In my story, there is a puppet master who uses disturbingly realistic marionettes in his theater. His goal is to create a marionette that is wholly indistinguishable from a real person, aside from the strings. Currently, he is able to fully replicate the movements of a human being using a complex version of classic marionette control bars.

The puppeteer is unhappy with his current puppets, however, as they cannot express emotion in the same way as a real actor could. So, he has decided to use a flexible sheet stretched over a frame to emulate the face, with strings attached to the points where a normal face would warp to form emotions. These facial strings will be controlled by another set of control bars that his assistant will handle.

So, my question is, is it possible to fully emulate a human's facial expressions using a set of marionette control bars? If not, what is the maximum number of points the puppeteer can hope to control at one time?

  • 3
    $\begingroup$ Experiments like this have been done with humanoid robots and they have set a new meaning to "disturbingly realistic". There's an effect called the uncanny valley that makes an almost-but-not-entirely realistic puppet extremely creepy. It's also assumed to be the reason why some people are creeped out by clowns. $\endgroup$ – Elmy Jan 4 at 8:32
  • 1
    $\begingroup$ What technology level are you after? 21st century? $\endgroup$ – chasly from UK Jan 4 at 9:04
  • $\begingroup$ @chaslyfromUK the technology level shouldn't matter, but let's assume it is 21st century $\endgroup$ – Bewilderer Jan 4 at 15:10

There are a number of ways to approach answering this question and the most unnerving (no pun intended) aspect of it is that it is not explored how deep a range of emotions we are seeking to emulate. The very fact that it is claimed that all human movement can be simulated through the use of control bars implies that there is some simplification at work; can this puppet be manipulated in such a way that it can accurately play Chopin while seated at a piano?

How much extra effort would the puppeteer have to undertake by comparison to having someone perform it directly? One could argue that having a puppet emulate Chopin would take the puppeteer far more skill than it would take to play Chopin directly, and that's saying something.

So, back to facial expressions. If we think the fine motor skills of the human hand are tough to emulate with strings, then the subtleties of human expression would also be quite difficult. That said, let's go through the mechanics of it all.

There are 43 muscles in the human face, and these are largely controlled via 5 branches of a primary nerve line. Sure, these muscles do more than just demonstrate emotion; they're also used to blink eyes, chew food, etc. But for the purposes of this answer let's assume that we need all 43 to demonstrate emotions.

We do have some economies here. Most emotions involve using muscles in our face symmetrically, and we've already stated that there really are only 5 major branches of nerves that drive the face. Assuming therefore that we an limit the strings to around 10 (2 for each nerve line), it's possible to emulate some emotions via marionette control bars.

That said, unlike the fingers, you can't assume that gravity is your friend. When operating the fingers to play a piano, you can merely drop the string a little on the finger that needs to strike the key, and raise it again when the finger needs to come up. With facial muscles, it's not that simple. You might be able to do something similar with eyebrows, perhaps even with the nose to simulate distaste (turning up your nose), but the lips for example will need far more control, including lateral movements. Surprise will need you pushing the edges of the lips together, while the top lip goes up, the bottom lip goes down to form a crude 'O' with the mouth. Sadness needs the two edges to go down, but the middle of both lips to remain where they are. This is not as easy to manage without looking at emulating musculature rather than areas of the face like the mouth directly with strings.

If you emulate the musculature, you'll be capable of a wide range of facial expressions, but at the cost of a highly complex set of controls. Could a single person use them? I doubt it, but then I also doubt that a single person could control a marionette with sufficient precision and skill to play Chopin, especially given the complexity of control that would surround the hands alone.

The shortest answer I can give you is that the complexity of your control system directly correlates with the range and detail of emotional display possible. I suspect that your marionette's controls will fall somewhere within a happy balance between the two.


Going through the list of the facial muscles involved in facial expressions I count 21 different muscles.

Therefore to attempt mimicking facial expression there would be the need for at least 21 strings sets.

Assuming that each assistant can control 2 of them per time (1 per hand), it means there would be 11 assistants needed if all of them should be used in the same time.

So, the answer to your question depends on how complicate the design can be and how many people can work together in controlling the facial expressions of the puppet, together with how long can they train together to achieve synchronization of their actions.

  • $\begingroup$ A marionette puppeteer is not limited to one set of strings per bar, nor one bar per hand. They will often have at least two sets of strings on a single bar, where they can move the bar in a more complex pattern to control both at once. They also tend to do two-in-hand bars, but that number can be increased further by making the bars thinner without any noticeable decrease in control. $\endgroup$ – Bewilderer Jan 4 at 15:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.