The Difference Between Saying "I Don't" versus "I Can't"

This article reveals the drastic affect of saying "I don't" do something such as eating a tempting snack or skipping an exercise session versus saying "I can't" allow myself to eat that snack or skip my workout. The author explains why.

Monitor your immediate emotional reactions and you'll probably see what's going on. The "can't" framing implies an external restraint, which feels disempowering (even if you imposed the restraint on yourself). You might even be tempted to disobey solely to assert your independence. To say that you "don't" do something, by contrast, suggests autonomy, as well as long-term commitment.

 Be sure to check the links in the article for the research behind this conclusion.

UPDATE:

James Clear talks about the research that explores the difference in how our minds react to saying "I can't do X" versus saying "I don't do X." 

In a research study published in the Journal of Consumer Research, 120 students were split into two different groups.

The difference between these two groups was saying “I can't” compared to “I don't.” 

One group was told that each time they were faced with a temptation, they would tell themselves “I can't do X.” For example, when tempted with ice cream, they would say, “I can't eat ice cream.” 

When the second group was faced with a temptation, they were told to say “I don't do X.” For example, when tempted with ice cream, they would say, “I don't eat ice cream.”

Heidi Grant Halvorson, director of the Motivation Science Center at
Columbia University, explains why this happens.

“I don’t” is experienced as a choice, so it feels empowering. It’s an af rmation of your determination and willpower. “I can’t” isn’t a choice. It’s a restriction, it’s being imposed upon you. So thinking “I can’t” undermines your sense of power and personal agency.