Honoring childhood agency in developmental research: Best practices, applications, and insights

Abstract

Pediatric research requires caregivers to provide informed consent on behalf of their children. While not a formal requirement for children under the age of seven, it is important to involve child participants in the assent and decision-making processes in developmentally appropriate ways. This is especially important in longitudinal research, where the extent to which a developing child understands study tasks evolves over time. Although there is consensus that assent procedures are important and necessary, limited resources synthesizing strategies for pediatric researchers to encourage positive and respectful research experiences for young children exist. We describe methods used in an ongoing longitudinal study following caregiver-infant dyads from gestation through five years of child age. Study visits include repeated assessment of children’s behavioral, cognitive, and physical development. Additionally, we describe observations from a study that used art-based approaches to enhance agency during study visits with five-to ten-year-olds. We describe methods for promoting agency in research contexts including potential modifications based on developmental milestone achievement. We detail strategies for assessing and responding to child behaviors that may indicate dissent. By synthesizing this information, we provide a comprehensive resource that may be used to encourage positive and respectful research experiences for children. Such experiences are likely to improve data quality and retention and uphold developmental research ethics. Further, this work contributes to a larger conversation about child agency, which has been occurring for decades across academic disciplines. Promoting children’s agency in research also has potential to promote healthy long-term outcomes for developing children.

1. Introduction

Over the last three decades, pediatric research has shifted from “researching children” to emphasize “engaging children in research” (Dockett and Perry, 2011; Mason and Watson, 2013; McLaughlin, 2020; Pope et al., 2017). This shift followed the publication of documents such as the United Nations Convention on the Rights of the Child (Cohen, 1989) and the Ethical Conduct of Clinical Research Involving Children (Behrman and Field, 2004). These reports emphasized the need for pediatric research experimental designs to neither burden nor exclude children (McLaughlin, 2020; Pope et al., 2017). Federal regulations do not require children under the age of seven to provide formal assent to research based on the assumption that they cannot adequately understand what they are agreeing to prior to this age. However, children’s ability to indicate preference and aversion and their capacity to understand what is asked of them emerges long before middle childhood (Rossi et al., 2003; U.S. Department of Health and Human Services, 2018). Thus, while not a formally regulated requirement, best practices in pediatric research include explaining study procedures to children using developmentally appropriate language and visuals, including children in study procedure discussions, offering children opportunities to assent or dissent to study procedures, and appropriately responding to children’s verbal and nonverbal expressions of assent and dissent (Dockett and Perry, 2011; Roth-Cline and Nelson, 2013; Wendler, 2006).

Evolving perspectives on children’s cognitive, socioemotional, and physical capacities to consent to research procedures and the developmental importance of child agency underscores the need for meaningful assent—a relational process that acknowledges children’s wishes alongside informed consent from caregivers (parents or legal guardians) (Dockett and Perry, 2011; Mason and Watson, 2013; McLaughlin, 2020; Pope et al., 2017). Researchers across disciplines have called for a more involved assent process with children, including sociology, where there is robust literature discussing how policies that have been created to promote child well-being often exclude children from decision-making dialogue that affects their lives (Neale, 2002; Neale and Flowerdew, 2007). While conceptualizing child agency is an ongoing process that has been documented for centuries, there are constantly evolving perspectives on the role children play as “young citizens” in the world and how this role is reflected in the way they are treated by adults (Neale and Flowerdew, 2007; Varpanen, 2019).

While assent procedures aim to protect children from coercion and ensure ethical practices, they are often treated as a procedural formality (and may be entirely absent in research conducted with very young children). Building in opportunities for input on decision-making, as well as incorporating children’s voices and perspectives across all stages of research, demonstrates that we see them as competent social actors who can meaningfully contribute to science (Alderson, 2023; Coyne, 2010; Neale and Flowerdew, 2007). Empirical evidence indicates that children who feel their decision-making and agency are not respected by their caregivers exhibit decreased self-esteem and are at increased risk for developing depressive symptomology (Kawash et al., 1985; Lee, 2024; Yan et al., 2017). While there is limited empirical data regarding how researchers’ respect for agency impacts child participants’ long-term mental health outcomes, it stands to reason that demonstrating consideration and respect for children’s agency and decision-making processes in a research context may contribute to similar positive outcomes. Promoting child agency in research study settings in a way that preserves the integrity of the research protocol requires some forethought and flexibility on the part of the research team. However, making effortful attempts to foster trust and respect in this setting encourages children to practice independent and informed decision-making, which may serve them well in medical spaces, academic spaces, and other contexts throughout their lives (Neale, 2002).

While there is general consensus that obtaining child assent to research procedures is a beneficial process, researchers are often faced with the conflicting need to avoid deviations from standardized protocols in ways that compromise data integrity. While there are limitations to which aspects of research procedures can be altered before data are compromised, there often are opportunities for researchers to build in flexibility, to provide children with choices, and to capitalize on known developmental stages and skills in ways that do not carry substantial consequences for data quality. A complete review of the complexities of attaining assent from children in research is outside of the scope of this manuscript; however, we refer the reader to several excellent systematic and scoping reviews on the topic (Cayouette et al., 2022; Soll et al., 2020; Wasserman et al., 2024). These authors, and others (e.g., Morris et al., 2021; Wu et al., 2021), call for enhanced transparency in methods used to obtain consent/assent and suggest that researchers use dynamic, developmentally appropriate tools to do so. Despite these calls, few published studies describe child assenting methods in detail, and we are unaware of a published set of practical resources for use in supporting child agency in the research context.

The goal of the current manuscript is to describe our research efforts and create practical resources (Figs. 1 and 2) that may be utilized by other pediatric researchers to encourage positive and respectful research experiences for children in the 0–10-year-old age range.

Fig. 1.

Guidelines for attaining child assent. Figure depicts developmental milestones and their corresponding child assenting procedures. The color spectrum gradient from yellow to blue acknowledges neurodiversity and differences in individual needs as children develop.

Fig. 2.

