To cut or tear that is the question

Should lettuce be cut with a knife or torn by hand? I know I know, life-altering stuff being considered here at gimme patience.

Growing up my mother who was by no means a gourmet cook but did watch Julia Child and Graham Kerr whenever possible always told me that lettuce should be torn into bite size pieces NOT cut with a knife. If she told me why that piece of information went out with the dishwater but to this day if I ever slice into a head of lettuce I can hear her in my head yelling 'NO! Use your hands! Put the knife away!'

I have eaten many many salads including some prepared by me and others at fancy schmancy restaurants where the lettuce has obviously been cut not torn. Which begs the question (ok, maybe not but work with me here): What is the proper way to prepare lettuce? I have never lost any sleep over this question but not too long ago Alton Brown did a show on salad and guess what? As he was about to take a knife to a head of lettuce there were sound effects of breaks screeching to a halt and he came in close to the camera telling all of us at home that he knows we are yelling at him to put the knife down that he's now suppose to cut lettuce but tear it into bit size pieces. My jaw dropped. It was like Alton incarnated mom. What was going on here? He then went on to explain the scientific reasoning (which I was too dumbstruck to retain) for the whens and whys you cut or tear the lettuce.

The bottom line was something like this. First, it depended on the lettuce and had to do with cell structure (that where I tuned out). Second, the types of lettuce that shouldn't be cut with a knife will simply have their cut edge turn brown quicker than normal. So, if you are going to eat the whole thing and are chopping it up, go for it. If you are willing to slice off the brown part next time you use the lettuce, go for it. If you don't care because its just the color and doesn't alter the taste, go for it. So, there you go. The it doesn't matters have it.

Personally, I think torn is prettier but that's just me.