With eyes closed

Do we think differently with our eyes closed or closed? Apparently we do. And it is not just a simple difference like the brain having more to do when it is processing vision compared to when it is not receiving visual input. There is a difference in how we react to music with our eyes closed and in a dark room with our eyes open. A recent paper by Garuso and Gino elaborates on this phenomenon (pdf). Here is the abstract:

Four experiments demonstrate that closing one’s eyes affects ethical judgment and behavior because it induces people to mentally simulate events more extensively. People who considered situations with their eyes closed rather than open judged immoral behaviors as more unethical and moral behaviors as more ethical. In addition, considering potential decisions with closed eyes decreased stated intentions to behave ethically and actual self- interested behavior. This relationship was mediated by the more extensive mental simulation that occurred with eyes closed rather than open, which, in turn, intensified emotional reactions to the ethical situation. We discuss the implications of these findings for moral psychology and ethical decision making.

So we can imagine much more vividly with our eyes closed and this leads to more emotional involvement and finally to more ethical behaviour.

What does this say about consciousness? Perhaps we need to use the visual cortex in order to have more extensive mental simulations. Our full consciousness can then be used for the imagined scene. Perhaps the act of closing the eyes, in effect, gives permission to use the facilities of the visual cortex for imagining. The cascades of the eyes are somehow coordinated with the rhythm of the gamma waves that accompany consciousness; is this why there is a difference in imagining with the eyes closed? We often close our eyes when we want to concentrate on something, savour something or recall something. Perhaps closing the eyes is a way to strengthen ‘top-down’ control of attention. The cascades of the eyes also have some effect steering attention to the next point in space that will be the center of the visual field. Perhaps closing our eyes make us more viscerally aware and that heightens emotion. Here is Lerner etal’s overview of the eyes-closed state of consciousness:

Brain wise, the closed eyes position is well known by its unique electrophysiological signature of increased alpha rhythm. In a recent resting state study, fMRI and EEG signals were recorded simultaneously while participants intermittently were instructed to close or open their eyes. Using the combined measurements, two alpha rhythms were defined tempo-spatially with relation to the closed eyes position; one on-going and spontaneous distributed in the midline brain regions including the prefrontal cortex (PFC), cingulate cortex and thalamus, and the other stimulated by shift in eyes position from open to closed distributed in the fronto-temporal cortical regions. These data point to the possibility that closing the eyes indeed characterizes a specific brain state that can be affected by the individual’s mental set. Accordingly, the current study presumes that eyes closed position represents a well defined mental set by which perceived emotionality can be modulated, thus probing its neural respect.

They recorded substantial differences in amygdala activity. This is a very intriguing area of research.

ResearchBlogging.org

Caruso, E., & Gino, F. (2011). Blind ethics: Closing one’s eyes polarizes moral judgments and discourages dishonest behavior Cognition, 118 (2), 280-285 DOI: 10.1016/j.cognition.2010.11.008

Lerner, Y., Papo, D., Zhdanov, A., Belozersky, L., & Hendler, T. (2009). Eyes Wide Shut: Amygdala Mediates Eyes-Closed Effect on Emotional Experience with Music PLoS ONE, 4 (7) DOI: 10.1371/journal.pone.0006230

Confabulation and transparency

It is that time of year; Edge has published this year’s question and has over 160 answers so far.

James Flynn has defined “shorthand abstractions” (or “SHA’s”) as concepts drawn from science that have become part of the language and make people smarter by providing widely applicable templates (“market”, “placebo”, “random sample,” “naturalistic fallacy,” are a few of his examples). His idea is that the abstraction is available as a single cognitive chunk which can be used as an element in thinking and debate.

The term ‘scientific”is to be understood in a broad sense as the most reliable way of gaining knowledge about anything, whether it be the human spirit, the role of great people in history, or the structure of DNA. A “scientific concept” may come from philosophy, logic, economics, jurisprudence, or other analytic enterprises, as long as it is a rigorous conceptual tool that may be summed up succinctly (or “in a phrase”) but has broad application to understanding the world.

What scientific concept would improve everybody’s cognitive toolkit?

