Abstract
We asked 111 6- to 11-year-old maltreated children to tell “everything that happened” on their last birthday, the last time they did something they liked to do outside, and yesterday. All children produced details in response to the like to do and yesterday narratives, compared to 98% of children in response to the birthday narrative. Questions about yesterday were more likely to elicit productive responses (93%) than questions about the child’s birthday (90%) or things they liked to do (88%). Older children produced the most details in response to questions about yesterday, and older children’s birthday narratives were more productive than those about favorite activities. Narratives about children’s birthday and yesterday produced comparable percentages of negative details (15%), whereas 32% of children mentioned something negative when discussing a favorite activity. The results suggest that although children find yesterday easier to recall than their last birthday, the birthday narrative is a productive tool for encouraging children to practice recalling more remote events, preparing them for abuse disclosures.
Introduction
Forensic interviewing guides recommend that interviewers elicit a practice narrative from children in order to build rapport and allow the interviewer to practice asking broad free-recall questions (invitations) and the child to practice answering invitations with narrative information (ASPAC, 2012; Lamb et al., 2018 [NICHD protocol]; Lyon, 2014 [Ten Step interview]; Newlin et al., 2015 [OJJDP guidelines]; State of Michigan, 2017). One recommended topic is the child’s last birthday (Lyon, 2014; Roberts et al., 2011). However, concerns have been raised that the birthday topic may be unproductive (Roberts et al., 2011), and little is known regarding the relative productivity of different rapport topics. We compared the productivity of the birthday topic to other commonly used topics for narrative practice (things the child likes to do, everything that occurred yesterday), and the types of failures they elicit. In what follows we review prior research documenting the benefits of narrative practice and discuss the potential benefits of the birthday narrative.
Benefits of Narrative Practice
The use of narrative practice in forensic interviewing has received a great deal of support (e.g., Anderson et al., 2014; Hershkowitz, 2009; Lyon et al., 2014; Price et al., 2016; Roberts et al., 2004; Sternberg et al., 1997; Yi & Lamb, 2018). Observational research has shown that interviewers’ use of invitations during narrative practice is associated with increased productivity in children’s abuse reports (Anderson et al., 2014; Hershkowitz, 2009; Price et al., 2016; Sternberg et al., 1997). Experimental work has similarly found that narrative practice increased children’s accuracy (Roberts et al., 2004; Yi & Lamb, 2018) and productivity in response to subsequent questioning (i.e., number of details or words; Lyon et al., 2014; Saywitz et al., 2015; Yi & Lamb, 2018).
Topics for Narrative Practice
Noting that interviewers often expressed difficulty in choosing topics for narrative practice, Roberts and colleagues (2011) suggested several different strategies for doing so. One strategy they recommended is to ask the child about their hobbies or interests, and choose one as a topic for further exploration. In the Ten Step interview (Lyon, 2014), interviewers ask children to name things they like to do, and then pick an activity and ask the child to tell “everything that happened the last time” they engaged in that activity (p. 75).
Roberts and colleagues (2011) also recommended that interviewers ask parents, teachers, and other family members about recent significant events in the child’s life. Similarly, the NICHD structured protocol recommends that interviewers inquire into significant events before interviewing the child, and then tell the child “A few [days, weeks] ago was [a holiday, birthday party, other event]. Tell me everything that happened [during the event], from the beginning to the end, as best as you can” (Lamb et al., 2018, p. 241).
The problem faced by forensic interviewers is that they will often lack access to knowledgeable adults before interviewing the child, particularly in cases in which the accused is a family or household member and the child has been removed from the home, or when a primary caretaker does not accompany the child to the interview. Therefore, although they can ask about the child’s likes, they do not have access to information about recent significant events. There are three possible solutions to this problem. First, the NICHD protocol recommends that interviewers ask a yes-no screening question: “Did you do something special recently, like did you get to go somewhere or go to a birthday party?” If the child answers “no,” then the interviewer instead asks “So, I want you to tell me everything that happened [today, yesterday], from the time you woke up” (Lamb et al., 2018, p. 241). Hence, the NICHD protocol asks children to narrate their daytime activities as a fallback approach. A second approach is to simply ask all children about their birthdays. This is the approach taken by the Ten Step interview: interviewers routinely ask children about their birthdays, even if they are unsure if children celebrated. They ask about the birthday last, after eliciting narratives regarding things the child liked to do and didn’t like to do (Lyon, 2014). A third approach is to avoid the birthday topic altogether, on the grounds that birthdays will be difficult to remember at best, and unpleasant for many children at worst, particularly if they are from disadvantaged and abusive homes.
