**2.3. Memory and trauma**

**Memory and stress.** The nature of memory for traumatic events has been debated for decades. Early research supported the notion that memory for traumatic events was different than memory for neutral or positive events. The high emotionality and salience of traumatic events were thought to create "flashbulb memories"—memories that were embedded in one's mind like a "photographic imprint" (Conway, Anderson, Steer, & Donnely, 1994; Winograd & Killinger, 1983). These memories were thought to be highly accurate and fixed due to the overstimulation of the event, which led to over consolidation of memory (McGaugh, 1990; Pitman, 1989). However, more recent research supports the view that memory for traumatic events, like other events, is subject to alteration, is malleable, and is not necessarily completely accurate (Engelhard, van der Hout, & McNally, 2008; Southwick, Morgan, Nicolau, & Charney, 1997). The effect of traumatic experiences on memory is of great importance in the legal system because it could alter the accuracy and effectiveness of a child's eyewitness testimony.

Many crimes are highly stressful in nature and witnessing or being involved in a crime can be psychologically traumatic, particularly for a child. Findings from studies investigating the impact of stressful events on memory have been largely mixed. On the one hand, research has shown that highly stressful situations can adversely affect one's memory. For example, Quesada and others (2012) examined the effect of stress on 8- to 11-year-olds' memory performance. Children were randomly assigned to a stressful or non-stressful condition and then asked to play a memory game. Children who were exposed to stress performed worse, making more errors in retrieval. These decrements in memory performance may result because cognitive resources otherwise used to encode and store details of the events are focused on coping or self-regulation (Vandermass, Hess, & Baker-Ward, 1993) or because cortisol levels produced by stress can affect the hippocampus, which affects memory retrieval (Quesada et al., 2012).

88 Current Topics in Children's Learning and Cognition

their capacities.

**2.3. Memory and trauma** 

effectiveness of a child's eyewitness testimony.

reach. For instance, caution is warranted when asking young children to locate in time or enumerate past events (e.g., age, month, or season; which occurrence, 1st, 2nd, etc.; Friedman, Reese, & Dai, 2011), particularly maltreated children (Wandrey, Lyon, Quas, & Friedman,

Another challenge for all witnesses is cross-examination. Unfortunately, research examining children's performance under cross-examination suggests that they risk losing credibility, despite their cognitive ability to provide accurate information. This is because they often change answers in response to cross-examination – both their correct and their incorrect direct examination answers (Zajac & Hayne, 2003; Zajac, Jury, & O'Neill, 2009). In fact, preschoolers, older children *and* adults are vulnerable to the deleterious impact of crossexamination (Zajac & Hayne, 2006; Zajac & Cannan, 2009) – highlighting the fact that social pressures can undermine accurate memory reporting. Providing support persons for child witnesses and preparation for legal participation are procedures meant to alleviate some of the stresses of testifying for children and seem to offer some benefits (Malloy et al., 2007). Nevertheless, it is clear that the justice system demands a significant degree of communicative and linguistic competency from child witnesses, some of which is beyond

**Memory and stress.** The nature of memory for traumatic events has been debated for decades. Early research supported the notion that memory for traumatic events was different than memory for neutral or positive events. The high emotionality and salience of traumatic events were thought to create "flashbulb memories"—memories that were embedded in one's mind like a "photographic imprint" (Conway, Anderson, Steer, & Donnely, 1994; Winograd & Killinger, 1983). These memories were thought to be highly accurate and fixed due to the overstimulation of the event, which led to over consolidation of memory (McGaugh, 1990; Pitman, 1989). However, more recent research supports the view that memory for traumatic events, like other events, is subject to alteration, is malleable, and is not necessarily completely accurate (Engelhard, van der Hout, & McNally, 2008; Southwick, Morgan, Nicolau, & Charney, 1997). The effect of traumatic experiences on memory is of great importance in the legal system because it could alter the accuracy and

Many crimes are highly stressful in nature and witnessing or being involved in a crime can be psychologically traumatic, particularly for a child. Findings from studies investigating the impact of stressful events on memory have been largely mixed. On the one hand, research has shown that highly stressful situations can adversely affect one's memory. For example, Quesada and others (2012) examined the effect of stress on 8- to 11-year-olds' memory performance. Children were randomly assigned to a stressful or non-stressful condition and then asked to play a memory game. Children who were exposed to stress performed worse, making more errors in retrieval. These decrements in memory performance may result because cognitive resources otherwise used to encode and store

2012), as they may struggle to do so accurately until adolescence.