The question is the work of Steven Pinker and Daniel Kahneman. It is worth a read and all the answers are found here

One answer fits with the previous posting on the transparency of consciousness, Fiery Cushman’s piece on confabulation.

We are shockingly ignorant of the causes of our own behavior. The explanations that we provide are sometimes wholly fabricated, and certainly never complete. Yet, that is not how it feels. Instead it feels like we know exactly what we’re doing and why. This is confabulation: Guessing at plausible explanations for our behavior, and then regarding those guesses as introspective certainties. Every year psychologists use dramatic examples to entertain their undergraduate audiences. Confabulation is funny, but there is a serious side, too. Understanding it can help us act better and think better in everyday life.

This confabulation is well known and studied. It takes experimental situations to make it plainly evident. We are guessing at our motivation but we are not so wrong as to be laughable. Because we are not conscious of the transparent workings of our brain we can only guess.

Ironically, that is exactly what makes confabulation so dangerous. If we routinely got the explanation for our behavior totally wrong — as completely wrong as split-brain patients sometimes do — we would probably be much more aware that there are pervasive, unseen influences on our behavior. The problem is that we get all of our explanations partly right, correctly identifying the conscious and deliberate causes of our behavior. Unfortunately, we mistake “partly right” for “completely right”, and thereby fail to recognize the equal influence of the unconscious, or to guard against it.

Cushman still uses the conscious-unconscious model of thought and seems to assume that some of our cognition is not transparent. I prefer the transparent explanation. We get the guesses right because we are good and practiced guessers. He gives a number of examples of our guesses missing important motivations and then ends with this:

This brings me to the central point, the part that makes confabulation an important concept in ordinary life and not just a trick pony for college lectures. Perhaps you have noticed that people have an easier time sniffing out unseemly motivations for other’s behavior than recognizing the same motivations for their own behavior. … There is a double tragedy in this double standard.

First, we jump to the conclusion that others’ behaviors reflect their bad motives and poor judgment, attributing conscious choice to behaviors that may have been influenced unconsciously. Second, we assume that our own choices were guided solely by the conscious explanations that we conjure, and reject or ignore the possibility of our own unconscious biases.

By understanding confabulation we can begin to remedy both faults. We can hold others responsible for their behavior without necessarily impugning their conscious motivations. And, we can hold ourselves more responsible by inspecting our own behavior for its unconscious influences, as unseen as they are unwanted.

Or we can assume that everyone is only guessing all the time, but that by and large the guesses are pretty good. Their inaccuracy is usually in their self-serving quality – both for us and for others.

Transparency

Thomas Metzinger wrote an outline of his book, ‘Being No One’, which puts his theory of consciousness in a very brief, compact form. He puts forward a list of constraints that any system must have to be conscious. The first three constrains gives a simple form of consciousness which he then elaborates with further constrains. Less than the first three will not produce conscious experience.

Constraint 1 is globality: all the contents of consciousness are found in the form of a single globally available integrated world-model. Constraint 2 is presence: the experience of consciousness is as a present ‘now’ in a flow of time. Our experience is being now in the world. Constraint 3 is transparency: consciousness does not include awareness of the process that created it; the mechanism is transparent.

“the most elementary form of conscious experience conceivable: The presence of a world. The phenomenal presence of a world is the activation of a coherent, global model of reality (Constraint 1) within a virtual window of presence (Constraint 2), a model that cannot be recognized as a model by the system generating it within itself (Constraint 3)… Phenomenal selfhood … it is a function realized by a lack of information.We do not experience the contents of our self-consciousness as the contents of a representational process, but simply as ourselves, living in the world right now. ”

It is the transparency that makes the experience seem to be direct when it is very indirect. It does not feel like the ‘world’ is constructed; that the ‘now’ is constructed; that the ‘self’ is constructed.

Here is a philosopher that has successfully turned his back on introspection as a source of knowing about the nature of consciousness. I cannot state too strongly how satisfying this theory is to me. It fits so well with what I think about consciousness and I will return to it in future posts.

It is worth reading this precis but be warned – this is a German philosopher writing in English and condensing an extremely long book. There are some hum-dingers of sentences.

Note: original link was wrong and has been corrected. Also, there is an alternative link in comment from helpful reader – thanks.