There are potential problems with each of these approaches. First, asking screening questions may overlook birthday information. Several aspects of the screening question may lead to false omissions: the yes-no form of the question, using the general term “something” (Szojka et al., 2023), the reference to something “special” and “recent,” and the reference to going to a birthday party, as opposed to observing one’s birthday. Children may answer “no” with minimal reflection. Interviewers may thus give up on the birthday topic, and moving prematurely to questions about daytime activities may reduce the productivity of narrative practice.
Second, always asking children about their birthday may lead to narrative practice failures because of children’s difficulty in recalling details or because of the negative content in many maltreated children’s birthday experiences. Potential problems with memory have been raised by some researchers (Roberts et al., 2011; Whiting & Price, 2017), and both memory problems and concerns about negative content were expressed by forensic interviewers in a recent survey (Wylie et al., 2024). The third approach, in which one avoids birthday narratives altogether, may have the opposite problem: it may exaggerate difficulty and negativity, and fail to obtain the advantages of the birthday narrative. In the aforementioned survey, over a third of the respondents trained to use the Ten Step interview reported that they rarely or never used the birthday narrative (Wylie et al., 2024).
There is support for asking all children about their birthdays. Birthdays tend to include highly memorable events, objects, and people (Lee et al., 2009). There is evidence that narrative practice about birthdays is superior to narrative practice about daily activities. Whiting and Price (2017) found that asking children about a unique event (e.g., a birthday) rather than a routine event (e.g., yesterday) enhanced subsequent productivity. Analogously, research has shown that narrative practice inquiring into specific episodes is superior to eliciting children’s generic memory about scripted events (Brubacher et al., 2011).
Birthdays are universally observed and celebrated (Redlich, 2020). A survey of low-income rural American mothers found that only 3% stated that they did not celebrate children’s birthdays due to religious objections or negative parental beliefs (Lee et al., 2009). Mothers reported that they made special efforts to have typical celebrations despite their lack of resources. Only 11% of mothers reported that they “did not or could not celebrate children’s birthdays in ways other families do” (Lee et al., 2009, p. 542), though the survey did not inquire into whether a celebration of any sort occurred.
Of course, interviewers are right to worry that maltreated children will be overrepresented among children whose birthdays are neglected. However, both maltreated and non-maltreated children (from predominantly low-income homes) are almost universally capable of recalling substantive details about their birthdays, both in the lab (Henderson et al., 2022) and in actual forensic interviews in which children allege sexual abuse (Wylie et al., 2024). Specifically, 99% of non-maltreated children and 97% of maltreated children in Henderson and colleagues’ (2022) study of 4- to 9-year olds were able to recall details about their last birthday with encouragement from the interviewers. Similarly, 96% of children in a sample of 350 forensic interviews with 4- to 12-year-old children questioned about sexual abuse recalled substantive information about their last birthday when interviewers persisted, though the percentage dropped to 85% if one included cases in which the interviewers failed to persist (Wylie et al., 2024). The remoteness of children’s last birthdays (i.e., the number of days that had elapsed) did not affect the likelihood that they were able to recall substantive information (Henderson et al., 2022; Wylie et al., 2024). Moreover, negative content was uncommon in maltreated children’s birthday narratives (6% of responses included negative details, with 21% of children mentioning one or more negative details; Wylie et al., 2024).
Interviewers may be particularly concerned that younger children will have difficulty recalling their birthdays, given their immature recall skills (Pipe et al., 2004). 3- and 4-year-old children produce fewer details in response to invitations than more direct questions, in contrast to children five years and older (Hershkowitz et al., 2012). Throughout grade school, younger children produce less information than older children in response to narrative practice in general (Ahern & Lyon, 2013; Roberts et al., 2004) and birthdays are no exception. Wylie and colleagues (2024) found that younger children in forensic interviews with 4- to 12-year-olds were less responsive to invitations about their last birthdays than older children. Similarly, Henderson and colleagues (2022) found that younger children were less likely to recall their last birthdays than older children, and were less productive when they did. Nevertheless, 93% of the 4-year-olds recalled information about their birthday with persistent encouragement.
