Does dressing casual lead to a more productive lifestyle?

No, dressing casually could cause an employee to feel less focused and alert says Dr. Karen Pine, professor of psychology at the University of Hertfordshire and fashion psychologist. 

“When we put on an item of clothing it is common for the wearer to adopt the characteristics associated with that garment. A lot of clothing has symbolic meaning for us, whether it's 'professional work attire' or 'relaxing weekend wear', so when we put it on we prime the brain to behave in ways consistent with that meaning.”

Research shows your alertness is affected by what you wear. This study found that people wearing a doctor’s lab coat displayed heightened attention. When the same people then wore an identical coat, but were told it was a painter’s coat, they weren't as attentive as when they wore (what they perceived to be) the doctor's coat. The research found: “The influence of clothes thus depends on wearing them and their symbolic meaning.”

“This theory supports the notion that we would stay more focused when wearing appropriate work clothes, and may be more cognitively alert than if we dressed down,” adds Dr. Pine.