In high school, we said things like, "Why is she dating him?" In later years, since we're all grown up and mature and stuff, we don't say anything -- but sometimes we still take a second look.

That's because, for the most part, couples tend to be fairly equal in terms of physical attractiveness. (Although I'm the exception that proves the rule; I married way over my head.)

That's why we -- and by "we" I mean shallow people like me -- notice when couples differ greatly in terms of physical attractiveness. (Oh, admit it. Sometimes you notice, too.)

According to research, people who get to know each other over time tend to differ to a greater degree in terms of physical attractiveness than couples who get involved within a month of meeting; those couples tended to be closely matched in physical attractiveness.

According to a co-author of the study,

"This study shows that we make different sorts of decisions about whom to marry depending upon whether we knew the person before we started dating.

If we start dating soon after we meet, physical attractiveness appears to be a major factor in determining such decisions, and we end up with somebody who's about as attractive as we are.

If, in contrast, we know the person for a while before we start dating -- or if we're friends first -- physical attractiveness appears to be much less important, and we are less likely to be similar to our spouse on the dimension of looks."

All of which makes sense. Physical attractiveness is a nearly reflexive decision; it only takes a second to realize another person looks good on the outside. It takes a lot longer to figure out whether they are attractive on the inside -- which, ultimately, is what matters. That's why almost everyone can point to at least one time when they started dating someone attractive... only to realize later that person was extremely unattractive on the inside.

And that's why all of us have hired people based on their initial "attractiveness" -- only to realize later that it was a mistake.

Take hiring for skills and ignoring attitude. On paper a candidate may be awesome. But skills and knowledge are worthless when they aren't put to use. Experience, no matter how vast, is useless when it is not shared with others.

The smaller your business, the more likely you are to be an expert in your field. Transferring those skills to others is relatively easy. But you can't train enthusiasm, a solid work ethic, and great interpersonal skills--and those traits can matter a lot more than any skills a candidate brings.

According to one study, only 11% of the new hires that failed in the first 18 months failed due to deficiencies in technical skills. The vast majority failed due to problems with motivation, willingness to be coached, temperament, and emotional intelligence.

(That's why, if you're ever in doubt, hire for attitude. You can train almost any skill... but it's almost impossible to train attitude.)

Of course finding out if a candidate lacks interpersonal skills and attitude takes time. You can't just look at credentials and experiences. You can't just make a snap "attractiveness" judgment. While the candidate who lacks certain hard skills may be a cause for concern, the candidate who lacks interpersonal skills and enthusiasm is waving a giant red flag.

Of course the same thing can happen in reverse. You may decide a candidate is unattractive on the surface -- but if you dig deeper, they may be perfect for your needs.

The sales whiz with an incredible track record of doubling revenues -- while also struggling to handle admin tasks in a timely manner -- won't immediately turn over a new attention-to-detail leaf just because you hire him. The programmer who refuses to work anything other than Dracula hours won't magically embrace a standard nine-to-five.

For some people, the work, and how they perform that work, is what matters most -- not the job.

You won't be able to change them.

But sometimes that's okay. Occasionally the right decision is to accept the total package. If you desperately need engineering skills, you might decide to live with a diva-like engineering superstar. You might decide to let Dracula's daughter work nights even if everyone else works normal hours, and communication will be less than optimal.

We've all hired people we just knew would be superstars... that turned out to be duds. We've all passed on people... who turned out to be superstars at another company. 

The best way to avoid that is to take the time to look inside -- because that, and not the shiny (or seemingly dull) exterior, is what matters most.