Cognition and the Child Witness : Understanding the Impact of Cognitive Development in Forensic Contexts

© 2012 Segovia and Crossman, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cognition and the Child Witness: Understanding the Impact of Cognitive Development in Forensic Contexts


Introduction
Children's normal cognitive development allows them to thrive and succeed in a wide variety of contexts, particularly those well suited to their emerging abilities. However, there are domains in which children are forced to participate that are not necessarily well adapted to their developing cognitive skills and abilities. One of these is the legal system. Designed to operate with adults in mind, children are often poorly equipped to cope with its demands and rigors (Malloy, Mitchell, Block, Quas, & Goodman, 2007), and their performance in these contexts is often evaluated in ways that might under-or overestimate their contributions (Bottoms, Golding, Stevenson, Wiley, & Yozwiak, 2007). Hence, examining children's cognitive abilities in forensic contexts can be an important means of helping calibrate the usefulness of their contributions.
While the nature of children's participation in the legal system varies, child witnesses must have certain basic cognitive abilities, such as the capacity to perceive, recall and communicate appropriate, relevant information clearly and accurately to provide evidence in legal contexts (Federal Rules of Evidence 601, 602). They must be able to understand and respond to questions effectively, without succumbing to suggestion or interviewer influence, and they must be able to do so credibly, or their evidence might be disregarded, dismissed or otherwise disbelieved (Leippe & Romanczyk, 1989;Ruva & Bryant, 2004). Thus, beyond the cognitive capacity to perceive, recall and report on past events, child witness credibility is an important factor in the extent and type of impact a child witness might have in a given case.
While there are numerous influences on perceptions of child witness credibility, it is likely that their cognitive development impacts both their actual accuracy and perceptions of their accuracy and credibility. Yet, this impact likely varies as a function of case content. That is, cognitive maturity might be an important consideration in weighing a child's custody preferences, but be considered less relevant for an alleged sexual abuse victim, for whom perceived trustworthiness is more critical (Crossman, Powell, Principe, & Ceci, 2002;Duggan, Aubrey, Doherty, Isquith, Levine & Scheiner, 1989). To understand the role and impact of child witnesses in the legal system, it is thus important to consider what aspects of cognitive development, if any, are related to child witness accuracy and credibility.
In the current chapter, cognitive development is explored as it pertains to children in different forensic contexts. First, aspects of memory development are considered in terms of how they likely impact child witness perception and reporting of events, in addition to factors that might influence witness memory, such as trauma. Then, additional factors related to child witness strengths and vulnerabilities are considered, including intelligence, source monitoring abilities, and suggestibility. Finally, the interplay between case content and cognitive development is explored for its impact on child witness effectiveness. While the central focus of this chapter is on children as victims/witnesses, children also interact in the justice system as suspects and perpetrators. One of the central concerns in those cases is with lie-telling, which is addressed elsewhere in this volume, but here we consider issues such as juvenile confessions in relation to their cognitive development.

The developing cognitive abilities of the child witness
There is no one "child witness" and the variety of forensic contexts in which children participate makes it difficult to define uniform aspects of cognitive development that are relevant to all child witnesses. Nevertheless, various aspects of cognitive development have been heavily examined for their importance to child witness accuracy and credibility, as detailed below.

