Introduction: When Small Objects Create Big Confusion
Have you ever observed a young child trying to ride a miniature toy horse? Or attempting to sit on one of the tiny chairs in a dollhouse?
At first glance, these behaviors may seem funny or strange. However, they actually reveal an important cognitive phenomenon in early childhood known as scale error. Scale error refers to situations in which children fail to grasp the size of a small object and interact with it as if it were a real-sized object (Casler et al., 2011). For example, a child playing with a toy car might try to sit inside it as if it were a ride-on car, or a child might attempt to wear a coat meant for their doll. These behaviors are classic examples of scale error.
This phenomenon provides valuable insight into how children perceive the physical properties of objects and how they organize action plans to interact with them.
The DeLoache Experiment: How Scale Errors Were Observed
DeLoache and colleagues (2004) designed a study involving three age groups: children aged 15–20 months, 20–24 months, and 24–30 months. Initially, the children were allowed to play with a slide, a car, and a chair that were all appropriate for their size. Afterward, the children were briefly removed from the room and then returned, at which point they were presented with miniature versions of the same objects.
The results were striking. Out of 54 children, 25 exhibited scale errors, producing a total of 40 scale-error behaviors. In other words, nearly half of the children attempted to use the miniature objects in the same way they had used the full-sized versions. The phenomenon was most frequently observed around the age of two.
These findings suggest that during early childhood, the integration between perception, action, and cognitive control is still under development.
Cognitive Explanations Of Scale Error
Researchers have proposed two main models to explain why scale errors occur.
1. Perception–Action Model
The brain contains two primary visual processing systems: the ventral system and the dorsal system (Goodale & Milner, 2006; DeLoache et al., 2004).
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The ventral system, often referred to as the “What?” pathway, is responsible for object recognition and identification. It is closely linked to long-term memory.
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The dorsal system, known as the “How?” pathway, processes spatial information and guides movement. It operates rapidly, in real time, and largely outside conscious awareness.
Research indicates that children who make scale errors do not have deficits in either system individually (Ware et al., 2005). Instead, the issue lies in a communication breakdown between the ventral and dorsal systems.
For example, after previously riding a full-sized toy car, a child encounters a miniature version. The ventral system correctly identifies the object as “a car.” However, the dorsal system retrieves an action plan associated with cars—such as sitting and steering—without properly adjusting for the object’s size. As a result, the child attempts to interact with the small object as if it were full-sized.
According to this model, scale error occurs because the child cannot yet inhibit or rescale the action plan triggered by object recognition.
2. Planning–Control Model
The Planning–Control Model emphasizes the timing of motor planning and execution (Glover, 2004).
In the planning stage, the brain creates an action plan based on prior experience and expectations. When a child sees a miniature toy car, past experiences with full-sized cars may activate the plan: “I should get into the car.” This stage relies on higher-level visual and cognitive processes.
During the control stage, however, the dorsal system uses real-time visual feedback to adjust movements. As the child approaches the miniature object, the brain may recognize that it is too small and attempt to correct the action mid-movement.
In this model, scale error arises during the planning phase rather than the execution phase. The error is often partially corrected once sensory feedback becomes available.
Comparing The Two Models
Both models explain why children struggle to translate visual information into appropriate actions, but they focus on different mechanisms.
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The Perception–Action Model attributes scale error to poor communication between the ventral and dorsal visual systems.
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The Planning–Control Model explains scale error as a mismatch between early action planning and later movement correction.
Together, these models highlight the developing nature of perception–action integration in early childhood.
Conclusion: What Scale Errors Teach Us About Development
Scale errors provide a unique window into how young children integrate mental representations with motor actions. These behaviors emerge because the neural systems responsible for perception, planning, and action are not yet fully coordinated.
As children grow, they gradually learn to align their actions with the physical properties of objects, refining both their cognitive control and motor planning abilities. What may appear to be a humorous mistake is, in fact, a meaningful indicator of healthy cognitive development.
References
Casler, K., Eshleman, A., Greene, K., & Terziyan, T. (2011). Children’s scale errors with tools. Developmental Psychology, 47(3), 857–866. https://doi.org/10.1037/a0021174
DeLoache, J. S., Uttal, D. H., & Rosengren, K. S. (2004). Scale errors offer evidence for a perception–action dissociation early in life. Science, 304, 1027–1029.
Glover, S. (2004). What causes scale errors in children? Trends in Cognitive Sciences, 8(10), 440–442.
Goodale, M. A., & Milner, A. D. (2006). One brain – two visual systems. The Psychologist, 19, 660–663.
Ware, E. A., Uttal, D. H., Wetter, E. K., & DeLoache, J. S. (2005). Young children make scale errors when playing with dolls. Developmental Science, 9(1), 40–45.