On the other hand, stress from emotionally salient experiences could lead eyewitnesses to have a stronger memory for a target event (Goodman, Hirschman, Hepps, & Rudy, 1991; Pezdek & Taylor, 2002; Shrimpton, Oates, & Hayes, 1998). Some researchers argue that the stressful nature of traumatic events renders them more personally meaningful and distinctive, which may lead to higher levels of cognitive activation directed toward encoding significant details of the event (Christianson, 1992; Hamann, 2001; Howe, 1997). Indeed, Ochsner, Zaragoza, and Mitchell (1999) found that children who witnessed a staged theft were more accurate on recall and recognition measures compared to children who viewed a similar but neutral event.

Finally, it is possible that stress is related to memory in a curvilinear fashion, with low levels of stress not eliciting enough attention to encode details of an event, but too much stress causing decrements in memory performance. Bahrick, Parker, Fivush and Levitt (1998) found that children exposed to moderate amounts of hurricane damage to their homes recalled more than those with minimal or extensive damage (i.e., low or high stress). However, follow-up interviews showed that the effect did not seem to persist over time (Fivush, Sales, Goldberg, Bahrick, & Parker, 2004).

Overall, studies investigating children's memory for stressful events have shown that younger children tend to recall less information and make more mistakes (e.g., Goodman, Quas, Batterman-Faunce, & Riddlesberger, 1994; Goodman, Quas, Batterman-Faunce, Riddlesberger, & Kuhn, 1997), but individual cognitive factors that affect memory have rarely been examined. However, there may be some cognitive factors that can predict children's memory performance for stressful experiences. For example, Alexander and her colleagues (2002) interviewed 51 children between the ages of 3 and 7 years, two weeks after they received inoculation shots at the doctor's office—an experience that can be very stressful for children. They found that children with better cognitive inhibition ability were less likely to provide incorrect details in free-recall and were less likely to make omission errors when asked misleading questions (e.g., "The nurse didn't give you a shot, did she?") than children with lower cognitive inhibition, controlling for age. Cognitive inhibition, briefly, is the ability to process information while impeding other irrelevant or distracting information or stimuli (Harnishfeger & Bjorklund, 1994; Lorsbach & Reimer, 1997). Alexander and her colleagues reasoned that children with better inhibitory skills were better able to prevent distractions from impeding encoding during the inoculation, thus allowing for better memory of the event. Further, they also argued that their superior inhibitory skills allowed them to suppress suggestive thoughts, allowing them to better resist suggestive questions. More research needs to be conducted to further probe these results and to explore what other cognitive processes affect memory for stressful events.

**Memory and maltreatment.** Examining the effect of stress on memory is important to the legal arena, but it is particularly important to investigate if these findings generalize to

children who face recurrent stressful experiences, such as children who are victims of abuse. Maltreated children may come into contact with the legal system frequently, especially if the abuse has been substantiated and if they are required to testify. Maltreated children may differ from children who only experience traumatic or stressful events once, in that the constant exposure to stress may affect how maltreated children encode and retrieve information. Some research has yielded evidence for developmental delays in maltreated children, especially those who have been physically abused or neglected (see Veltman & Browne, 2001 for a review). Maltreated children have been shown to perform at levels one or two years behind nonabused peers in areas such as intelligence, language, short-term memory, and executive function (Alessandri 1991; Carrick, Quas, & Lyon, 2010; Cicchetti, Rogosch, Maughan, Toth, & Bruce, 2003; Trickett & McBride-Chang, 1995). These delays can be problematic when obtaining a memory report from a maltreated child because they can affect a child's ability to adequately understand and respond to questions (e.g., Eigsti & Cicchetti, 2004; Zajac & Hayne; 2003).