Memory development -Witnessing an event
Most critical for child witnesses is memory development. Although the ability to create memories seems to be present at least from birth, lasting autobiographical memories that a child can report of an experienced event are rare until approximately 3 years of age (Fivush, 1994(Fivush, , 1997Jack, Simcock, & Hayne, 2012), likely facilitated and organized by language development (Simcock & Hayne, 2002). Nevertheless, once developed, children's memories can be highly accurate. In terms of eyewitness identifications, child witnesses can be as accurate in identifying a culprit as adult witnesses (Humphries, Holliday, & Flowe, 2012;Pozzulo & Lindsay, 1998).
Generally speaking, to be effective witnesses, children must be able to communicate facts of a forensic nature about which they are knowledgeable because they directly perceived and remember them. Thus, a child's ability to properly encode an event in memory is paramount. Effective encoding can be influenced by attention and prior knowledge, while memory retention might be affected by memory strength, script knowledge, and memory storage capacity.
Prior knowledge. Children's knowledge, which grows with age, impacts the accuracy of their event memory as well. It influences what they attend to, how they understand and interpret events and what they encode into memory (Principe, Ornstein, Baker-Ward, & Gordon, 2000). For example, a child expert in a domain (e.g., chess) can outperform an adult in recalling locations of chess pieces on a chess board (Chi, 1978), and prior expert knowledge can overwhelm the effect of general intellectual aptitude on story recall (Schneider, Bjorklund, & Maier-Brückner, 1996).
On the other hand, children begin to develop awareness of culturally-based stereotypes during the preschool years (e.g., obesity, mental illness, sex, race; Corrigan & Watson, 2007), and these stereotypes can lead children to selectively encode or inaccurately reconstruct their memories to be in line with their stereotypes (Bigler & Liben, 1993;Klaczynski, 2008;Martin & Halverson, 1983). This suggests that child witness memory accuracy could be undermined by children's stereotypes (Leichtman & Ceci, 1995a, b). Overall, then, knowledge can enrich and deepen a child's event recall and understanding, but also undermine their accuracy.
Memory strength and scripts. Once encoded, strength of a memory likely influences a child's ability to recall that memory. That is, events that are highly salient or meaningful to a child, or events that are repeated, might be associated with a stronger memory trace. This can protect the memory over time from degradation or other influences, such as suggestion (Christianson, 1992;Hamann, 2001;Holliday, Douglas, & Hayes, 1999;Howe, 1997;Pezdek & Roe, 1995). With sufficient replication, children can develop scripts, or generalized event representations abstracted from repeated instances of an event. For example, a child might develop a script for 'going out to eat' that involves multiple actors (e.g., host/hostess; waiter/waitress) and a particular set of ordered events (e.g., order beverages; read menu; order; eat; pay bill). The same abstraction can occur for abuse events (Roberts & Powell, 2001).
Children become more efficient in their ability to abstract event scripts with age. Farrar and Goodman (1992) showed that 4-year-olds did not seem to develop an event script following three repetitions of an event, while 7-year-olds did. More generally, children increasingly connect meaning across different exemplars of a target with age (e.g., apple juice, lemonade, and orange juice are all sweet drinks; Brainerd, Reyna, & Ceci, 2008). Thus, in some cases, younger children might not yet have the elaborate scripts that older children have developed. This can insulate them from making erroneous assumptions or interpretations about events (Brainerd et al., 2008;Lindberg, 1991;Pickel et al., 2008).
However, despite their efficiency, event scripts can interfere with recall of specific, individual instances of an event, such as abuse (Powell & Thomson, 1996). This could be problematic for a testifying child witness asked to describe and differentiate between multiple abuse incidents -perhaps because the defense is seeking to present alibi evidence. If the incidents were so similar that they became script-like for the child, it could be extremely difficult for the child to differentiate the events or to identify a unique incident at a specific date and time (Roberts & Powell, 2001), potentially undermining their credibility.
Memory storage. Children's memory capacity grows with age (Gathercole, Pickering, Ambridge, & Wearing 2004), such that they become increasingly able to recall larger amounts of information over time. For child witnesses, this can become visible when they are asked to provide free recall reports in response to open-ended questions, such as "What happened?". Younger children tend to provide very little event detail when asked such questions. Nevertheless, even young children are capable of accurately recalling and reporting their experiences from memory (Goodman, 2006). An important moderator of children's ability to store memories is the amount of time between encoding and retrieval. With longer delays, child witnesses have greater difficulty providing complete and accurate memory reports, particularly younger children, as their memory traces seem to decay more rapidly than older children or adults (Brainerd & Rayna, 1995). However, offering children an opportunity to recall an event after a short delay might help to inoculate their reports and maintain them over time (Peterson, Pardy, Tizzard-Drover, & Warren, 2005), particularly when the event context is reinstated during the interview (La Rooy, Pipe, & Murray, 2007). This suggests that the development of children's memory storage facilitates better witness reports with age. It also suggests that there are means of helping even young children to overcome some of their memory shortcomings.

