tag:blogger.com,1999:blog-11679714.post3078486223157471364..comments2024-03-28T03:32:41.433-04:00Comments on Half an Hour: Networks, Neighbourhoods and Communities: A ReflectionStephen Downeshttp://www.blogger.com/profile/06140591903467372209noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-11679714.post-82671077170723910972011-02-05T11:40:15.702-05:002011-02-05T11:40:15.702-05:00(part 2)
Some history: the theory of connectivis...(part 2)<br /><br /><br />Some history: the theory of connectivism wasn't intended to included courses at all. Certainly that is not my preferred approach. The idea of the course - an event limited in time and participation - is almost the opposite of networks. <br /><br />That said, the value of the course seems to be the creation of new connections between participants anew. It is as though each new course shakes up the network and allows it to grow again. Now that's not back-propagation. But it does address some of the problems of purely associative network formation.<br /><br />The comments and criticisms people who are in courses receive could (broadly be speaking) be thought of as back-propagation on an individual level. But this would need to be looked at in more detail. Do connections actually strengthen and weaken as a result of criticism? I can't imagine that they don't - but there's no way I would support such a simple inference as "person A criticizes -> x connections are impacted". I know it's not remotely that simple.<br /><br />Similarly, what about connections between people in a social network. Are there things that strengthen and weaken connections between people; it there a feedback mechanism to group-formation that tends to dissipate the group, or parts of the group. Arguably. Would I expect a nice neat statement of 'event A -> weakening of group B'? That is probably too much to hope for.<br /><br />All of these are empirical questions. They can't even be decided simply by looking at courses or groups or people learning. They have to be modeled, and the scenarios run over and over. I am very aware of this. I have always taken care to underline that the things I have to say on learning mechanisms must always be subject to actual empirical investigation by people who specialize in these fields.<br /><br />But, of course, it is not possible to run through the full set of qualifications in every single blog post. That's why it's important to consider my work as a whole.<br /><br />The references added to this post have been useful and appreciated. More references (especially to open access material that I can accually read) would greatly assist my work on the post on learning mechanisms I am currently writing.Stephen Downeshttps://www.blogger.com/profile/06140591903467372209noreply@blogger.comtag:blogger.com,1999:blog-11679714.post-44524746437025447092011-02-05T11:37:45.298-05:002011-02-05T11:37:45.298-05:00(part 1)
The main point I want to make here is th...(part 1)<br /><br />The main point I want to make here is that it is simply not true that I have not addressed the topic of backpropagation, and that it is not true that it plays no role in connectivist pedagogy.<br /><br />I talk about network learning routinely, as it is a core element of the theory. It is quite right to point out that the concept is not mentioned in the post above. But it is not correct to say it is not addressed anywhere in my work.<br /><br />Here, for example, it is briefly mentioned: http://www.slideshare.net/Downes/personal-professional-development Slide 33, where it is used to underlie the actual descriptive principle of pedagogy (because, you know, teachers in classrooms can't 'back-propagate' - rather, corrective mechanisms are described in terms of 'reflection', 'interaction' and 'feedback'.<br /><br />I also talk about them in a little more detail here: http://halfanhour.blogspot.com/2007/10/homophily-and-association.html<br /><br />Let me quote at some length:<br /><br /><<< there are other principles of association. I would like to list four (usually I list three, but I think that the fourth should become part of this picture). I'll give brief examples of each:<br /><br />1. Hebbian associationism. People are connected by common interests. Affinity groups, religions, communities of practice - these are all examples of similarity-based association.<br /><br />2. Accidental, or proximity-based, associationism. People who are proximate (have fewer hops between them) are connected. You may have nothing to do with your neighbour, but you're connected. The mind associates cause and effect because one follows the other (Hume). Retinal cells that are beside each other become associated through common connections.