Author: smackenz

Why Is Sleeping More Difficult for Some Children?

smackenz/ / Emotion, Haptic touch, Hearing, Interoception, Posts, Proprioception, Sensory Profile, Sleep, Smell, Taste, Vestibular, Vision

Although all brains perceive and process sensory information, people differ in how much sensory input it takes for their brain to respond. For example, some only notice vivid colours, while others are overwhelmed by soft pastels – without trying to actively change the colour by adding or removing light. These groups simply respond passively. Other people seek sensory input, sometimes even creating it themselves by fidgeting, and some become overstimulated by certain types of input and withdraw. Both of these groups respond actively. (See our blog for the crossmodal correspondences between the senses, Crossmodal brain plasticity and empowering of sensory abilities, Multisensory processing, Growing into one’s own body and How the internal senses may connect sight and sound). And, how the brain responds to sensory information, may also affect how well people sleep.

In this post, I have invited Assistant Professor, Büşra Kaplan Kılıç, University of Health Sciences, Turkey to write about how people’s responses to sensory information can affect their sleep. She calls it: “the hidden link between sleep and sensory processing.” Her research includes several scientific publications on sensory integration, sensory processing, and sleep.

The Hidden Link Between Sleep and Sensory Processing in Toddlers

Sleeping child - icons for loud and quiet noise above their head.
AI-generated illustration for SmartSense

When a baby or toddler has trouble falling asleep, it is often thought to be due to fussiness, habit, or excessive activity. However, science tells us that sleep is not only a state of rest, but also a process closely related to how the baby perceives the world. Especially in the first years of life, the connection between sleep and sensory development becomes quite important.

So, the question we should be asking is not, “Why aren’t they sleeping?”. But rather: Do children perceive the world the way we think they do?

How Do Children Perceive the World?

We constantly receive information from our surroundings: light, sound, touch, movement, taste, smell… Our brain filters and organizes this information and ensures we behave accordingly. This process is called sensory processing. Each individual has a different threshold value for these stimuli. Some of us can comfortably read a book in a crowded environment, while others may be disturbed by even the ticking of a clock.

Each child has a different sensory threshold: Child's head surrounded by icons for strong and weak sensory input.
AI-generated illustration for SmartSense

Similarly, some young children notice environmental stimuli immediately and experience them very intensely. Others notice stimuli later or ignore them. Some become distressed and prefer to avoid them. All these differences are part of children’s sensory profiles and are not problems in themselves. However, when these sensory characteristics are combined with a sensitive process such as sleep, challenging situations may arise. This suggests that sleep is not only a behavioral problem, but also deeply connected to the child’s biological makeup and sensory world.

We therefore conducted a study1, with 220 children aged 1-3 years, half with and half without sleep problems, to explore two key questions:

  • Do children with and without sleep problems have different sensory responses?
  • In which areas do these differences appear?

 

The results were quite surprising

Compared to their peers, the sensory profiles of children in the group with sleep problems differed from typical development in three areas.

  1. They had excessive sensory sensitivity

Children with sleep problems can be much more sensitive to sounds, visual stimuli, or touch. These children become irritated more quickly by stimuli in their environment and react more intensely. This can cause them to wake up at the slightest sound during sleep. Even small movements during sleep, such as turning or stretching, can cause rapid arousal in some children and make it difficult to maintain sleep.

  1. Their sensory avoiding tendencies were high

Some children may feel sensorially overwhelmed because they notice stimuli very quickly. This situation can increase the child’s tendency to avoid daily activities, starting with bedtime routines. A constantly avoiding and alert profile can cause the child to become restless during bedtime routines. For example, brushing teeth, putting on pajamas, and the characteristics of sheets and blankets can be overly stimulating.

  1. They exhibited intense low awareness behaviour

Another notable finding in the study was the low registration behaviour exhibited in response to sensory stimuli. In other words, some children needed more intense input to notice stimuli from their environment. These children may struggle to notice the calming stimuli in their environment (such as lullabies or gentle rocking). In this case, they may miss the relaxation signals needed to fall into sleep. Consequently, the transition to sleep can naturally take longer.

This study tells us that we should approach infant and child sleep problems from the perspective that “sleeping is difficult for them” rather than “they don’t want to sleep.”

Understanding sleep through the lens of sensory processing offers everyone a more nuanced and compassionate framework for supporting children and their families.

Recommendations

  • Consider sensory processing as part of sleep assessments. When observing a child with sleep difficulties, it may be valuable to reflect on their sensory profile. How does the child respond to sound, light, touch, or movement throughout the day? Sensory sensitivity, avoiding, or low registration patterns may help explain why falling asleep or staying asleep is challenging.
  • Think developmentally, not diagnostically. Sensory differences are part of typical developmental variability. Rather than labeling sleep difficulties as “problematic behavior,” interns and professionals are encouraged to view them as signals of how the child interacts with their sensory environment.
  • Reflect on the role of the environment. Sleep does not occur in isolation. Lighting, noise levels, textures, and routines can all interact with a child’s sensory thresholds. Understanding this interaction can support more individualized and supportive approaches in both educational and clinical settings.
  • Value interdisciplinary perspectives. Our study1 underscores the importance of collaboration between disciplines such as occupational therapy, psychology, pediatrics, and education. Addressing sleep difficulties through a sensory lens often requires shared perspectives and integrated support strategies.

See our blog for Activities; especially 88-90.

Some suggestions for further listening and watching:

– How do Parents Assess Their Child’s Sensory Profile?