Memory development -Reporting an event
Having witnessed an event (e.g., a crime), the child witness's next responsibility is to report the relevant facts, as observed. A child's memory report accuracy is therefore dependent on his or her memory retrieval ability and communication/linguistic skills.
Memory retrieval. When asked to retrieve a memory (i.e., reconstruct the event from memory storage), children become increasingly able to structure that information into narrative form with age (Lamb et al., 2003). Younger children must often rely on adult assistance, in the form of questions, to provide a narrative account of an event. Older children, on the other hand, are increasingly able to provide a structured, coherent narrative description of their experiences in response to simpler prompts, such as "What happened?". Thus, interviewers (and parents) frequently ask questions that are more supportive, or "leading", with younger children, in part to provide the narrative structure children need to produce a coherent event account (e.g., Dent & Stephenson, 1979;Hudson, 2006;Poole & Lindsay, 1998).
However, researchers consistently find that the least directive questions (e.g., free recall) tend to elicit the most accurate information and have the lowest risk of eliciting false information from children. They also elicit less information overall from children (Bjorklund et al., 2000;Poole & Lindsay, 1995). Interview strategies have thus been designed that attempt to provide additional structure and cues to children to maximize the amount of accurate event recall, while minimizing false recall. Techniques include contextreinstatement (La Rooy et al., 2007) and full interviewing protocols such as the Cognitive Interview (Fisher & Schreiber, 2007) and the NICHD Protocol (Lamb, Orbach, Hershkowitz, Esplin, & Horowitz, 2007). These practices seem to facilitate child witnesses' attempts to reconstruct events from memory.
Communication and linguistic ability. A child who cannot communicate effectively in the justice system may lack credibility, leading perhaps to future victimization or to conviction, in the case of a juvenile defendant. Most child victims, for instance, must be able to disclose abuse in order for the abuser to be stopped or prosecuted. However, it seems clear from the number of adults who never reported childhood abuse that this remains a problem for many children (Bottoms, Rudnicki, & Epstein, 2007;London, Bruck, Wright, & Ceci, 2008). Yet, when abuse is suspected, the interview strategies noted above can help children to disclose .
Some child witnesses must testify in court, subsequent to a disclosure. This can be traumatic, particularly if it must be repeated (Quas et al., 2005). In many cases, children must first undergo a competency evaluation. These typically attempt to assess their understanding of truths and lies, which emerges in the preschool years and becomes more nuanced with age (Talwar & Crossman, 2012). However, it is likely that competency evaluations underestimate children's understanding of truth/lie concepts and are not likely to be related to a child witness' actual truth-telling (Talwar & Crossman, 2012), raising questions about their usefulness.
When they testify, children are immersed in the linguistically foreign legal system, for which they are often not developmentally prepared (Walker, 1993). They may face the challenge of deciphering legal jargon, as well as linguistically complex questions that they are ill equipped to answer (as are many adults; Carter, Bottoms, & Levine, 1996;Perry et al., 1995). However, this might not undermine children's credibility, as one study of trial transcripts found that complex questions asked by defense attorneys predicted convictions, rather than acquittals in those cases (Evans, Lee, & Lyon, 2009). Nevertheless, children also may be required to offer testimony on concepts that are developmentally beyond their 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, 1 st , 2 nd , etc.; Friedman, Reese, & Dai, 2011), particularly maltreated children (Wandrey, Lyon, Quas, & Friedman, 2012), as they may struggle to do so accurately until adolescence.
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 their capacities.

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).
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;. 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(Eisen et al., , 2007.

