Part-black Generally Means All-black In Americans' Minds.

Identical Twins Are Ideal Lab Specimens For Studying The Difference Between Learned And Inherited Traits Since They Come From The Womb Preloaded With Matching Genetic Operating Systems. Any Meaningful Differences In Their Behaviors Or Personalities Are Thus Likely To Have Been Acquired, Not Innate.

Certainly, People Can Get Along Without Siblings. Single Children Do, And There Are People Who Have Irreparably Estranged Relationships With Their Siblings Who Live Full And Satisfying Lives, But To Have Siblings And Not Make The Most Of That Resource Is Squandering One Of The Greatest Interpersonal Resources You'll Ever Have.

The Mind And The Body Are Inextricably Entwined, And Rarely Are Their Inseparability Clearer Than When We're Under Some Kind Of Mental Pressure. The Moment We Start Trying To Learn A New Skill, Make A Decision Or Otherwise Think On Our Feet, Our Nervous System Reacts - With Accelerated Pulse Rate, Increased Respiration, Even Sweating.

When We're Awake, Cortisol Can Fragment Memories - One Reason Eyewitness Crime Scene Accounts Are So Unreliable. But At Night That Very Fragmentation Allows Creative Recombinations Of Ideas.

The Vexing Thing About Human Behavior Is That When We Say We Know We Should Do Something, We Really And Truly Do Know It. It's Hard To Be 50 Lbs. Overweight Or Smoke A Pack A Day Or Feel Miserable Every Moment You Spend At Work And Not Understand In A Deep And Primal Way That Change Is In Order - And That In Some Cases It Could Even Save Your Life.