Tuesday, May 27, 2008

Curated Collaborative Filtering: Listening to Pandora

How is a museum like a radio station? Both are collections of discreet, loosely organized content pieces that are both familiar and new. Your overall enjoyment of the content experience is determined to a large extent by the balance of items you like and those you don’t, those you know and those that are new. The more time between the good stuff, the less likely you are to tune in again in the future. And your loyalty to the radio station (its stickiness) relies on the regular introduction of unfamiliar content in an enjoyable context.

These criteria aren’t easy to meet, and the result is lots of people like me who never listen to non-talk radio. But recently I’ve become obsessed with a new kind of (internet) radio station, one that’s converted me back from my CDs to the radio. It’s called Pandora, and its successes reveal interesting lessons about aggregating museum content.

Pandora uses collaborative filtering to create a real-time radio station for you based on your preferences. You enter a seed artist or song (or several) and Pandora starts playing music that it interprets as related in some way to your selections. The extraordinary thing about Pandora is the complexity of its filtering. It doesn’t just group artists together and play music by similar musicians. Instead, it uses hundreds of tags, signifiers assigned to each song by a team of musicians, to find
correlated songs that may be of interest. Pandora is a product of the Music Genome Project, in which musicians define the individual “genes” of a song via signifiers and use those to generate song “vectors” that can then be compared to create highly specific and complex musical narratives.

For example, I created a radio station today based on just one song: Diamonds on the Soles of Her Shoes by Paul Simon. That radio station then played:

  • She’s a Yellow Reflector by Justin Roberts
  • If Only the Moon Were Up by Field Music
  • She’s Going by The English Beat
  • You’re The One by Paul Simon
  • Withered Hope by They Might Be Giants
  • Big Dipper by Elton John
  • Wait Until Tomorrow by New York Rock and Roll Ensemble
  • The Tide is High by Blondie
Most of these songs were a. new to me and b. enjoyable (thus meeting the radio stickiness criteria). For each song, I could click a “Why?” button to see Pandora’s explanation for why it was played. For example, this image explains why The Tide is High was included:
There are over 400 different tags used to relate songs in the Music Genome Project, ranging from “brisk swing feel” to “lyrics that tell a story” to “sparse tenor sax solo.” From a single seed song, Pandora will generate a whole channel of music, and will shift and refine that channel based on your thumbs up/down rating of each song played. In this way, Pandora makes inferences about what you might like and introduces you to new music.


And it’s the introduction to new music that makes Pandora uniquely interesting to me as a museum person. When we talk about allowing visitors to curate their own museum experiences by voting for exhibits or aggregating custom tours, the fear among curators is that such projects will denigrate the collection and turn the museum visit into a kind of popularity contest. In short, we fear that visitors, if given the tools to create their own narratives, won’t want or use the ones we provide.


Pandora is a model for an alternative. Rather than user-based collaborative filtering, in which visitors receive recommendations based on what other “people like you” enjoyed, Pandora is an example of item-based collaborative filtering, in which visitors receive recommendations based on the similarity of previously selected items (seed songs) to potential members of the collection.

Pandora and the Music Genome Project is controlled by experts, musicians who, like curators, are uniquely skilled at identifying and tagging songs to create musical genes that represent the full spectrum of musical expression.
And their expertise makes for a better experience for me as a user/visitor. As an amateur listener, I could not tell you the particular elements of “Diamonds on the Soles of Her Shoes” that appeal to me. Listening and reacting to the Pandora-generated songs allowed me to understand the nuance of what I like and don’t like. Turns out that I enjoy songs with “extensive vamping.” Could I have articulated that at the start? No. Not only does Pandora introduce me to new music, it expands my vocabulary for discussing music. I learned something! From experts!

Users of Pandora are protective of the Music Genome Project experts. There have been interesting discussions on the Pandora blog about the slow inclusion of user-based filtering, and listeners' related fear that it will taint the waters of the high-quality item-based process. The Music Genome Project involves visitors' submissions in a limited way. The core value is in the professional categorization of the songs.

Which means that curators still have a powerful role to play in the future of museums. Imagine if an art museum worked this way, if curators tagged every piece with tags representing everything from “misogynistic undertones” to “Picasso blue period” to “asymmetrical” and generated a tour for you real-time on a handheld device. You could have a personalized trip through the museum, enjoying an experience that is both highly responsive to your preferences and one which deepens your understanding and ability to articulate why you like what you like. In some cases, people might be surprised to learn that they prefer artists whose subject matter comes from childhood memories, or those who work in a specific medium. While the museum can’t be physically rearranged for each visitor, the content can be remixed conceptually to present a progressively engrossing, educational experience.


