Influences of misleading postevent information: misinformation interference and acceptance

Because of the biasing nature of retrieval tests, evidence that the introduction of misleading postevent information will impair the memory for an original event has recently been in dispute. In two experiments, a retrieval test sensitive to both biasing effects of misinformation (misinformation acceptance) and influences of the misinformation on memory (misinformation interference) was used. Both experiments demonstrated misinformation acceptance, and one of the experiments suggested that misinformation interferes with the ability to remember the original event. Two misinformation interference hypotheses are evaluated; they suggest that the misinformation may have either impaired memory or led to confusion regarding what had occurred during the event.     

Recognition memory after short retention intervals in fornix-transected monkeys

Fornix-transected monkeys were impaired in recognition memory after brief retention intervals for short lists of either colours or spatial positions. The results were contrasted with the existing evidence in human amnesic patients for a neurologically separate, intact short-term memory system.     

Mnemonic benefits of retrieval practice at short retention intervals

The testing effect refers to the retention benefit conferred by prior retrieval of information from memory. Although the testing effect is a robust phenomenon, a common assumption is that reliable memory benefits only emerge after long retention intervals of days or weeks. The present study focused on potential test-induced retention benefits for brief retention intervals on the order of minutes and tens of seconds. Participants in four experiments studied lists of words. Some of the items were subjected to an initial cued recall test, and others were re-presented for additional study. Free recall tests were administered in each experiment following retention intervals ranging from 30 s to 8 min. When initial retrieval practice was successful (Experiments 1 through 3), or feedback compensated for unsuccessful retrieval (Experiment 4), significant testing effects emerged at all retention intervals. Results are discussed in the context of a bifurcated item-distribution model and highlight the importance of initial test performance and the type of analysis employed when examining testing effect data.     

Memory distrust and acceptance of misinformation

Relying on a community sample (N = 80), the present study examined whether memory distrust is related to an increased tendency to accept misinformation and whether it interacts with passage of time. Participants were shown video footage of an armed robbery. Approximately 30 minutes later, they were asked to describe as accurately as possible what they had seen. Either 1 day or 2 weeks later they were presented with their own statements, to which five misinformation items had been added. The results showed that people suffering from memory distrust accepted more misinformation than those with optimistic beliefs about their memory. In addition, both age and free recall seemed to modulate this relationship. However, memory evaluation did not interact with time interval. Copyright © 2009 John Wiley & Sons, Ltd.     

Recognition memory for words and pictures at short and long retention intervals

In two experiments, subjects studied a long series of words and pictures for recognition. Retention intervals varied from several minutes to a few months. The complicated testing procedures in Experiment I required the use of a traditional correction for guessing to obtain estimates of subjects' memory performance. A comparable, but simpler, design in Experiment II permitted the calculation of sensitivity and bias measures. In both studies, pictorial memory was superior to verbal memory at all retention intervals tested, and this advantage was essentially constant over time. In addition, the experiments identified an increasing tendency to call verbal test items "old" over time. Bias scores in Experiment H revealed that subjects adopted a more lenient criterion in responding to words than to pictures, and increased leniency was noted for both item types over time. Explanations of the results are offered in terms of differences in initial encoding and of a loss of discrimination between experimental and extraexperimental materials.     

Cue-framing effects in source remembering: A memory misattribution model

During source remembering, selectively emphasizing one source in the retrieval query “Is this item from Source A?” can yield different accuracy than emphasizing the alternate source in “Is this item from Source B?” even if those are the only two possible origins. One account of this cue-framing effect holds that it reflects different active monitoring strategies encouraged by the two cue frames. An item memory misattribution (IMM) model instead assumes that this effect reflects the uncontrolled use of item recognition during confirmatory source judgments, and an IMM model simulation predicted a quantitative relationship between recognition levels and the cue-framing effect. Experiments 1 and 3 confirmed these predictions by using study repetitions to manipulate recognition levels, and Experiments 2 and 3 also demonstrated the effect with new source tasks not previously considered. The data suggest that, in addition to qualitative monitoring strategies, subjects also use the availability of item memory in a heuristic fashion during confirmatory source attributions.     

Misleading postevent information and memory for events: arguments and evidence against memory impairment hypotheses

The claim that a person's memory for an event may be altered by information encountered after the event has been influential in shaping current conceptions of memory. The basis for the claim is a series of studies showing that subjects who are given false or misleading information about a previously witnessed event perform more poorly on tests of memory for the event than subjects who are not misled. In this article we argue that the available evidence does not imply that misleading postevent information impairs memory for the original event, because the procedure used in previous studies is inappropriate for assessing effects of misleading information on memory. We then introduce a more appropriate procedure and report six experiments using this procedure. We conclude from the results that misleading postevent information has no effect on memory for the original event. We then review several recent studies that seem to contradict this conclusion, showing that the studies do not pose problems for our position. Finally, we discuss the implications of our conclusions for broader issues concerning memory.     