Although prior research has demonstrated that virtually all children are capable of recalling their birthdays, a limitation of the research is that it has failed to take a comparative approach. Interviewers might justifiably complain that birthdays are comparatively unproductive, because of the need to recall a more remote event, and because maltreated children’s birthdays are the source of unhappiness.
The Current Study
The current study examined a sample of 111 6- to 11-year-old maltreated children who underwent narrative practice. Children were asked to provide narratives about their previous birthday, what they like to do, and what they did yesterday. All questioning was scripted to ensure that interviewers asked invitations, starting with “Tell me everything that happened the last time” and including “What happened next” and “Tell me more about [child-generated detail]” prompts.
Based on prior research finding that very few children are unable to recall their last birthday (Henderson et al., 2022; Wylie et al., 2024), and the fact that questions about likes and the child’s day place few demands on children’s memory, we anticipated that all three of the topics would be comparably productive, though we expected that the birthday narrative might be more difficult for children to recall than the other topics. We also predicted that the likelihood children produced negative information would be comparable across the three topics, given the low rate of negative content in a field study of the birthday topic (Wylie et al., 2024). We included age as a variable in analyses given prior research showing age increases in productivity (Henderson et al., 2022; Wylie et al., 2024).
Method
Sample
The sample consisted of 111 6- to 11-year-old (M age = 8.4 years old, SD = 1.7, 48% males) children who were under the custody of the Dependency Court because of maltreatment. Children were predominantly Latino (62%), with about a fourth African American (28%), and the remainder Caucasian (8%), and Asian (2%). An additional 29 participants (M age = 7.8 years old, SD = 1.8, 63% males) were excluded from the study, either because of script errors (n = 4), the child choosing not to complete the study (n = 7), or court business, such as an attorney interview, a family visit, or a court appearance. Because children had been removed from their parents’ or legal guardians’ custody, the Presiding Judge of Juvenile Court granted consent for all children to participate in the study. Children were ineligible if they were awaiting an adjudication or contested disposition hearing on the date of testing (because they might be asked to testify). The study materials and procedures were approved by the University of Southern California Institutional Review Board.
Procedure
After obtaining the child’s assent, the interviewer began a scripted narrative practice with the child in which three topics were discussed: what happened on the child’s last birthday, things the child liked to do outside, and what happened yesterday (hereinafter Birthday, Outside, and Like to Do). Children were specifically asked what they like to do “outside” to encourage discussions about action-oriented behaviors and to narrow the topic to increase the consistency of conversations across children. Children were asked about what happened “yesterday” rather than “today,” because on the day of the interview, children had been transported to the Dependency Court for a hearing, and we wished to avoid discussing the child’s case. The order in which children were asked about the three topics was counterbalanced. The interviewer began the first narrative by saying, “So [child’s name], today I’m going to ask you about three different things. This is the very first time we have ever met, and I want to know more about you.” For the Birthday narrative, the interviewer asked “Tell me about your last birthday. Tell me everything that happened.” For the Yesterday narrative, the interviewer asked, “Tell me about everything you did yesterday from the time you woke up.” For the Like to Do narrative, the interviewer first asked, “First, tell me about things you like to do outside.” Following the child’s response, the interviewer would select the activity most likely to involve others (e.g., soccer rather than drawing) and follow up with, “All right, [child’s name], you said you like to [X]. Tell me everything that happened the last time you [X].” If children failed to provide narrative details in response to the Birthday prompt, or if the child’s birthday narrative lasted less then 5 minutes, the interviewer moved to a question about the child’s last Halloween (“Tell me everything that happened last Halloween”). Furthermore, across all narrative prompts, if the child initially failed to provide a sequence, the interviewer would follow up with, “What is the first thing that happened?” The interviewer then continued to ask “what happened next” questions until the child stopped providing information, or until 5 minutes elapsed, which pilot testing suggested was a feasible length of time for each topic. If the child stopped providing information before 5 minutes had elapsed, interviewers spent the rest of the time following up on main events by asking, “You said [X]. Tell me more about that.” At the end of each narrative, the interviewer then asked a series of wh- or yes-no questions not relevant for this study (Henderson et al., 2023).