Figure depicts tools used to engage children in study procedures. Panel A depicts an EEG Cap being modeled by a teddy bear, Panel B depicts paper crowns to approximate head circumference. Panel C depicts a social story to increase procedure comprehension in preschoolers, and Panel D depicts a sticker chart for preschoolers to follow along throughout the visit. Panel E depicts choice of backpack for preschoolers.

These resources:

1. Provide researchers with a developmentally scalable guide (Fig. 1), including helpful behavioral markers for forming an impression of child research participation willingness,

2. Can be used to increase child understanding of research procedures and context to facilitate decision-making (Fig. 2), and

3. Support a child’s developing agency in a research context.

1.1. Shifting perspectives on children’s roles in research participation

In pediatric research, researchers primarily rely on caregiver permission for child involvement. This is because children are presumed unable to engage in the complex weighing of risks and benefits required to obtain informed consent (Field and Berman, 2004; U.S. Department of Health and Human Services, 2019) and caregivers are considered a child’s most appropriate proxy. Although it is often a secondary consideration, obtaining child assent, or affirmative agreement to participate, is both a moral obligation and is essential to providing participants with positive research experiences. Assent is distinct from consent, which involves a fully informed and voluntary decision by individuals with the legal capacity to understand the risks and benefits involved (Dockett and Perry, 2011). While regulations may differ depending on state and local law, typically, individuals must be at least 18 years old to provide consent without caregiver permission (U.S. Department of Health and Human Services, 2019).

Assent is appropriate for children for whom it may be more developmentally appropriate to expect an expression of basic preference that can be reasonably obtained, even with a less complex research understanding. While federal regulations only require formal assent procedures be used with children seven years and older, we assert that children can provide indication of their interest or agreement to participate (and, often more clearly, can express their dissent) prior to this age. Autonomy, or the ability to make self-directed choices without the influence of external factors, typically evolves across development (Erikson, 1968; Piaget, 1932). Thus, as children age, procedures for obtaining child assent should be adjusted in parallel with the child’s developing socioemotional and cognitive capacity (See Fig. 1).

A key distinction exists between the concepts of autonomy and agency. Autonomy implies independent thought and action—something that very few young children fully possess, as their decision-making is still largely influenced by others due to their developmental stage and dependence on adult guidance (Mühlbacher and Sutterlüty, 2019). In contrast, agency refers to the capacity to act, make decisions, and engage with others in ways that affect both one’s own life and the lives of others (Sutterlüty and Tisdall, 2019). Children are active contributors within the social world, shaped by and influencing the relationships around them. Importantly, children’s agency cannot be equated with autonomy because it is a relational concept influenced by ongoing and dynamic social interactions, such as the asymmetrical relationship between children and adults (Mühlbacher and Sutterlüty, 2019). For the purposes of this manuscript, we discuss prioritizing the support and recognition of children’s agency. Nevertheless, fostering children’s agency can serve as a foundation for the development of autonomy over time, as their ability to make independent choices strengthens alongside their evolving social roles and capacities.

1.2. Disseminating developmentally appropriate child assent methods

While many researchers advocate for practices that support emerging childhood agency, one challenge to implementing such practices is that the field lacks a concise summary of what emerging agency looks like and how it can be applied to research protocols (Centers for Disease Control and Prevention, 2024a; Mayne et al., 2016; McMillan, 2022; Sherwood and Parsons, 2021). As children develop, procedures for obtaining child assent should be reevaluated and modified with respect to the child’s emerging capacity to understand and provide assent. Here, we describe recommended assenting procedures based on developmental milestones which may be relevant to emergent assenting and dissenting behaviors displayed across different childhood stages. We note that large individual differences in development exist among both neurotypical and neurodiverse children and that there is a critical need to customize assenting approaches for each child at every age.

We detail our methods of attaining assent developed for the Prenatal Environment And Child Health (PEACH) Study], an ongoing longitudinal study following 310 mother-infant dyads from the second trimester of pregnancy until children reach five years of age. The study protocol includes a number of ongoing postnatal follow-up visits—of which 1565 have been completed (at 1-, 6-, 12-, and 18- months of age, and 2-, 3-, 4-, and 5- years of age). The PEACH Study, which includes repeated assessments of children’s development during a period of rapid growth, presents a unique opportunity to engage in the applied practice of eliciting child participation in research while supporting their emerging agency over the first five years of development. Our study visits include an array of behavioral tasks, many of which involve observations of child temperament, including tasks intended to elicit emotional reactivity and regulation. Our extensive experience administering both enjoyable and potentially emotionally evocative research protocols (that are designed to capture a range of emotional reactivity and regulation) have provided us with extensive experience observing and interpreting children’s verbal and nonverbal displays of assent and dissent. Below we also note observations from a Draw-and-Tell study, including techniques and considerations that are important to respectfully engaging older children in research. This study engaged children ages 5–10, using art-based approaches to enhance agency during study visits. Building on observations made across studies, we encourage researchers to use a dynamic approach to navigating assent, carefully considering the individual needs and abilities of each child (concisely synthesized in two visual resources, see Figs. 1 and 2). These resources may encourage and support the efforts of other pediatric researchers to engage in dynamic attainment of child assent in research and may be adapted for their purposes.

We conclude by describing some of our “Lessons Learned” relevant to research with pediatric populations.

