Inoculating against eyewitness suggestibility via interpolated verbatim vs. gist testing

In real-life situations, eyewitnesses often have control over the level of generality in which they choose to report event information. In the present study, we adopted an early-intervention approach to investigate to what extent eyewitness memory may be inoculated against suggestibility, following two different levels of interpolated reporting: verbatim and gist. After viewing a target event, participants responded to interpolated questions that required reporting of target details at either the verbatim or the gist level. After 48 hr, both groups of participants were misled about half of the target details and were finally tested for verbatim memory of all the details. The findings were consistent with our predictions: Whereas verbatim testing was successful in completely inoculating against suggestibility, gist testing did not reduce it whatsoever. These findings are particularly interesting in light of the comparable testing effects found for these two modes of interpolated testing.     

Question format shifts bias away from the emphasised response in tests of recognition memory

The question asked to interrogate memory has potential to influence response bias at retrieval, yet has not been systematically investigated. According to framing effects in the field of eyewitness testimony, retrieval cueing effects in cognitive psychology and the acquiescence bias in questionnaire responding, the question should establish a confirmatory bias. Conversely, according to findings from the rewarded decision-making literature involving mixed incentives, the question should establish a disconfirmatory bias. Across three experiments (ns = 90 [online], 29 [laboratory] and 29 [laboratory]) we demonstrate a disconfirmatory bias – “old?” decreased old responding. This bias is underpinned by a goal-driven mechanism wherein participants seek to maximise emphasised response accuracy at the expense of frequency. Moreover, we demonstrate that disconfirmatory biases can be generated without explicit reference to the goal state. We conclude that subtle aspects of the test environment influence retrieval to a greater extent than has been previously considered.     

Witnesses’ memories for lineup fillers postdicts their identification accuracy

Witnesses who have quick, automatic recognition experiences when viewing a lineup tend to make more accurate decisions than witnesses who engage in slower, more deliberative processes. A novel postdictor of identification accuracy is predicted from these findings: memories for lineup fillers should be stronger among inaccurate, rather than accurate, witnesses. Undergraduate students (N = 320) viewed a mock crime, made a lineup identification decision, and were given a surprise test for their memory for the lineup fillers. Consistent with predictions, better memories for lineup fillers postdicted mistaken identifications and the suspect's innocence. Information gain analyses showed that under some conditions, memory for lineup fillers provided as much information about the suspect's guilt as a lineup identification. Findings are consistent with the idea that postdictors of eyewitness accuracy are valuable to the extent that they measure the automaticity or deliberativeness of the witness's experience when viewing the lineup.     

The role of working memory and visual processing in prototype category learning

To investigate whether working memory and visual processing have the same role or different roles in A/B and A/not A prototype category learning, the present study adopted an A/B or A/not A category learning task in control and dual conditions. The results of Experiment 1 showed that an additional dual visual working memory task rather than a dual verbal working memory task reduced accuracy of the A/B task, whereas no dual tasks influenced accuracy of the A/not A task. The results of Experiment 2 revealed that an additional dual visual processing task impaired accuracy of the A/B task, whereas the dual visual processing task did not influence accuracy of the A/not A task. These results indicate that visual working memory and visual processing play different roles in A/B and A/not A prototype category learning, and support that these two types of prototype category learning are mediated by different memory systems.     

Retrieval practice and elaborative encoding benefit memory in younger and older adults

Retrieval practice has been identified as a powerful tool for promoting retention. Few studies have examined whether retrieval practice enhances performance in older adults as it does in younger adults. Younger and older adults learned unrelated word pairs and were administered a test after a short (10 min) and long (2 day) delay. Encoding condition was manipulated between subjects, with participants studying the pairs twice, studying them once and taking an immediate test with feedback, or encoding them twice under different deep encoding conditions. In both age groups, equivalent benefits of testing relative to restudy were found. Deep processing also improved memory relative to restudy, suggesting that one factor that might benefit retention is varying the type of encoding task (either by testing or by providing a different instructional manipulation) to increase the accessibility of cues. Retrieval practice can support older adults’ memory and is a viable target for training.     