Coding
Interviewers’ questions were coded as invitations or “other” prompts (i.e., interviewer clarifications, clarification resolutions, facilitators, and supportive statements). For each topic, children’s responses were treated as an overall success if they produced any non-negative substantive information, and as a failure otherwise. On a question-by-question basis, children’s responses were coded as a success if the child provided at least one non-negative substantive detail. Failed responses included don’t know responses, clarification seeking responses, non-responsive utterances, boundary responses (indications the child had told ‘everything’; e.g., “that’s it”/”nothing else”), deficient responses (in which the child reported a lack of something with no positive information; e.g., “I didn’t get cake”), pseudotemporal responses (only temporal information was provided when it wasn’t requested), and negative responses (in which the child’s response entirely consisted of negatively valenced information; e.g., “my parents got into a fight”). The scheme is the same as that adopted by Wylie and colleagues (2024) for assessing children’s birthday narratives in forensic interviews. Deficient responses and negative responses would be considered responsive when coding children’s substantive reports, but we considered them failures because during narrative practice they could be viewed as undermining rapport. Pseudotemporal responses suggest that the child misinterpreted the question as requesting temporal information (Friend et al., 2022). A reliability coder coded 20% of the sample and inter-rater agreement for all response types was high (i.e., for all variables, Kappa >0.87 and percent agreement >96%).
Results
Preliminarily, we assessed whether interviewers provided equal proportions of “other” prompts across topic (i.e., interviewer clarifications, clarification resolutions, facilitators, and support), allowing us to exclude those prompts and solely focus on invitations (i.e., “Tell me everything that happened,” “What happened next,” and “Tell me more about [child-mentioned detail]”) in subsequent analyses. For the substantive analyses, we first examined the rates of overall success and whether children produced negative information across the three rapport topics, hereinafter Birthday, Like to Do, and Yesterday. We then analyzed response successes and failures and determined whether they varied by topic and age. For the Birthday topic, we considered whether the remoteness of the child’s last birthday affected success and failure. We conducted similar analyses examining word count productivity when children succeeded.
Substantive analyses were conducted using generalized linear mixed effect models (GLMMs). GLMMs combine the properties of linear mixed models (which incorporate random effects) and generalized linear models (which handle non-normal data) and are preferable to traditional analysis of variance (ANOVA) models because they have fewer assumptions, handle binary response variables, and maximize power while simultaneously estimating between-subject variance (Bates et al., 2015). GLMMs were performed using the glmer function in the R package lme4 with the bobyqa optimizer (Bates et al., 2015). Models were cross-validated in order to identify the best fit model, and it was determined by the Akaike Information Criteria (AIC), an estimator of the relative quality of a model for a given set of data (Vrieze, 2012). Adjusted means were computed using the emmeans function in the R package emmeans (Lenth, 2020). The results from the best-fit models are reported alongside the unstandardized fixed effects estimates (B), standard errors of the estimates (SE) and estimates of significance (Z and p values). A by-subject random effect was included for each child to account for differences in individual response characteristics.
Preliminary Analyses
Preliminary analyses confirmed that interviewers’ use of “other” prompts did not differ for the Birthday (10%, SE = 1.2), Like to do (10%, SE = 1.1), and Yesterday topics (10%, SE = 1.1), ps > 0.75. Therefore, “other” prompts were subsequently excluded from analyses.
Overall Success and Negatively Valenced Information
All 111 children provided at least one non-negative substantive detail in response to the Like to do topic or the Yesterday topic. 98% (n = 109) of children did so when asked about their last birthday. In the two cases in which a child failed to recall any birthday details, the interviewer asked one to two questions before moving to the Halloween topic. Of all children, 49% (n = 54) mentioned something negative at some point during rapport building. 15% of children mentioned something negative in response to the Birthday prompt, compared to 32% of children in response to the Like to do prompt and 15% of children in response to the Yesterday prompt.
Response Successes and Failures
We analyzed the rate at which children succeeded in response to individual questions with a model that included rapport topic and child’s age (in months). The best fit model included a main effect of topic, reflecting lower rates of success for the Birthday and Like to Do topics (B = 0.37, SE = .14, Z = 2.65, p = .008). Posthoc comparisons revealed that the Birthday (90%, p = .022) and Like to Do topics (88%, p < .001) were less likely to elicit successful responses than the Yesterday topic (93%). Regarding age, younger children were less likely to succeed than older children (B = −1.96, SE = .65, Z = 3.02, p = .003). For the Birthday topic, we examined whether the remoteness of the child’s last birthday (in days) affected success rate, controlling for age, and the relation was not significant.
