Does cognitive theory expkain why a 4 year old might hzve regression while toliet training?

Toilet-training : after age 3 in an otherwise neurotypical child is a delay, usually behavioral, but sometimes medical in origin. Scolding, nagging, coercion, painful BM's or trauma.can cause regression. See http://www.healthychildren.org/English/ages-stages/toddler/toilet-training/Pages/Overcoming-Obstacles-While-Toilet-Training-an-Older-Child.aspx. If no medical cause or consequence, seek behavioral therapy.