ResearchBlogging.org
Thomas Metzinger (2005). Precis of – Being No One Psyche – An Interdisciplinary Journal of Research on Consciousness, 11 (5)
http://www.theassc.org/files/assc/2608.pdf

Is quantum uncertainty necessary?

I just read a post (here) called “We Seem to be Zombies” by Stuart Kauffman. It repeatedly annoyed me. I try very hard not to write angry postings but really this was just more than I could stomach. I apologize to those readers who dislike angry posts and I will still try to avoid them in future.

So here is a list of annoying bits.

  1. The introduction starts with this picture: “according to some of our finest scientific minds, you are not conscious at all. You are a mechanical zombie, a calculating-machine idiot. You have no responsible free will. You are not even an ‘I’, the subject of experiences that you naively have the illusion you have. You cannot act responsibly because machines are machines, you are a machine, and like a marble rolling down the side of a bowl, mechanisms ‘happen’ they do not act. So you cannot act. You cannot be a autonomous agent blazing with life, its anguish and joy”. I would like to see the names of a handful of ‘our finest scientific minds’ who have said such things. The impression is given that this exaggerated picture is accepted science in some quarters – why not name them? My impression is that most scientists, especially those with fine minds, believe that we are living organisms not mechanical machines and that we are aware not zombies. Why this unrealistic characterization of science?

  2. After a historical look at dualism he says: “Virtually all contemporary thinkers on the subject assume that mind and brain are identical.” You would assume that he included himself in contemporary thinkers. But, no, a couple of sentences later, he reverts to a dualist mind set, mind and brain are now not identical. “if the brain is a deterministic system, like the billiard balls, the current state of the brain is entirely sufficient to determine precisely the next state of the brain. Woefully, there is NOTHING FOR MIND TO DO! Worse, there is no way for MIND TO DO AYTHING TO BRAIN ANYWAY.” The capitals are his. This does not sound like a description of a brain and mind that are identical. It sounds dualist. There is an ‘if’ at the start so it is just as possible that he is abandoning a deterministic system because he thinks it leads to dualism. Is it identity of mind/brain or causality that he is questioning? Why is this not clear?

  3. Ah, here comes the clarification. It is a confusion of mind and consciousness. “Maybe mind really is an illusion? Maybe it is an epiphenomenon?” What is the definition he is using for this ‘mind’ that can at the same time be: identical to the brain, have nothing to do while the brain is ‘doing’, and be an illusion. Come on, is he talking about consciousness or is he talking about thought (perception, cognition and action)? He is not communicating what he means to me – is he talking down to me or is he trying to confuse me with a bait and switch?

  4. Now is a history of positivism and its ilk which he shows is as much of the dead end as dualism. Then he goes on, as if positivism was alive and well, to look at computer artificial intelligence and finally the Turing machine. All this is outlined as if it is relevant to the subject of our brain/minds and not just fit for symbolic logic or digital computers. In capital letters, we learn that a Turing machine and a very particular type of artificial ‘neural’ network are absolutely defined, algorithmic and understandable in terms of entirely classical physics. So what? He says that this has led to the belief in computer science, cognitive science and neuroscience that “the mind MUST BE algorithmic” and “IF consciousness is real, consciousness will somehow emerge when sufficiently many computer chips are coupled together.” This is a funny way to abandon the spirit of positivism. For heaven’s sake, who are these people who believe that the brain works like the most mundane (or universal) computer imaginable or works like the first try at artificial intelligent networks? I am sure there are scientists who believe that the brain is probably algorithmic but how many believe it must be? The comparison of brain/mind and computer is a metaphor not some strict specification and most scientists know that. Why am I being led down the garden path to think the brain is algorithmic?

  5. So now we have the key statement: “In the world of classic physics, the only hope its proponents hold out for consciousness so that we are not zombies is that a sufficiently complex network of calculating gadgets will ‘emerge’ into consciousness.” So now I am asked to accept two ideas without the help of either logic or evidence: (a) what has just been described in the terms of brain-being-computer is the sum total of what classic physics has to offer. Does biochemistry, biophysics, physiology etc. now require something more than the physics it has always used to underpin chemistry? What is it? I have to assume it is the uncertainty principle in quantum physics the only part of quantum physics that does not usually figure in chamistry; (b) mind has now become consciousness. Where did the other mind go, the one that was identical to the brain – the one that is perception, cognition and action? I insist that I will not be dealt some slight of hand that confuses thought with awareness of thought. That is like confusing the actual tree with my awareness of the tree. It will not do. And how did non-algorithmic brain/mind come to be impossible by classic physics?