1. It is critical that researchers consider individual differences in child development when administering study tasks and assent procedures,

2. The child’s caregiver can be a valuable and uniquely informative research partner,

3. Promoting agency in pediatric research settings is feasible and has potential to promote positive long-term outcomes for developing children, and

4. Respecting child agency can have positive implications for data quality and retention.

2. Infancy: 0–1 years old

2.1. Infant developmental milestones and existing literature on assenting procedures

Infancy, typically defined as the first year of life, marks the earliest postnatal development stage in which neonates rapidly obtain motor, language, cognitive, behavioral, and social-emotional skills. Notable changes occur during infancy, with infants progressing from an inability to hold up their heads in the early months to standing by one year of age (Scharf et al., 2016). Infant skills at one-month are limited to emergent movements and expressions such as turning their heads while supine, startling to sounds, crying in distress and noticing their mother’s voice (Centers for Disease Control and Prevention, 2024a). By six months, however, infants can lean on their hands to support themselves, vocalize when spoken to, caregiver-infant attachment has formed, and they exhibit laughter, reciprocal smiling, and understand the word “no” (Centers for Disease Control and Prevention, 2024a; Scharf et al., 2016). Between six and 12 months, infants are able to pull up to a standing position and walk with the aid of furniture, gestures begin to develop, echolalia (repetition of speech sounds) emerges, and infants respond to simple phrases like “come here” and typically orient to their names. At this age, infants may also stop when they are told “no” and can follow one step commands with gestures. By the age of one, infants enjoy playing games and can share interest in objects.

These first-year milestones mark the emergence of human agency, although a review of the literature suggests that they are often overlooked as such in a research setting (Miller et al., 2004; Rossi et al., 2003). Research regarding assent does not typically cover infancy or discuss the nuances of assent at this age. Consenting procedures during this developmental period typically rely solely on caregiver input—and in birth cohort studies like the PEACH study—caregivers may have consented to their child’s involvement in research prior to their birth. Few studies mention procedures for assessing and responding to dissent, making common practice in this age range unclear. A common reported marker of assent/dissent in this age range appears to revolve around extreme expression of negative affect. For example, in one longitudinal study working with four-month-olds, authors referred to missed task participation due to infant fussiness (Bruce et al., 2023), suggesting modification to the study visit based on infant dissent. Another study examining the still-face paradigm, in which a caregiver exhibits a flat, unresponsive face for a short period between play, described ending the task after an infant cried for 30 consecutive seconds (Ekas et al., 2013). These examples utilize fussiness or upset to indicate infant dissent; a pattern common across studies. However, little to no research discusses assent in the infancy period, highlighting the need for a standard of practice for assenting and dissenting procedures encompassing all developmental periods, including infancy.

2.2. PEACH Study assent methods: infants

In the PEACH Study, we utilize a standard assent/dissent procedure that dynamically adjusts with developmental age and in response to individual child needs. Caregiver-Infant dyads attend study visits at 1-, 6-, and 12-months of age. Given that infants have more limited communication abilities, at these assessment timepoints, researchers rely heavily on caregiver input on their child’s emotional expressions and comfortability, with explicit efforts to partner with caregivers in making child-centered procedure modifications, as needed. Researchers work with parents to interpret the child’s verbal and nonverbal cues, and research staff provide caregivers with opportunities to control the pace of the visit, the timing and duration of transitions between tasks, and/or are offered opportunities to skip or reorder study tasks. It is crucial to recognize that the caregiver serves as the child’s advocate during these early stages of development. They are uniquely helpful interpreters of child behavior and preferences, making it important for them to understand the protocol and to be given the opportunity to communicate their interpretation of their child’s needs and preferences. It is important to note that not all caregivers are equally attuned to their child’s needs and expressions. In this case, caregiver input should be considered as additional context for researcher in-laboratory observations.

To optimize communication between researchers and caregivers, PEACH Study staff members provide both visual and descriptive explanations of tasks. This includes showing caregivers pictures of stimuli that their child may interact with during the visit (and receiving input about their child’s expected reaction), allowing caregivers to touch stimuli so that they can anticipate the sensation they might experience (for example, to feel the stickiness of an electrocardiogram (ECG) electrode prior to their placement on the child). Caregivers are provided with time to ask questions prior to starting the visit, as well as before each task begins. Additionally, it is made clear that caregivers can opt out of any portion of the visit and/or stop any task at any time without penalty. We utilize a standard protocol across visits in which we stop a task if the child is upset for longer than 20 s. We explain this to caregivers prior to task administration, to provide them with a sense of what to expect if their child were to become upset and an opportunity to express concern prior to task administration. This waiting period before ending a task was selected based on standards reported in the literature (e.g., Adamson and Frick, 2003), though we have the ability to adapt this to account for individual differences in child response. This period may be shortened if a child expresses concerning signs of being upset such as holding their breath, turning red, or strong distress vocalizations. It may also be abbreviated based on caregiver request. These are common examples of potential dissent or discomfort in infant participants. In cases like this, the researcher may facilitate a break (e.g. breast/bottle feeding, a distracting toy such as bubbles, or providing a comfort item like a pacifier or a blanket) to help regulate the infant prior to making a decision to skip or alter the task. Language in the PEACH Study visit scripts include recognition and reinforcement of the flexibility and choice that the parent has throughout the visit. For example, we explicitly communicate our belief that caregivers know their children best, and we encourage them to let us know if they feel uncomfortable or would like to stop before the standard 20 s. After each task, caregivers are provided an opportunity to interact with their child in an unstructured way, allowing them to soothe their child, as needed. Additionally, caregivers are actively involved in decisions related to the timing of transitioning between tasks, so these recovery periods can easily be extended.

3. Toddlerhood: 1–2 years old

3.1. Toddler developmental milestones and existing literature on assenting procedures

Toddlers, defined here as one-to two-year-olds, reach many developmental milestones, progressing incrementally throughout this year. Toddlerhood begins around 12 months, when a child first begins to walk without assistance (Zubler et al., 2022). Around one year, typically developing toddlers begin to form their first words and by two years old, toddlers are usually beginning to form two-word sentences (Zubler et al., 2022). Toddlers’ receptive language skills are typically more complex than their expressive language skills, suggesting that they understand more than they are able to communicate overtly. Children this age are often able to follow simple directions and understand gestures (Zubler et al., 2022). By two years, toddlers are mobile, although their coordination skills are still developing (Zubler et al., 2022). Gross motor skills acquired this year include running and walking, standing up from a squat without support, walking up and down stairs alone, jumping in place, and kicking a ball (Mcbee et al., 2025). Toddlers experience rapid development of socioemotional functions, including exhibiting egocentrism and expressing more advanced emotions such as pride and shame (Ener, 2015). Socially, most toddlers begin to form a sense of self and an interest in connecting with peers, and they engage in pretend play, which supports their developing curiosity and allows them to practice problem solving (Ener, 2015).