An interfering dot-probe task facilitates the detection of mock crime memory in a reaction time (RT)-based concealed information test

The present study aimed to test the hypothesis that an interfering task in the concealed information test will help the detection of concealed memory based on participants' behavioral performance (e.g. reaction time, error rate). Here, after participants enacted a mock crime, they were introduced to a concealed information test either with or without an interfering dot-probe task. Results showed that the RT-based pure-CIT (without interference) can detect concealed memory well above chance (AUC = .88). The detection efficiency was higher (AUC = .94) in the interference-CIT based on participants' performance of the interfering task. The findings suggested that the elevation of cognitive workload could possibly increase the detection efficiency of concealed memory based on behavioral measures.     

Impaired retention is responsible for temporal order memory deficits in mild cognitive impairment

Temporal order memory, or remembering the order of events, is critical for everyday functioning and is difficult for patients with mild cognitive impairment (MCI). It is currently unclear whether these patients have difficulty acquiring and/or retaining such information and whether deficits in these patients are in excess of “normal” age-related declines. Therefore, the current study examined age and disease-related changes in temporal order memory as well as whether memory load played a role in such changes. Young controls (n = 25), older controls (n = 34), and MCI patients (n = 32) completed an experimental task that required the reconstruction of sequences that were 3, 4, or 5 items in length both immediately after presentation (i.e., immediate recall) and again after a 10-min delay (i.e., delayed recall). During the immediate recall phase, there was an effect of age largely due to reduced performance at the two longest span lengths. Older controls and MCI patients only differed during the five span (controls > MCI). During the delayed recall, however, there were significant effects of both age and MCI regardless of span length. In MCI patients, immediate recall was significantly correlated with measures of executive functioning, whereas delayed recall performance was only related to other memory tests. These findings suggest that MCI patients experience initial temporal order memory deficits at the point when information begins to exceed working memory capacity and become dependent on medial temporal lobe functioning. Longer-term deficits are due to an inability to retain information, consistent with the characteristic medial temporal lobe dysfunction in MCI.     

Negative emotion elicited in high school students enhances consolidation of item memory,but not source memory

The study examined the effect of negative emotion on consolidation of both item and source memory. Participants learned words read by either a male or female. Then they watched either a negative or a neutral video clip. Memory tests were carried out either 25 min or 24 h after learning. The study yielded the following findings. First, negative emotion enhanced consolidation of item memory as measured by recognition memory in the 25-min delay, and enhanced consolidation of item memory as measured by free recall in both the 25-min and the 24-h delay. Second, negative emotion had little effect on consolidation of source memory, either in the 25-min or the 24-h delay. These findings provide evidence for the differential effects of negative emotion on item memory and source memory and have implications for using emotion as a strategy to intervene memory consolidation.     

Initial Testing Does Not Necessarily Affect Eyewitness Recall Assessed by Specific Questioning

In eyewitness situations, open recall is followed by specific questioning about the witnessed event. We examined whether initial testing affects later recall of actions and specific details. After watching a video of a bank robbery, participants completed an initial testing phase that involved free recall, specific questions about the actions or details of the event or a control condition with no initial testing. In the final test, correct and incorrect answers, accuracy and response confidence for actions and details were analysed. Initial testing affected neither recall nor confidence. The participants were more accurate for actions than details. Response confidence was higher for correct than incorrect answers and higher for details than actions in correct answers. The results showed that specific questioning affects differently the recall of event actions and details and that remembering details increased confidence. Investigative interviewers can use this evidence when questioning information not reported in initial testing.Copyright © 2015 John Wiley & Sons, Ltd.     

