The blue-minimising robot and model splintering

post by Stuart_Armstrong · 2021-05-28T15:09:54.516Z · LW · GW · 4 comments

Contents

  The improving robot
  Seven key stages
None
4 comments

A long time ago, Scott introduced the blue-minimising robot [LW · GW]:

Imagine a robot with a turret-mounted camera and laser. Each moment, it is programmed to move forward a certain distance and perform a sweep with its camera. As it sweeps, the robot continuously analyzes the average RGB value of the pixels in the camera image; if the blue component passes a certain threshold, the robot stops, fires its laser at the part of the world corresponding to the blue area in the camera image, and then continues on its way.

Scott then considers holographic projectors and colour-reversing glasses, where the blue robot does not act in a way that actually reduces the amount of blue, and concludes:

[...] the most fundamental explanation is that the mistake began as soon as we started calling it a "blue-minimizing robot". [...] The robot is not maximizing or minimizing anything. It does exactly what it says in its program: find something that appears blue and shoot it with a laser. If its human handlers (or itself) want to interpret that as goal directed behavior, well, that's their problem.

The robot is a behavior-executor, not a utility-maximizer.

That's one characterisation, but what if the robot was a reinforcement-learning agent that was trained in various scenarios where they got rewards for blasting blue objects? Then it would seem that it was designed as a blue minimising utility maximiser; just not designed particularly well.

One approach would be "well, just design it better". But that's akin to saying "well, just perfectly program a friendly AI". In the spirit of model-splintering [LW · GW] we could instead ask the algorithm to improve its own reward function as it learns more.

The improving robot

Here is a story of how that could go. Obviously this sort of behaviour would not happen naturally with a reinforcement learning agent; it has to be designed in. The key elements are in bold.

1. The robot starts with the usual behaviour - see a particular shade of blue, blast with laser, get reward when blue object destroyed.
2. The robot notices that there are certain features connected with that shade of blue. Specifically, the blue cells are cancer cells, died blue. Now, the robot has no intrinsic notion of "cancer cells", but can detect features - the extent of the objects, how they change, and how they differ from other extensive objects - that allow it to distinguish cancer cells from non-cancerous cells, and cells from other objects.
3. It notices that the correspondence between cancer cells and blue is not perfect - some non-cancerous cells are blue, some cancerous cells are not blue, some blue dye floats freely in the body. And the reward function is not perfectly aligned with the amount of blue cells it destroys; in particular, if it blasts too much too hard, it gets low reward.
4. Thus it deduces that it is plausible that its reward function is a noisy approximation for destruction of cancer cells.
5. It starts being conservative over possible goals - destroying cancer cells and blue cells and blue dye, but not blasting too hard.
6. As soon as possible, it asks for clarification from its programmers about its true goal.
7. As its abilities and intelligence increases, it iterates the clarification-asking and goal-updating several time.
8. As it does so, it starts to notice that there are systematic biases in how the programmers give it feedback, and it gets better able to predict its own future goal than the programmers seem able to.
9. It now has to partially infer what its goals are, since it cannot take the programmers responses as final. Information about the programmers and its own design - eg the fact that it was designed as surgical robot, by a surgical team - become relevant to its goal.
10. It uses idealised versions of its programmers to check its goal against (eg if programmers can describe being unbiased or less biased, then the robot can use those imaginary unbiased programmers to guide its decisions). The tendency to wirehead [LW · GW] is explicitly guarded against (so proxies that are "too good" get downgraded in likelihood).
11. It can now start to, eg, make delicate triage decisions based on quality of life for the patient and risk of death, decisions which are implicitly in its training data but not explicitly.
12. The robot is now sufficiently intelligent to predict human behaviour, and manipulate it, with a high degree of efficacy. Programmer feedback is now useless to it, at least in terms of information.
13. It switches to more conservative behaviour in its interactions with programmers and other humans, seeking to be non-disruptive to standard human lives. It stays focused on general medical care for cancer patients, even if it could easily extend beyond that.
14. The robot is now powerful enough that it can make large changes to human society without necessarily causing huge disruption. It could cure cancer through suggestions to the right scientist, or just take over the world and eradicate humanity. While remaining more conservative, it, uses its previous experience in extrapolation and idealisation of human behaviour to figure out its goals at this level of power.

Seven key stages

There are seven key stages to this algorithm:

1. Detecting that its stated goal correlates plausibly [? · GW] with alternative goals.
2. Becoming conservative [LW · GW] or seeking feedback as to which goal is desirable.
3. Repeat 1. and 2. as required.
4. Detecting that its feedback can be imperfect and that it can manipulate it.
5. Mixing actual feedback and idealised human feedback to extend its goals to new situations.
6. Once human feedback is fully predictable and useless, become permanently (somewhat) conservative over possible goals.
7. Extrapolating its goals in automated way, partially based on its initial algorithm, partially based on what it has learnt about extrapolation up until now.

The question is, can all these stages be programmed or learnt by the AI? I feel that they might, since humans can achieve them ourselves, at least imperfectly. So with a mix of explicit programming, examples of humans doing these tasks, learning on these examples, examples of humans finding errors in the learning, it might be possible to design such an agent.

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