoted a greater number of schema-consistent memory errors than lowassociative-strength lists.
743 Table 2. Memory errors in discussion relative to final group consensus. Critical nonpresented items
All memory errors
M
SD
M
SD
2.85 1.15 2.02
24.72 11.14 13.59
8.71 5.40 4.88
2.70 1.20 1.92
18.66 8.35 10.31
7.65 4.23 4.02
Errors in discussion All lists 6.72 Low 1.41 High 5.31 Consensus errors All lists Low High
6.20 1.17 5.03
As summarized in Table 2, aggregated across all lists, groups generated significantly more critical nonpresented items in discussion than were included in their final consensus recall, t(28) = 3.55, p < .01, d = .19. This finding remained for both low-, t(28) = 2.54, p < .05, d = .20, and highassociative-strength lists, t(28) = 3.27, p < .01, d = .14. These findings indicate that when group members recalled critical nonpresented items, a significant proportion of these errors were corrected regardless of the strength of the group’s shared representation. Similarly for all memory errors, groups generated significantly more memory errors in discussion than were included in their final consensus recall, t(28) = 8.34, p < .001, d = 1.12. Again, this finding remained for both low-, t(28) = 4.78, p < .001, d = .58, and highassociative-strength lists, t(28) = 7.68, p < .001, d = .73. These results indicate that groups also corrected a significant proportion of all falsely recalled items through discussion regardless of the strength of shared representation present in the group. Proportional to the total number of critical nonpresented items recalled in discussion for low- or high-associative-strength lists, groups corrected more critical nonpresented items for low-associative-strength lists (M = 0.22, SD = 0.40) than for high-associative-strength lists (M = 0.06, SD = 0.08), t(21) = 2.07, p < .05 (one-tailed),
744 d = .55. Consistent with Hypotheses 3 and 5, these results suggest that groups are relatively successful at correcting memory errors among their members when shared representations are weak, that is, about 22% of memory errors were corrected. In contrast, when shared representations are strong, group members are more likely to accept one another’s memory errors and only about 6% of errors were corrected. Consistent with Hypothesis 6, groups were also observed to correctly recall more words from high-associative-strength lists (M = 63.63 summed across all lists, SD = 7.87) than from low-associative-strength lists (M = 59.53, SD = 9.15), t(29) = 3.65, p < .01, d = .48. Individuals exhibited a similar pattern, correctly recalling more words from high-associative-strength lists (M = 43.16, SD = 9.28) than from lowassociative-strength lists (M = 37.16, SD = 11.56), t(30) = 4.96, p < .001, d = .57. These results suggest that strong task representations do not exclusively lead to schema-consistent memory errors, but also aid schema-consistent correct recall. Lastly, it was predicted in Hypothesis 7 that groups would remember more presented information than individuals. Aggregated across all lists, groups (M = 123.17, SD = 15.92) correctly recalled significantly more items than individuals (M = 80.32, SD = 19.86), t(59) = 9.28, p < .001, d = 2.38. This effect of individual versus group condition was not qualified by an interaction with associative strength of lists, F(1, 59) = 1.32, p > .05.
Discussion Results from Study 1 support the set of hypotheses put forth in the context of recall memory. As the strength of cognitive representations and shared representations among participants increased, so did the frequency of their schemaconsistent memory errors. When shared representations were strong, groups erroneously recalled significantly more nonpresented items than individuals. When shared representations were weak, groups produced approximately the
Group Processes & Intergroup Relations 16(6) same quantity of nonpresented items as individuals, with the means suggesting a tendency to produce slightly fewer errors. Central to Study 1 was our inspection of memory errors among groups produced in discussion relative to those included in consensus recall, which allowed us to examine the proportion of errors corrected for both high- and lowassociative-strength lists. Consistent with expectations, groups corrected proportionally far more errors for low-associative-strength lists than for high-associative-strength lists. This suggests that schema-consistent memory errors are far easier to correct when shared representations are weak than when they are strong. Moreover, examination of the group discussions from which these analyses were obtained provide additional support for the role of shared representations. Often, group members endorsed the memories of members that were consistent with the schema of presented lists regardless of their own recollections. For example, when asked if the nonpresented item “skyscraper” should be included in their recall, one participant replied “It fits the topic. Let’s go with it.” This observation is objectively supported by the results for all memory errors (see Figure 3). Although individuals produced approximately the same number of memory errors for high- and low-associativestrength lists, groups produced more memory errors for the high-associative-strength lists than for the low-associative-strength lists. Strong shared representations clearly played a role in the memory responses of the groups. Finally, groups were observed to produce more correct recall than individuals for both high- and low-associative-strength lists. These findings replicate extensive previous research (Betts & Hinsz, 2010). More interesting, perhaps, is the finding that groups and individuals correctly recalled more items from the highassociative-strength lists than from the lowassociative-strength lists. These findings suggest that a complex relationship exists between cognitive representations and memory performance. Although strong cognitive representations and shared representations promote
Betts and Hinsz memory errors, they also can aid correct recall given that presented stimuli are consistent with the representation.