Sensory memory consolidation observed: Increased specificity of detail over days

Memories are usually multidimensional, including contents such as sensory details, motivational state and emotional overtones. Memory contents generally change over time, most often reported as a loss in the specificity of detail. To study the temporal changes in the sensory contents of associative memory without motivational and emotional contents, we induced memory for acoustic frequency by pairing a tone with stimulation of the cholinergic nucleus basalis. Adult male rats were first tested for behavioral responses (disruption of ongoing respiration) to tones (1–15 kHz), yielding pre-training behavioral frequency generalization gradients (BFGG). They next received three days of training consisting of a conditioned stimulus (CS) tone (8.00 kHz, 70 dB, 2 s) either Paired (n = 5) or Unpaired (n = 5) with weak electrical stimulation (～48 μA) of the nucleus basalis (100 Hz, 0.2 s, co-terminating with CS offset). Testing for behavioral memory was performed by obtaining post-training BFGGs at two intervals, 24 and 96 h after training. At 24 h post-training, the Paired group exhibited associative behavioral memory manifested by significantly larger responses to tone than the Unpaired group. However, they exhibited no specificity in memory for the frequency of the tonal CS, as indexed by a flat BFGG. In contrast, after 96 h post-training the Paired group did exhibit specificity of memory as revealed by tuned BFGGs with a peak at the CS-band of frequencies. This increased detail of memory developed due to a loss of response to lower and higher frequency side-bands, without any change in the absolute magnitude of response to CS-band frequencies. These findings indicate that the sensory contents of associative memory can be revealed to become more specific, through temporal consolidation in the absence of non-sensory factors such as motivation and emotion.     

Infants' eyewitness testimony: Effects of postevent information on a prior memory representation

In eyewitness testimony research, postevent information impair retention of the original event and increases the probability that interpolated information will be identified as part:of the original event. The present experiments studied these effects with 3-month-olds. Infants learned to kick to move a particular crib mobile and then were briefly exposed to information about a novel mobile. The novel postevent information impaired recognition of the-original mobile when it immediately followed training but not when it was delayed by 1 day. Like adults, infants treated the postevent information as part of the original training event, continuing to do so for at least 2 weeks. We propose that postevent information displaces conflicting information coactive with it in primary memory and creates a new, updated memory token of the event. Once the new token leaves primary memory, however, it is protected; only a copy can be retrieved and modified in the future.     

Memory states and memory tasks: an integrative framework for eyewitness memory and suggestibility

An integrative framework (IMP) is presented which depicts performance in eyewitness suggestibility experiments as the participants' solutions of memory tasks, depending on (a) a specified task-relevant memory base and (b) the participants' perception of the memory task. Three theoretical explanations of the effect of misleading post-event information are reinterpreted and reduced to one single core: individuals answer test questions while assuming the consistency of event and post-event information. The impact of such consistency assumptions (a) is demonstrated in a first experiment, where the usual misinformation effect obtained with the Loftus standard test procedure disappeared when the participants' consistency assumptions were destroyed prior to testing, and (b) manifests itself in a qualitative analysis of individual processing strategies for discrepancies between details. Experiment 2, employing methodological innovations suggested by IMP, examined the memory base and found no evidence for memory impairment or misattributions of post-event details to the witnessed scene. However, a follow-up study conducted four and a half months later revealed a strong tendency for such misattributions which might indicate long-term integration of information.     

Rehearsal of faces and details in action events

The relationship between mental rehearsal and facial identification accuracy was explored in two experiments involving either a staged classroom event or a video scenario. The results suggest that when subjects rehearsed immediately following an event, compared to subjects in non-rehearsal conditions, identification accuracy was increased when the target face was unchanged in appearance but was reduced when the face was changed slightly in appearance from viewing to test. However, when rehearsal of the event was delayed 10 minutes, identification accuracy was improved even when the face had changed in appearance. Immediate rehearsal, in contrast, led to a reduction in identification performance. In short, in some circumstances the gains in specific memory brought about by mental rehearsal serve to reduce than improve identification accuracy. The relevance of these findings to memory theory and everyday eyewitness testimony is discussed.     

