It seems a smile goes a long way - especially if you're a robot.
People have a strong preference for robots with human-like features on their display screen, according to an Auckland University study.
Study leader Dr Elizabeth Broadbent from the university's Department of Psychological Medicine said that although it was not entirely logical, people tended to think robots were better at their work if they looked more like humans.
"People form ideas of what they can do based on what they look like and they think they can do more and do it better if they look more human-like,'' she said.
Robots have been depicted in human form in popular culture for decades, from the Jetsons' robot maid Rosey, to Star Wars' C3P0, Robocop and Metal Mickey.
This research appears to give some academic weight to these humanoid designs of fiction.
The majority of the 30 participants (60 per cent) preferred a robot displaying the most human-like virtual face over a robot with no face display (30 per cent) and a robot with silver-coloured simplified human features (10 per cent).
Advances in technology had meant robots were now being developed for services including healthcare roles such as monitoring blood pressure, Dr Broadbent said.
"It's important for robot designers to know how to make robots that interact effectively with humans, so that people feel comfortable interacting with the robots,'' she said.
"One key dimension is robot appearance and how humanlike the robot should be.''
Professor Bruce MacDonald from the university's department of Electrical and Computer Engineering said the research would help develop software that could be exported to robot manufacturers.
"What we're trying to do is develop the software for robots and work together with the people who make robots to make it into an export business,'' he said.
It was a relatively new area of research and more will have to be done to identify what characteristics people respond to the best, he said.
Although the research suggested people warmed to a robot with a human face, it was unlikely that we would see robots that looked and acted like humans, he said.
"It will be more expensive to make a robot more and more human like and it's not clear that people actually want that, because there's some evidence to say that if you make it too human like people might find it freaky.''
The study, a collaboration between researchers in health psychology and in robotics from Auckland University, was published this week in the online journal Plos One.