Some, albeit few, studies describe dissent and assent procedures in research with toddlers. As was true for research on infants, the most frequent reference to assent/dissent in toddlers is when researchers report a particular task being terminated if the child became “too distressed” (Ekas et al., 2013; Potegal et al., 2007), though few studies have operationally defined this state. It is also common for researchers to report the amount of data that are missing due to child refusal or intolerance of the protocol (e.g., Calkins and Johnson, 1998), though the details surrounding how dissent is assessed and typically expressed in these cases is rarely provided. We also note that there are studies who describe protocol deviations that were made when children appeared fearful or indicated that they did not want to engage with a particular stimulus (common dissent cues in this developmental period). For example, one study conducted with 20-month-olds described replacing the standard stimulus toy with a different toy if a toddler became too frightened (Ekas et al., 2013). As these examples illustrate, typically when dissent is mentioned, authors equate dissent to distress or refusal. While less common, there have also been studies that describe methods for increasing toddler engagement and communication in a research context. For example, Dockett and Perry (2011) describe giving two-year-old participants a dog toy so they could indicate assent to the study by making the dog nod its head. A different study using the Snack Delay Task, a delayed gratification task assessing child self-regulation skills and inhibitory control (Kochanska et al., 2000), reported allowing 30-month-olds to choose between two types of snacks to encourage interest in the task (Kerr-German et al., 2022). Another study conducting electroencephalograms (EEGs) on 24-month-olds suggests building in breaks to relieve infant fatigue (Dickinson et al., 2024). While few studies explicitly mention assent in toddlers in terms of willingness to engage in study procedures, some researchers provide elements of choice or optional breaks for child participants.

3.2. PEACH Study assent methods: Toddlers

When adapting the PEACH Study’s methods for use with toddlers (12-, 18-, and 24-month-olds), we considered the typical developmental achievements of children this age. Our lens of longitudinal research here is especially helpful: in the transition from infancy to toddlerhood, we see a wide variety of milestones and newly developed abilities in our participants, which further necessitates adapting our procedures. Of particular relevance with toddlers is children’s emerging ability to speak, understand language and gestures, and engage in pretend play.

As was the case for working with infant participants, our starting point with toddler participants is to work with the caregiver to better understand child preferences and cues. We actively engage the caregiver in decisions on how to proceed when a child indicates distress, discomfort, or a preference not to engage in a particular portion of the study visit. We continue to utilize a standardized protocol for ending a task early if a child is upset for longer than 20 s (or if the caregiver indicated they would like to stop the task). In addition to utilizing the dissent cues that infants display (e.g., crying, fussiness), toddlers can express their discomfort in new ways due to their developing physical and verbal abilities. This may include ignoring the study staff or caregiver, shaking their head, or protesting with words like “no”, “stop”, or “don’t” (Zubler et al., 2022). With these dissent cues in mind, we adapted our procedures to toddlers’ growing sense of independence and control, using toddlers’ emerging communication skills and desire for agency as a guide, while maintaining study integrity. While respecting child displays of dissent is of clear importance, we would like to note that in our experience many toddlers display conflicting or ambiguous cues (e.g., saying “no” while laughing or indicating interest in engaging in the task) which adds complexity to assessing assent in this age group. Similarly, we have observed children not wanting to engage in one specific portion of the visit while simultaneously indicating interest in other activities (e.g., they may not want to lay down to have their weight assessed but may be interested in sitting or standing on the scale), which can further make assessing assent challenging. These complexities underscore the importance of partnering with caregivers to understand child preferences and intentions (including getting caregiver suggestions for ways to further probe child desires in these ambiguous situations).

To explain study procedures and elicit child assent with toddlers, our team demonstrates tasks, such as a body measurement or wearing an EEG cap, on a doll or stuffed animal first (Fig. 2, Panel A). This capitalizes on the knowledge that many toddlers use pretend play as a way of understanding their social environment (Ener, 2015). In executing this method, we also assess the child’s degree of comfort with each study task. If the child seems hesitant to wear an EEG cap, for example, study staff may wear one first to demonstrate. Staff members also utilize the caregiver as a teammate in this process. Caregivers may demonstrate tasks like body measurements, biological sample collection, ECG electrode placement, or EEG on themselves to convey how the stimuli work, what the child can expect when participating in study activities, and to show the child that the stimuli are safe. Study staff and caregivers may also encourage the toddler to touch or interact with the stimuli if they desire to, with the thought that interacting with the stimuli may increase child comfort and familiarity with the task. These procedures are designed to allow children to learn about study activities through play and exploration and are intended to build upon children’s developing inclination to copy or mimic their caregiver (Zubler et al., 2022). Such strategies are often a response to common examples of dissent within toddlers. Toddlers may immediately say “no” upon seeing the EEG cap due to its novelty, and their fear of something unfamiliar on their bodies. In this circumstance, our next steps are to gently invite the child to touch the stimulus to help them acclimate. If the toddler is still expressing dissent, we demonstrate by having the caregiver or staff member try on the electrodes or cap to match the child. When seeing a trusted person safely interact with the stimulus, toddlers often feel reassured and eager to emulate their caregiver. Thus, the modeling process may encourage toddlers to change their minds from their original dissent and participate instead.

Along with these opportunities to explore the research stimuli and environment, we try to incorporate play into procedural components of the study visit. For example, we offer children the opportunity to put paper crowns of varying sizes on their head prior to EEG cap placement. This play period has benefits for data collection (each crown corresponds to an EEG cap size, and through the play process the research staff can determine the correct EEG cap size), but also can help researchers build rapport, invoking pretend play and involving the child in picking out their own cap (Fig. 2, Panel B). Utilizing a familiar stimulus that children often associate with pretend play (such as crowns) may also ease potential intimidation towards the unfamiliar EEG procedures, and scaffold the process of wearing the cap. While toddlers may not provide verbal confirmation of understanding or assent, researchers should explain study tasks and processes to toddlers using developmentally appropriate language and simple terms, as they typically can understand language to a greater degree than they can speak it.