Productivity
Next, a model including rapport topic, child’s age, and an interaction between topic and age examined associations with response productivity (i.e., word count). First, we ran the model with Birthday as the reference category, but the model showed no significant effects. We then selected Like to Do as the reference category, because the descriptives suggested that it was the least productive topic. There was a main effect of rapport topic: Yesterday was more productive than Like to Do, (B = −.54, SE = .23, Z = 3.32, p = .020) whereas there was no difference between Birthday and Like to Do (p = .108). Age was positively associated with productivity (B = 1.15, SE = .38, Z = 3.02, p = .003). However, both topic and age were subsumed in a significant interaction (see Figure 1 and Table 1). Examination of productivity at each age showed that whereas topics made no difference for the 6- and 7-year-olds, Yesterday was more productive than Birthday and Like to Do by eight years of age (ps ≤ .017), and Birthday was more productive than Like to Do by 10 years of age (p = .043). For the birthday topic, we examined whether the remoteness of the child’s last birthday affected productivity, controlling for age, and the relation was not significant, p > .05. Mean productivity by rapport topic and age. Mean (SE) Productivity by Rapport Topic and Age. Note. These means and standard errors were calculated from adjusted means after GLMM. Matching letter subscripts represent nonsignificant differences across topics (within rows) and non-matching letter subscripts represent significant differences.
Discussion
This study examined 111 6- to 11-year-old maltreated children’s productivity when asked to tell “everything that happened” regarding three narrative practice topics: Their last birthday, an activity they liked to do outside, and yesterday. All children were able to recall at least one substantive non-negative detail about something they liked to do outside and what happened yesterday, compared to 98% of children recalling their birthday. On a question by question basis, questions about children’s last birthday elicited substantive details 90% of the time. This was comparable to questions about things they liked to do (88%), but lower than questions about yesterday (93%). Measuring productivity by the number of words, yesterday was the most productive topic by eight years of age, and the child’s birthday was more productive than things the child liked to do by ten years of age. Because the younger children produced fewer details in general, their performance across the different topics appeared similar. The remoteness of children’s birthdays did not affect their ability to recall details, nor the number of words they produced. Whereas 15% of children mentioned something negative when asked about their last birthday, an equal percentage did so when asked about yesterday, and 32% did so when asked about things they liked to do. The results suggest that although children have less to say about their last birthdays than what happened yesterday, their last birthday is nevertheless a productive narrative topic.
The results regarding the birthday narrative are comparable to prior research. As noted in the introduction, 97% of maltreated 4- to 9-year-olds were able to recall details of their last birthday in a study by Henderson and colleagues (2022), and 96% of 4- to 12-year-old children questioned about suspected sexual abuse recalled details of their last birthday in a study by Wylie and colleagues (2024). Moreover, as in this study, those studies failed to find a relation between the remoteness of children’s birthdays and their ability to recall details (Henderson et al., 2022; Wylie et al., 2024). Finally, the 15% rate for whether children mentioned anything negative about their birthday is comparable to the 21% rate in Wylie and colleagues (2024).
This is the first study to compare children’s performance when questioned about the birthday to other topics. It suggests that although the birthday narrative is productive in virtually all children, it is somewhat less productive than questions about the day before the interview, and more productive than questions about things the child liked to do. Although the numbers are too small to demonstrate statistical significance, it is notable that whereas all children produced details regarding what they liked to do and what they did yesterday, two children failed in response to the birthday question. In this study, the interviewers were trained to switch to Halloween as a topic if children struggled with the birthday question. Prior research has found that interviewers may need to persevere in order to enable children to begin remembering details of their birthday. In Henderson and colleagues study examining 4- to 9-year-olds (2022), 11% of maltreated children initially failed to produce details when asked about their birthdays, but this number dropped to 3% with encouragement from the interviewers. The encouragement was mild: Interviewers might repeat the question, offer a supportive statement (“It’s really important that I get to know you,”) or slightly narrow the question (“What did you do on your last birthday?”). In Wylie and colleagues (2024), which examined forensic interviews of 4- to 11-year-old children alleging sexual abuse, 41% of children initially failed to provide details about their birthday during narrative practice, but this dropped to 4% when interviewers persisted with three or more questions. Along the way, however, interviewers simply gave up 11% of the time.
