People are โattracted to [โฆ] robots not because of the way they look, but because of the way they behave.โย โ Mari Velonaki, Ph.D., Director of Creative Robotics Lab, Univ. of New South Wales.
Does a robot have to look like a human to be humanlike? For decades, Disney animators have brought the illusion of life and emotion to animals, objects and even machines.
With some simple programming, your robot, too โ no matter its form โ can boost its humanness quotient. Here are 10ย techniquesย taken from a rich history of animation principles andย human-robot interaction research.
Ifย your robot has a head or eyes…
1) Blink.
Actor Haley Joel Osment has said that โDonโt blinkโ was anย acting trick he used toย transform himself into David, the uncanny robot boy in the movie A.I. Artificial Intelligence. According to this study, the average human blink rate is about 17 blinks per minute, while during conversation it increases to 26, and gets as low as 4.5 when reading. Check out thisย great blink animation tutorial to learn more about how to animateย natural-looking blinks. For example, opening the eyes should takeย slightly longer than closing the eyes, and blinks can even be used to show intention and feeling.
2) Avoid staring.
Researchers have found that, while eye contact is important,ย gaze aversion can make a robot look more intentional, thoughtful, and creative. Some simple rules for where to place your robotโs gaze include:
- look upwards when thinking
- look away occasionally when speaking
- look away in-between phrases, to show youโre not done speaking
- look at the other person when youโre finished talking, to indicate itโs their turn to respond.
3) Head-turn with a blink and a tilt.
Stretch your arms straight out to your sides and turn your head to look at one hand, then the other. Did you notice that you blinked during the head turn? Animators follow this simple rule when turning the head:
- add a blink, then
- tilt the head down slightly in the middle of the turn.
The head dip is related to the animation principle of movement in arcs.
If your robot speaks…
4) Hedge a little.
Adding extra words called hedges (โmaybe,โ โprobablyโ or โI thinkโ ) and discourse markers (โYou know,โ โjust,โ โwell,โ โlikeโ and โum.โ) increases the likeability of robots. ย Take, for example, this great line from Samantha, the artificially intelligent OS in the movie โHerโ, where hedges and discourse markers appear 5 times: โWell, I was thinking, we don’t really have any photographs of us. And I thought this song could be like a photo that captures us in this moment in our life together.โ
Sure you can’t, Hal.
5) Match the tone of voice to the content of the words.
When HAL 9000 said, โIโm sorry Dave. Iโm afraid I canโt do that,โ why did it sound so creepy? One reason might be because its words didn’t match its tone of voice. Based on Table 2 in this paper, the acoustic profile of HALโs famous words looks closer to โenjoymentโ than apologetic โsadnessโ. HAL didnโt sound sorryย at all! Beware text-to-speech systems that have happy voices as a default – aย robot apology may come off as insincere.
6) Express feelings, opinions, preferences.
Script writers are pros at writing interesting characters. Part of it is to define the characterโs backstory, including likes and dislikes, education, and so on. To use Spike Jonzeโs Samantha character once more, the A.I. constantly expressed her opinion and feelings, and even openly laughed:
- (Giving herself a name:) โI like the sound of it. Samantha.โ
- Samantha laughs, โYeah, there are some funny ones!โ
- โOh, I love this first one from Roger to his girlfriend. Thatโs so sweet.โ
- โYouโre being very stubborn right now.
If your robot moves…
7) Move back before going forward, move down before going up.
In animation, this extra motion in the opposite direction is called anticipation. For example, in this clip with Wile-E Coyote (from 0:36), we see him pull backwards before launching forward in pursuit of the Road Runner. Similarly, a ballerina bends at the knees downwards before leaping up into the air. Does your robot anticipate its movements, or lurch on forward?
8) Lead with bigger joints.
Letโs say that your robot is going to point at something with its arm. Is it simply a case of moving the end-effector from A to B? How do you make that simple movement look more humanlike? In animation, you use something called successive breaking of joints. The idea is to use the bigger joints first, so in this case: first, move at the shoulder, then the elbow, then the wrist, then finally the fingers (if your robot has them). Try it yourself!
9) Use motion for emotion.
Your robot doesnโt have a face? No problem – itโs still possible to use other cues to convey emotion. For example, to convey happiness, have your robot make large, regular movements. For sadness, make your robot movements small and slow with even timings. To show fear, give the robot jerky, small and fast movements at irregular intervals, away from the source of fear. Large, irregular and abrupt movements can convey anger, especially towards the object of anger.
Finally…
10) Add randomness.
1/f or โpinkโ noise is found in many biological systems. Itโs somewhat counter-intuitive to add randomness after making your robot controller as accurate as possible, but purposely adding randomness has been shown to increase the perception of humanness in computer systems. The Sibelius music composition software is also knownย to include random variations in volume to render its MIDI playback more natural. If possible, add randomness not only in interactions (e.g. different ways of saying ย โyesโ, such as โokayโ, โsounds goodโ, or โgot itโ), but also in timing (e.g. blink timings) and movement in space (e.g. gaze aversion to different places). Interestingly, some new robots have mechanical randomness โbuilt-inโ, such as those in the field of soft robotics. Just think – what if your robot never acted the same way twice?
This week marks the official launch of Make: Volume 39 โ Robotics, which drops on newsstands the 27th. Be sure to grab a copy at a retailer near you, or subscribe online right now and never miss another issue.
We are celebrating with five days of robot-related articles, pictures, videos, reviews and projects. Tune into this space for Robot Week!
ADVERTISEMENT