Study 2 Results from Study 1 provided strong support for a causal relationship between the strength of cognitive and shared representations and memory errors. Moreover, analyses revealed that strong shared representations interfered with error correction processes in groups. In Study 2, we extend our investigation to recognition memory using a similar methodology. Specifically, we reexamine Hypotheses 1, 2, 4, 6, and 7. By utilizing a recognition memory task, we hope to generalize the pattern of findings observed in Study 1 beyond that of recall memory. Additionally, this second study may produce a conceptual replication of the results of Study 1 using a complete set of word lists without having to drop suspect word lists. Moreover, Study 2 involved six-person groups and two different orders of the low- and high-association word lists. Generally, with the exceptions noted, the procedure of Study 2 was similar to that of Study 1.
Method Participants. Participants were undergraduate students drawn from lower level psychology courses at NDSU and received course credit for their participation. The sample includes 287 participants (146 female, 141 male; 41 six-person groups, 41 individuals). Experimenters were upper level undergraduate students trained to conscientiously follow a script. Word lists and recognition task. Six of the ten 30-word lists (consisting of two 15-word lists) used in Study 1 were converted into two 90-word lists for use in Study 2. One list consisted of words high in associative strength and the other consisted of words low in associative strength― and each 15-word list was associated with one critical nonpresented word (see full lists in Table 1). About half of each condition received
745 the lists in the low- then high-associative-strength order and the other half in the high- then lowassociative-strength order. Following the presentation of each list, participants were given 2 minutes to complete as many simple arithmetic problems as they could, and then were presented with a recognition task. Recognition task items consisted of one third of the presented items (five from each sublist, either 30 from the high-associative-strength list or 30 from the low-associative-strength list), all of the critical nonpresented items from the highassociative-strength list (six items) or low-associative-strength list (six items), and several nonpresented items intuitively judged to be unrelated to any of the high-associative-strength list items (24 items) or low-associative-strength list items (24 items). In all, each test had 60 items; 30 from the presented list, six critical nonpresented items, and 24 distractors. Recognition items were presented on computers in a single randomized order for all participants and without time limit. Participants were asked to indicate whether or not each item was presented in the preceding list. Group members were asked to reach consensus through discussion on whether each item was or was not presented in the list. Procedure. Study 2 followed a similar procedure to Study 1, differing only in the number of presented word lists, form of memory assessment, and group size.
Results Preliminary analyses. As in Study 1, responses to arithmetic problems were analyzed to ensure that participants were distracted following the presentation of each word list. Due to a computer malfunction, responses to a small subset of the arithmetic tasks (N = 16) were lost, but all participants successfully completed these tasks. On average, participants completed 10.83 problems (SD = 4.17) with 74.18% accuracy (SD = 0.18). These results indicate that participants were engaged with the arithmetic tasks. Further, there were no differences between
Group Processes & Intergroup Relations 16(6)
746
6
5.46 Recognion of Crical 5.2 Nonpresented Items 5 4.54 4
3.63 Individuals
3
Groups
2 1 0
Low Strength
High Strength
Figure 4. Individual and group recognition of critical nonpresented items.
