Forensic Psychology

by Graham M Davies

  How do we come to conform our memory reports to another person’s? The updateable memory hypothesis proposes that the misinformation effect occurs because stored memories are overwritten with the misinformation we encounter (Loftus, 1979; Loftus, Schooler, & Wagenaar, 1985; Loftus & Hoffman, 1989; Wright & Loftus, 1998; Braun & Loftus, 1998). According to this account, memory is the product of reconstruction, and we continually reinterpret events that we see. To illustrate, a witness in the Loftus et al. (1978) experiment who accepts the misinformation embedded in the questionnaire might visualise the misleading detail as part of the scene. The witness will then assimilate the fragments of misinformation into their memory of the event. When they come to recall it, their memory will be based on all of the fragments, misinformation included.

  There are several other theoretical accounts of the misinformation effect (see Ayers & Reder, 1998 for a review). The strategic effects account proposes that memory is not impaired by misinformation, but rather participants’ memory reports are affected by task demands and test-taking strategies (McCloskey & Zaragoza, 1985a, 1985b; Zaragoza, McCloskey, & Jamis, 1987). The blocked memory access account of the misinformation effect proposes that memory traces for the original event and the misleading information coexist in memory. There is response competition between the traces, and whether the originally witnessed information is retrieved from memory depends on whether memory for the misinformation is relatively stronger and blocks memory retrieval (e.g., Bekerian & Bowers, 1983; Chandler, 1991). The source monitoring account proposes that people sometimes have difficulty distinguishing the source of their memory, and will mistakenly report misinformation as something they had actually witnessed (Lindsay & Johnson, 1987).

  When are witnesses most likely to report misinformation? One factor influencing susceptibility to the influence of misinformation seems to be whether processing the misinformation requires retrieval of the original event information (Ayers & Reder, 1998). Other predictive factors concern the quality of the source providing the post-event information. People are more likely to incorporate information given by someone else into their own testimony if they think that the other person’s memory of the event is better than theirs (Allan, Midjord, Martin, & Gabbert, 2012; Gabbert, Memon, & Wright, 2007). People may also conform their testimony to others when the cost of disagreeing is large (Wright, Memon, Skagerberg, & Gabbert, 2009), when they are acquainted with one another (Hope, Ost, Gabbert, Healey, & Lenton, 2008), and when the source of the information is a credible expert (Williamson, Weber, & Robertson, 2013). In contrast, memory reports are changed less readily when people are given strict warnings about reporting incorrect information (Wright, Gabbert, Memon, & London, 2008), and when a person’s memory for the original event was accurate to begin with (Wright & Villalba, 2012).

  6.5.2 False Memories

  What about significant and emotional life events: is it possible to develop false memories about these types of events? There has been heated controversy over whether adults can recover memories of sexual abuse they experienced as children. On one side of the debate, it is argued that unpleasant memories can be suppressed. Furthermore, people can suffer global amnesia and then spontaneously recover memory, typically through therapy (e.g. Bass & Davis, 1994). On the other side, it has been maintained that memories for events that did not actually happen can be implanted by even well-meaning therapists (e.g. Ofshe & Watters, 1994). Additionally, in a systematic review of traumatic memory studies, Pope, Oliva, and Hudson (1999) concluded that traumatic amnesia rarely occurs.

  To demonstrate that people can develop false memories for entire events that did not actually happen, Loftus and Pickrell (1995) conducted suggestive interviews with young adult participants about three true events and one false event that ostensibly occurred during their childhood. The true events were collected by contacting their parents for relevant examples. The false event concerned the participant having been lost in a shopping mall as a child, something the parents said had never occurred. While participants mostly confirmed the true events, about 25% of the participants affirmed, in whole or in part, the false event. Subsequent studies reported similar results using other types of fictitious childhood experiences and using different testing procedures. As examples, research participants have reported false memories of taking a hot air balloon ride (Wade, Garry, Read, & Lindsay, 2002), being licked by Pluto at Disney World (Berkowitz, Laney, Morris, Garry, & Loftus, 2002) and spilling punch on the bride at a wedding (Hyman, Husband, & Billings, 1995).

  Theoretically, what is the underlying psychological mechanism that accounts for the development of false memories? Hyman and Loftus (2002) propose that false memories may arise from source monitoring errors: Other similar memories are activated when people imagine false events. Memory traces comprising elements of true and false events are formed (also see Wade, Garry, Read, & Lindsay, 2002). Subsequently, when people retrieve a false event from memory, they are not able to discern the original source of the information.

  In generalising theories about false memory formation to the legal system, there are some caveats raised by researchers to consider. It has been argued that whether adults and children form a false memory of an event depends on the plausibility of the false event (Pezdek & Hodge, 1999; Pezdek, Finger, & Hodge, 1997). For instance, Pezdek, Finger, and Hodge (1997) reported that none of their participants affirmed a suggested memory of having an enema in childhood. Another factor that may be considered is that there are individual differences in susceptibility to false memory development, such as individual capacity of working memory (e.g., Watson, Bunting, Poole, & Conway, 2005).