We also implement several procedures intended to support children’s emotional regulation and to promote toddlers’ comfort. This includes the above-described opportunity for caregivers and children to interact with one another after each emotionally evocative task and offering breaks between all tasks. We provide bubbles or music between visit tasks to give children an opportunity to stretch, move their bodies, or calm down as needed. These breaks may even involve the research staff dimming the lights or leaving the testing room so the caregiver can help the child regulate without extraneous sensory input. For tasks that some children may find physically overstimulating, like placing the EEG cap or ECG electrodes, we utilize distraction techniques (e.g., small hand-held regulation or fidget toys) that can help toddlers channel energy into a tactile device to self-soothe and regulate. Depending on caregiver comfort level and child age, we also may provide a brief period of screen time via a tablet with child-friendly content to help with distraction. We provide these levels of choice to acknowledge toddlers’ developing sense of self and preferences, and to encourage control within their own study visit. Our efforts to assist the child with emotional regulation reflect our goal of generating an environment where they are calm enough to understand the task with which they are being presented and are therefore able to assent or dissent accordingly.

4. Preschool age: 3–5 years old

4.1. Preschool age developmental milestones and existing literature on assenting procedures

The preschool years, typically defined as ages three to five, are a crucial period of development characterized by significant cognitive, social, and physical changes. During the preschool years, children generally enjoy pleasing others and helping with tasks, while also demanding more control over their environments as they experience a desire for increased agency (Centers for Disease Control and Prevention, 2024a). They show significant changes in physical mobility and fine motor movements (Centers for Disease Control and Prevention, 2024a; Zubler et al., 2022). Between the ages of three and four, children typically engage in more complex pretend play, are interested in new experiences, eat and dress with more independence, and speak in more complex sentences (Centers for Disease Control and Prevention, 2024a; Zubler et al., 2022). By ages four and five, children typically reach milestones such as being more likely to agree with rules, able to tell stories, understand time, and identify shapes, colors, numbers, and common objects (Centers for Disease Control and Prevention, 2024a; Zubler et al., 2022). Growing independence at this stage is critical in a child’s ability to embrace new challenges and learning opportunities, such as participating in research. When a preschool-aged child has a sense of control over their environment, they are more likely to approve of trying new experiences (Giving children choices, 2016).

Given the rapid developmental changes during this stage, it is essential to consider how assent may evolve as children progress through these years. While the existing literature on assent and dissent among preschool age children is limited, it emphasizes enhancing children’s comprehension of procedures and research purposes through visual aids and interactive tools. For example, Mayne et al. (2016) utilized an interactive narrative (a storybook delivered via interactive retelling) to help three-year-old children understand research procedures and participate in the informed consent process. Pyle and Danniels (2016) used a picture book to explain research processes and gain assent from children aged four to six years, demonstrating that children could engage effectively in discussions and make informed decisions.

In addition to evolving assent behaviors, children’s dissent behaviors also become more nuanced during this developmental period. For example, Dockett et al. (2012) identified examples from studies with children ranging from two to six years old on how they expressed dissent to participation in research. Examples of dissent highlighted by these authors included a four-year-old refusing to make eye contact, five- and six-year-olds circling a figure of a thumbs down, and a five-year-old saying, “I don’t know,” shrugging shoulders, and making excuses to leave the situation.

4.2. PEACH Study assent methods: Preschoolers

We developed and implemented various procedures designed to enhance children’s comprehension and facilitate informed assent, taking into account typical developmental milestones. These procedures were especially informed and aided by our study’s longitudinal design, which allowed us to maintain rapport with children over time as well as to witness and track their changing abilities. One example is our use of a social story to enhance comprehension of study procedures and data collection protocols (Fig. 2, Panel C). This approach involves sending the child a digital copy of a picture book prior to the study visit. The story outlines what the child can expect to encounter during a study visit using simple terms and visual aids. Study procedures are illustrated using cartoon pictures, providing caregivers and children an opportunity to discuss what will happen as part of the study visit and to give caregivers the opportunity to answer any child questions prior to their laboratory arrival. Utilizing this social story is intended to allow preschoolers to better comprehend study tasks, to participate in the study visit more actively, and to opens the opportunity for communication between the child and study staff members (Centers for Disease Control and Prevention, 2024a; Zubler et al., 2022). A physical copy of this social story is also kept in the laboratory testing room for reference throughout the visit. Social stories are commonly utilized for autistic children and have been shown to enhance social skills, communication, self-regulation, and reciprocal interactions (Saad, 2016). While originally developed for neurodivergent children, it is likely that most children benefit from the improved understanding, communication, and engagement facilitated by the use of social stories (Pyle and Danniels, 2016).

Another tool we regularly use with children of preschool age is an interactive sticker chart, where children are given a sheet of paper with symbols corresponding to each visit task (Fig. 2, Panel D). Visit tasks are listed in the order in which they typically are administered, providing children with a visualization of the study visit timeline. The sticker chart is developmentally appropriate for preschool-aged children, utilizing familiar symbols and pictures to stimulate curiosity about the new experiences they will encounter as part of the visit (Centers for Disease Control and Prevention, 2024a). The sticker chart helps children to follow along with visit tasks, to monitor visit progress, and to earn small rewards (stickers) for each completed task. We have found that using sticker charts encourages active involvement in study procedures, introduces upcoming tasks, and helps give the child a sense of visit flow and the passage of time.

