TRIESTE, Italy, April 24 An Italian neuroscientist and veterinarians have determined dogs show pleasure by wagging their tails more to the right while negative feelings get a lefty wag.Dr. Giorgio Vallortigara, a neuroscientist at the University of Trieste and veterinarians Angelo Quaranta and Marcello Siniscalchi at the University of Bari videotaped 30 caged family pets of mixed breeds over 25 days, with 10 tests per day.The dogs were shown four visual images through a slat of their cages of their owner, an unfamiliar human, a cat and an unfamiliar, dominant dog, The New York Times reported Tuesday.The most familiar image -- that of the owner -- evoked the most right-oriented wagging, while the dominant dog image elicited the most left-sided wagging, the report said.The study appeared in the March edition of Current Biology.Copyright 2007 by UPI