  EXERCISE 6.1 MEMORY RETRIEVAL EFFORTS AND AMNESIA

  Adult survivors of childhood trauma often report that they have prior periods of impaired memory or amnesia for the abuse that they suffered when asked “Was there ever a period of time when you remembered less about the event than you do now?” Affirmative answers to this question have been taken as evidence of repressed memory for abuse suffered in childhood (Read & Lindsay, 2000).

  How well can you remember non- traumatic events from your childhood (e.g. music or dance lessons, sports camps, family reunion)? Spend a few minutes thinking about one of these events. How well do you remember this particular event? Try to recall as many details about the event as possible (e.g. other people present, the places involved, conversations you had). If possible, talk to other family members about the event, and look for photographs and other mementos to help you remember. Following this, how well do you think you initially remembered the event? Did your memory seem to improve as you tried to recall more information?

  Read and Lindsay (2000) asked participants to rate their current and prior memories of several non-traumatic events from their childhood and adolescence. Participants then engaged in retrieval activities directed towards helping them remember more about the event for four weeks. Following this, a substantial number of participants reported that their memory for the event was poor prior to retrieval. These findings support Read and Lindsay’s (2000) argument that appropriate control conditions are needed to test whether the nature of forgetting really differs between traumatic and non-traumatic memories.

  6.5.3 Delay

  The delay, or length of time, between the crime and when the witness provides testimony, can vary from a few minutes to several years. All other things being equal, information is more likely to be forgotten with longer delays. For example, Van Koppen and Lochun (1997) performed an archival analysis of eyewitness descriptions of commercial bank robbers, and found that accuracy and completeness decreased the longer the delay between the crime and the eyewitness being asked for the description.

  Memory reports may be especially accurate when witnesses are interviewed immediately after the crime, because memory traces are the strongest, most accessible and most available (Tuckey & Brewer, 2003a). Additionally, both in the basic memory literature (e.g. Wixted & Ebbesen, 1991), and in the eyewitness literature (e.g.,
Tuckey & Brewer, 2003a), memory initially decays rapidly, followed by a much slower decline.

  CASE STUDY 6.2 INVESTIGATING MEMORY IN HISTORIC ABUSE CASES

  There has been a surge in so-called historic cases of abuse and sexual assault in recent years. Police investigations into historic cases of child sex abuse have reported accounts from alleged victims of more than 1400 suspects in the UK, of which 260 were celebrities (National Police Chiefs’ Council, 2015). For instance, after his death, Jimmy Savile, the television entertainer, was accused of sexual abuse of some 450 people in the period between 1955 and 2009, the ages of the complainants at the time of the assaults ranging from 8 to 47 years (Davies, 2014). A number of cases involving historic abuse have been brought to trial in the UK against living celebrities, some of which have led to convictions, whereas others have been exonerated (see Operation Yewtree, n.d.). Haber and Haber (1998) have suggested criteria the legal system could use to determine the likely accuracy of the testimony, including whether there is evidence that the victim’s memory has been tainted by erroneous post event information. Additionally, Porter, Campbell, Birt, & Woodworth (2003) advised that in historic cases, central details of the experience may endure accurately in memory, whilst more peripheral details are more likely to be distorted with time. If you were an investigator in a historic case, what questions would you ask the victims and witnesses to determine whether memory has been distorted?

  Real-world eyewitnesses might recall the critical incident on several occasions before they provide testimony. This has implications for forgetting over time. The extent to which memories are forgotten depends on whether a person has had their memory tested during the retention interval. For example, Ebbesen and Reinick (1998) had research participants interact briefly with a stranger. After 28 days, they tested the participants’ memories for what the other person looked like. The number of correct descriptors recalled by participants did not decrease over 28 days if participants had their memory repeatedly tested several times during the 28-day period. In contrast, if participants’ memory was tested for the first time after a delay of between 7 to 28 days, accuracy decreased as the length of time between the critical event and initial testing increased. These findings suggest that the accuracy and amount of information that might be forgotten over time is minimised by questioning witnesses relatively soon after the crime.

  Having said this, it should be borne in mind that repeated interviews have complex effects on memory reports. Across repeated interviews, studies find evidence of hyperamnesia (e.g., Scrivner & Safer, 1988), reminiscence (e.g., Howe, 1991) and increased inconsistencies (e.g., Warren, Hulse-Trotter, & Tubbs, 1991). Additionally, information is more likely to be accurately reported across interviews when it is consistent with a crime schema (i.e. conceptual knowledge structures regarding a crime, including events, roles and scenes) (Tuckey & Brewer, 2003a).

