# Scale error

In developmental psychology, Scale error is a serious attempt made by a young child to perform a task that is behaviorally inappropriate for the object because of a mistaken difference in the perceived and actual size of the objects involved. The child does not consider the size of their body in relation to the object and may attempt to fit into miniature objects or toys. An example of this would be a child attempting to slide down a toy slide or attempting to enter and drive a miniature toy car.
This phenomenon was first documented and studied by DeLoache et. al in 2004. Recent studies have added to the wealth of knowledge on the topic including evidence of the prevalence of scale error outside of the laboratory, as well as investigations into the frequency of scale errors in children.

## Criteria for scale errors

For an action to be considered a scale error under the strictest definition, a child must:
* Perform or attempt to perform part or all of the actions done with the large object, on the smaller object.
* Make actual physical contact with the relevant body part.
* Perform the behavior with such seriousness that they are obviously not pretending; often the behavior is repetitive, and the lack of success becomes frustrating to the child.

## DeLoache study

Psychologists DeLoache, Uttal, and Rosengren conducted and documented the first study on the aspect of Scale Error. In their study children were introduced to large (normal-sized) objects and given a chance to familiarize themselves with them. Some children were also prompted to engage in play behavior with the objects. After several minutes, the large objects were replaced with smaller versions of the same object. In several cases, regardless of prompting, the child attempted to interact with the small object in the same way they would have interacted with the large object.
The researchers believed that the error was caused by a underdeveloped functioning between the part of the brain that controls the actual physical movement with the part that controls the planning of the action, as well as a lack of inhibition. When the child sees the toy chair the occipital lobe, the part of the brain responsible for seeing the object and planning the next action, is activated and recognizes the object as a part of the chair category, but does not take the size of the chair into account. Next, the motor cortex, which controls the physical movement of the action, recognizes the appropriate movement/action for a chair, and the child then takes "appropriate" action—attempts to sit in the chair. During this step the child performs the action proportionate to the miniature object, and thus is able to carry out precise movements. However, the step itself is initiated based on a larger mental representation.
In older more developed children, these steps are usually inhibited by recognition and integration of the true miniature size of the object into the child's action plan. The child in this case would then go about playing with the toy normally.
The study also found that if the child is given the choice, they will never choose to interact with the smaller object over the larger object.
According to surveys taken by the researchers, the phenomenon is not common; parents more often reported that their child did not engage in the behavior. It is speculated, however, that parents may not remember less striking errors or they may not have been present to witness them.

## Additional studies
### Rosengren et. al 2009

Additional studies were conducted to document and quantify how often scale errors were committed by children daily. Rosengren et. al (2009) instructed parent participants to observe their children and note when they engaged in a scale error. Parents were also instructed to differentiate between a scale error and pretense, or pretend play.
Rosengren et. al (2009) found that almost all parents documented an instance of scale error in their children. These results concluded that children will and do commit scale errors in early childhood.

### Ware et al. 2010

In order to provide evidence of scale error prevalence outside of the laboratory, Ware et al. (2010) conducted multiple studies to explore the presence of scale errors in children's daily lives.
Throughout 2 studies, researchers had participants complete internet surveys questioning if the participant had ever seen a child engage in a scale error. Responses were screened and in the second study participants were interviewed through a secondary phone call about the incident they had identified.
Ware et al. (2010) concluded that scale errors occurred both in and out of the laboratory setting. The study provided the first evidence of children making scale errors outside of the laboratory setting.

## Age

The frequency of scale errors seems to differ for children across age ranges. Across 18-30 month olds, frequencies of scale error peaked around 24 months.