Despite becoming increasingly lifelike in appearance, robots
still have terrible body language, writes New Scientist's
Colin Barras.
But Bilge Mutlu and
colleague's team at Carnegie Mellon University, Pittsburgh, is
changing that with robots that "leak" non-verbal information
through eye movements when interacting with humans, according to
this article which first appeared on our
sister website New Scientist.
The eyes of a robot may not provide a window into its soul, but
they can help humans guess the machine's intentions.
Humans constantly give off non-verbal cues and interpret the
signals of others – but without realising it at a conscious level,
says Mutlu. The trembling hands of a public speaker betray their
nerves even before a word is uttered, while poker players leak
subtle signs such as eye flickers or twitches that can be used to
spot bluffers.
But when faced with a robot all our interpretive skills are
irrelevant. Robots leak no information, so it is virtually
impossible to read their intentions, which makes them hard to get
along with.
Video: Robots are easier to get along with when their
eyes signal their intentions
Dead giveaway?
Mutlu's team tested strategies to improve robot body language
using a guessing game played by a human and a humanoid robot. The
robot is programmed to choose one object from around a dozen
resting on a table, without making a move to actually pick it
up.
The human must work out the object it has mentally selected,
through a series of yes and no questions.
The 26 participants involved in the study took on average 5.5
questions to work out the correct object when the robot simply sat
motionless across the table and answered verbally.
In the second trial, it answered in exactly the same way, but
also swivelled its eyes to glance at its chosen object in the brief
pause before answering two of the first three questions. When faced
with a robot "leaking" information like that, the same 26
participants needed fewer questions to identify the correct object
– an average of just 5.0 and a statistically significant
result.
When the robot in question was the lifelike Geminoid with
realistic rubbery skin, around three-quarters of participants said
they hadn't noticed the short glances. But the fact their scores
improved suggests they subconsciously detected the signals, says
Mutlu.
Improved interactions
The study suggests that people make attributions of
intentionality and mental states to robots like they do humans, he
says, although apparently only as long as the robot appears to be
lifelike.
When the same experiment was repeated with Robovie – a less
lifelike robot with large glassy eyes – the participants'
efficiency at completing the guessing game was the same whether or
not Robovie took short glances at the chosen object.
Sylvain Calinon works on
human-robot interactions at the Swiss Federal Institutes of
Technology in Lausanne, Switzerland.
"From my experience I would say that some communication cues do
not necessarily have to be subtle," says Calinon. Simply giving
robots the ability to turn towards a user or nod during a
conversation are important for improving the efficiency and quality
of human-robot interactions, he says.
Calinon thinks that the subtle cues explored by Mutlu's team
could improve the quality of interaction further, although to be
most useful the robot would have to be able to "read" the human's
body language.
Mutlu presented his work at the
Human Robot Interaction 2009
conference in La Jolla, California, last week.