Hacker News Reader

Comment by peterlk | Hacker News Reader

I think I will forever be bitter about an argument that I had with a professor in college about statistical significance. There was a study with 12 (or some other tiny N) people who were told to click a button when they saw some change as a laser was moving in a circle. They were then asked to go back and pick the place where the laser was when they observed the change. The study found that people remembered clicking the button 10ms (or some other tiny value) before they actually did. This was clearly grounds for all of us to question whether humans had free will at all, because the result was statistically significant after all! When I challenged the professor on this, I was told that I should take a statistics class. I think that professor still turns me off from philosophy to this day. This happened in a philosophy class

View on HN

Your description almost matches an experiment done in EEG research called the Libet experiment [1], although it's a bit different than how you describe it I'm confident this is what you are referring to.

They find that when you perform an action, there is a EEG spike [2] in the motor cortex well before you actually consciously decide to perform the action. The experiment is conducted with a dot running around a circle and the subject has to tell when (as per where the dot was) he decided to act. The EEG potential is seen prior to that decision moment.

This is related to free-will as it is as if the decision of acting is not coming from your conscious self but from a deeper layer.

[1] Libet experiment: https://www.youtube.com/watch?v=OjCt-L0Ph5o

[2] Bereitschaftspotential: https://en.wikipedia.org/wiki/Bereitschaftspotential

Perhaps I'm missing the point here but why does this say anything about free will? Of course you can't make split second conscious decisions. But you've still made a conscious decision to prime your subconscious facilities to act in a certain way.

The consciousness is super slow. It doesn't make sense to have it "do" anything. But it's good for making executive decisions. The CEO doesn't make the product.

That's pretty much my line of thought. If I decide to bicycle somewhere, I'm certainly not consciously thinking through most of the act of actually cycling, but I have no doubt that the "uuugh, this is going to suck but I need the exercise" decision happened on a conscious level.

It meshes with certain other results, for example on timing of predictions (http://www.kurzweilai.net/more-evidence-that-youre-a-mindles...), and most interestingly on split-brain patients (http://www.powerofstories.com/our-brains-constantly-confabul...). In the latter case, split-brain people would make choices based on information only available to their right brain, then when asked to explain them would unconsciously invent an explanation for that choice which was based only on information from their left brain.

I'm not sure philosophically whether our inability to understand our decisions undermines our free will, but it certainly undermines any ability to consciously prime ourselves to make certain decisions - hard to have that feedback loop when you don't even know what decision you made!

Is saying it "meshes with specific other results" just a signal of cognitive bias?

I personally would confidently guess there are unconscious faculties in the mind, but I dont see how this experiment is remarkable in proving this, see here(1). Is it not an equally likely conclusion that the brain takes a few hundreds of a second to develop a conscious decision? Actually, the inverse of that is what would be remarkable.

1-https://goo.gl/images/MkT2PQ

The issue isn't whether a decision is unconscious or conscious. It's that we often think that we've made a conscious decision when the decision process we narrate for ourselves and others is provably impossible.

I should have phrased the original as "it is a relatively weak example of this specific set of experimental results".

Why isn't the explanation that the reporting function is slow? Your "free will" -which we won't explain- decides to fire the motor neurons, and then does the reporting, which is pretty unnatural compared to moving a muscle, to do the thinking about where the dot was.

Or maybe you overcompensate when calculating where you thought the dot was.

The video addresses that. The experiments were constructed not so that you report "I decided to press the button", but rather by reporting "The state of the world [as measured by this rotating dot on the screen] was this at the time I decided to press the button." And he found that the state of the world that people reported when they pressed the button was consistently 200 ms before actually pressing the button (which is in accord with other experiments measuring human reaction time), but the EEG spike in the motor context were 350 ms before the subject's perception of reality at the time they made their decision, and 550ms before pressing the button.