<br /><br />3. Back-propagation. Existing structures of association are modified through feedback. Complain about the 'me too' posts, for example, and they decline in number. Adversity creates connections.<br /><br />4. Boltzmann Associationism. Connections are created which reflect the most naturally stable configuration. The way ripples in a pond smooth out. This is how opposites can attract - they are most comfortable with each other. Or, people making alliances of convenience.<br /><br />Two of these forms are qualitative. They are based on direct experience. They are not critical or evaluative. They tend to lead to groups.<br /><br />The other two - Back Propagation and Boltzmann associationism - are reflective. They are created through a process of interaction, and not simply through experience. They are critical or evaluative. They tend to lead to networks. >>><br /><br />Now, there are several criticisms that are accurate and useful:<br /><br />1. I do not have a comprehensive set of references for each of these four forms of network learning. Typically I just refer back to Rumelhart and McClelland, but clearly more detailed and recent work is needed.<br /><br />2. I do not describe these in sufficient depth, with a cashing out of the very general principles of back-propagation. This is work that is high on my list of priorities. My next Huffington Post article is intended to address association and connection-formation specifically. If you look at the dates you'll notice my series has stalled. I'm working on it.<br /><br />3. There is no clear back-propagation mechansism in connective courses. This to me is the most interesting of the observations and one well worth exploring in some detail.Stephen Downeshttps://www.blogger.com/profile/06140591903467372209noreply@blogger.comtag:blogger.com,1999:blog-11679714.post-91244629099845620092011-02-05T06:51:26.946-05:002011-02-05T06:51:26.946-05:00"The learning algorithm referred to as backpr..."The learning algorithm referred to as backpropagation (or more formally, retropropagation of error) " - http://wing.comp.nus.edu.sg/pris/ArtificialNeuralNetworks/ArtificialNeuralNetworksIndex.html<br /><br />The point I am trying to introduce really is not about the specifics of the backprop nets. It is about the notion of "retro-propagation of error" and the fact that in the absence of any mechanism of this type, highly connected networks are known to be useless. <br /><br />That was left out of the graph. It is as well left out of the connectivist theory. Without such mechanism, no new knowledge emerge. Or as you are not keen on the notion of knowledge construction anyway, the best way to phrase it in connectivist terms is that this leads a lot of noise propagating through the connections, with no outcome, no improvement in the network performance, no "growth".<br /><br />The guys at CMU have had 30 years to think about connectionist theories given that some of the most important teachers in that field work there. McClelland, O'Reilly. That university is famous for active cross-disciplinary collaboration. <br /><br />Yet, when it came to implement their own openLearning Framework, http://oli.web.cmu.edu/openlearning/, they put a lot of importance on the feedback mechanism.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-55044486327972970962011-02-04T07:02:18.813-05:002011-02-04T07:02:18.813-05:00Anonymous, the Sandu and Leon paper does not suppo...Anonymous, the Sandu and Leon paper does not support your point about the use of the term 'retro-propagation'. The term 'retro' is used exactly once, and not in any of the references; 'back-propagation' is used 10 times, in some section headings, and in various references. The term 'retro' is described in the paper as equivalent to the much more widely used term 'back-propagation'.<br /><br />As for, "do you have a theory that explains that no learning should ever be expected to take place when people randomly connect," you may want to look at this paper http://www.downes.ca/post/53305 which uses the concept of induction as an analogy to explain how a non-transfer theory works.<br /><br />Finally, while I welcome comments critical of the theory or any of the work I do, I do not welcome the snide and sometimes rude tone of the remarks. Personal attacks (ie., any sentence that describes me, rather than the issue) are not acceptable. Comments that are not professionally written will be deleted from this thread without notice or comment. Last warning.Stephen Downeshttps://www.blogger.com/profile/06140591903467372209noreply@blogger.comtag:blogger.com,1999:blog-11679714.post-16838504918725884282011-02-03T21:43:24.566-05:002011-02-03T21:43:24.566-05:00Tracing a group of people in a virtual course with...Tracing a group of people in a virtual course without any programming software, How we can trace the nodes in a simple virtual course? Maybe using sociogram, drawing the positions or exist any friedly Web 2.0 tool? My thesis project is a virtual course for tracing the connections and networks so..I know spicynodes any other tool? Grasshopper is complicate for me....Mayrahttp://connectknowledge.