We also utilize several developmentally appropriate communication strategies to optimize preschoolers’ ability to assent or dissent to participation in research. One such strategy involves verbally encouraging questions from the child (“What questions do you have?”), which both fosters interest in new experiences and encourages child agency by enabling them to gain information relevant to their assent or dissent decision (Centers for Disease Control and Prevention, 2024a). For example, sometimes children ask questions such as, “Why do you want my spit?” (referring to saliva samples) or “What is the cap for?” (referring to the EEG cap). When such questions arise, our team answers using language and explanations appropriate for the child’s developmental stage. For example, “Your spit can help us learn about how you are feeling, and how your body grows and stays healthy” (referring to saliva samples) or “This is a special cap that helps us listen to your brain. It can tell us what your brain is doing, like when you’re playing, thinking, or resting” (referring to the EEG cap). We have observed that addressing these inquiries can enhance child comprehension, foster interest, and, in some cases, increase enthusiasm for participating in our research. Answering these questions also encourages children to ask additional questions throughout the study visit, increasing communication between study staff and young participants.

Another strategy is offering the child a choice between two stimuli that are both acceptable options from the researcher’s perspective. For example, the PEACH Study collects child ECG data throughout the study visit. In order to allow children to move freely, we place the ECG leads and the mobile device used to capture their cardiac data into a small backpack that the child can wear throughout the visit or that can be placed on their chair while seated. When we introduce the ECG data collection procedures to the child, we offer them a choice between two different colorful backpacks (Fig. 2, Panel E). The appearance of the backpack does not have consequences for the ECG data quality (and thus either choice is an acceptable option from the researcher’s perspective); however, providing the child with a choice gives them a sense of agency and control. Similarly, when recording child anthropometric measurements, we show children two tape measures that have different animal stickers on them. Children are given the choice of which tape measure they would like the study staff member to use when taking these measurements. Other choices offered include a choice of toys to play with during transitions and breaks, a choice of snacks, options of where to sit in the testing room, and the color of their end-of-visit gift. These strategies help meet preschoolers’ needs for control, supporting their emerging agency (Centers for Disease Control and Prevention, 2024a). Similarly, our team allows for flexibility in the order of tasks and allows for study visits to be completed over the course of multiple days, if necessary, to meet the child’s preferences or capacities.

5. Middle childhood: 6–10 years old

5.1. Middle childhood developmental milestones and existing literature

During middle childhood, which includes ages 6–10, children enter elementary school, expand their social contact with the external world, and navigate new social norms and pressures (Markus and Nurius, 1984; Wilmshurst, 2012). Children develop confidence and show more independence from caregivers and family members (Centers for Disease Control and Prevention, 2024b). Although abilities vary widely within this age range and may be impacted by learning disabilities and neurodiversity, children ages 6–7 typically learn to complete activities of daily living including dressing, bathing, and feeding themselves with little to no assistance from caregivers (Centers for Disease Control and Prevention, 2024b). Children ages 8–10 typically become capable of preparing their own meals, navigating their communities independently (e.g., walking to school), managing their time, and taking responsibility for regular tasks (e.g., packing a lunch, completing chores) (Centers for Disease Control and Prevention, 2024b). Children ages 6–10 are capable of logical thinking and reasoning and become more adept at regulating their emotions (Markus and Nurius, 1984; Wilmshurst, 2012). They also undergo notable language development including improved comprehension and more complex storytelling abilities (Centers for Disease Control and Prevention, 2024b; Wilmshurst, 2012). Children ages 6–7 typically learn to read and write, and by ages 8–10 many can read chapter books and write multiple-paragraph essays (Centers for Disease Control and Prevention, 2024b). Children in middle childhood typically develop stronger peer relationships and demonstrate perspective-taking and empathy (Centers for Disease Control and Prevention, 2024b). Yet just as we see with younger children, children ages 6–10 continue to favor internal sensory cues to process, organize, and retrieve information over semantic, language-based, and external cues which are typically favored by adults (Greene and Hogan, 2005; Halford, 2014).

Approaches to research assent in middle childhood must account for both children’s expanded attunement to and engagement with the external world and their ongoing reliance on internal sensory cues (Greene and Hogan, 2005). For example, children’s increased awareness of social norms may influence their willingness to participate in research (e.g., attunement to social cues may lead a child to assent to participation because it is the “right” thing to do) (Li et al., 2021). Rather than relying on simplified vocabulary, verbal cues, and visual prompts to assess children’s willingness to participate, integrating kinesthetic and sensory-based approaches such as allowing them to manually manipulate a tool to start/stop an activity (e.g., controlling the dial on a timer) or incorporating arts-based means for study participation (e.g., in the Draw-and-Tell study described above, we ensure that researchers are creating an environment for children that facilitates and enhances children’s sense of agency and thus their willingness to participate (Coyne, 2010; Driessnack and Furukawa, 2012; Mauthner, 1997).

5.2. Assent methods: Middle childhood

In this study, a bicoastal US-based sample of 12 5- to 10-year-old children were invited to draw and tell about their social supports and medical experiences, utilizing the Draw-and-Tell Conversations method (Barfield and Driessnack, 2018; Coyne, 2010; Driessnack, 2006; Driessnack and Gallo, 2013; Kim, 2023; Linder et al., 2018; Pope et al., 2018; Robledo Castro et al., 2023; Water et al., 2020; Wiseman et al., 2019). Using a community-engaged approach, we consulted with children during the conceptualization, data collection, data analysis, and interpretation phases of the study. We invited eligible children and their primary caregivers to meet us in person at a location of their choosing. Half of the participants chose to meet at home, and half met us in public spaces such as parks and university conference rooms. During the consent procedure, we introduced a social story to describe the context and process of the research study prior to assenting participation. We also gave potential participants an assent form written in simplified language and offered tangible examples of what they would be doing, allowing them to touch and explore materials they would engage with during the research. Children were invited to ask questions, and occasionally we shared simple and anonymized stories about other participants’ experiences in the study in response to their questions. Once a child assented, their primary caregiver was invited to give permission (McMillan, 2022; Te One, 2011). This sequencing distinction is important. Children in middle childhood should be given the chance to decide for themselves whether they would like to participate with minimal caregiver influence, to preserve their sense of agency (McMillan, 2022; Te One, 2011). To compensate the children for their participation, we gave them a gift card to their favorite book, art, or toy store. Although our methods were consistent for all study participants regardless of age or developmental stage, we noted developmental distinctions in children’s perception of and motivation to engage in the study. Many of the younger study participants were physically drawn to the tactile experience of using the study’s art materials whereas many of the older participants were motivated by the study’s premise, research questions, and prospect of receiving a gift card.

