1 00:00:00,000 --> 00:00:08,087 Let's spend a few more minutes on our hidden agenda of the link between search 2 00:00:08,087 --> 00:00:15,199 and the mind before we return to technology and algorithms. 3 00:00:15,199 --> 00:00:23,975 So page rank as we've seen is quite intuitive and we rely on it more and more. 4 00:00:23,975 --> 00:00:32,178 How does this behaviour of ours affect the accuracy of page rank? 5 00:00:32,178 --> 00:00:41,019 Does page rank get better because we use it more and more to search? 6 00:00:41,019 --> 00:00:46,154 Does it get worse? Or are these two things completely 7 00:00:46,154 --> 00:00:50,717 unrelated? Let's think about it in this way. 8 00:00:50,717 --> 00:00:56,221 Page rank relies on hyperlinks between web pages. 9 00:00:56,221 --> 00:01:03,915 Well, why should we include hyperlinks in our web pages when it's easier to just 10 00:01:03,915 --> 00:01:09,354 Google anything? Increasingly, more and more people are 11 00:01:09,354 --> 00:01:16,180 putting fewer and fewer hyperlinks in the new material that they put up. 12 00:01:16,180 --> 00:01:24,588 This is bad for page ranks. Since we have fewer hyperlinks in the web, 13 00:01:24,588 --> 00:01:29,515 the accuracy of page rank gets worse and worse. 14 00:01:29,515 --> 00:01:37,915 The more we use page rank, the less we put in hyperlinks and the more inaccurate page 15 00:01:37,915 --> 00:01:43,006 rank will get. Now let's ask the reverse question. 16 00:01:44,015 --> 00:01:49,085 We find it hard to remember facts, so we increasingly use Google. 17 00:01:50,078 --> 00:01:55,047 How does this affect our ability to remember things? 18 00:01:55,047 --> 00:02:02,073 It's generally believed that our memories rely on building associations between 19 00:02:02,073 --> 00:02:08,019 words, incidents, facts. Each of these being strengthened every 20 00:02:08,019 --> 00:02:16,090 time we duress them during acts of recall. In this case, the more we use Google to 21 00:02:16,090 --> 00:02:23,445 remember things, the less we can remember, because we don't traverse our associations 22 00:02:23,445 --> 00:02:30,012 as much as we did before. This is actually the argument made by 23 00:02:30,012 --> 00:02:37,003 Nicholas Carr in his 2010 book, The Shallows, what the internet is doing to 24 00:02:37,003 --> 00:02:44,074 our brains. But, is there a positive side to the story 25 00:02:44,074 --> 00:02:48,074 as well? Let's talk about Google first. 26 00:02:50,031 --> 00:02:57,598 Mere indexing based on words and their occurrence in documents is quite poor at 27 00:02:57,598 --> 00:03:02,071 capturing deeper associations between documents, words and concepts. 28 00:03:05,006 --> 00:03:13,892 However, when we search and retrieve documents, we also divulge information on 29 00:03:13,892 --> 00:03:20,504 the relative relevance of the search results in comparison to our query. 30 00:03:20,504 --> 00:03:26,862 So for example, if we click on document which page rank returns to us, we are 31 00:03:26,862 --> 00:03:33,418 revealing that we are actually interested in that particular result as opposed to 32 00:03:33,418 --> 00:03:38,081 others. Exploiting such relevance feedback. 33 00:03:38,081 --> 00:03:41,534 From users. Can actually improve search. 34 00:03:41,534 --> 00:03:52,235 And be used to augment, page rank itself. So our use of search itself can be used to 35 00:03:52,235 --> 00:03:58,841 improve search. Even while page rank's original avatar 36 00:03:58,841 --> 00:04:06,147 might get less and less relevant as we use fewer and fewer hyper-links. 37 00:04:06,147 --> 00:04:15,261 But what about us and our memories. Well, exercising recall abilities is not 38 00:04:15,261 --> 00:04:21,995 the only time connections are built between synapses in our brain. 39 00:04:21,995 --> 00:04:29,587 We use and create fresh connections when reasoning about things as well. 40 00:04:29,587 --> 00:04:38,996 But reasoning relies on a lot of facts. And Google provides these facts abundantly 41 00:04:38,996 --> 00:04:42,889 and easily. Encouraging more reasoning, and so 42 00:04:42,889 --> 00:04:47,232 building more and probably deeper associations. 43 00:04:47,232 --> 00:04:54,546 Just think how much easier research has become when we can recall facts from 44 00:04:54,546 --> 00:04:59,058 Google, rather than relying on our own memories. 45 00:04:59,058 --> 00:05:04,042 Well we shall soon return to technology and search. 46 00:05:05,006 --> 00:05:13,012 But hopefully this diversion into our hidden agenda will spark some interesting 47 00:05:13,012 --> 00:05:18,007 discussions on the forum. I'm looking forward to it.