There are interesting commonalities and contrasts between the four DISC styles.  In this blog, I’d like to compare D’s and I’s with S’s and C’s.  Then, we will look at D’s and C’s with I’s and S’s. 
In his book, The Emotions of Normal People, William Marston explained that D’s and I’s perceive themselves as more powerful than forces in the environment, while S’s and C’s perceive themselves as less powerful.  This dichotomy formed the foundation for the split between D’s and I’s versus S’s and C’s.  Additional ways to look at this dichotomy includes: 

More powerful than the world Less powerful than the world
More assertive Less assertive
Verbal Reserved
Control Adapt
Tell Ask
Extrovert Introvert
Act Plan
Fast-paced Even-paced
Big-picture (general) Detail-oriented (specific)
Spontaneous Planned
Bold (risk-taking) Thoughtful

William Marston also discussed the difference between D’s and C’s versus I’s and S’s.  In this case, he described the environment as either favorable or unfavorable.  He explained that favorable environments are supportive of the person, such that the individual can feel comfortable in them. Unfavorable environments are antagonistic to the person, whereby the person feels challenged by them.  In his view, D’s and C’s viewed the environment as unfavorable, while the I’s and S’s viewed the environment as favorable.  Other ways of looking at this dichotomy include: 

World is hostile World is friendly
Task People
Detach Affiliate
Questioning Accepting
Logic-focus People-focus
Challenging Agreeable
Skeptical Receptive
Autonomy Affiliation
Goal Oriented Relationship Oriented
Function Form
Words Style (Tone/ Body Language)
Business first Rapport first

By considering the dichotomies of the DISC styles, we gain greater insight into the similarities and differences of what makes each style tick.