  6.5.4 Emotional and Traumatic Memories

  Are some memories more resistant to decay over time? One area of research that addresses this question is research on flashbulb memories, which concerns autobiographical memory for significant and unexpected events. According to some conceptualisations (e.g., Brown & Kulik, 1977), flashbulb memories arise from a special memory mechanism that produces highly vivid, accurate and detailed memory traces. According to this view, flashbulb memories are retained for a long time, perhaps indefinitely, with people accurately remembering the original event and its reception context (i.e. where they were when the event occurred, who they were with, what they were doing, the aftermath of the event, personal and other people’s reactions to the event).

  Emotional memories are often recalled with a high degree of vividness (Porter & Birt, 2001). There is evidence that emotional memories may be more accurately remembered (Terr, 1979; 1983; Thompson, Morton, & Fraser, 1997; Wagenaar & Groeneweg, 1990; Yuille & Cutshall, 1986). For example, Terr (1979) studied the memory reports of 25 children who were kidnapped and buried underground in a tractor-trailer. After several hours, the roof of the tractor-trailer collapsed and the children dug their way out. The memory reports were still intact and detailed after 13 months (Terr, 1979) and when assessed again four years later (Terr, 1983). As another example, Wagenaar and Groeneweg (1990) reported evidence that concentration camp survivors’ memories, particularly for information central to the traumatic experiences, were accurate and consistently reported decades later. One reason emotional memories may be better remembered is because they are often rehearsed (Tinti, Schmidt, Testa, & Levine, 2014).

  However, people’s memories for significant emotional events may not always be especially accurate, even when the memory seems vivid. There is evidence that memories of highly symbolic events are influenced by reconstructive processes, and are altered over time, as the event becomes more personally important and emotionally impactful (Christianson, 1989; Neisser, 1982, also see Wright, 2008). Thus, flashbulb memories show forgetting over time, just like ordinary autobiographical memories (see Curci & Lanciano, 2009).

  A large body of research has investigated people’s memory for emotionally charged public events, including more than 20 studies on the 9/11 attacks (see Hirst et al., 2015 for a review). Although people do not forget the event, even if it happened a long time ago, the decline in accuracy of people’s memory reports are similar to that of other autobiographical memories. In analysing the consistency of people’s memory reports of the 9/11 attack over a 10-year period, Hirst and colleagues (2015) found considerable initial forgetting over the first year, particularly of noncritical details, errors of omission (i.e. failures to report information) and errors of commission (i.e. reporting inconsistent information). Additionally, external influences, such as exposure to information reported in the media, shaped what was remembered and forgotten.

  6.6 RETRIEVAL FACTORS

  An interview with a witness or a victim provides criminal investigators with an opportunity to potentially gather important leads and evidence necessary for solving a case. Indeed, in some cases, such as sexual assault, the testimony given during an interview may be the only direct evidence in the case. Research has demonstrated that the completeness and accuracy of information varies depending on how questions are asked. Additionally, memory itself may be affected by how witnesses are questioned.

  PHOTO 6.3 Loftus and Palmer (1974) showed participants films of road accidents and found that when questioned later, the severity of the verb used (“smashed” vs. “bumped”) influenced the estimates of speed of the vehicle involved.

  Source: © Evgeny Murtola/Shutterstock

  6.6.1 Question Format

  The format in which questions are asked can influence the accuracy of the response given. With an open-response format (e.g. “Describe the attacker”), the participant is asked to freely report information that they remember. A closed-response format limits the response of the witness (“What colour was the attacker’s shirt?”), as do yes/no questions (“Was the attacker’s shirt black?”). The accuracy and completeness of the response varies dramatically, depending upon question format (e.g. Clifford & George, 1996; Davies, Westcott, & Horan, 2000; Fisher, Geiselman, & Raymond, 1987; Memon & Vartoukian, 1996). People tend to provide accurate answers more often to open-ended questions, and to questions that are less specific (Kebbell & Wagstaff, 1999). Additionally, people find questions involving double negatives (“Did the man not tell you not to get on the ground?”), compound questions (“Did the men enter the premises at 9:30? Did you look for an exit?”) and questions with complex syntax (“Before or after you ran away, did the men move towards the front or the back of the room?”) difficult to answer (see Kebbell & Gilchrist, 2010 for a review).

  6.6.2 Suggestive Questioning

  Leading questions suggest to witnesses the answer that is required. In their groundbreaking study, Loftus and Palmer (1974) demonstrated that leading questions influence responses. Participants were shown a film of cars colliding. Following this, they were asked a question about the speed t
hat the cars were traveling before they impacted. There were different versions of the question. One asked, “How fast were the cars going when they smashed into each other?” Other versions substituted the word “smashed” with the word “bumped”, “collided”, “hit” or “contacted”. Speed estimates varied depending on the version of the question asked, with participants giving lower estimates of speed on average when asked the question with the word “bumped” compared to the word “smashed”. Additionally, participants who had the question including the word “smashed” were much more likely later to report having seen broken glass at the crash scene, compared to those who had the question including the word “hit”. The severity implied in the question had influenced their memories of the original event.