  6. Next is the promise that future postings will explain synapses in terms of coupled Trans-Turing Systems. I will probably read these postings but I am not hopeful that they will be very enlightening and I fear that they will continue the unconvincing paths of this posting.

To set the record straight I will state clearly what I think is likely so. The brain is physical (as in matter and energy with no supernatural, non-physical or magical bits). The brain has biological function and its function is perception, cognition, learning, memory, action (muscular and glandular), conscious awareness and perhaps other associated processes. We have a word for this biological function, it is ‘mind’. Brain does mind in the same way as heart does circulation or stomach does digestion or lung does gas exchange. Brain is a living organ and mind is the function of that organ. Mind does not exist in the sense that the brain exists, it exists like circulation exists. Mind is not res cogitans; it is not ‘Res’ anything because it is not a thing, not an object. There is no shred of evidence that the brain does its mind function using algorithmic calculations and at least some evidence against it. Why the assumption that thought must be a fixed, stepwise procedure. There is no reason to think that the functions of the brain give predicable results in the sense of actually being able to predict them. It does not matter whether the attempt to predict uses classical physics or not – it is not in practice possible and therefore it doesn’t really matter if prediction is theoretically possible. Who cares? We can assume that consciousness is an important part of the function of the brain because it is biologically expensive. We can assume that it interacts with other aspects of the function of the brain (ie consicousness is part of mind but not a large part of it and is integrated with other parts of mind – mind being what brain does). There is nothing in this that makes us non-autonomous, machine-like things or zombies. There is nothing here that gives us freewill either, if by free we mean free from physical/material constraints. Our brain/minds make real decisions, and act on them and are then responsible for those decisions – the decisions are neither free or un-free, they are not determined or un-determined. Freewill and determinism is a dichotomy that is fictitious – neither term is true or false – but instead they are meaningless – they are not possible. They are silly answers to a silly question. It does not seem useful to bring the uncertainty of very, very small things into the discussion of processes that scan of few inches, produce electrical fields that can be measured through the skull bone, weighs many grams, and use the energy of a fifth of what we eat. It may turn out that we need quantum uncertainty in order to explain the brain/mind and if we do than so be it. If it turns out that an explanation of the brain/mind needs the uncertainty principle, that still will not give meaning to either freewill or determinism. Why?

Because if we start with the ridiculous assumption that the mind makes decision which it then imposes on the brain, we still have the problem of exactly how the mind makes decisions. Does the mind have a process? Does the mind have a mind in an endless regression, or is it random, or is there a magical way?

Postscript: Still feeling that I should not be so annoyed by Kauffman’s blog, I have set this aside and waited for his next two posts on the subject. The first read almost identically to the ‘Zombie’ blog. The next blog dealt more with the physics. I am still annoyed after a suitable wait and so I am posting this.

Faster scan

For humans (as opposed to animals) there are at present very few ways to look at the brain. Researchers can look at the electrical fields on the outside of the skull (EEG). This give clear ‘whens’ for events but poor ‘wheres’. Looking at blood flow in the brain (fMRI) gives better ‘wheres’ but poorer ‘whens’. Anatomy in autopsy can be compared to behaviour during life in individuals with trauma, surgery or congenital damage to part of the brain, but there is little control as each case is individual. Occasionally electrodes are placed in the brain in preparation for brain surgery and patients permit investigation of the neurons in the region of the electrodes. The effects of deep brain stimulation is another source of data. These last two paths are also somewhat one-off with limited duplication or control. Various chemicals can affect the brain and behaviour but here the ‘wheres’ and ‘whens’ are very poor. All and all it is a meager experimental toolkit.

So it is great news that fMRI setups can have a pair of modifications that together increase the speed by over seven times. Shorter duration scans will give much better ‘when’ definition. The Connectome Project will benefit as well as the usual ‘coloured patches in the brain’ type research.

