We have discussed in the previous chapters the importance of the home and neighborhood environment for thriving development. In this section, we will discuss many topics for the first time such as autism and ADHD and we will continue our conversation for other topics such as sleep quality and nutrition access that impact cognitive development in the preschool years. Let’s start our conversations with factors found within the home environment and proceed with those that are influenced at both home and neighborhood environments.

7.15.1 Screen time

Our world is surrounded by screens and some children have an extensive exposure to these at home, school, and many other places. Screens are easy to access and parents are using them more and more for both activities and entertainment. But are screens good or bad for children? Research thus far shows that the use of screens can be beneficial to children at some level such as using these for educational purposes (Radeskey et al., 2015), however, the prolonged use of screens has also been linked to many negative developmental health outcomes including behavior problems (Tamana et al., 2019), speech delays (van den Heuvel et al., 2019), lower executive functioning (Kostyrka-Allchorne et al., 2017), academic problems (Adelantado-Renau et al., 2019) among many others. Nonetheless, it seems that both negative and positive effects depend on the age of exposure, the purpose of usage, and the duration of use (Kerai et al., 2022). Evidence-based guidelines recommend limiting the use of screen time to one hour daily for children under five years of age. Screen time includes the use of television, smart phones, tablets, computers, and video game consoles. Kerai and colleagues (2022) found that children that used screen time for more than one hour daily were more likely to be at risk in all five developmental domains including language and cognitive development and communication skills.

7.15.2 Sleep

Adequate sleep is crucial for thriving development as it is a building block of multiple developmental domains. Sleep has a direct impact on alertness and attention, cognitive performance, vocabulary development, and learning and memory, especially in early childhood (Zhou et al., 2015). Yet, the American Academy of Pediatrics estimates that about 25 percent of children are impacted by sleep problems (Mindell & Owens, 2015). So, what happens when a child does not get enough sleep? If you ask a parent, they will tell you that if their child does not get adequate sleep, they might be grumpy, unfocused, or hyperactive. But, what do we mean by adequate sleep? Evidence-based recommendations by the American Academy of Pediatrics include 11 to 14 hours for 1-2 year olds, and 10 to 13 for 3-5 year olds.

Now that we have discussed screen time and sleep, let us discuss the intersection of the two. As we just learned, both sleep and screen time impact cognitive and language development in early childhood. Screen time, especially right before bedtime, affects sleep quality and quantity. The use of screens before bedtime can impact alertness, therefore preventing children from being able to relax during bedtime. Additionally, nighttime screen use impacts children’s ability to fall asleep, increases wakings and nightmares during the night, and causes sleepiness during the day. For example, Garrison et al., (2010) found that children between the ages of 3 and 5 had trouble sleeping when they had screen time after 7 p.m. Furthermore, the results showed that the amount of violent content in the program or game appears to be a contributing factor too.

7.15.3 Nutrition

We have discussed previously the importance of adequate nutrition for thriving cognitive and language development. So, what do we mean by adequate nutrition? Essentially, brain development requires a well-balanced diet including proteins, fats, carbohydrates, vitamins, minerals, and water to maintain proper functioning. Nonetheless, many micronutrients including iron, zinc, choline, iodine, folate, B12, among many others have been identified to play a special role in cognitive development (Bourre, 2006). It is estimated that almost 11 percent of children aged 5 and under experience food insecurity (Ullman et al., 2022). As you can imagine, most of these children, if not all, live in low-income households. Therefore, interventions targeting food insecurity are fundamental to cognitive development in early childhood.

7.15.4 Mental Health

In this section, we will discuss several common mental health issues that may start to emerge in the preschool period. All these conditions can have an effect on cognitive and/or language development. For example, attention-deficit hyperactivity disorder (ADHD) is linked to impaired cognitive development (Coghill et al., 2014) in early childhood and autism spectrum disorder (ASD) is associated with difficulty developing language skills (NIH, 2020). Let’s dive in!

7.15.4.1 Attention Deficit Hyperactivity Disorder

According to the Centers for Disease Control and Prevention (CDC), ADHD is one of the most common neurodevelopmental disorders in early childhood. However, thriving preschoolers are full of energy and can appear rumbustious, inattentive and hyperactive at times. Therefore, the line between typical developmental changes and symptoms of ADHD is blurry. This makes ADHD difficult to diagnose. Nonetheless, children with ADHD might experience trouble paying attention, with impulsivity (acting without thinking of consequences), and they might be overly active (CDC, 2022). Let’s discuss common signs and symptoms of ADHD.

First, keep in mind that it is typical of thriving preschoolers to have trouble focusing and behaving at times. Children are constantly learning, evolving, and developing. However, children with ADHD do not grow out of these behaviors, the symptoms not only continue, but they can cause difficulties at home, school, and with relationships. A child with ADHD might daydream a lot, forget or lose things often, squirm or fidget, have difficulty getting along with others, and may have trouble resisting temptation (CDC, 2022).

There are three different types of ADHD. However, symptoms and the presentation may change over time. Below, we briefly discuss them:

Predominantly inattentive presentation – children with this type of ADHD have difficulty organizing and finishing tasks, paying attention to details, or following instructions and conversations. Daily routines and remembering details is difficult too.

Predominantly hyperactive-impulsive presentation – children fidget and talk a lot with this type of ADHD. It is difficult to sit still for long, and younger children may jump, run, climb, and move their extremities constantly. Restlessness and impulsivity may be common and a child with impulsivity might get injured or have more accidents than others (CDC, 2022).

Combined presentation – symptoms of the other two types are equally present in a child.

You might be wondering, what are the causes of ADHD? Although scientists are actively researching the cause(s), risk factors, and better ways to treat, manage, and prevent this condition, the cause(s) and risk factors are still unknown. Current research shows that genetics may play a role (Faraone et al., 2021). However, in addition to genetics researchers are studying brain injury, environmental exposure during pregnancy or at a young age, substance use during pregnancy, premature delivery, and low birthweight among others (CDC, 2022). Nonetheless, research does not support popular and somewhat controversial views that ADHD is caused by high sugar consumption, too much screen time, parenting, or social and environmental factors including poverty or family dynamics (CDC, 2022). Yet, many things, including the ones mentioned above, can worsen symptoms, especially in certain children. But the evidence is not strong enough to determine that these are the main causes of ADHD (CDC, 2022).

7.15.4.2 Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disability caused by brain differences that can cause major social, communication, and behavioral challenges (NIH, 2020). But before we dig in, let’s explain what we mean by spectrum. Children with autism present a wide range of symptoms, skills, and level of impairments. Therefore, spectrum here refers to this wide range among people with autism. Children with ASD may experience various levels of difficulty with language development, and comprehension. Additionally, they may experience difficulty with nonverbal communication such as body language, eye contact, and facial expressions (NIH, 2020). Some examples of signs and symptoms related to ASD include avoiding and/or not maintaining eye contact, does not show facial expressions like happy, sad, angry, or surprise, ignores other children and they do not play or interact with them, they do not sing, dance, or act among many others (CDC, 2022).