According to the reformulated learned helplessness theory, an individual's attributional style for life events is a key factor in the development of depression. This style is characterized by three dimensions of explanation for an outcome: internal vs. external (attributing the cause to personal factors or situational factors), stable vs. unstable (viewing the cause as permanent or changeable), and global vs. specific (seeing the cause as affecting all areas of life or just one). Research indicates that individuals who consistently make internal, stable, and global attributions for negative events perceive a greater lack of control, which increases their vulnerability to developing depression.