Personalization doesn’t just give you what you want. It exposes you to new things, and it gives you a vocabulary for articulating and refining why you like what you like. Pandora’s collaborative filtering process contextualizes data from a very personal starting point. You get the analysis and the narrative, but you get the slice that will resonate most with you. The world is opened a little wider and hopefully, you keep listening.

8 comments, add yours!:

Paul Orselli said...

Hi Nina,

The good thing about systems like Pandora's or Netflix is that they help you find more things like those you're already interested in.

Where such systems seem less successful is the area of serendipitously "bumping into" things that you will enjoy but might not have ever found through such a targeted system.

Two quick examples:

1) The Toaster Exhibition at the City Museum in St. Louis would not be an exhibition I would normally go out of my way to see. (I mean, I LIKE toast, but an entire exhibition on toasters?) The "design" of the City Museum seemed to encourage (even more than most museums) a congenial browsing approach.

2) Fox News vs. NPR. Each in their own way, has become an "echo chamber" for a particular end of the political spectrum. Which is o.k. I guess, but if you only hear opinions you agree with, is that a good thing?

Madama Ambi said...

Hello Nina Simon whoever you are: I'm just coming off of spending 3 intense months inside of BarackObama.com, posting, blogging, social networking, plus some of us renegade creators pushing new content. I unhooked myself yesterday because the exchanges had become repetitive and except for a wonderful group on Feminists for Obama, the level of discourse was missing thoughtful listening.

I learned about your site from browsing Blogher, and apart from being a museum lover, reading intelligent, grounded postings on the interface between museum and patron (a word I don't identify with) is like a massage for my aching brain muscles. So, thanks.

As I was reading, a few images popped into my head and I thought I would share them, fwiw. In general, the person who loves something, no matter what it is, will attract willing listener/participants. I don't go to art museums for social interaction, and I relate to the place in such an individual way that I won't even stroll through an exhibit with my husband unless I've already "met" the art. However, on many occasions, we've happened upon a group following a docent who was worth hearing. A truly talented docent naturally engages the group and doesn't need to be given the "job" of interacting--interacting happens when a passionate person is around the subject she loves.

I don't like the word "docent" or "explainer"...they are both overly academic. "Lover" would be closer to how I think about the best person to open up the interface, but this might need work! If I were in charge of talent on the floor, I would hire personalities and promote them. There are all kinds of ways to do this. Museum-goers could see a preview video of the personality giving her/his spiel, and choose to tour with that "Lover" or show up during an unstructured time when the "Lovers" are high profile and available, but not intrusive. Also, like a public swimming pool has adult swim, free swim, hours blocked out for swim team practice, etc., or even divides the pool into lanes for mixed use, I wonder if museums could use some of your profiles/hierarchies to offer an interactive "menu" for different kinds of users. Maybe this can't happen all at the same time, but the more you help people identify why they're there, the more you help them identify for themselves why they need museum-time.

Ok, here'a good one--is there any discussion of chucking the word "museum" and reconceiving this place where self-education happens? Boy, I could riff on that one...

I'm in the category of creator, so probably not the best person to put into a focus group asking the community what it wants from its museums, but this might be the wrong question to ask. Maybe the more pertinent question is "Can you imagine your community without museums? Hold that idea and describe what would be missing from your life." I'm not suggesting this as a guilt-trip, but as a starting point for a process to discover...something...yeah, just...something...can museums curators handle that much unknown? Mebbe not. Mebbe the problem with museums is that they are run by museum-runners...you sprinkle in lively personalities from other disciplines and let them create/push content, and you will already be "interactive."

The interactive exhibit can be wonderful and I'm not diminishing it, by any means. But, the museum itself can get way more interactive with its community, or communities. Maybe this is skunkworks territory?

MadamaAmbi
Interview4Obama
http://madamaambi.blogspot.com

Lucia @ Pandora said...

Wow, Nina! What a fascinating article / post. Your descriptions of Pandora are right-on, and I love your ideas and comparisons.

I work at Pandora, and I completely see your points. In fact, we have a job title "Music Curator," for those who choose which cds to add to our collection. Yes, we call it a "curated collection!"