The face of an angel: Effect of exposure to details of moral behavior on facial recognition memory

The Dangerous Decisions Theory (DDT; Porter & ten Brinke, 2009) posits that instantaneous perceptions of trustworthiness based on a stranger's face influence the manner in which ensuing information about the target is processed. This study tested a bi-directional DDT model, proposing that information concerning a target's moral behavior could distort eyewitness memory for the individual's facial trustworthiness. Participants (N = 141) viewed a target individual's face (previously rated as appearing “neutral” on trustworthiness) and then were exposed to one of the three vignettes describing the target's behavior (either immoral, morally neutral, or altruistic). Following a delay, observers were asked to identify the target individual on a facial morph video (continuously ranging in levels of perceived trustworthiness). Results indicated that behavioral information varying in morality influenced facial recognition memory; specifically, faces were recalled as having less trustworthy features following a disclosure of immoral/criminal behavior.     

Acute effects of alcohol on memory: Impact of emotional context and serial position

Although the amnestic effects of alcohol in humans are well known, its effects on emotional memory are unclear. In this study, using a randomized double-blind placebo-controlled design, we examine narrative emotional episodic memory in healthy human female volunteers (n = 32) who received either a single dose of alcohol (0.6 g/kg), or a placebo and then viewed neutral story elements presented in either a neutral or emotional context. Memory was tested for gist and detail of the neutral elements 3 days later in a surprise recognition test. Since alcohol modulates GABAergic neurotransmission and may exert its effects on emotion through the limbic system, we predicted that acute alcohol treatment would reduce the expected emotional memory-advantage for gist, leaving detail memory relatively unaffected. Furthermore, given previous findings showing that ‘primacy’ memory is enhanced by physiological arousal, we predicted that reduced arousal produced by alcohol would have the opposite effect and impair primacy memory relative to the middle or ‘recency’ sections of the narrative. Emotional arousal was expected to oppose this effect, so impaired primacy memory following alcohol was only expected in the neutral version of the narrative. Although there was a main effect of story phase (though not of story version), contrary to expectations, alcohol impaired primacy memory for emotionally encoded neutral material. The results suggest that under certain circumstances emotional context or physiological arousal make memories labile and susceptible to disruption through pharmacological manipulation during encoding.     

Fallacies in memory for conversations: Reflections on Clarence Thomas,Anita Hill,and the Like

This study examines conditions that relate to fallacies in memory for conversations. This research tests a cognitive interpretation for why a conversation might be vividly memorable to one eyewitness but not to another. Specifically, a test of gist and verbatim memory for sexual versus non sexual material is presented. In addition, the relative memorability of sexual versus non sexual mateial is tested as a function of the consistency of the context in which it is presented. In two experiments participants heard a recorded conversation between a man and a woman that included four sexual and four non sexual target sentences. The conversation was framed as having been recorded in either a singles bar (the consistent context) or an office setting (the inconsistent context). Sexual items were recalled and recognized better than non sexual items, on both gist and verbatim memory tasks, and the difference in gist (but not verbatim) memory between sexual and non sexual items was greater in the inconsistent than in the consistent context. The discussion considers how this pattern of results might illuminate slippages in memory that may have occured during the Clarence Thomas-Anita Hill hearing (U. S. Supreme Court appointment review; October 1991) as well as memory slippages more generally.     

Resource depletion does not influence prospective memory in college students

This paper reports an experiment designed to investigate the potential influence of prior acts of self-control on subsequent prospective memory performance. College undergraduates (n = 146) performed either a cognitively depleting initial task (e.g., mostly incongruent Stroop task) or a less resource-consuming version of that task (e.g., all congruent Stroop task). Subsequently, participants completed a prospective memory task that required attentionally demanding monitoring processes. The results demonstrated that prior acts of self-control do not impair the ability to execute a future intention in college-aged adults. We conceptually replicated these results in three additional depletion and prospective memory experiments. This research extends a growing number of studies demonstrating the boundary conditions of the resource depletion effect in cognitive tasks.     