To further preserve and enhance children’s agency, we gave children access to non-verbal tools to indicate their willingness to participate or continue participation (e.g., a stop sign they can point to; red and green circles to choose whether they want to stop or go), and opportunities to make choices. We invited children to choose their own adventure by picking out the materials they wanted to use to communicate their stories (e.g., pencils, watercolors, modeling clay, Legos). Adjusting art materials was effective when children dissented or expressed hesitancy. For example, one child was interested in participating in the study but did not want to do so via the methods initially suggested (e.g., drawing, painting). They were invited to explore other materials, and staff helped brainstorm some additional ways they could participate. The child ultimately decided to proceed using Legos, so staff adapted the study procedure on the spot to discuss their Lego creation instead of discussing their drawings. We found children were more willing to share their experiences with us when they could do it on their terms, aligning with the literature suggesting that when elementary-aged children are given the space to express their preferences they gain a sense of agency, increase their willingness to participate, and are more likely to navigate future research and clinical experiences with confidence (Driessnack and Furukawa, 2012; Mauthner, 1997; Mayne et al., 2018).

6. Discussion—Lessons Learned

Obtaining pediatric assent is crucial in research settings, especially during periods of rapid neurodevelopmental change (Hester and Miner, 2023). A dynamic approach to navigating child agency respects growing independence, while also accounting for diverse developmental trajectories. The authors acknowledge that many of these experiences are drawn from clinical and developmental psychology and neurodevelopment research settings. While this scope has limitations, the curation of a single resource that synthesizes literature, direct experiences, and modifications to procedures may be useful across multiple disciplines. As a result of our experiences conducting longitudinal research with children, we developed four reminders for navigating assent in pediatric research, provided here as “Lessons Learned.” These reminders are informed by observational data, developmental stages, and learned experience. These “Lessons Learned” acknowledge the unique needs and abilities of children at each developmental stage, extending the standard guidelines.

6.1. Lesson 1: Each child is different

One important consideration is that there are substantial inter-individual differences in the developmental course and not all children fall under the framework of typical developmental milestones. While milestones in “numerous domains” appear to be attained at similar ages across populations, suggesting universal guidelines for neurotypical children (Ertem et al., 2018), these guidelines are based on standards and statistical norms and will not fit all children (de Lima et al., 2023). Researchers must continue to adapt methods beyond chronological age to account for differences in neurodevelopment within study populations. Our methodology acknowledges the wide-ranging spectrum of individual differences in child development, encouraging an individualized approach by providing a wide array of options for attaining child assent and promoting agency (See Fig. 1). In longitudinal research, we recommend adapting or utilizing different strategies as children develop uniquely and age over the study’s course. A review conducted by Miller et al. (2004) examined empirical literature on children’s competence for consent and assent. The authors highlighted the need for observational and longitudinal methods to provide real-world context, showing how the ability to assent changes over time (Miller et al., 2004). Future research may aim to develop a personalized dynamic “toolbox” for study staff, offering a variety of strategies that enhance children’s engagement in research while respecting their agency (See Fig. 2).

6.2. Lesson 2: Caregivers are important partners

Pediatric researchers should consider caregivers as partners in research settings. Caregivers typically provide consent to the research on behalf of their children and therefore may play a critical role in the attainment and research surrounding pediatric assenting procedures. McMillan (2022) describes the interaction between caregiver and child during assent as “intimate” and allows for “unique communication styles”. Caregivers and children are closely attuned to the behavior of each other and caregivers can describe research practices in a manner that resonates with their child’s understanding. In the PEACH Study, researchers look to caregivers to orient staff to verbal and non-verbal cues which may be useful in understanding their child’s feelings or behaviors. It is critical that both the caregiver and the child feel comfortable with study procedures. As caregivers understand their children well beyond the researcher, it should be common practice to rely on caregivers for support in bridging the gap between child and researcher.

6.3. Lesson 3: Supporting child agency may have far-reaching implications

The prioritization of child agency and decision-making in research can have long-term positive outcomes for children into adulthood. The field of psychology broadly supports the importance of consideration of child agency, beginning especially with Ryan and Deci’s self-determination theory (Deci and Ryan, 2013). Self-determination theory argues that social contexts that support a child’s agency “facilitate the development of intrinsic aspirations, support high-quality relationships, and yield psychological wellbeing” (Deci and Ryan, 2013). The existence of autonomous environments early in a child’s life will often set them up for a successful future. Other studies agree supporting a child’s burgeoning agency helps guarantee their right to make embodied choices throughout their life and become securely individuated (Fox and Thomson, 2017). Research also shows that children who lacked informed agency in clinical settings early in life can face long-term trauma outcomes such as post-traumatic stress disorder (Alderson, 2023). The practice of respecting child agency in a research study setting, which is low in stakes but high in choice variety, can encourage children to practice confident and informed decision-making in other settings such as medical and healthcare spaces, as well as different situations throughout their life.

6.4. Lesson 4: Consideration of child agency in research is an opportunity for improving research practices and data quality

While our primary motivation for respecting child agency in the research context surrounds the presumed impact on the child’s experience and self-esteem, we note that providing children with a positive experience may have ancillary benefits to the research study. A child’s experience at study visits can greatly affect the child’s interest in study continuation and their family’s perception of the study and of research participation in general. It is our experience that caregiver-child dyads who trust that study staff will recognize and respond to the child’s cues are more likely to continue to participate in the study visit, even if the child becomes distressed during a portion of the visit. Similarly, families who express having an enjoyable time at their visit are more likely to return for subsequent visits. Retention is essential for identifying trajectories and determinants in longitudinal studies and thus these procedures may enhance data quality (Murray and Xie, 2024). A literature review on pediatric study retention strategies confirms the importance of fostering enthusiasm among child participants, including adding “fun” components for children, and using age-appropriate materials (Schoeppe et al., 2014). The literature also largely emphasizes building trusting relationships between study staff and participants as an effective means of encouraging participant retention (Ely and Coleman, 2007; Murray and Xie, 2024).