group members and individuals for the number of problems attempted, t(269) = 1.41, p > .05, or the proportion answered correctly, t(269) = 0.82, p > .05. Primary analyses. Consistent with Hypothesis 1, results indicate that across group and individual conditions, participants falsely recognized more critical nonpresented items for high-associativestrength lists (M = 5.33 out of six, SD = 0.92) than for low-associative-strength lists (M = 4.09, SD = 1.47), t(80) = 7.19, p < .001, d = 1.01. Moreover, there was a significant interaction between group or individual condition and the associative strength of the lists, F(1, 80) = 13.46, p < .001, ηp2 = .14. In line with Hypothesis 2, groups incorrectly recognized more critical nonpresented items (M = 5.46, SD = 0.81) than individuals (M = 5.20, SD = 1.0) for high-associative-strength lists, although this difference did not reach traditional levels of significance, t(80) = 1.33, p = .09 (one-tailed), d = .29. In line with Hypothesis 4, groups incorrectly recognized fewer critical nonpresented items (M = 3.63, SD = 1.56) than individuals (M = 4.54, SD = 1.21) for low-associative-strength lists, t(80) = 2.93, p < .01, d = −.65. These findings are depicted in Figure 4. When groups develop a strong shared representation, they produce more schema-consistent false memory errors than individuals. In contrast,
when groups develop a weak shared representation, they produce fewer schema-consistent memory errors than individuals. It is also interesting to consider participant recognition of unrelated distractors. Recall that unrelated distractors are items that were not presented and are unrelated to any items that were presented. Averaged across lists, groups (M = 2.80 out of 24, SD = 2.45) falsely recognized fewer unrelated distractors than individuals (M = 5.71, SD = 4.54), t(162) = 5.09, p < .001, d = −.79. Further, groups falsely recognized fewer unrelated distractors for the high-associativestrength lists (M = 2.10, SD = 2.21) than for the low-associative-strength lists (M = 3.51, SD = 2.49), t(40) = 2.62, p < .05, d = −.60. Individuals exhibited a similar but nonsignificant pattern, falsely recognizing somewhat fewer unrelated distractors for the high-associative-strength lists (M = 4.80, SD = 4.20) than for the low-associativestrength lists (M = 6.61, SD = 4.74), t(40) = 1.72, p = .09 (one-tailed), d = −.40. For groups, these patterns of relationships appear consistent with a shared-representations framework. When a shared representation is strong, unrelated distractors are easily dismissed as nonpresented because they do not fit the schema on which groups are relying. When a shared representation is weak, schemas are less coherent, and consequently groups experience greater difficulty differentiating between information that was or was not presented as compared to when they exhibit a strong shared representation. Further analyses examined how strong and weak shared representations influenced correct recognition. In contrast to recall memory in Study 1, groups did not correctly recognize more items from high-associative-strength lists (M = 26.85 out of 30, SD = 2.30) than from low-associativestrength lists (M = 26.44, SD = 2.19), t(40) = 0.97, p > .05, a possible ceiling effect. In contrast, individuals did correctly recognize more items from high-associative-strength lists (M = 24.27, SD = 4.56) than from low-associative-strength lists (M = 21.29, SD = 5.08), t(40) = 4.58, p < .001, d = .62. At least relative to weak shared representations, it appears that strong shared representations
Betts and Hinsz in groups do not result in greater correct recognition of schema-consistent words. Consistent with Hypothesis 7 and previous research, averaged across both lists, groups (M = 26.65, SD = 2.24) correctly recognized significantly more items than individuals (M = 22.78, SD = 5.02), t(162) = 6.36, p < .001, d = 1.00. This group–individual difference was qualified by an interesting significant interaction with associative strength of lists, F(1, 80) = 10.88, p = .001, ηp2 = .12. For high-associativestrength lists, groups (M = 26.85, SD = 2.30) correctly recognized significantly more items than individuals (M = 24.27, SD = 4.56), t(80) = 3.24, p < .01, d = .71. Similarly for low-associative-strength lists, groups (M = 26.44, SD = 2.19) correctly recognized significantly more items than individuals (M = 21.29, SD = 5.08), t(80) = 5.96, p < .001, d = 1.32. The significant interaction indicates that the difference between groups and individuals in correct recognition is stronger for low-association lists than for highassociation lists. However, ceiling effects for the high-association lists could contribute to the appearance of this significant interaction.
