Simple: After 7 shots you’re too damn drunk to know that you’re drunk.
Well ok, maybe not exactly. I, for one, have never taken any stock in the theory that certain types of drinks give you worse hangovers, etc, etc. But there are still certain indisputable truths: Shots are going to screw you up if you drink them like diluted drinks. Mix that same amount of alcohol with a carbonated beverage, drink it ALL in the exact same amount of time, and you’re going to get drunk even faster.
In the 4 beers case, I’m going to guess that your 4 beers just gives you TIME to gradually realize that you’re getting tipsy, and subsequently drunk. Do 7 shots and you’ll feel nothing for a while, but then it basically nails your head to the floor before you know what’s coming. (And at that point are you really going to know you’re drunk? Maybe.)
Now your one beer and 3 shots does have some scientific reasoning behind it. All that crap is sloshing around your stomach (assuming you drink them all within a reasonable amount of time), the carbonation is increasing the alcohol absorbsion rate slightly, so you’re going to get drunk “faster” but not BAM all at once. I’ll leave it to a former alcholic M.D. such as my father to give a more accurate answer.
Myself, I usually drink about 10-15 rum&cokes a night. Yeah usually I end up intoxicated. And yeah, I ALWAYS end up legally intoxicated. I used to drink beer, and Scotch occasionally. When I drank beer, I knew when I had too much. I felt it. When I drank Scotch, I was in the bathroom before I knew what was happening. shrug
[But I think a lot of it is in one’s own mind] wink