Longitudinal work presents an opportunity for researchers to get to know children’s preferences over time. Sociohistorical researchers have raised the question of how to maintain best ethical practices while sustaining dynamic, longitudinal relationships with participants (Neale, 2021). The concept of ethical mindfulness in longitudinal research is the active engagement of these practices, and a constant awareness of potential ethical concerns and implications (Thurman, 2015; Warin, 2011). This helps us address the external factors that can impact families in the duration of their participation. Thurman (2015) recommends recording ethical comments throughout the duration of longitudinal studies, for example in “off-camera observations” ranging from the passing of a loved one or certain medical issues that may impact the participant in a direct or indirect way. In the PEACH Study, we utilize a comprehensive spreadsheet, with a separate internal sheet for each timepoint, in which we document notes during and after each visit related to the child’s experience, preferences, and caregiver comments. The notes range from “child dislikes being touched” to “child did not tolerate EEG and caregiver would like to opt-out moving forward.” Collecting this information in a concise and accessible way allows study staff to be prepared for consequential visits and may promote increased rapport and positive experiences for child participants. Furthermore, these notes are utilized to ensure that children’s needs and preferences are respected over time.

Child comfort and enjoyment also bolster data quality by encouraging children to complete more tasks, finish tasks, and maintain their engagement. We provide age-appropriate gifts at the end of each study visit in addition to parent compensation to show our appreciation for both participants in the dyad, with the goal of leaving the child with an overall sense of enjoyment. By involving children in their own study visit, providing them with choices in materials like toys and snacks, and continuously adjusting assenting methods in accordance with neurodevelopment, we cultivate strong relationships with participants and reinforce children’s agency.

7. Consequences, challenges, and considerations for research studies

While we have highlighted the benefits of supporting children’s agency in research, there are limitations and challenges to be considered. It is imperative to consider the possible consequences that prioritizing child assent may have for data quality and completeness. We have noted that establishing trust and respect for child agency may increase participant retention, which is critical for longitudinal studies and allows the study to accurately capture trajectories of child development. However, on a measure-specific basis, higher levels of data loss may result from allowing increased flexibility related to children’s choices to participate. For example, if study staff follow a child’s dissent cues instead of waiting for a caregiver’s input or allowing a predetermined amount of time to pass, they may end the task early, ultimately omitting data from final analyses. On the other hand, building rapport and trust with a child (and their parent) may allow the visit to continue even after a brief period of upset and allow the child to complete subsequent tasks, even if one was skipped. This consideration becomes more complicated as children age. For example, a preschooler may articulate their fear, discomfort, or concern about possible task performance in anticipation of a task. If the researcher ends the task immediately, they may miss an opportunity to further explain the task to increase child comfort, to attempt administration, and possibly to be able to complete the task. This dilemma has been observed often by members of our study team across a variety of study tasks, and while we have found that it is best to take a personalized approach to deciding whether to continue with the study task, further research should investigate additional methods to elucidate these complexities.

Another challenge may occur when a child and their caregiver disagree about whether they want to continue a task or visit. We tend to expect caregivers to be their child’s advocate and help explain their child’s cues as they know them best. Sometimes, however, a caregiver encourages researchers to move forward with a task despite their child seeming to be uncomfortable. In these situations, it becomes difficult to rely solely on the caregiver’s report, and instead it may fall on the study staff to make a final decision about whether to proceed. This situation may arise when a caregiver feels some pressure to comply with study procedures or to provide data, even if they recognize their child’s distress. When working with caregiver-child dyads, staff should be aware of this potential difficulty and use their best judgment to proceed with study procedures only if the needs of the child are able to be met and communicate to caregivers that their and their child’s comfort is the study’s highest priority.

We have also encountered some study-specific challenges when it comes to assessing and responding to children’s assent and dissent. The PEACH Study’s measurement battery includes well-validated and widely used tasks some of which are designed to elicit individual differences in emotional responses (which may include feelings of frustration or fear) and recovery. As detailed above, we describe each task to the caregiver prior to the start of task administration, and we show the caregivers photos of any stimuli their child will be exposed to as part of the task. Based on this informed conversation with study staff (and/or on the child’s experience with the task at an earlier visit), some caregivers have asked that we do not administer specific tasks to their child. For participants who opt to participate after the task has been explained to them, the task procedures often provoke further consideration regarding how to gauge the extent of a child’s discomfort. For example, if a child is crying during a task in which we may reasonably expect them to cry, researchers must decide at what point the task should be stopped or how long to wait to see if the child will recover on their own. Despite our standard protocol, the timing of the decision to stop a task remains an ongoing challenge that requires a great deal of flexibility, adaptability, and understanding of each child. Further, some children may feel uncomfortable displaying outwards expressions of discomfort, especially in an unfamiliar setting. In this case, they may not tell their caregiver that they did not enjoy a procedure until after it was completed. This is unfortunately a limitation of all child assent processes, as researchers would not know that they should adjust their procedures if outward expressions of dissent are not observed. This complexity underscores the importance of actively involving caregivers in the assessment of child comfort.

8. Conclusion

In summary, our documentation of developmentally appropriate approaches to child assent in research will provide researchers with information to access when working with children (See Figs. 1 and 2). This resource seeks to address the wide variation within the developmental spectrum, increase both the child and caregiver’s involvement in their own visits, and support children’s developing self-esteem. These tools may also have the ancillary benefit of improving study participation and retention. When pediatric researchers take the opportunity to acknowledge a child’s level of understanding and value that child’s decision to participate, they uplift the child’s voice and opinion in a space typically controlled by adults. Children deserve to experience autonomous exchanges early in life. By utilizing developmentally appropriate assenting methods, researchers can create a healthy environment that benefits both the participating family and the research study.

Data availability

No data was used for the research described in the article.