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-23897678967512373892011-02-03T21:23:22.135-05:002011-02-03T21:23:22.135-05:00Red: If this is what connectivism is, then it has ...Red: If this is what connectivism is, then it has negative value to education.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-6568869145032525552011-02-03T20:38:41.413-05:002011-02-03T20:38:41.413-05:00Anyway, you haven't addressed the main point. ...Anyway, you haven't addressed the main point. Heavily interconnected networks that you used in this article as analogy for human networks are useless without a learning algorithm. <br /><br />You say "Connectivism is a learning theory" but later, you claim "Hence, in connectivism, there is no real concept of transferring knowledge, making knowledge, or building knowledge". So, do you have a learning theory or do you have a theory that explains that no learning should ever be expected to take place when people randomly connect, in non structured way over the internet. <br /><br />That it could be the later rather than the former is much substantiated by the content of that page "What is connectivism". As you state, you have been working and writing on these ideas for decades. You also have worked in the field of instructional design for at least as long. <br /><br />You have done so, mostly, using the connected approach that your promote. You use your own success as an illustration of the value of that approach. But what is the value? The connectedness that you practice yourself is mostly in a kind of guru mode. One-to-very many without any rigorous feedback mechanism obviously. Comments on the blogs suggest that over time, the audience has limited itself to converts. Is this kind of connectedness a good thing? <br /><br />Which brings me back again to my main point. The absence of any learning rule, of any retro-propagation mechanism in your model of human connectedness. The absence of any mechanism to warn you and provide critical information when the reality is not quite what you assume of it. What are the possible dangers to not introduce in the system any mechanism that will help keep in check the need we all have for feeling important (status and identity).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-92216091697818000752011-02-03T20:37:10.857-05:002011-02-03T20:37:10.857-05:00@Downes I am surprised that you never heard the te...@Downes I am surprised that you never heard the term "retro-propagation" as it has been used interchangeably with "back-propagation". cf "the retro-propagation algorithm, or back-propagation algorithm." http://florinleon.byethost24.com/bepalia/papers/0907.pdf. I used the more generic retro-propagation as the term back-propagation is strongly associated with the PDP model of Rumelhart and McClelland (1986) which assumes a layer of hidden units between input and output, an idea that is difficult to apply to the notion of nodes between people. To be successful, the back-propagation algorithm also must assume non-linear activation functions which are difficult to transfer to human networks as well. Neither hidden units or non-linear activation functions appeared in your diagram or explanations.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-65694425736490137202011-02-03T06:49:56.337-05:002011-02-03T06:49:56.337-05:00> If you use diagrams directly or indirectly bo...> If you use diagrams directly or indirectly borrowed from associationist or connectionist models to give some credence to your ideas<br /><br />@Anonymous: Don't be snide unless you've done your research. I've been working and writing on these ideas for decades. I am very familiar with associationist and connectionist principles and people who are familiar with my work know this.