Slashdot Mirror


Is the iPod Shuffle Playing Favorites?

marksilverman writes "Steven Levy at Newsweek is reporting that his iPod Shuffle seems to favor certain songs. Is Apple receiving kickbacks to promote certain artists? Apple denies it, of course, and Levy had the good sense to ask a mathmatician and a cryptographer who explained that it's probably just humans finding patterns where there are none." Less neurotically, both CNet and PCWorld have discussions of the Shuffle's interior spaces.

14 of 524 comments (clear)

  1. humans are wired to... by jxyama · · Score: 4, Interesting

    ...look for patterns, to at least internally provide an explanation. (whether it's true or accurate is irrelevant.) go to craps table - unless you are neurotic, everyone develops a pattern to how they roll the dice. no reasons, no explanations. we are just made to take emotional comfort in attributing some pattern, real or otherwise.

    1. Re:humans are wired to... by fafalone · · Score: 5, Interesting

      We actually talked about this in my statistics class today. The professor actually had a friend who could flip a coin and get it to land on whatever he wanted, virtually every time. Made alot of money hustling people with that. It is possible to develop patterns of manipulating 'random' events, through skill of hand (or programming skill), that to most people still look like they're obeying pure randomness, but are actually being subtly manipulated behind the scenes. There's no doubt in my mind it's a possibility that Apple is trying to walk that line.

    2. Re:humans are wired to... by Rei · · Score: 5, Interesting

      Or it could be an accident. For example, picture this code:

      const int song_id=random()%num_songs;

      At a first glance, that might look reasonable; however, once you start to get a lot of songs (and you start to approach RAND_MAX), it will skew your result in favor of low-ID songs.

      Who knows if anything is going on here, though.

      --
      Don't take a knife to a gunfight, or even a knife to a knife fight. Take a gun to a knife fight.
    3. Re:humans are wired to... by yali · · Score: 5, Interesting

      This page has more information about this phenomenon, called the clustering illusion. Another manifestation is streak scoring in sports, a.k.a. the hot hand in basketball. Players are often though to be "on a roll" when in fact their larger scoring pattern fits a random distribution around a mean.

    4. Re:humans are wired to... by Zorilla · · Score: 5, Interesting

      This is got to be a result of the random number generator. Winamp and XMMS are exactly the same in this regard. When my music collection got big enough, I usually just put the player into shuffle mode. It always seems to pick the same songs over and over. Of course, the results are slightly different in XMMS as compared to Winamp.

      Of course, I just opened Winamp to test this out and it knows I'm blabbing about it and it's playing music I have not heard in a while.

      --

      It would be cool if it didn't suck.
    5. Re:humans are wired to... by displaced80 · · Score: 4, Interesting

      ... and this is exactly what iTunes and the iPod/iPod mini seem to do (no idea about the shuffle).

      Hit Play when shuffle's enabled, and it will shuffle the playlist before commencing playback. You're guaranteed not to get repeats until the playlist loops. The other benefit is that you can skip forward and back through the shuffled playlist normally. Mine often randomly picks 4 or 5 songs in a row that go well together, so I'm able to skip back and listen to those in that order when I like.

      --
      What's the frequency, Kenneth?
    6. Re:humans are wired to... by Motherfucking+Shit · · Score: 4, Interesting
      This page [skepdic.com] has more information about this phenomenon, called the clustering illusion.
      Thanks for that link. It's a good explanation of something one of my college professors said, which has stuck with me ever since: "A random number generator isn't truly random unless it can potentially generate the same number many times in a row." The idea being that if an RNG was programmed to avoid producing the same number repeatedly, it wasn't really generating random output.

      The "clustering illusion" (I never knew there was a name for it) has some interesting applications in real life. Dice in a casino is probably the most obvious example, but things get more interesting as the field gets lower; like, say, 1 and 0. This example applies decently to MMORPGs, where things like whether or not you strike your foe, or whether or not you gain in a skill, are based on your skill times some sort of random number. I was a hardcore addict of Ultima Online for a few years, and one of the common complaints was "I have a skill level of X, but I failed to land a hit on my opponent Y times in a row, something is wrong!"

      I guess the next time my UO addiction recurs, I'll have a valid explanation for that phenomenon.

      (Would have posted this about 3 hours ago, but Slashdot went down, or something, and I lost my original comment. Had to rewrite from memory.)
      --
      "BSD: Free as in speech. Linux: Free as in beer. Windows 10: Free as in herpes." --Man On Pink Corner in #52607549.
  2. Reminds me of another discussion... by MyDixieWrecked · · Score: 4, Interesting

    On macslash.org, there was an Ask MacSlash about iTunes somehow figuring out what songs sounded good together using some crazy sonic algorithm. The guy was asking if it was plausible that iTunes analyzed the songs in the playlist to spit out the best mix possible.

    The basic consensus in the discussion was either "dude, your entire playlist is songs you like, of course it's gonna be a good mix.," or, the option mentioned above about humans looking for patterns.

    Although, throughout my history of having large (over 1000 song) playlists, I've found that no matter what mp3 player I used (hardware, software, or otherwise), there always seemed to be certain bands or artists that would get play more often. I've had weeks at a time where I'd hear Snoop Dogg's Lodi Dodi, Iron Maiden's Quest for Fire or In Flames' Clayman nearly every time I picked up my iPod

    --



    ...spike
    Ewwwwww, coconut...
  3. shuffling is not as easy as it sounds by martin-boundary · · Score: 4, Interesting
    Instead of asking some random mathematician, the journalist should have asked and expert in shuffling. It's entirely possible that Apple's engineers believe they are producing random orderings without actually doing so. For example, Persi Diaconis showed that you need 7 riffle shuffles to randomize a pack of cards. Other possibilities include the fact that the simplest random number generators such as rand() are utter shit.