Gee, I sure would love it if your hand-held personalized tour idea came to pass. I was at San Francisco's Legion of Honor museum last weekend, and I was noticing I loved all of the artwork that featured electric blue coloration....


:) Lucia, from Pandora
lucia AT pandora.com

missnae said...

Hi Nina,

Interesting post about Pandora. I've known about them for some time now but have never really explored how the system worked. Mostly because I'd already hooked on another social networking site for music, Last.fm.

The 'musician's only' approach to tagging no doubt allows for a level of quality but in the 2 years that I've been a member of Last.fm I've made connections to interesting people and music through, as Paul mentions, serendipitous browsing. The Last.fm model allows for everyone to tag: musicians, labels and fans and this mix yields really balanced results. I never underestimate the granular approach to description that fans are capable of in the musical realm. They are the ones that got through their formative years brooding to The Cure on repeat after all, or jumping about to Hot Chip's synth pop tones from gig to gig (I actually know someone who did that when they came to Australia not so long ago - crazy!).

But all that emotional fandom aside, I thought you might be interested to know what makes serendipitous browsing work so well on Last.fm.

1. As a new member you create a profile. All the songs played on your computer are referenced by Last.fm and scrolling popularity charts are created over time.

2. As you listen, you develop 'neighbours'. These are other members of the community that have listening habits in common with you, although they more often than not listen to things you may not have heard of.

3. You add 'friends' along the way. Sometimes these are people you know offline but have very little in common with. Other times they are people you stumbled across online who have curiously inviting listening charts that you want to know more about!

4. All of this influences the songs that are served up on your 'recommendations' radio which you can then tweak to include 'more obscure' or 'less obscure' references, choose to 'love' songs as you listen or alternatively, 'ban' them so you never have to hear them ever again. The radio becomes a way of automating serendipitous discovery. Funnily enough, on that note, you can listen to radio in 'discovery' mode which is yet another way of introducing you to new things.

It's all really rather neat.

Nina Simon said...

madama,
Thank you so much for your thoughtful comment! Museum people often end up talking "to ourselves" and it's wonderful to have perspectives from lovers of all kinds. I once talked with a game designer who wanted to record all kinds of tour guides--from comedians to little kids--giving tours of famous historical sites. His idea was you could choose which guide to use for different parts of a virtual tour, and you could even
boot a guide who wasn't working for you (something that's harder to do with live guides).

Paul Orselli made a comment on another post about the concept of museum "fans." Fandom comes when you love something enough to want to share it with others. We need to find ways not only to grow more museum fans but to support the fans/lovers we already have so that they can be part of our outreach and expression in the community. Fandom is how music spreads... why not museums?

Harold Overdijk said...

Hi Nina,

How funny that we are just working on a similar problem. Although I LOVE the examples you give I think life's not so simple.. but it doesn't make it less possible.

First off: Paul Orselli wrote about the problem of personalization pushing you into an echo-chamber. For certain themes, like "news" this can be a dangerous situation: automatically I am pushed into the FOX News (heaven forbid) chamber.. or because I viewed 25 articles on "the rainforest" suddenly the war in Iraq is not high in my list anymore.. did I really intend to achieve that, because I was reading many rainforest articles at this point in time ? However I am not so sure if this is a problem when dealing with art. I may be pushed into one "area" but still within that area there's a lot I do not know about.

If I happen to like "electric blue" then this has a totally different result when I look at toasters then when I look at paintings.. am I in an echo-chamber in that case ?

I TOTALLY AGREE though that many "experts" FEAR the user-generated/web 2.0 wave.. we see it every day in a project we work on. And obviously there is a lot to be said that not every random user can be an expert in a random topic.

In our case we work with jewelry artists, goldsmiths and gemstones. A user can be an "expert" in how you would wear or combine this piece of jewelry. However an expert is an "expert" when it comes to treated rubies and laboratory tests to find out. Each person has his/her role to play, and it's the interaction between these groups that makes it powerful AND engaging.

That fits in nicely with the community comment of Ambi: to engage your communities does not mean you can do without expert knowledge.

However... in the case of museum curators: isn't the problem much more than museum curators benchmark themselves with the opinion of other curators and experts instead of the general audience ? *grin*

Data Recovery said...

In some respects, Pandora seems like an appealing ideology (taste is intrinsic to our authentic self, is not social) more than a business—or rather, what it sells is the hope that its animating ideology is truth.

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