Humans versus Jack (4)Computer Bridge 4: Jack Just Isn't Human(published in Dutch Bridge Magazine IMP February 2006)To gauge the playing strength of Jack, we matched him against seven strong Dutch pairs. This instalment covers the match against internationals Bart Nab and Gert-Jan Paulissen. Previous instalments reported Jack's success in the first six matches. The seventh and final match was against several-time Dutch champions Nab-Paulissen. Unfortunately, things didn't go as well as against Jack's other opponents. To start with, the laptop crashed and we had to make arrangements to play at a computer at the office of the Dutch Bridge Federation. A bad omen? Well, let's see. disadvantageAlmost all top players have the same disadvantage when playing against Jack (or any other computer program). They are not used to playing against a computer and they don't know what to expect. However, Gert-Jan Paulissen has a lot of experience with computer bridge. He worked for several years on 'Eindeloos Bridge' (endless bridge) a program known only in the Netherlands. Eindelos Bridge does not play nearly as well as Jack, but Paulissen learned a lot about the way computers 'think' (or rather, are 'taught to think'). So it is no coincidence that Nab and Paulissen, who played with poise and concentration, were able to exploit Jack's weaknesses. They beat Jack by a very large margin, 90-26, earning a well-deserved victory. We had organised the matches not only to gauge Jack's performance but also to discern where he failed with a view to improving the program. Thus we found it very interesting to analyse the match against Nab-Paulissen. One learns most from one's mistakes. Of course we knew about Jack's rigidity and credulity, but in the other matches these weaknesses proved nowhere as harmful as against Nab-Paulissen. When computers play against each other, these flaws matter little, but people are clever and flexible enough to take full advantage. Without minimizing the excellent performance of Nab and Paulissen, I would like to focus on Jack's errors. Perhaps such analysis can help us find solutions for the specific problems Jack encounters playing against clever human experts. For Jack to lose 90 IMPs (while winning only 26) in 28 boards is unusual for Jack. We found six categories to account for this extreme loss.
Most of the losses occurred in category F. Before looking at some
typical examples, I must explain how Jack 'thinks.' His programmers have
taught him to believe almost everything during the early stages of the
bidding, and to draw firm inferences from the opening lead. Isn't that
normal? If an opponent opens 1 Playing against other computers that are as reliable as he is, Jack can trust their bidding and opening leads to 'read' the cards accurately without need for mid-course adjustments. Against human opponents things are a bit different... watch and shiverIn the three deals that follow, Nab and Paulissen told some small 'lies.' Against their human peers, that would have had little effect, but Jack believed everything they told him. Watch and shiver! Example 1 (directions rotated):
1 2 West leads the However, Paulissen doesn't give up. He leads another diamond to West's ace, producing this ending, with declarer needing the rest of the tricks.
As you can see, West can give East a heart overruff. However, Jack led
the Why didn't Jack lead the Thus Jack lost 4 IMPs needlessly. Example 2 (directions rotated):
After East (Nab) opens 1
It is easy to see that Jack, who can afford to lose only one more trick,
will make 4 stupidWhy did he play so stupidly?Actually, it wasn't Jack but Jack's programmers who had erred. WE had specified the Nab-Paulissen opening leads as fourth-best from length and second-best from three small, so Jack assumed rigidly that West's plays of the ![]() ![]() If Paulissen deliberately led the Example 3 (directions rotated):
West led the Why in heaven's name didn't East unblock his ace? As always, there was
a reason. Jack's programmers had specified a 1NT 'overcall' as showing
about 15-17 HCP. Even allowing for a slight 'underbid,' Jack could not
'bend' enough to picture Paulissen with as much as 20 HCP. So East expected
to beat 3NT several tricks. If he took his This error is hard for us simple human beings to understand, but it is
nothing special for a computer without nerves. Jack could have succeeded,
however, had his programmers described South's 1NT as showing 15-20 HCP.
Then, uncertain of beating 3NT by ducking the Actually, credit must again be given to Paulissen, who knew what few human bridge players know: that a 1NT 'sandwich' (a bid coming between two opposing bidders) shows a hand about as good as the one he had, a full trick stronger than a strong 1NT opening. Paulissen was simply making the right bid, not trying to deceive poor Jack. So, should Jack be programmed to expect 18-20 HCP for a 1NT sandwich? Not really, even though this is an appropriate range. For most human opponents still bid 1NT sandwiches with 15-17 HCP. To read this sequence correctly, Jack must know not only good bidding, but also how much his opponents know! It is obvious that Jack must learn to be much more flexible. That sounds very logical, but it masks the real problem. Bridge is a game in which full disclosure plays an important role. Players must explain their partnership agreements upon request, but they need not explain what they know from bridge logic. In Example 3, a human East might suspect that South had more than 17 HCP, and thus might inquire, but Jack has no 'sixth sense,' let alone the ability to ask a direct question. He depends entirely on the information about his opponents' methods that has been given by his program. full disclosureWhy did we make Jack so rigid? Wasn't it better to make a more flexible
program? The answers to these questions are very simple. The early bidding
and the opening lead are very reliable. It would be a waste not to trust
this information to narrow Jack's construction of the unseen hands as much
as possible. In fact, it is costly not to do so. When computers play
against each other, the programmers are very strict about full disclosure.
As soon as a call deviates from normal expectation, opponents are given
this information to enter in their program. In Example 1 this might be:
'The 1 At the table, however, things are not that simple. Would a human being have asked, and would the answer have helped him? If so, then Jack should have gotten all the extra information. But do you have to be a good player to think of these questions? And is Jack such a good player? To avoid raising the issue of whether Jack's team was helping him illicitly during the matches, we had decided beforehand to leave Jack on his own without asking questions at the table. It is clear that this handicapped Jack when playing against Nab-Paulissen. Had we taken notice of the problems shown by the three examples, and made the appropriate corrections, Jack would have lost by about 32 IMPs instead of 64---still a big win for Nab-Paulissen, but more in keeping with the real difference in strength. So using imagination and judgement in ways that will not confuse your partner gives you a big advantage against Jack. That is, if you don't tell Jack what might be going on and his programmers have not anticipated it. Importantly, we have learned from these matches that disclosure about partnership methods when playing against human opponents is different from disclosure when playing against other computers. If Jack is to play matches against humans again, some clear procedures for more thorough disclosure must be provided. By the way, letting Jack ask is not a good remedy. If permitted, Jack might ask hundreds of questions (most of them trivial) on every deal. A few years ago Matt Ginsberg, GIB's programmer, suggested this solution, interpreting 'full disclosure' as the right to ask countless questions. That sounds reasonable, but if implemented it could lead to questions of the form, 'What would your program bid with this hand?' repeated for each of the myriad hands that might be encompassed by any given call. Such an inventory, of course, is not intended by the requirement for 'full disclosure.' Bridge is still a game in which inference and judgment must always play an important role. The matches have given us very useful material, and we thank the pairs that joined our experiment. We hope they will cooperate again in the future! The final results:
Wim Heemskerk | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||