The effects of repeatedly recalling a traumatic event on eyewitness memory and suggestibility

ABSTRACT

The aims of this study were to examine the effects of repeatedly recalling a traumatic event on recall performance and eyewitness suggestibility. We also investigated whether these effects were moderated by the type of details recalled and the completeness of retrieval. Participants watched a video depicting a fatal car accident and were randomly allocated to one of four conditions in which they: (1) repeatedly recalled the traumatic (central) details of the event only (trauma-focused); (2) repeatedly recalled the non-traumatic (peripheral) details of the event only (non-trauma focused); (3) repeatedly recalled the entire video (complete); or (4) did not recall the video at all (no-recall control). Results indicated that repeated complete recall was beneficial for memory retention of the entire traumatic event and that, in general, trauma-related (central) post-event information (PEI) was less likely to be reported than trauma-unrelated (peripheral) PEI. It was also found that repeated trauma-focused recall increased trauma-related confabulations. These results not only illustrate the value of repeated complete recall to best preserve the integrity of eyewitness memory, but, perhaps more critically, warn of the dangers of repeatedly questioning witnesses specifically about the central or traumatic details of an event.     

Learning under stress impairs memory formation

Converging lines of evidence indicate that stress either before or after learning influences memory. Surprisingly little is known about how memory is affected when people learn while they are stressed. Here, we examined the impact of learning under stress in 48 healthy young men and women. Participants were exposed to stress (socially evaluated cold pressor test) or a control condition while they learned emotional words and neutral words that were either conceptually associated with or unrelated to the stressor. Memory was assessed in free recall and recognition tests 24 h after learning. Learning under stress reduced both free recall and recognition performance, irrespective of the emotionality and the stress context relatedness of the words. While the effect of stress was comparable in men and women, women outperformed men in the free recall test. These findings show a memory impairing effect of learning under stress in humans and challenge some assumptions of current theories about the impact of stress around the time of learning on memory formation.     

Behavioral memory induced by stimulation of the nucleus basalis: Effects of contingency reversal

Specific behavioral associative memory induced by stimulation of the cortically-projecting cholinergic nucleus basalis (NB) is dependent on intrinsic acetylcholine and shares with natural memory such features as associativity, specificity, rapid formation, consolidation and long-term retention. Herein, we examined extinction and the effects of stimulus pre-exposure. Two groups of adult male rats (n = 4 each) were first tested for behavioral responses (disruption of ongoing respiration) to tones (1–15 kHz), constituting a pre-training behavioral frequency generalization gradient (BFGG). They next received a first session of training, 200 trials of a tone (8.00 kHz, 70 dB, 2 s) either paired with electrical stimulation of the NB (100 Hz, 0.2 s, ～67 μA, NBstm) (group IP) or unpaired (group IU). Twenty-four hours later, they were tested for behavioral memory by obtaining post-training BFGGs. Then the contingencies were reversed yet another 24 h later; the IP group received tone and NBstm unpaired and the IU group received them paired. A final set of generalization gradients was obtained the next day. All stimuli were presented with subjects under state control indexed by regular respiration. Tested 24 h post-initial training, the IP group developed specific associative behavioral memory indicated by increased responses only to CS-band frequencies, while the IU group did not. After subsequent training with unpaired stimuli, the IP group exhibited experimental extinction. Furthermore, after initial exposure to the CS and NBstm unpaired, the IU group exhibited a tendency toward reduced conditioning to CS/NBstm pairing and a significant increase in latency of conditioned responses. The present findings provide additional support for the hypothesis that engagement of the NB is sufficient to induce natural associative memory and suggest that activation of the NB may be a normal component in the formation of natural associative memory.