The birthday narrative thus provides an opportunity for interviewers to engage children in effortful recall. In contrast, if interviewers’ goal is to make narrative practice as easy as possible for children (and, incidentally, for the interviewer as well), then asking about yesterday is optimal. However, given its unique advantages, there are reasons to ask about birthdays. As noted in the introduction, Whiting and Price (2017) found that questions about significant events (including a birthday) were more likely to increase the productivity of the child’s subsequent narrative than questions about routine events (including what happened yesterday), and they speculated that it had to do with the child’s recall of a specific episode, as opposed to the routine events of daily activities.
The fact that birthdays require recall of an event that is relatively remote may be a feature rather than a bug. The NICHD structured protocol recommends that when selecting an event for narrative practice, interviewers “choose an event that took place at about the same time as the alleged or suspected abuse” (Lamb et al., 2018, p. 241). Given that abuse often takes place over an extended period of time (McElvaney et al., 2020), and that a substantial percentage of children delay disclosure (Hershkowitz, 2006), it is quite likely that children asked about their abuse will be recalling events that occurred at least several months previously, particularly when attempting to recall the first episode of abuse. If a child is going to find remote recall difficult, it is especially helpful to first encounter memory challenges during narrative practice. At this stage of the interview, the interviewer can provide encouragement and reinforcement without appearing suggestive, and the child can learn to engage in effortful memory search before giving a “don’t know” response.
Limitations and Future Directions
Because we asked children about their personal experiences rather than the details of a lab event, we were unable to verify the accuracy of children’s responses. However, the interviewers exclusively elicited details through invitations, which are broad open-ended requests for free recall. Children’s recall is quite accurate (Ceci & Bruck, 1993), and invitations will elicit more accurate responses than other types of questions (Brown et al., 2013).
Another limitation is that we did not script follow-up questions designed to encourage children to remember. Given findings that children may only begin to recall details of their birthday after several prompts, and that interviewers may struggle to maintain their use of invitations, an important topic for future research is what prompts are most effective in encouraging recall. The Revised NICHD protocol includes a number of suggested prompts for enhancing children’s interview performance, but these prompts largely focus on overcoming children’s reluctance rather than memory failure (Blasbalg et al., 2018). For example, our anecdotal experience suggests that when children initially claim that they can’t remember an event, asking the child to “take a minute to think about it” often elicits a productive response. This is analogous to research finding that interviewers elicit more information with “wait-time,” in which they extend the amount of time they give children to respond to a question (Rezmer et al., 2020).
Implications for Practice
Practitioners who wish to maintain a positive relationship with the child while encouraging the child to make efforts to recall information during narrative practice may wish to start with questions about activities the child enjoys, given the ease with which children can produce information on this topic. In order to encourage children to practice making the effort to recall more remote events (which are likely to include abuse experiences they will later be asked to recall; McElvaney et al., 2020), practitioners may then ask children about their last birthday, but recognize that some children will need to make several attempts to recall information, coupled with encouragement. If repeated attempts fail, asking about the child’s day could ensure that narrative practice ends with a productive narrative. Of course, in cases in which interviewers know sufficient background information about a child in order to ask about special events that occurred in the same time frame as the suspected abuse, substituting questions for that event for questions about the birthday would be appropriate.
Conclusion
Questioning 6- to 11-year-old maltreated children about what happened on their last birthday, things they liked to do outside, and what happened yesterday, we found that children were most likely to give productive responses when they were asked about yesterday. Moreover, older children were also most productive overall when they were asked about yesterday, compared to the other topics. Nevertheless, children were almost always able to produce details about their birthday and answered 90% of questions about their birthday productively. Furthermore, the birthday narrative was no more likely to produce negative information than asking about yesterday, and less likely to do so than asking about things children liked to do. The results support use of the birthday narrative as a means of encouraging children to recall information in the pre-substantive phase of forensic interviews, particularly when they may need to recall remote events in the allegation phase.
Footnotes
Acknowledgements
We would like to acknowledge the testers for this project, including Samantha Hardy, Rayna Enriquez, Hailey Konovalov, Owen Friend, Tianyu Wang.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported in part by the National Institute of Child Health and Human Development (Grant HD101617).