– Sensory Processing Disorder

– Sensory Profile explained

– Understanding your sensory code

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1Kaplan Kılıç, B., Kayıhan, H., & Çifci, A. (2024). Sensory processing in typically

developing toddlers with and without sleep problems. Infant Behavior and Development, 76, 101981.

How the internal senses may connect sight and sound

smackenz/ / Art, Crossmodal correspondences, Emotion, Hearing, Interoception, Movement, Posts, Proprioception, Vestibular, Vision

Certain information is associated across the senses. Some of these crossmodal associations are shared by most people. For example, in the Bouba/Kiki-effect, more than 95% of people around the world match the spoken word “Bouba” with a rounded shape and the spoken word “Kiki” with an angular shape. Other crossmodal associations are subjective; while some people see colours when hearing music, others read braille in colour. And it seems these subjective associations between the external senses may be closely related to the internal senses. (See our blog for How anxious individuals perceive odours, Emotional perceptions associated with sound environments, and Growing into one’s own body.)

I have invited Dr Marina Iosifian, School of Divinity, University of St. Andrews to write this post about crossmodal associations between visual paintings and sounds. Dr Iosifian has contributed to several scientific papers and public outreach events on how the internal senses might create crossmodal associations between vision and hearing.

Have you ever noticed that certain colours seem to “fit” certain sounds? For example, dark red might feel like it matches a low, deep voice, while pink feels more like a high, light voice. These kinds of connections between different senses—such as sight and hearing—are called cross-modal associations. Researchers study them to understand how our brain brings together information from different senses to form a unified picture of the world, even though each sense works separately (our eyes only see, our ears only hear).

Why do these associations happen? One possible explanation involves emotion. For instance, dark red and a low voice might both feel connected to sadness, while pink and a high voice might both be linked to happiness or playfulness.

But emotions aren’t the only reason. Another explanation has to do with the body’s movements and sensations. For example, when people are asked to name two round tables—one large and one small—they often call the large one “mal” and the small one “mil.” This may be because of how our mouths move when saying these sounds: “mal” requires a wider, more open mouth shape, similar to something large, while “mil” involves smaller, tighter movements, like something small.

Girl in garden scene with a cat and a dog
The Garden Walk, by Emile Friant. Retrieved from WIKIART

In our study, we explored these bodily mechanisms—the ways our physical sensations and actions might shape how we connect sights and sounds—to better understand how cross-modal associations arise.

To explore these associations, we collected a set of sounds produced by the human body, such as the sound of someone drinking. We called these embodied sounds. To provide a contrast, we also included sounds that cannot be produced by the human body, such as electronic or synthesized sounds, which we called synthetic sounds.

Because we were interested in how sounds are connected with visual experiences, we also gathered a collection of images. These included two types of paintings: figurative paintings, which show recognizable subjects like people or objects (eg, The Garden Walk by Emile Friant), and abstract paintings, which do not represent specific things (eg, Sky above clouds by Georgia O’Keefe). We then paired the paintings with the sounds and asked our participants a simple question: “Does this sound and this painting fit together?”

Glowing horizon with fluffy white clouds below
Sky above clouds, by Georgia O’Keefe. Retrieved from Custom Prints, Georgia O’Keefe Museum

We found that embodied sounds were more often associated with figurative paintings, while synthetic sounds were more often linked with abstract paintings. This suggests that the body—and the way we experience sensations physically—plays an important role in how people connect what they see with what they hear.

Why might these associations occur? One possible explanation lies in the difference between concrete and abstract ways of thinking. Figurative paintings depict familiar, tangible things—people, objects, and scenes—so they may evoke more concrete thinking. Abstract paintings, on the other hand, invite a more imaginative or distant mindset.

Interestingly, previous research has shown that people tend to associate abstract art with more distant situations—whether in time or space—compared to figurative art. This idea is related to the psychological concept of psychological distance, where concrete things feel close to us and abstract things feel farther away. Our results suggest that this distinction between the concrete and the abstract may also shape how we connect sights and sounds.

Some researchers believe that psychological distance is one of the main concepts which can help us understand how the mind works. They developed the Construal Level Theory or CLT – which explains how our mental distance from things – called psychological distance – affect the way we think about them. Psychological distance can take many forms: something can feel distant in time (happening in the future or past), in space (far away), in social distance (involving people unlike us), or in hypotheticality (something uncertain or imaginary). It is suggested that people think about things that feel close to them—such as events happening soon or nearby—in a more concrete and detailed way. In contrast, things that feel distant in time or space, are understood in a more abstract and general way.

If abstract thinking is linked to distant, less embodied experiences, and concrete thinking to close, bodily ones, then the way we perceive and connect sounds and images may depend on how “distant” or “close” they feel to us psychologically. In other words, our sense of distance—both mental and sensory—may shape how we integrate what we see and hear.

Thus, the concept of abstraction offers valuable insight into how people interpret and understand the world around them. Art, in particular, provides a powerful way to explore these processes. Recent research suggests that engaging with beauty in art can encourage people to think in more abstract ways, making art an especially meaningful tool for studying perception and the connections between our senses.

See our blog for Activities; especially 85-87.

Some suggestions for further reading, listening, and watching:

Applying Bodily Sensation Maps to Art-Elicited Emotions

From Perception to Pleasure

From Sensory to Movement

How Does Your Body React to Art?

How Music Changes Your Mind

Processing Internal Sensory Messages

See What Your Brain Does When You Look at Art