People often yell as they feel a loss of control and are overwhelmed with a situation or person. Yelling is an expression of anger that very rarely solves the problem. Children know how to push the right buttons and always seem to choose the day to ignore or rebut your requests on a day when your stress levels are already heightened. For the most part, children will bounce back and complete the task required after they have been reminded.
However, there is also research to suggest that yelling affects children differently depending on the child and their demeanor.
Children tend to disregard the message being conveyed whilst being yelled at and tune out. Their focus is directed to the tone and volume of the voice, rendering the requests virtually useless. Children are usually more responsive when a message has been delivered clearly and calmly.