Computer scientist Joseph Weizenbaum died earlier this month, reminding us that his most famous creation, the computer program ELIZA, lives on. Weizenbaum created ELIZA in the mid 1960’s as a model of “natural language” interaction between a human subject and a computer. ELIZA mimics a talk therapist, rephrasing statements made by the user as open-ended questions, encouraging further discussion. Weizenbaum named his program after Eliza Doolittle, the famous subject of Henry Higgins’s tutelage in the play Pygmalion (more popularly known for its musical adaptation, My Fair Lady).

Of course, this human-computer interaction only works to a point, as ELIZA has no real understanding of what the user is saying — it’s just parsing the user’s responses into a series of canned responses. Depending on how you respond to ELIZA’s questions, you may have a reasonable conversation for several lines, but at some point it will make a strange misstep, tipping you off that there’s no intelligence on the other end. For example, here’s a conversation I had with an online version of ELIZA:

> Hello, I am Eliza.

* Hello.

> How are you today.. What would you like to discuss?

* My coffee is really bitter this morning.

> I’m not sure I understand you fully.

* Well, okay — so I made some coffee and I think I did it wrong. It tastes bad.

> Do you really think so?

* Yes.

> Are you Sure?

* Yes, I’m certain.

> Do you believe it is normal to be certain?

* Um…yes?

> Are you Sure?

* Yes, I’m sure.

> Do you enjoy being sure?

ELIZA elicited interesting responses from users in the 1960’s. From the Wikipedia article on ELIZA:

In the article “theNewMediaReader” … he references how quickly and deeply people became emotionally involved with the computer program, taking offence when he asked to view the transcripts, saying it was an invasion of their privacy, even asking him to leave the room while they were working with ELIZA.

…

Lay responses to ELIZA were disturbing to Weizenbaum and motivated him to write his book Computer Power and Human Reason: From Judgment to Calculation, in which he explains the limits of computers, as he wants to make clear in people’s minds his opinion that the anthropomorphic views of computers are just a reduction of the human being and any life form for that matter.

You can try ELIZA yourself — see how far you can take a decent conversation! I like this online version (which, amusingly, offers me ads for psychotherapy in my hometown), or check out this list of other implementations. Computer science students should check out Weizenbaum’s original paper on ELIZA.