Discussion Results from Study 2 provide strong support for stated hypotheses in the context of recognition memory. As with recall memory, schema-consistent recognition memory errors appear to increase as the strength of cognitive representations and shared representations increase. When presented with high-associative-strength lists and shared representations were strong, groups tended (not significantly) to falsely recognize more critical nonpresented items than individuals. When presented with low-associative-strength lists and shared representations were weak, groups falsely recognized fewer critical nonpresented items than individuals. Notably, the finding that groups produced more schema-consistent memory errors than individuals when shared representations were strong did not reach traditional levels of significance (p = .09 with a directional test). On average, both groups and individuals falsely recognized
747 more than five of the six (89%) critical nonpresented items. Although this outcome was unanticipated prior to running Study 2, it is possible that strong representations for individuals or groups dramatically facilitate false recognition rates with resulting ceiling effects. In other words, regardless of whether a recognition test consisted of six or 60 critical nonpresented items, groups and individuals might recognize these items as presented simply because they fit their strong representation about items that were presented. Unique to Study 2, we examined group and individual recognition of unrelated distractors for high- and low-associative-strength lists. Consistent with a shared-representations framework, groups were better able to correctly reject unrelated distractors for the high-associativestrength list when shared representations were strong. Individuals were equally likely to correctly reject items for high- and low-associativestrength lists. The fact that this effect occurred uniquely among groups provides further evidence for our argument that shared representations likely play an important part in group memory performance. Consistent with previous research (Betts & Hinsz, 2010), groups correctly recognized more items than individuals for both high- and lowassociative-strength lists. More interesting, however, the influence of strong shared representations on group recognition memory in this study is in contrast with results for group recall memory presented for Study 1. Although strong shared representations aided correct group recall memory relative to weak shared representations, this pattern did not arise for correct group recognition memory. Similar to results for the critical nonpresented items, it may be that when recognizing items from the lists, groups adopt a very liberal standard of acceptance in contrast to the conservatism bias for recall. That is, nearly any item that fits their shared representation will be recognized as presented.
General Discussion A central finding in the current research concerned the influence of shared representations on
748 memory errors in groups. Previous research indicates that groups are sometimes able to correct the memory errors of their members, resulting in relatively accurate group recollections (Clark et al., 2006; Hinsz, 1990; Pritchard & Keenan, 2002). Unique to this research, we found that groups tended to produce more recall memory errors of schema-consistent words than individuals following the presentation of high-associative-strength lists. This finding can be partially explained in terms of the influence of shared representations on memory errors. A strong cognitive representation about presented information appears to encourage specific memory errors among group members and individuals. When this representation is shared among group members, groups exhibit particular difficulty correcting these memory errors. We also found that when recalling and recognizing items from low-associative-strength lists, groups tended to produce fewer memory errors than individuals. Weak shared representations result in few memory errors among groups because these errors are more easily corrected. Providing further evidence for our hypotheses, groups in Study 2 were observed to correctly reject more unrelated distractors for high-associative-strength lists than for low-associative-strength lists. This indicates that when presented items clearly do not fit the group’s shared representation about presented information, they are more easily rejected. The current research also provides concrete evidence for the ability of groups to correct memory errors among their members as well as the impact of shared representations on this process. Much previous research designed to assess memory errors in groups has assumed that errors were being corrected if groups produced fewer errors than individuals working alone. Although this technique is an effective proxy, it does not truly examine error correction in groups or explore the role of collaboration on such processes. Study 1 incorporated audiovisual recordings to compare memory errors arising among group members during discussion with final consensus recall. Results from Study 1 clearly confirmed that groups do correct memory errors
Group Processes & Intergroup Relations 16(6) among their members. Moreover, groups were observed to correct proportionately fewer schema-consistent errors when recalling items from high-associative-strength lists, when shared representations were strong. Consistent with hypotheses, strong shared representations appear to impair groups in correcting schema-consistent memory errors among their members, although they can assist groups in avoiding schemainconsistent errors, as demonstrated in Study 2. Figure 1 depicted a schematic model for the correction of memory errors in groups. We presented this model as an aid for understanding how errors might be corrected or left uncorrected during discussion. We did not, however, collect data that would allow for an adequate test of the specific processes involved. Researchers wishing to test this model or alternative ones are encouraged to do so because such analyses could contribute to our understanding of the social aspects of memory that arise during collaboration. Researchers wishing to conduct such analyses could focus on error correction as we did, error inclusion without an emphasis on error correction, how correct memories emerge in groups, or different processes related to group recollection. Methodologically, these findings have implications for group research utilizing the Deese– Roediger–McDermott (DRM) paradigm. The DRM paradigm is thought to be an effective way to compare group and individual memory errors (Maki et al., 2008; Takahashi, 2007; Thorley & Dewhurst, 2007, 2009). The studies reported here indicate that the high associative strength of items within DRM lists encourages schemaconsistent memory errors in groups to a greater extent than among individuals. If researchers seek to compare group and individual memory errors appropriately, the associative strength of list items needs to be taken into consideration. Groups should be expected to produce more schema-consistent memory errors than individuals when presented with high-associative-strength DRM lists because of the strong shared representation that emerges. When presented with other stimuli, groups may produce the same or fewer memory errors than individuals.