Vulnerability to error and influence
Beyond memory issues, additional factors can influence the accuracy of children's memory reports -and their vulnerability to influence. These include children's intelligence, mental health, source monitoring ability, suggestibility and the use of suggestive interview aids.
Intelligence and mental health. For child witnesses, intelligence is most relevant to memory accuracy and resistance to suggestion. That is, individuals with higher IQ scores tend to have better memory skills and to provide more detailed recall when reporting an event 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 less accurate and more suggestible in their event reporting than are TD children.
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 account when considering child and adolescent witness and defendant statements.
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 samethat 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 what factors might influence source monitoring.
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, particularly when encouraged to identify the source of the suggestions, they are less able to do so when those suggestions are consistent with their event schema (Roberts & Powell, 2006). When information that is similar in nature is encoded, there are few cognitive cues to help to distinguish the sources (Day, Howie, & Markham, 1998;Roberts & Blades, 1999). This can be important in instances where children experience multiple similar incidents, such as in the case of prolonged child abuse. Unfortunately, in forensic contexts such as court, children may be asked to distinguish between these multiple incidents or identify multiple perpetrators.
On the other hand, children tend to make fewer source monitoring errors when the target information regards the self rather than others (Baker-Ward, Hess, & Flannagan, 1990;Roberts & Blades, 1998). In other words, they are better able to accurately report on events that happened to themselves than on events they witnessed other people experiencing. For example, Roberts and Blades (1998) found that 6-and 9-year-olds were more accurate and made fewer source monitoring errors answering questions about activities they had performed versus those they observed, while 4-year-olds showed the reverse relation. Further, children remember better actions performed by a familiar person compared to an unfamiliar person (Baker-Ward et al., 1990). Some have posited that this is due to the cognitive processes that are elicited when encoding familiar (self and peer) information (Baker-Ward et al., 1990;Foley et al., 1989). Specifically, children in these situations are using cognitive processing that requires them to use more cognitive effort-they are anticipating what must be done, anticipating the action's consequence, and reflecting on the cognitive processes that were required to perform that action (Ratner, Foley, & Gimpert, 2000). Children can then use records of these cognitive processes as cues to discriminate between sources (Roberts, 2002).
All of these factors are relevant when considering child witnesses and techniques for interviewing them. For example, misleading or suggestive interview questions that are script-consistent and plausible are more readily accepted by child witnesses and are more likely to elicit source monitoring errors (Pezdek, Fingers, & Hodge, 1997). Additionally, the nature of the inquiry can impact the accuracy of the report. For instance, Roberts and Blades (1995) found that younger children were more accurate in their source identifications when asked to report information nonverbally compared to verbally. Moreover, children committed fewer source monitoring errors during free recall than when answering specific questions (Roberts & Blades, 1998, 1999, reinforcing the importance of free recall when interviewing child witnesses. To date, however, explicit training in source monitoring appears to be beneficial for older (i.e., 7-to 8-year-old), but not for younger (3-to 6-year-old) child witnesses (Poole & Lindsay, 2002).
Suggestibility. Another potential source of children's errors in forensic contexts is via suggestibility. Suggestibility has been defined as the ease with which a person is persuaded and influenced, and the degree to which one accepts and changes one's own judgments, opinions, or patterns of behavior without critical response (Drukteinis, 2001). In a forensic context, this is usually exhibited by changes in memory reports due to suggestive questioning by an interviewer. For example, a question such as, "Was the man's jacket red or blue?" is suggestive because it implies that the man was wearing a jacket (he may or may not have been). Children may have difficulty accurately answering suggestive questions because they may not have the cognitive or social skills to identify that they do not know the answer and do not have to choose an answer.
Studies to date indicate that individual difference variables may be more likely to influence the degree to which people are suggestible than situational factors (Gudjonsson, 1994). Indeed there are several traits that might make an individual more susceptible to suggestive questioning (Bain, Baxter, & Ballantyne, 2007;Singh & Gudjonsson, 1992), such as age. Both adults and children are susceptible to suggestive questioning, but younger children tend to be especially vulnerable to suggestive interview techniques (Ceci & Bruck, 1993Chae, Goodman, Eisen, & Qin, 2011;Eisen et al., 2002). These age differences can usually be explained by differences in cognitive development between older and younger children. In fact, when age is controlled, children with better cognitive functioning are overall less suggestible and produce fewer memory errors due to suggestive questioning (Chae et al., 2011;Karpinski & Scullin, 2009). Moreover, as noted above, children with intellectual disabilities are highly susceptible to suggestive questioning (Henry & Gudjonsson, 1999, 2007. Findings for other potential cognitive predictors of suggestibility have been mixed (see Bruck & Melnyk, 2004 for a review). However, research has shown that children with advanced language skills, better memory test performance, (Clark-Stewart et al., 2004;Danielsdottir, Sigurgeirsdottir, Einarsdottir, & Haraldsson, 1993;, better event accuracy (Marche, 1999;Marche & Howe, 1995;Pezdek & Roe, 1995), and/or more creativity (Brown, 1999;Clarke-Stewart et al., 2004) are often less suggestible than other children.
Concerns about children's suggestibility are common in legal cases, especially in instances where the child's memory report is key evidence. In fact, in child sexual abuse cases, the child's accusation may be the only evidence available to the court. It is thus important to consider interviewing techniques and the potential for suggestion when evaluating child witnesses' memory reports.
Interview aids. A special case of suggestibility might be said to arise through the use of some interview aids, such as anatomically detailed dolls. First used clinically as a means of communicating nonverbally about children's emotional issues, forensic interviewers began to use anatomically detailed dolls to assist children in reporting difficult or embarrassing events (i.e., sexual abuse; Poole, Bruck, & Pipe, 2011). Unfortunately, the dolls seemed to be inherently suggestive, leading some children to demonstrate genital or anal cavity insertions on the dolls that did not occur (Bruck, Ceci, & Francoeur, 2000). Thus, researchers and policy groups have concluded that children's interactions with such dolls are not diagnostic of abuse, they should not be used to elicit abuse reports, their use is particularly problematic for children under age 5, and they do not appear to facilitate or enhance children's reporting even when used after verbal reports have been provided .
Part of the reason for the dolls' ineffectiveness with very young children could be children's immature representational abilities (DeLoache, 2000). That is, young children may have difficulty perceiving the doll as a representation or symbol of themselves and acting on it as such. They might also have difficulty ignoring the dolls' salient, play-like qualities and unique features to use it as a symbol instead (DeLoache, 2000;. More recent efforts have focused on the use of body diagrams -pictures -to assist children in reporting abuse allegations. Although pictures seem less challenging for children to use as symbols, concern remains about their suggestiveness . Specifically, as with dolls, use of the diagrams seems to increase false reports of bodily touch, even among school-aged children (Poole & Dickinson, 2011). Further, their use seems to lead interviewers away from recommended, open-ended questioning styles toward more leading, specific questions (Aldridge et al., 2004;. Finally, their use does not seem to enhance children's disclosures or lead to greater elaboration of their reports (Bruck, 2009). Thus, these symbolic interview aids seem to be suggestive, particularly for young children who might not be capable of using them symbolically, and their forensic use is discouraged .