Cognition and the Child Witness 91

have better memory skills and to provide more detailed recall when reporting an event (Gudjonsson & Henry, 2003; Zhu et al., 2010). Although a legal professional might not need to take into account the intelligence of typically developing (TD) children, it is important to be aware that children who suffer from learning and other intellectual disabilities (ID) may be more vulnerable in forensic contexts (Henry & Gudjonsson, 2007). Indeed, the rate at which children's memory performance improves across age may be slower for ID children than for TD children, with mental age a better predictor of eyewitness memory performance than IQ measures (Henry & Gudjonsson, 2007). Thus, children with ID are at risk of being

These effects may be exacerbated among children who are in the justice system as defendants. ID is overrepresented among juvenile delinquents (Najdowski, Bottoms, & Vargas, 2009), as is mental illness (Redlich, 2007), both of which increase adolescent vulnerability to interrogative pressure, which is already heightened among youths (Redlich, 2007; Richardson, Gudjonsson, & Kelly, 1995). Indeed, research demonstrates that children and adolescents (particularly ID and mentally ill juveniles) are at greater risk for falsely confessing transgressions that they did not commit (Najdowski et al., 2009; Redlich, 2007). Given these findings, it is vital that intellectual ability and mental health be taken into

**Source monitoring.** Children's memory reports can also become inaccurate due to faulty source monitoring, which is the process of determining the origin (or source) of their knowledge, memories and/or beliefs (Johnson, Hashtroudi, & Lindsay, 1993). Child witnesses, like any other witnesses, might be asked to provide specific details about criminal events, such as when a crime happened, who committed it, where it happened, and distinguish whether it was a perpetrator's actions or someone else's that they are recalling. Unfortunately, pre- and post-event information from outside sources can influence one's memory, thus making it difficult to distinguish between real event details and suggested details (Poole & Lindsay, 2002; Roberts & Blades, 1999; Thierry, Spence, & Memon, 2001). The source of one's misinformation can vary from television, to word-of-mouth, to intentional suggestion, to name a few. But regardless of the source, the concern is the same – that a child exposed to incorrect information following an event will fail to identify the true source of the novel information and provide inaccurate testimony as a result. Indeed, there is clear developmental growth in the ability to recall source information, identified at the neural level (Sprondel, Kipp, & Mecklinger, 2011). Hence, researchers have begun to explore

There are several factors that can influence the likelihood of committing source monitoring errors for children. These include the similarity of events, delays in recall, suggestive interviewing, and agent identity (i.e., whether the event was about oneself, a friend, or an unfamiliar person; Roberts, 2002). When pre- or post-event information is similar to the target information, it is more likely that children will make source monitoring errors (Johnson et al., 1993; Lindsay, Johnson, & Kwon, 1991). Indeed, although children with stronger source monitoring abilities seem better able to resist post-event suggestions,

less accurate and more suggestible in their event reporting than are TD children.

account when considering child and adolescent witness and defendant statements.

what factors might influence source monitoring.

On the other hand, a child's constant exposure to traumatic events might help his or her memory. The constant stress may lead a child to adopt processing strategies that make him or her hyper-vigilant to stressful stimuli, thereby encoding that information better than nonstressful stimuli (McNally, Metzger, Lasko, Clancy, & Pitman, 1998). A maltreated child may also have extensive knowledge of trauma-related information, which could support better memory (Goodman, Quas, & Ogle, 2010). However, there is evidence to suggest that this hyper-vigilance is generally associated with emotion-regulating strategies (McNally, Kaspi, Riemann, & Zeitlin, 1990; Williams & Broadbent, 1986), rather than cognitive factors.

Overall, despite the findings of developmental delays among maltreated children, research has shown that maltreated children can be as accurate in their memory reports as their nonabused counterparts (Goodman et al., 2010; Howe, 1997; Howe, Toth, & Cicchetti, 2011). For example, Eisen and others (2002) examined 189 3- to 17-year-olds who were allegedly maltreated. These children were questioned about an anogenital examination they received as part of their child maltreatment investigations. Results mimicked those found by studies examining nonabused children: younger children made more errors and reported fewer details than older children. Importantly, the children with prior histories of abuse performed on par with children with no prior history of abuse. Thus, child maltreatment does not necessarily deprive children of their ability to provide accurate event reports, nor does it seem to alter the predictors of memory accuracy (Eisen et al., 2002, 2007).