Dissociating familiarity from recollection in human recognition memory: Different rates of forgetting over short retention intervals

Two functionally distinct forms of recognition memory have been identified in human and nonhuman species—the ability to recollect qualitative information about previous events, and the ability to differentiate between familiar and novel stimuli. Separate dual-process theories have been developed in the animal and human literatures to account for these findings. However, it is not clear whether these theories describe the same two underlying memory processes. On the basis of animal studies of medial temporal lobe function, familiarity is expected to exhibit disproportionately fast forgetting compared with recollection over short retention intervals. We tested this prediction in healthy human subjects by examining recognition forgetting rates across a range of 8–32 intervening items and found significant forgetting in the accuracy of familiarity-based discriminations and no evidence of forgetting in the accuracy of recollection-based discriminations. In agreement with the results from nonhuman species, the present results indicate that item familiarity decreases more rapidly than recollection over short retention intervals.     

Habitual acceptance of misinformation: Examination of individual differences and source attributions

This study identifies individuals who are habitually susceptible to accepting postevent misinformation across testing on three separate events. The results indicate that those individuals identified as habitually susceptible exhibited higher dissociation scores and less of an association between memory accuracy and confidence than did the individuals identified as nonhabitually susceptible. When they were asked to identify the source of the remembered information, similar patterns of source attributions were found for all individuals when they were responding correctly and incorrectly to nonmisinformation and when they were correctly rejecting items of misinformation. Importantly, from a source-monitoring perspective, individuals identified as habitually susceptible demonstrated a different pattern of source attributions than did those classified as nonhabitually susceptible when they were accepting misinformation. Habitually susceptible individuals were as likely to attribute the source of their memory incorrectly to something seen in the experienced event as to attribute it correctly to something read after the fact.     

Memory for fact, fiction, and misinformation: the Iraq War 2003

Media coverage of the 2003 Iraq War frequently contained corrections and retractions of earlier information. For example, claims that Iraqi forces executed coalition prisoners of war after they surrendered were retracted the day after the claims were made. Similarly, tentative initial reports about the discovery of weapons of mass destruction were all later disconfirmed. We investigated the effects of these retractions and disconfirmations on people's memory for and beliefs about war-related events in two coalition countries (Australia and the United States) and one country that opposed the war (Germany). Participants were queried about (a) true events, (b) events initially presented as fact but subsequently retracted, and (c) fictional events. Participants in the United States did not show sensitivity to the correction of misinformation, whereas participants in Australia and Germany discounted corrected misinformation. Our results are consistent with previous findings in that the differences between samples reflect greater suspicion about the motives underlying the war among people in Australia and Germany than among people in the United States.     

Updating metacognitive control in response to expected retention intervals

In five experiments, we investigated whether expected retention intervals affect subjects’ encoding strategies. In the first four experiments, our subjects studied paired associates consisting of words from the Graduate Record Exam and a synonym. They were told to expect a test on a word pair after either a short or a longer interval. Subjects were tested on most pairs after the expected retention interval. For some pairs, however, subjects were tested after the other retention interval, allowing for a comparison of performance at a given retention interval conditional upon the expected retention interval. No effect of the expected retention interval was found for 1 min versus 4 min (Exp. 1), 30 s versus 3 min (Exp. 2), and 30 s versus 10 min (Exps. 3 and 4), even when subjects were given complete control over the pacing of study items (Exp. 4). However, when the difference between the expected retention intervals was increased massively (10 min vs. 24 h; Exp. 5), subjects remembered more items that they expected to be tested sooner, an effect consistent with the idea that they traded off efforts to remember items for the later test versus items that were about to be tested. Overall, this set of results accords with much of the test-expectancy literature, revealing that subjects are often reluctant to adjust encoding strategies on an item-by-item basis, and when they do, they usually make quantitative, rather than qualitative, adjustments.     

Trauma and memory: effects of post-event misinformation, retrieval order, and retention interval

The present study concerned effects of misinformation, retrieval order, and retention interval on eyewitness memory for a traumatic event (a vivid murder). Relations between misinformation acceptance and compliance were also examined. The classic three-stage misinformation paradigm (Loftus, 1979) was employed, with a multi-component recognition test added. Either immediately or 2 weeks after viewing a distressing film, 232 adults read a narrative (misleading or control) about the murder and then took a recognition test that tapped memory for central and peripheral details. Test-item order either matched the chronology of the film or was randomly determined. Significant misinformation effects were obtained. Moreover, control participants were more accurate in response to questions about central than peripheral information; however, this was not so for misinformed participants. Sequential but not random retrieval order resulted in a higher proportion of correct responses for central as opposed to peripheral misinformation questions. Compliance was significantly related to misinformation effects. Delay increased participants' suggestibility, impaired memory accuracy, and produced higher confidence ratings for misinformed participants compared to controls. Findings indicate that even for a highly negative event, adults' memory is not immune to inaccuracies and suggestive influences.     