Most people think of their consciousness as "That part of my mind which integrates all my sensory information into a coherent experience of reality at this moment, and then decides what to do within that reality." You could redefine free will as the EEG potentials themselves operating within your brain - but that's not how most people, subjectively, experience it, particularly because they are not generally aware of most of these EEG potentials directly.

I remember hearing psych-major classmates discussing that experiment in the dorms after class. It's kinda mind-blowing when you think about it.

I read (in a book sitting in a science museum giftshop, so take with the appropriate grain of salt) that most of Freud's theories have been shown to be bullshit in the century and a half since he lived, but his enduring influence was showing that the vast majority of human behavior is unconscious. Instead of thinking of your consciousness as the primary actor that determines what you do, you have to think of it as a vague overseer that occasionally notices the body doing something and can intervene with enough time, exposure, and practice. And whole industries have been built upon that principle - advertising, mass media, propaganda, behavioral finance, therapy, coaching, education, gaming, gambling, cigarettes, coffee, travel, social media.

There was a HN thread 2 days ago about the rise and fall of scientific authority and how to bring it back. I cynically commented that the rise of the physical sciences came from the ability to win wars with them. You could look at the rise of the psychological and social sciences as coming from the ability to make money with them.

Wars are fought and won with psychology every day. Only fairly trivial “big army” wars are possible today.

Though Freud is often credited with coming up with the concept of the unconscious, it was actually quite well known before him.

I'm not going to pretend like I'm sat here on my couch and know more than those scientists, so can someone help me understand how they generated a free will hypothesis about this? Seems to me I could explain this with something like "short term memory assignment is delayed," i.e. the decision was made by the conscious brain, but the memory of making the decision had a long write time and therefore a later "timestamp."

> They find that when you perform an action, there is a EEG spike [2] in the motor cortex well before you actually consciously decide to perform the action.

No, that's not what they find. What they find is that the time of the change in EEG (it's not really a "spike", it's more like the leading edge of an increased action potential that lasts for a significant time) is a few tenths of a second before the time that the subject reports as the time they "made the decision". But you can't assume that the time the subject reports is "the time they made the decision", because the process of generating the conclusion "this is when I decided to act" also takes time--and that time was not measured. All you can really conclude from this experiment is that people are not consciously aware of all of the neural processes that actually go into their making a conscious decision.

Actually, this explains a feeling I've been having lately. In various occasions where I have to randomly pick between some things, I choose X but I can somehow feel that the actual choice happened a tiny fraction of a second before I was actually aware of it (kind of a contradiction, but I can't explain it better).

Basically, it feels like the decision was made a tiny bit earlier than "I" made it.

Isn't that easily explained by the time it takes to decide to speak after deciding to act?

I would submit this other similar experiment from YouTuber Vsauce [1] where a machine is trained to react to his subconscious thoughts before he consciously chooses to press a button.

[1] https://www.youtube.com/watch?v=lmI7NnMqwLQ Note: full video is behind YT Premium but the preview is enough to understand the experiment.

Coming from a deeper layer does not mean it's not freewill.

I'm sorry an incompetent professor left such a bad taste in your mouth, and on the field as a whole.

What's strange to me, is that my interpretation of the results of such an experiment wouldn't even lead to your professor's conclusion. The takeaway being the fallibility of sensory perception, where I might then prompt the class for a discussion of their intuitive refutations of empiricism before diving into the literature.

Unfortunately, being a philosophy major myself, I know all too well that a crap teacher can totally ruin a philosophy topic (let alone a topic of any subject). From my 4 years in philosophy classes of varying levels of difficulty, the common denominator between a fruitful time spent in class has been the willingness of the professor to engage with their students. Whether it's logic, metaphysics, epistemology, ontology, &c, the principal property of a quality professor is his/her dialectical ability.

Hell, that's how philosophy & theology was taught in the first universities! The professor would profess and then the students would engage their master in the subject at hand.

TIL:

profess

/prəˈfɛs/

verb

1. claim that one has (a quality or feeling), especially when this is not the case.