<br /><br />I appreciate the references to some discussions of associationist learning principles, which I've discussed in many talks over the years. The three I refer to most frequently are Hebbian associationism, back propagation (as it is properly called) and Boltzmann mechanisms. <br /><br />Obviously, not everything about connectionist and associationist principles can be covered in a single post. This post is introductory, intended to familiarize readers with basic components of networks, and no more.Stephen Downeshttps://www.blogger.com/profile/06140591903467372209noreply@blogger.comtag:blogger.com,1999:blog-11679714.post-74804271320185577812011-02-02T23:04:40.294-05:002011-02-02T23:04:40.294-05:00In Network Components, there is a major omission....In Network Components, there is a major omission. Learning rule. <br /><br />If you use diagrams directly or indirectly borrowed from associationist or connectionist models to give some credence to your ideas, you might as well provide to your audience with the knowledge they need to evaluate the value of your propositions. <br /><br />Neural networks are absolutely useless unless they are trained. Knowledge is acquired via some mechanism. Common ones are hebbian learning (http://www.nbb.cornell.edu/neurobio/linster/lecture4.pdf) or retro-propagation of errors (http://www.generation5.org/content/2000/nn00.asp). <br /><br />Worth a read too: "Letting structure emerge: connectionist and dynamical systems approaches to cognition"<br />http://www.princeton.edu/~matthewb/Publications/McClelland_etal_TICS_2010.pdfAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-23767237912644185212011-02-02T11:55:03.843-05:002011-02-02T11:55:03.843-05:00A more recent study, and arguably a more relevant ...A more recent study, and arguably a more relevant one, is the RSA report, "Connected Communities." The whole report is found here:http://www.thersa.org/projects/connected-communities<br />It develops language such as social resources, social capital, and social networking analysis. Building on the information provided in the RSA's Social Brain Report, "For the last two decades, the model of the rational individual- 'homo economicus'- that has underpinned our faith in democracy, reliance on the market, and trust in social institutions has been consistently undermined by social psychology, behavioural economics and neuroscience."<br /><br />Sherry Turkle, who in her 1995 book "Life on the Screen" had high hopes for the positive aspects of the digital age, raises interesting concerns about the effects social media can have on social networks in her in book, "Alone Together". "We aren’t “happy” anymore: we’re simply a semicolon followed by a parenthesis." she laments. And this can apply to the on-line learning community as well, where discourse too often is reduced to words on a screen. But we need to be reminded that social media and the communities it forms, such as Facebook, are the same point computers were in the 1980's, in term of the evolutionary experience that may be afforded us in terms of moving beyond geographic community.dustproductionhttps://www.blogger.com/profile/17175799632729075455noreply@blogger.comtag:blogger.com,1999:blog-11679714.post-32745358237639829692011-02-01T23:00:37.433-05:002011-02-01T23:00:37.433-05:00Stephen,
Nice posting though I become more confu...Stephen, <br /><br />Nice posting though I become more confused with the concepts behind networks by the day. Which, I suppose, is a good place to start. <br /><br />On Sunday night while watching an Al-Jazeera video of demonstrators in Cairo pushing the police back into their barracks the commentator noted that closing the net and cell service seemed to have little effect in dampening the protests. The speculation was that without word from your friends to rely on for updates and locations of hot spots, protesters simply had to venture out on their own. As if news from friends actually dampened the urgency to "be there" by making it KNOWN and oddly less interesting. Or conversely increasing the anxiety level by creating a vacuum of information that could only be resolved by personal attendance. <br /><br />I'm trying to understand if this is a dynamic of networks? To actually rush to the scene of silence, as if no-news was a more powerful attractor than full coverage. Of course, those used to an abundance of network activity may tag silence as a most extraordinary event which compels resolution by whatever means is available.<br /><br />At first I was thinking this had something to do with the influence of weak interactions--as in the network conversation is weakened by being turned off. But it feels more like the power of a network to remain intact by adapting to changing conditions. Is it a characteristic of a network to seek equilibrium? If so, there must be some sort of shared identity that allows many individuals to collect and disburse. Can that be simple group membership? Or something different?<br /><br />Scott JohnsonAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-11679714.post-63793659159969174512011-01-30T18:03:13.366-05:002011-01-30T18:03:13.366-05:00speaking of cross-silo connecting, I just sent the...speaking of cross-silo connecting, I just sent the Wellman/Leighton paper to a friend working in small business and community developmentVanessa Vailehttps://www.blogger.com/profile/04647639725252430851noreply@blogger.com