Theory of Mind is subject of interest to psychologists, primatologists, and those interested in artificial intelligence alike. In a nutshell, having a Theory of Mind is indicated by being able to anticipate or "read the mind" of others. Humans use it every day to, for example, guess what their spouse is mad about, anticipate what their boss really wants to hear, or imagine what someone is thinking about their presentation. It's still up for grabs whether animals grasp a true Theory of Mind, but scientists interested in A.I. consider a Theory of Mind to be one of the hallmarks of true and useful intelligence.

That said, does Data have a true Theory of Mind? In many instances, Data is perfectly able to anticipate the thoughts and feelings of peers. In others, he is taken aback by his crew members' reactions to certain (especially emotional) situations. Perhaps Data is simply autistic, which adds another wrinkle to the TOM inquery.

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    An autistic android. Now there's a thought. That would mean that his/its programming malfunctioned and doesn't operate like it should, right?
    – Xantec
    Mar 27, 2012 at 15:45
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    I fear Autistic may not be being used correctly here...
    – AncientSwordRage
    Mar 27, 2012 at 15:59
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    According to the Theory of Mind Wikipedia page, autism is explicitly discussed as a condition where the theory of mind for an individual does not function correctly. So, the OP comment about autism is not entirely unfounded. Though strictly speaking, the manner in which Data functions may be similar to that of an autistic human, it is not a defect - it is normal for Data. Mar 27, 2012 at 16:13
  • “In a nutshell, having a Theory of Mind is indicated by being able to anticipate or "read the mind" of others.” Is it? I always thought it meant being aware that other people had a mind of their own, like your own. May 29, 2013 at 23:23

4 Answers 4


As you say, he can sometimes anticipate the thoughts of others (or at least their actions) and sometimes not. There are plenty of examples of both in TNG. So we know that he does have a Theory of Mind, and we know that it's not perfect-- no one's is.

There may have been a turning point at the beginning of "Star Trek: Generations" when data disastrously misapprehends a social situation, and decides it's finally time to install Dr. Sung's emotion chip:

LaForge: What ever possessed you to push her in the water in the first place?

Data: I was attempting to... "get into the spirit of things". I thought it would be amusing. Is she still angry?

LaForge: I'd stay out of sickbay for a couple of days if I were you.

Data: ...I believe my growth as an artificial life form has reached an impasse... I am unable to grasp such a basic concept as humor.

So when his attempts to construct a mental model of others seem to reach a limit, he tries to inherit a basic empathic model, the way human beings do. What he displays later is a combination of the two; he just acquired them in reverse order, intellectual first, then emotional.


Data definitely has a theory of mind. He is able to recognize that Picard has his own individual thoughts on what ought to be done during the events of Data's Day

Data voices over his prediction of the 17% chance that Captain Picard will call for advice from Starfleet, and is rewarded with Picard's call to red alert and an order to intercept the Devoras.

Of course, earlier in the same episode we see that it's not very good...

Keiko informs Data that she's unhappy, and that she would like to call off the wedding to Miles O'Brien, and that this decision would make her happy. In the mistaken belief that making Keiko happy by canceling the wedding will make Chief O'Brien happy, Data allows himself to be talked into taking the "bad" news to O'Brien, who reacts entirely opposite to Data's prediction.

But accuracy is not, I believe, a chief requirement for a true Theory of Mind exercise - in both instances, he is able to imagine the thoughts of others, whether accurately or inaccurately. His lack of accuracy in this case is owing to his inexperience in such matters (Data has never been a bride, and has very little relationship experience). One could liken his lack of experience to childlike innocence.

In short, Data does exercise a Theory of Mind, though because of his unique nature and 'upbringing', he sometimes has trouble getting an accurate 'read' on a person.


I believe that yes, Data did have the presence of Theory of Mind. Data's only problem is that he was limited in what he was able to anticipate due to not fully understanding people. Namely, he did not understand emotions. As Thaddeus pointed out, this was a planned design feature when Doctor Soong built Data, although Soong had planned to add this feature later. Should the Enterprise have found a race of beings that truly had no emotions (Vulcans do not count), Data likely would have been able to relate to them perfectly.

