You said “dialing” and that is what I did for about 50 years. Yes, back then we actually had dials on our phones. Round things with little holes in them. That was before they discovered electricity, so all the phones were run by kerosene. 
So, I always used my right index finger to dial. What else, the pinkie?
Now I still use that same finger to (dial) punch in numbers on any of my cordless phones and also my cell phone.
I’m 82.
I bet you had numbers near the low end of the range. My home number had a few that were aaaallllllll the way at the end of the dial, and sometimes your finger hurt from cranking a stiff dial around once, so you had to switch out for another number to give the index finger a break!
Pretty much the right thumb regardless of the corded/cordless/cell phone, 39.
If I’m using a land line, or a phone that is bigger than a cell phone I both my first and second finger on my right hand to dial the numbers. On my iphone, I use only my right pointer finger. I’m 23.
I still have a couple of dial phones, though they’re not connected.
I had a phone with an actual dial until about 9 years ago. It came with the apartment.
Say what you want about those old phones, but they sure were *sturdy *- you try using a modern telephone as a murder weapon!
As to the OP - I use my forefinger (35, never had a game console). I’ve been training myself to use my thumbs with my new touch-screen phone’s QWERTY keyboard, though.
Right index finger. I’m 45 (today!) and right-handed.
Happy birthday!
Right thumb, 36.
So people who use the index finger to dial, does this mean you hold the phone in one hand, then key with the other? I guess you would have to. That’s weird.
I use my thumb.
Why is that weird? It’s a normal human motion - like writing on a notepad.
Duh. It’s weird because I don’t do it.
Right thumb.
50 (and right-handed).
If it were truly dialling, I’d use my right index finger assuming I could spare it in the fight against the dinosaur that would surely be chasing me 
Right thumb for cell phone, right index finger for touch-tone or dial landlines. 26.
This thumb stuff is freaking me out and classified under things I really never wanted to know. I can’t imagine why you would use it if you have an intact index finger.
Thumb, 51, and have never touched a Nintendo game controller!
middle finger
For some reason I use my middle finger for stuff like wiping my eye or the phone.
Right index finger, 51 years.
Thumb for the mobile, right index finger for the cordless phone. Never played Nintendo, aged 55.
Not me man, I have strong**** fingers.
I’d forgotten, but there was an old joke, that said if you need operatior assistance, you put your finger in the operator’s hole. I was about 12 when i heard that and though it was hilarious. Something else in that joke instructed you to put your finger in the P hole. Oh, well.
If I’m just scrolling through my address book or recent calls, as is usual, I hold the phone in my right hand and use my right thumb.
If I’m actually entering a new number, I hold it in my left, and use my right index finger, because the number buttons are a little smaller and my thumbs are big.
I’m 32.
Our youngest son, age 6, has a habit of pointing with his middle finger. We’re trying to break him of it, lest he give offense sometime to a touchy adult.