"he had professed his love for her only to walk away" synonyms: declare, announce, proclaim, assert, state, affirm, avow, maintain, protest, aver, vow;

2. affirm one's faith in or allegiance to (a religion or set of beliefs).

"a people professing Christianity" synonyms: state/affirm one's faith in, affirm one's allegiance to, make a public declaration of, declare publicly, avow, confess, acknowledge publicly "in 325 the Emperor himself professed Christianity"

Brief etymology of "professor":

From Latin "profiteri", to the form "profess-" meaning "declared publicly", and to "professor", then to Late Middle English as "professor".

So a professor's practice is probably closer to definition 2: "make a public declaration of" whatever one's skill or knowledge of a particular art might be.

Genuine question. What about the professor's statements were inaccurate or incompetent? Is the sample size really too small? Is the claimed conclusion about free will invalid? Or is the criticism just the dismissive tone toward the student?

I mean N = 12 is incredibly small to make such a sweeping statement about all of humanity but further it implicitly accepts that 1. free will is demonstrable via the experiment, 2. the reaction wasn’t preempted by free thought leading to the decision, and otherwise, 3. you’re a bad philosophy teacher if you’re trying to prove philosophy with statistics, imo.

The incompetence originates from the disregard of the parent commenter's question/concern. It's the result of not engaging in good faith with your student, not necessarily the conclusions drawn. As I mentioned in my original comment, the value in taking a philosophy class (especially as a student in a different field) is the chance to engage with both the professor and your peers; it serves as a veritable petri dish for developing one's ability to succinctly articulate and debate topics. If you're expected to sit in a philosophy class and just absorb the material without any contrary thought, something is seriously awry. It goes against the very nature of why humans pursued philosophy in the first place.

Furthermore, it seems strange for a professor of philosophy to so easily dismiss criticism out of hand. Of all subjects, a philosophy professor has a pedagogical imperative to entertain contradictory positions and explain why or why not one ought to follow a line of reasoning. In addition, the question about the merit of a small sample size could itself serve as a valuable aside in teaching fundamental notions in the philosophy of science.

Note: This is from the perspective of Western analytic philosophy, but the spirit of debate and discussion is no less integral to the continental tradition.

This reminds of a professor of mine who jokingly says that he is no longer teaching, but preaching.

This is a well known experiment that has deep implications (https://en.wikipedia.org/wiki/Neuroscience_of_free_will see Libet experiment among others). It doesn't question free will directly. Making decisions without being consciously aware doesn't contraindicate free will.

Personally, I side with Dennett (as always).

Also, many studies have n=12 and still have statistical power.

I imagine that it takes longer for your vision system to generate a useful output than whatever is responsible for telling you that you just stubbed your toe.

If signals like touch, smell, sight, etc. arrived at the input to your perceptual system immediately, you'd get a bunch of inputs for the same event at different times, and it would probably be difficult for your perceptual system to make sense of of them.

I think the only thing the spinning wheel experiment shows is that the brain has some sort of perceptual delay/compensation mechanism that's probably there to account for these differences in input processing times. And it probably backdates the "timestamp" of the event so that things that rely on short time intervals (e.g. control tasks like balancing) still work reliably.

I don't know why anybody would think this says anything about free will. Philosophers are weird.

> I don't know why anybody would think this says anything about free will.

If some decisions that we think are made consciously are actually unconscious, then how do we know that any decisions we make are really conscious decisions?

What if our consciousness makes no decisions, and is just a figment of our imagination.

Hm. I used to do competitive air rifle shooting (fwiw top five in the nation at the time), and this experiment comes close to the sort of training that I would do with my coach. He would act as a spotter and after every single shot, would ask me where my shot was (eg, 9pt at 4o'clock). We did this probably 300 times in the course of my training. Despite the "jitter", it was something that could eventually be done with surprising consistency after a while of training this way. It would be a completely different matter if the training was done on a new shooter (who were never, ever good when they first start). The training was also complete ineffective if I had caffeine, or wasn't in the right mood. My guessing ability would then effectively match what was seen in this test.