Keep in mind, that while you may be tempted to write off Data's appearance of a Theory of Mind as being simply fancy programming, our own Theory of Mind may be nothing more than fancy organic programming.

Data's brother, Lore, did have emotions from the start. He, however, used his physical and mental superiority to prey upon the humans of Omicron Theta. One could say that he had a "super" Theory of Mind, and used it to maximum advantage in tormenting people. (Lore's actions led to Dr Soong's choice to leave emotions out of Data at the start).
Lal, Data's daughter, did not have emotions from the start. Her ability to experience emotions were a side-effect symptom of her neural network degrading. Whether this gave her an advantage when anticipating emotional human behavior or not is speculative, as she did not last long after this point (in fact she went directly to Data's lab without speaking to anyone).
As for the android Julianna, she was a much more advanced model. Built to not only act like a human (emotions and all), she was designed to fool medical apparatuses (transporters included) into returning bio-signs. But more than just having additional hardware, she also had had the memories of her biological namesake implanted in to her. Aside from biological/synthetic differences, this android was as human as they come (notwithstanding the enigmatic "soul"). She likely had a perfectly fine Theory of Mind, helped by having been formed from when she was a living biological human.


I would say that Data's Theory of Mind is incomplete and was intentionally left so.

He was designed to be an aid to Dr. Soong, not to stand as a complete individual. As such, Data was not designed with a personality, nor was he given the ability to perceive and anticipate other human responses. These were not part of his core subroutines. Data is first and foremost a hyper-sophisticated piece of hardware and software programming.

As he began to evolve his program, he tapped into the heuristic algorithms that allowed him to continue to learn and engineered himself to be able to take on other personalities as he does in the holodeck. These subroutines had to be modified to work with his positronic brain, and likely did not exist before he created them (seeing as there were no other positronic brains that needed said programming before he did.)

Wikipedia reference:

Before the emotions chip, Data was unable to grasp basic emotion and imagination, leading him to download personality subroutines into his programming when participating in holographic recreational activities (most notably during Dixon Hill and Sherlock Holmes holoprograms) and during romantic encounters (most notably with Tasha Yar and Jenna D'Sora). Yet none of those personalities are his own and are immediately put away at the conclusion of their usefulness.

He would remove such sub-routines at the end of his sessions, the same way we would remove clothing designed for an event such as skiing. Useful for the entertainment but hindering otherwise.

The problem with Data and his development is that it was artificially inhibited by Dr. Soong. His cognitive abilities are a result of his programming, first and foremost. He does have a learning AI but before he integrates his emotion chip, he had reached the limits of his heuristic programming and could make no further leaps, as limited by the programming he received. He was designed to be limited, likely as a safeguard against his being perceived as "too human." He was designed to assist, not replace humanity. His ability to develop a Theory of Mind was likely not part of his original programming as that would be beyond the scope of his design.

In that regard, Dr. Soong failed. Despite all of his efforts to keep Data a cold, logical, efficient piece of machinery, his efforts to make his device, "user-friendly" would eventually lead it to developing a personality and eventually to mimic in every way imaginable the very humanity he sought to exceed.

I considered it strange Dr. Soong would develop the emotion chip but then I remember the Lal incident (Data attempts to recreate a positronic brain but imbues it with emotional capacity). Lal later dies (ceases to function) when fear overwhelms her. Perhaps Dr. Soong already know his design was incompatible with emotional input and the emotion chip is held outside of the main brain, isolating the emotion information required to function.

It can be assumed that later designs including the android Julianna Soong (incorporated an entire suite of emotion modules) which allowed her to appear perfectly human. Would that include a Theory of Mind. Perhaps. Or perhaps it simply created the illusion based on the programming subroutines similar to ones used by Data in the holodeck. For all intents and purposes, it would appear to a normal human to be the same thing.

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