Memory impairment in the weapon focus effect

Two experiments are reported in which postevent source of misinformation was manipulated within weaponpresent and weapon-absent scenarios. Participants viewed slides depicting either a weapon or a newspaper event and then received either incomplete questioning or a narrative. Both postevent sources contained misleading information about a central and peripheral detail concerning either the weapon or the newspaper scenario. With a modified test in Experiment 1, questioning was found to increase misinformation effects concerning the central item, as compared with a narrative, and more misinformation effects were found for the weapon-peripheral than for the newspaper-peripheral item. In Experiment 2, the participants were more likely to claim to have seen contradictory and additive misinformation about the central item in the slides following questioning, and more contradictory and additive misinformation effects occurred for the weapon-peripheral than for the newspaper-peripheral item. The findings are considered in terms of the effects of both postevent and encoding factors on memory.     

Information processing and estimation of short time intervals.

Duration estimates were assessed by the method of reproduction with filled reproduction intervals. Mental arithmetic, reading and mirror-image drawing were used in pairs as initial and/or reproduction tasks. All nine possible pairs of tasks were used in a 9 X 5 X 5 mixed design with five Ss per task pair and five interruption intervals for each initial task. Results indicated that, when arithmetic was used as the initial task, Ss underestimated the duration of the initial interval. When arithmetic was used as the reproduction task, Ss overestimated the duration of the initial interval. A significant correlation was obtained between arithmetic outputs and the lengths of the duration estimates. Results are interpreted as supportive of Burnside's (1971) interpretation of Ornstein's (1969) storage-size hypothesis.     

Variations in perception of short time intervals during menstrual cycle

The hypothesis that women experience heightened sensitivity and responsivity premenstrually was tested by asking 10 women to produce short time intervals at four phases of the menstrual cycle. 10 men were assigned to "pseudo-cycles" and tested as a control. The test was based on the assumption that a greater sensitivity to stimuli is reflected in a "slowing down" of subjective time. The women produced the shortest time intervals three to four days before menses, confirming the hypothesis.     

Reality monitoring and resistance to forgetting under short delay intervals

In three experiments, participants were asked to perform simple action statements or to imagine performing the actions in a single study session. In a test session that occurred 1 hr, 24 hr, 48 hr (Experiments 1a and 1b), or 1 week later (Experiments 2 and 3), participants were instructed to tell whether the action statement had been carried out or imagined. The primary finding was that, overall, recognition and reality monitoring showed a comparable rate of forgetting. The results add evidence to the hypothesis that, also after long retention delays, discrimination between an internal and an external source may not be inferior to item recognition. A new theoretical proposal to account for these findings is outlined.     

Reality monitoring and resistance to forgetting under short delay intervals

In three experiments, participants were asked to perform simple action statements or to imagine performing the actions in a single study session. In a test session that occurred 1 hr, 24 hr, 48 hr (Experiments 1a and 1b), or 1 week later (Experiments 2 and 3), participants were instructed to tell whether the action statement had been carried out or imagined. The primary finding was that, overall, recognition and reality monitoring showed a comparable rate of forgetting. The results add evidence to the hypothesis that, also after long retention delays, discrimination between an internal and an external source may not be inferior to item recognition. A new theoretical proposal to account for these findings is outlined.     

Response conflict determines sequential effects in serial response time tasks with short response-stimulus intervals

In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather than repeat from trial N-2 to trial N-1. Different accounts of this RT pattern in terms of perceptual noise, response-selection monitoring, and response conflict were tested in 4 experiments. Second-order RT costs were caused by the response sequence rather than the stimulus sequence. Manipulation of stimulus contrast, stimulus classification difficulty, and set-level compatibility did not modulate the response-related second-order RT effect, whereas this effect increased when spatially incompatible responses were demanded. These findings support a response conflict account of higher order sequential effects in short-RSI situations.     

Mental reinstatement of the misinformation context and the misinformation effect in children and adults

The present study investigated the effects of mental reinstatement of the context in which misleading information about an event was presented on later recognition memory for the event. Five‐year‐olds, 7‐year‐olds and adults were shown a short video depicting a children's adventure and were asked a set of misleading questions to introduce misinformation one week later. Before the recognition memory test was administered another week later, half of the participants were given instructions to mentally reinstate the context of the misleading interview. Memory was assessed with a set of forced‐choice recognition questions once in the misleading interview context and for the children a second time at home one week later. When participants were instructed to mentally reinstate the context of the misleading interview prior to the recognition test, false memory reports occurred more often for adults than for children and had a stronger impact on peripheral information than on central information for both 7‐year‐olds and adults. When 5‐ and 7‐year‐olds were tested at home, false memory reports decreased. Thus, reinstating the context of an interview introducing misinformation can reduce the accuracy of memory reports; the context dependence of both accurate and inaccurate memory reports in children and adults is discussed. Copyright © 2003 John Wiley & Sons, Ltd.