The following excerpt comes from an article entitled Aliens might not be friendly, warns astronomer which is to be found here in the Telegraph online
Professor Simon Conway Morris, a Cambridge University evolutionary biologist, will be talking at the Royal Society on 'Predicting what extraterrestrial life will be like – and preparing for the worst."
He thought that, given that the principles of Darwinian evolution should be universal, it was "inevitable" that intelligent life would have developed elsewhere in the universe given the right environmental conditions.
"If that is correct – and it applied to manipulative skill – then that suggests there should be alien technologies," he said.
Some scientists are puzzled as to why no messages have been sent back even though humans have been transmitting radio and television signals for the last century.
Prof Conway Morris reasoned that if he were in their shoes "I'm not sure I'd answer the telephone."
One might quip that if aliens had been investigating the origination point of the messages we've been sending they may have themselves abandoned all hope of finding intelligent life elsewhere in the Universe.