Conclusions
In this chapter, we reviewed aspects of cognitive development that are most relevant to child witnesses and, to some extent, child suspects in the criminal and juvenile justice systems. The findings above highlight the areas of concern with any witness -but particularly child witnesses. Yet, their implications are not uniform. In fact, the implications of children's cognitive development in forensic situations are likely to vary as a function of a variety of factors, including the type of witness and case involved, as a child's credibility may be dependent on assessments of their trustworthiness and competence. Children who are perceived as lacking competence for a variety of reasons are likely to be considered lacking in credibility. However, this effect is likely more pronounced in some types of cases than in others. Cases requiring strong memory for detailed information that was experienced only once might demand a higher expectation for cognitive ability than a case of child neglect by a well-known caregiver. Similarly, a child's trustworthiness is likely impacted by the type of case, with some arguing that in child sexual abuse cases, honesty is more salient than cognitive abilities -and that perceived suggestibility likely impacts perceptions of the child's honesty in such cases (Connolly et al., 2010). The type of child witness is important as well. Children with intellectual disabilities might be more vulnerable to suggestion as witnesses. Children who are defendants in the juvenile justice system are at higher risk of suffering from both cognitive deficits and mental illness, making them particularly susceptible to suggestion and false confession. At the same time, one's identity as a defendant likely raises more questions about trustworthiness than when one is a child witness.
Despite many of the risks for child witnesses, however, and the poor fit between children's cognitive development and the justice system, it is clear that children are capable of participating accurately and effectively as witnesses. They often partake in family court decision-making, provide evidence in eyewitness identification cases, and testify against their assailants in child abuse cases. There is a great deal still to be learned about important cognitive factors, such as whether there are means of improving younger children's source monitoring skills, how to improve children's eyewitness identification accuracy when the perpetrator is not present in a lineup, and how to help children resist misleading questions and suggestions. More needs to be learned about the impact of emotion on children's eyewitness memory and recall as well. Perhaps the growing research on the neural correlates of children's memory will further our understanding and allow for greater forensic sensitivity to child witness strengths and vulnerabilities. These and other results, it is hoped, will contribute to more effective interviewing, testimony and treatment of child witnesses.

Author details
Daisy A. Segovia and Angela M. Crossman John Jay College and the Graduate Center, Cuny, USA