Betts and Hinsz Interesting results were also obtained for correct recall and recognition. Previous research indicates that groups are able to remember more information than individuals (e.g., Hinsz, 1990; Vollrath, Sheppard, Hinsz, & Davis, 1989). This finding was replicated in both studies, and for both high- and low-associative-strength lists. Moreover, we found that participants correctly recalled more items for high-associative-strength lists than for low-associative-strength lists. This finding suggests that a strong cognitive representation about presented items may aid the recall of presented items. In fact, observations from audiovisual recordings in Study 1 indicate that when group members reached a point at which they felt unable to recall any more items, further recall was sometimes stimulated after the category of presented items was recalled. The finding that strong shared representations can also help groups correctly recall more information reminds us to view our primary findings in context; strong shared representations may help groups to recall more information, but as we have demonstrated throughout this article, shared representations can lead to memory errors as well. The findings presented here can be integrated with existing research on information processing in groups. The tendency for groups to produce more or fewer memory errors than individuals resembles the group accentuation and attenuation patterns observed on other cognitive tasks (Hinsz et al., 2008; Hinsz et al., 1997). Groups tend to display more homogenous cognitive processes than their members, and these processes can promote more extreme responses (although see Hinsz et al., 1997; and Kerr et al., 1996, for conditions in which heterogeneity can arise). Groups tend to accentuate the widely shared biases of individuals as well as attenuate uncommon biases. Consistent with this literature, groups in the present research tended to accentuate the memory errors of individuals when shared representations were strong, and attenuate these errors when shared representations were weak. Work on groupthink is also relevant (Janis, 1971, 1982). Symptoms of groupthink such as conformity pressures and self-censorship might discourage sharing of memories inconsistent with the shared representation of the group,
749 and encourage sharing of memories consistent with the shared representation. Mindguards might disparage memories inconsistent with the shared representation of the group. Kerr et al. (1996) provide an extensive review of biases in judgment that exist among groups and individuals. The present research informs this much larger literature. Research on collaborative inhibition is also relevant to this work. Collaborative inhibition refers to the general finding that groups recall less information than the same number of individuals working alone (i.e., nominal groups). For example, Finlay, Hitch, and Meudell (2000) found that collaborative recall tends to converge around fewer semantic categories than individual recall and this tendency contributes to diminished recall (also see Basden, Basden, Bryner, & Thomas, 1997; Weldon & Bellinger, 1997). Given that participants in our research attempted to recall items from semantically associated lists, interesting questions arise. Do highversus low-associative-strength lists affect retrieval strategies? As a function of associative list strength, do varying types of retrieval strategies that arise impact collaborative inhibition? To speculate, it may be that recall from high-associative-strength lists converges around fewer semantic categories than recall from low-associative-strength lists. When items are already highly associated, individuals should be likely to recall items highly consistent with the specified semantic category. Further, groups may exaggerate this effect given that Finlay et al. (2000) find collaborative recall converges around fewer semantic categories than individual recall. For lowassociative-strength lists, the semantic categories of items recalled may fit both the specified semantic category of the list and other more weakly associated categories related to the specified semantic category. Future research may be able to address these questions using high- and low-associative-strength lists such as those implemented in our research. Importantly, the implications of this research go beyond laboratory groups. We began this paper with a discussion of how strong cognitive representations might affect the recollections of intelligence personnel. Other groups exhibiting strong shared representations may also experience outcomes similar to those discussed in this paper.
750 Professional groups such as hiring committees, top-management teams, legal teams, educational boards, or military units—perhaps the same groups that we trust to remember information most accurately—should all be vulnerable to these errors (cf. Clark et al., 1990). Nonprofessional groups that develop strong shared representations may also produce more memory errors. Juries, for example, may develop norms, perspectives, or cognitive processes that impact their memory responses. Regardless of the type of group in question, decision makers should be aware of additional memory errors that may emerge when conditions are such that strong shared representations may develop. Acknowledgements Preparation of this article was supported by a grant to the second author from the National Science Foundation (BCS 0721796). We appreciate the efforts of Chris Sjol and Lee Hinsz for helping to collect data for the experiments reported.
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