Graded effects of social conformity on recognition memory

Playing nice: a multi-methodological study on the effects of social conformity on memory

Conformity is an important aspect of social behavior. Two main motives have been identified: people may adapt their behavior to “play nice” despite knowing better (normative conformity) or they may accept the others' opinion as a valid source of information (informative conformity). Neuroimaging studies can help to distinguish between these two possibilities. Here, we present a functional magnetic resonance imaging (fMRI) study on memory conformity in a real group situation. We investigated the effects of group pressure on activity in hippocampus and anterior cingulate cortex (ACC) which likely support informative and normative memory conformity, respectively. Furthermore, we related the single nucleotide polymorphism (SNP) rs4680 [called Catechol-O-methyltransferase (COMT) Val158Met] on the gene coding for COMT to both behavior and fMRI activation. Homozygous Met-allele carriers (Val−) behaved more conformist than carriers of at least one Val-allele (Val+). In the neuroimaging data, we compared trials in which subjects were confronted with a majority of incorrect group responses to trials in which they were confronted with a majority of correct group responses. We found increased hippocampal activity when the majority of the group was correct, possibly indicating retrieval processes. Moreover, we observed enhanced activity in the ACC when the majority of the group was incorrect, suggesting that conformity was mostly normative. Most interestingly, this latter effect was more pronounced for Val− as compared to Val+ participants. This offers a speculative explanation for the higher behavioral levels of social conformity in Val− allele carriers, because their subjectively perceived conflict in the presence of an incorrect group majority may have been higher. Overall, this study demonstrates how the mechanisms leading to complex social behavior such as conformity can be studied by combining genetic analyses and fMRI in social neuroscience paradigms.

Are valence and social avoidance associated with the memory conformity effect?

Pairs of participants were shown photographs which varied in terms of valence from negative to positive, and two days later, together, they were given a memory recognition test. When the first person responded the second person saw the response. This affected how the second person responded, what is called memory conformity. The memory conformity effect was larger for previously unseen stimuli (fillers) than for previously seen stimuli (targets), and was greatest for those with low scores on a social avoidance measure. While memory for negative (and most arousing) stimuli was most accurate, the memory conformity effect did not differ significantly by the stimulus valence. Implications for theories of memory malleability and for assessing the reliability of memories in a forensic context are discussed.

Metacognitive awareness and adaptive recognition biases

Prior literature has primarily focused on the negative influences of misleading external sources on memory judgments. This study investigated whether participants can capitalize on generally reliable recommendations in order to improve their net performance; the focus was on potential roles for metacognitive monitoring (i.e., knowledge about one's own memory reliability) and performance feedback. In Experiment 1, participants received explicit external recommendations (Likely Old or Likely New) that were 75% valid during recognition tests containing deeply and shallowly encoded materials. In Experiment 2, participants received recommendations of differing validity (65% and 85%). Discrimination improved across both experiments when external recommendations were present versus absent. This improvement was influenced by metacognitive monitoring ability measured in the absence of recommendations. Thus, effective incorporation of external recommendations depended in part on how sensitive observers were to gradations of their internal evidence when recommendations were absent. Finally, corrective feedback did not improve participants' ability to use external recommendations, suggesting that metacognitive monitoring ability during recognition is not easily improved via feedback.

The costs and benefits of memory conformity

We examined the influence of external recommendations on memory attributions. In two experiments, participants were led to believe that they were viewing the responses of two prior students to the same memoranda they were currently judging. However, they were not informed of the reliability of these fictive sources of cues or provided with performance feedback as testing proceeded. Experiment 1 demonstrated improvement in the presence of reliable source cues (75% valid), as compared to uncued recognition, whereas performance was unaltered in the presence of random cues provided by an unreliable source (50% valid). Critically, participants did not ignore the unreliable source, but instead appeared to restrict cue use from both sources to low-confidence trials on which internal evidence was highly unreliable. Experiment 2 demonstrated that participants continued to treat an unreliable source as potentially informative even when it was predominantly incorrect (25% valid), highlighting severe limitations in the ability to adequately discount unreliable or deceptive sources of memory cues. Thus, under anonymous source conditions, observers appear to use a low-confidence outsourcing strategy, wherein they restrict reliance on external cues to situations of low confidence.

The response order effect: people believe the first person who remembers an event

When groups of people remember an event, the order in which they discuss their memories is important. In three experiments, a response order effect was shown in which participants believed the first speaker to be more accurate and more confident than a subsequent speaker. Further, participants were more likely to report as their own memory what the first speaker reported than what a subsequent speaker reported. The experiments showed that the response order effect was not due to intrinsic characteristics of what the first speaker said. Even when participants chose the response order themselves and the speakers' dialogue was counterbalanced, participants still believed that the first speaker was more accurate and confident than a subsequent speaker. Because in most situations the person who introduces a particular topic into a discussion is more accurate, people may assume that this is true, even when the response order is random.

Recognition confidence under violated and confirmed memory expectations

Individuals' memory experiences typically covary with those of others' around them, and on average, an item is more likely to be familiar if a companion recommends it as such. Although it would be ideal if observers could use the external recommendations of others' as statistical priors during recognition decisions, it is currently unclear how or if they do so. Furthermore, understanding the sensitivity of recognition judgments to such external cues is critical for understanding memory conformity and eyewitness suggestibility phenomena. To address this we examined recognition accuracy and confidence following cues from an external source (e.g., "Likely Old") that forecast the likely status of upcoming memory probes. Three regularities emerged. First, hit and correct-rejection rates expectedly fell when participants were invalidly versus validly cued. Second, hit confidence was generally higher than correct-rejection confidence, regardless of cue validity. Finally, and most noteworthy, cue validity interacted with judgment confidence such that validity heavily influenced the confidence of correct rejections but had no discernible influence on the confidence of hits. Bootstrap-informed Monte Carlo simulation supported a dual process recognition model under which familiarity and recollection processes counteract to heavily dampen the influence of external cues on average reported confidence. A 3rd experiment tested this model using source memory. As predicted, because source memory is heavily governed by contextual recollection, cue validity again did not affect confidence, although as with recognition it clearly altered accuracy.

Natural memory beyond the storage model: repression, trauma, and the construction of a personal past

Naturally occurring memory processes show features which are difficult to investigate by conventional cognitive neuroscience paradigms. Distortions of memory for problematic contents are described both by psychoanalysis (internal conflicts) and research on post-traumatic stress disorder (PTSD; external traumata). Typically, declarative memory for these contents is impaired - possibly due to repression in the case of internal conflicts or due to dissociation in the case of external traumata - but they continue to exert an unconscious pathological influence: neurotic symptoms or psychosomatic disorders after repression or flashbacks and intrusions in PTSD after dissociation. Several experimental paradigms aim at investigating repression in healthy control subjects. We argue that these paradigms do not adequately operationalize the clinical process of repression, because they rely on an intentional inhibition of random stimuli (suppression). Furthermore, these paradigms ignore that memory distortions due to repression or dissociation are most accurately characterized by a lack of self-referential processing, resulting in an impaired integration of these contents into the self. This aspect of repression and dissociation cannot be captured by the concept of memory as a storage device which is usually employed in the cognitive neurosciences. It can only be assessed within the framework of a constructivist memory concept, according to which successful memory involves a reconstruction of experiences such that they fit into a representation of the self. We suggest several experimental paradigms that allow for the investigation of the neural correlates of repressed memories and trauma-induced memory distortions based on a constructivist memory concept.