Depends on the circumstances. Listening to several voices at once is a challenge -it's natural to want to respond to everyone with eye contact and a sensible reply but too many cooks spoil the broth.
As for technology it's becoming increasingly clear to me that the younger generations can handle several machines at once with no loss of quality reponse. From computer to phone to i pad to blackberry to whatever's next on the conveyor belt!
If you have young family and they're hyperactive then adult energy levels drop and this can undermine concentration - you're so busy doing things for and with them you tend to lose the plot sometimes!
It's a wonder we're not all burnt out by the time we're 35!