I'm not sure how this test would have proven anything, especially with such a small sample size. As another poster mentioned, this very much sounds like a test for sensory motor latency, which is absolutely a nontrivial thing for this sort of test.

If the test you described was done against trained shooters, I'd imagine the conclusion would likely be the opposite.

How is this experiment related to free will at all? Sounds to me like something about sensory/motor latency.

Yeah I would've done the one were you have everyone in the room close their eyes and think of a "random" number, write it down, then compare the distribution.

Results like those are what make me question free will (My mind "weighted" my answers in ways I can't control).

How does being a bad random number generator mean that we don't have free will? I don't see these two as contradictory.

At least when I did it in class we had lots of certain numbers, essentially none of certain numbers. A lot of them lined up with common "lucky" or "unlucky" numbers, even if everyone said they didn't pick it for that reason.

To me that shows us how outside forces influence our thoughts. Did I want to buy this garbage bag because it's a good value, has a good design, or because I've heard "DONT GET MAD, GET GLAD!!" 1000 times? Every thought we have is affected by our experiences, and many experiences can be controlled - they call these advertisements.

I find this topic fascinating. I suffer from depression, and my thoughts during a major depressive episode can be the stark opposite from when I feel well (Let's say it's about suicide). How can I truly have "free will" if my decisions are so dependent on external influences?

How can I truly have "free will" if my decisions are so dependent on external influences?

You don't have actually free will, if by free you mean "uninfluenced by anything".

There's no evidence that such a thing exists, and anyone who claims such a thing invariably appeals to supernatural or hand-wavy explanations.

Note that many thinkers who claim free will exist actually are saying "what most people mean by 'free will' does exist", and usually that means "an agent capable of making choices without outside influence". This idea is compatible with determinism, so these people are called compatibilists.

How is being an agent capable of making choices without outside influence compatible with determinism? My understanding is nobody can ever be an agent capable of making choices without outside influence. A person is fundamentally influenced at birth by external forces and moulding the person by deterministic process without the person having any real control. Furthermore one could only say they had free will if before life one agreed to take role of birth as a specific person and with knowing how life will play out till the end. Compatibilists are people who don't understand determinism because free will doesn't work with determinism. /hard determinist.

I said "what most people mean by 'free will'"

For most people, "outside influence" means, "at this point in time, only the contents of my brain affect the choice I make" and "no force or agent outside myself is compelling me to make a different choice than the one I'd make otherwise".

It's a word game of course. Even if you try to be extremely precise with your definitions, to avoid this kind of thing, most people won't quite follow.

Compatibilists believe what you believe. They just agree to use the popular, vague definition of free will instead of the strict one you're using.

> How can I truly have "free will" if my decisions are so dependent on external influences?

because you can recognize this as a pattern, make a supposition that this is related to previous conditioning, and retrain yourself at picking numbers randomly to eliminate the previous bias that you yourself recognized as 'problematic' here.

That's fated to happen by the external forces making it happen.

These are good examples of the fact that our common intuitions about free will are disconnected from reality, often silly, and usually plain wrong.

For example, it's common to have the intuition that the choice when picking a number from 1 to 10 is completely unbiased and independent. That would imply a perfectly uniform distribution.

Of course that doesn't match reality, and it raises more questions for the intellectually honest thinker, but most people don't think about it beyond the simple intuition.

Yes, but that's just some humans being uneducated about how the human brain works. It doesn't really say anything about the existence of free will. In fact, the reason untrained humans are bad random number generators has little to do with the abilities of the human brain and more to do with how random distributions work.

Untrained people just don't know, for example, that long streaks of heads and tails are actually quite likely in a sequence of random coin tosses. If they did know the likelihood, and they were tasked with writing down a sequence of random coin tosses, they would probably do a much better job.