    So before dismissing thousands of people, I'd entertain the idea that Apple's engineers simply stuffed up. It wouldn't be the first bug that slips through QA testing.

  4. Random order versus random selection? by mc6809e · · Score: 4, Interesting

    This reminds me of the birthday paradox:

    "The birthday paradox states that if there are 23 people in a room then there is a slightly more than 50:50 chance that at least two of them will have the same birthday. For 60 or more people, the probability is greater than 99%. This is not a paradox in the sense of it leading to a logical contradiction; it is a paradox in the sense that it is a mathematical truth that contradicts common intuition. Most people estimate that the chance is much lower than 50:50."

    Applied here, suppose you have 365 songs. How many random selections must be played before you have about a 50:50 chance of hearing a repeat? Just 23 songs.

    What most people want is not random selection, but random order.

  5. Shuffling and randomness by shadowmatter · · Score: 5, Interesting

    First, there is the possibility that Apple screwed up the shuffling algorithm -- although not entirely likely. If you ask an introductory programmer to write some code to shuffle an array, you'll most likely get something like this:

    for i in range(array_length):
    j = random() % array_length
    temp = array[i]
    array[i] = array[j]
    array[j] = temp

    This code does NOT produce all permutations with equal probability! Instead, you must use the following code:

    for i in range(array_length):
    j = i + (random() % (array_length - i))
    temp = array[i]
    array[i] = array[j]
    array[j] = temp
    }

    This was cribbed from c2 -- see the full article text here for a more informative discussion.

    Second, I see a lot of people saying "I have a 20GB iPod -- and I swear sometimes it just NEVER plays this one song." Okay, let's assume that a 20GB iPod holds 5000 mp3 files. What's the probability that you play 5000 songs in shuffle mode, and never hear a particular song?

    It's the probability that 5000 times in a row, you hear some other song -- that is, one of the 4999 other songs. Calculating, we get:

    (4999/5000)^5000 = 0.3678.

    So we have a 36% probability of this happening -- which is not a negligible amount! This will further be compounded by two things: First, you have no way of recalling exactly it has been since you heard a particular song -- if your favorite song was played 1000 songs earlier, it probably feels like 2000. If it feels like 2000, it's probably 4000. Because it's a favorite song, your mind will exaggerate the amount. It's like if you crave nicotine, it can feel like days since you've had a cigarette when it's only been hours. Second, you probably have a lot of songs you would call a "favorite" -- with each having a 36% chance of not being played over the course of 5000 plays, your mind will probably register that at least one of them is "feeling neglected."

    Probability is a strange and beautiful thing. Don't expect your average audiophile to understand it. (And I'm not claiming to understand it either, beyond a very cursory level.)

    - shadowmatter

    1. Re:Shuffling and randomness by shadowmatter · · Score: 4, Interesting


      It's the probability that 5000 times in a row, you hear some other song -- that is, one of the 4999 other songs. Calculating, we get:

      (4999/5000)^5000 = 0.3678.


      Almost forgot -- I thought this number looked familiar. Note that as your number of songs approaches infinity, this number approaches 1/e (approx 0.3678, as seen above). Furthermore, this bound is being approached from below:

      (1/2)^2 = 0.25
      (2/3)^3 = 0.296
      (3/4)^4 = 0.316 ...

      So even if you keep ripping or downloading more songs, you're not going to decrease the chance of this phenomenon. Note how likely it is to occur regardless of how many songs you have -- which explains why everyone has probably "experienced" it.

      See, probability really is beautiful ;)

      - shadowmatter

  6. Statistics can tell you a lot about yourself .... by Gopal.V · · Score: 5, Interesting

    > You're absolutely right!@ There's an array inside the iPod shuffle of about 150 artists that will take precedence over all other artists.

    Back in late 2001, I wrote a simple program which learns which songs I press "Next(b)" before it completes. Finally after 8 weeks, I realized that I listen to
    • Eminem and other rap in the morning
    • Pop music later into the afternoon
    • Rock was for the 5-7 pm slots
    • After 10 , it was usually playing Enigma and instrumentals
    Was quite different on a weekend with no music on saturdays and often slow Elvis songs on sunday afternoons ... I would really love a portable player that understands this and plays accordingly (mpg321 + bash + grep works, but only when I start it properly).
  7. Re:anti-spoken word by igrp · · Score: 4, Interesting
    Or, alternatively, he could do what I do: use iTunes' smart playlist feature.

    That way, you have a lot more control over what songs get selected and - to tell you the truth - it's a lot more flexible than the autofill feature (it's sort of like discovering perl for the first time -- yeah, it's a lot more clumsy than just whipping up a simple shell script but it's also so much more powerful).

    Basically, what I have a bunch of custom smart playlists. The first randomly selects songs that are :

    • longer than 1:20
    • not comedy, spoken word or audio books (I enjoy listening to George Carlin's rants as much as the next guy but I really don't need to listen to them when I'm out running)
    • not longer than 8:00 (this excludes all jam songs etc.)
    • hasn't been played in three days (to keep things fresh)
    • are not named intro, interlude or skit (for obvious reasons), plus some very custom stuff.
    Then I have a second smart playlist select some my favorite songs that I haven't listened to in a while (5 days).

    I use the 1st playlist to fill my Shuffle up to 75% capacity. The second playlist gets to use the remaining 25%.

    You know, I used to think of all these software jukeboxes as bloatware. And whilst iTunes is undoubtedly quite demanding ressource-wise, I really believe it's well worth it. It's powerful and fun to use at the same time.