Have you just hit your foot daddy?
My own recent non-scientific experiment would concur with these findings. During some recent DIY maintenance I was distracted by my three year old daughter toddling towards the hole in which I was working, enough to hit my own foot with the sledge hammer I was using. Because of her presence I could not use the vernacular and I can testify it hurt more and for longer than if I had been able to explete. My pain was further compounded by her innocent questioning "Daddy, have you just hit your foot?" the answer through gritted teeth was "Yes darling I have" and, as I hobbled out of the hole "does it hurt daddy?" - it would have hurt a damned sight less had I been able to say "Of course is f@</ing hurts, oh sh1t and bl@@dy balls"!!!!! This is the real reason you never see young children on building sites.