If you take this to the limit, a human could learn to compute a pseudorandom generator in their head (at least in theory, although it may be very slow going) or perhaps figure out an effective way to gather entropy from the environment and turn it into a truly random sequence.

It's funny because statisticians are among the loudest critics of how easily statistics can be abused. I encourage you not to be turned away from a whole field because one bad representative. Professors are humans too and say a lot of dumb things. Very few are their field incarnate.

What do Bayesians say these days btw?

I still find Bayes to be more grounded and less “pie in the sky” than frequentists.

It all depends on your priors what they say. :)

But seriously, you can have the most pathological prior distribution, so you can then stick with it forever. (Let's say your prior predestines you to always find that whatever the new piece of data you get is so unlikely that it's more likely that it's an error/conspiracy than a real piece of data that you have to do belief update on.)

So, instead of coming up with a significance level, you have to estimate the chance of observing a null result, which determines how much new data moves your posterior distribution. The "advantage" of the Bayesian approach is that - in theory - you can incorporate every tiny little bit of data into your model (distribution). The disadvantage is, that it's very susceptible to various biases (through a biased prior).

Bayesian statistics are mathematically perfect, as long as your priors are true. Unfortunately, they are not.

I think it’s the opposite. Your confidence intervals are only true if your distribution is true. But how can it be that perfect? At least Bayesians adjust their knowledge like scientists.

STATISTICIANS actually do fine, generally. The problem is that no statisticians were involved in the analysis and write-up of almost all research that isn't statistics papers.

The statistics just don't mean what most scientists think/write they mean. They're using em wrong. As the OP explains some manners of, in fairly technical language.

Yes, I was just saying along with OP that a statistician would be most critical of the professor's reasoning. It's like a tyrant saying you should take a class in morals when you raise an objection to their atrocities.

Statisticians are doing fine indeed. The problem lies entirely in the ( non) design of experiments ( DoE) of the “scientists”. The sorry state of affairs of graduates from universities in properly designing experiments in which proper randomization, focus on sources of variability, between groups and within groups is not understood nor accounted for in the design is the true source of the problem. Scientists should always consult a statistician when undertaking an experiment. At least if they would like to make/draw sensible conclusions.

Dave Rubin recently had an interesting interview with Onkar Ghate, an objectivist philosopher, about free will. You might enjoy it and it might rekindle your interest in philosophy: https://youtube.com/watch?v=rvush0oW-cw

IIRC, this interview with neuroscientist Dale Stevens dives into the claims (similar to your example) from the past few years where scientists try to disprove free will: https://youtube.com/watch?v=X6VtwHpZ1BM

Maybe this professor knows it but has found themselves stuck for the rest of their life in this career.

The people with free will refused to do the experiment.

Reminds me of my last Google interview where, upon not being able to conjure up the complete solution to a puzzle solver in 25 minutes, the interviewer's response to my question of "well I thought the interview would be on actually implementing data structures & algorithms as opposed to using DS&A to solve puzzle challenges, do you have any recommendations on how to get better at these puzzles challenges?" to which he replied "yeah definitely study data structures and algorithms." .... like riiight, thanks for that useful nugget of information - I'll be sure to ask for a refund for all that college tuition since I've obviously never ever heard heard of those data structures and algorithms since I couldn't solve a problem in an arbitrary time span. Sorry, not trying to diverge from the topic at hand, but it was the same kind of ridiculous response that is so disconnected from the frame of reference of the question that I couldn't help but share.

I should have had him solve a captcha for me, still not convinced that it wasn't just a reverse turing test.

I can't stand when people give flippant responses to fair questions - I can totally imagine your frustration in your case.

They might not even know the answer themselves and have a solution in front of them that they are comparing yours to.

Then they just said the first thing that came to their mind rather than that they don't know.

Reply on news.ycombinator.com