Gap junctions

There are (at least) two types of junctions between neurons: chemical synapses and electrical synapses. In chemical synapses there is a tiny space between the membranes of the two neurons, molecules of neurotransmitter are bled into this space by one neuron and taken in by the other. In this way a signal is sent from the pre-synaptic neuron to the post-synaptic one. The signaling occurs when the pre-synaptic cell is firing and the post-synaptic cell is influenced to fire more easily, or less easily in inhibitory synapses. But there is a slightly simpler junction found both in the brain and in other tissues. It is a cluster of tiny channels in one cell membrane that lines up with a similar set of channels through another cell’s membrane so that small chemicals or electrical currents can pass directly between the two cells. The tiny channels can be opened and closed. We think of the brain as using only chemical synapses when actually the gap junctions exist in many areas of the brain, especially between glial cells. They are noted to pass electrical currents in the form of charged ions but may also signal using calcium ions and other chemicals. A group of cells connected by gap junctions have, in effect, a continuous cytoplasm as far as small molecules and electrical charge are concerned. The activity of cells using gap junctions is another whole level of activity in the brain.

In a recent paper reported in ScienceDaily (here) M. Fanselow and his group have looked at gap junction activity in the hippocampus especially during the memory of fearful situations.

Fanselow said, “We hypothesized that these gap junctions may be very important. Because the gap junctions cause the inhibitory neurons to fire together, they may cause these inhibitory neurons to act as a pacemaker for the excitatory neurons, making them fire at the same time so they are better able to make fear memories. Neuronal gap junctions form where inhibitory neurons touch one another. They are like an opening between nerve cells, a gap in the membranes separating the cells from one another; they let the electrical activity in one neuron affect the neuron it touches.

Gap junction may have (or are likely to have, really) a role in maintaining synchrony in the brain and synchrony appears to be a the heart of many process including consciousness.

Abstract: The role of electrical synapses in synchronizing neuronal assemblies in the adult mammalian brain is well documented. However, their role in learning and memory processes remains unclear. By combining Pavlovian fear conditioning, activity-dependent immediate early gene expression, and in vivo electrophysiology, we discovered that blocking neuronal gap junctions within the dorsal hippocampus impaired context-dependent fear learning, memory, and extinction. Theta rhythms in freely moving rats were also disrupted. Our results show that gap junction–mediated neuronal transmission is a prominent feature underlying emotional memories.

I could not reach the original paper but the citation is:

Stephanie Bissiere, Moriel Zelikowsky, Ravikumar Ponnusamy, Nathan S. Jacobs, Hugh T. Blair, Michael S. Fanselow. Electrical Synapses Control Hippocampal Contributions to Fear Learning and Memory. Science, 2011; 331 (6013): 87-91 DOI: 10.1126/science.1193785

Change blindness illusion

Jordan Suchow has some illustrations of an illusion (here) that accompany the paper whose citation is below. It an excellent demonstration of change blindness. Here is the abstract:

Loud bangs, bright flashes, and intense shocks capture attention, but other changes – even those of similar magnitude – can go unnoticed. Demonstrations of change blindness have shown that observers fail to detect substantial alterations to a scene when distracted by an irrelevant flash, or when the alteration happen gradually. Here, we show that objects changing in hue, luminance, size, or shape appear to stop changing when they move. This motion induced failure to detect change, silencing, persists even though the observer attends to the objects, knows that they are changing, and can make veridical judgments about their current state. Silencing demonstrates the tight coupling of motion and object appearance.

Illusions are always entertaining but my blog is about consciousness. So what does this paper say about that?

During silencing, rapidly changing objects appear nearly static, which raises an immediate question: What is the perceived state at any given moment? To illustrate, consider an observer who fails to notice an object change gradually from yellow to red. One possibility is that the observer always sees yellow, never updating his percept to incorporate the new hue – this is freezing, erroneously keeping hold of an outdated state. Another possibility is that he always sees the current hue (e.g. yellow, orange, then red) but is unaware of the transition from one to the next – this is implicit updating.

In the one case the color’s change does not attained a cognitive level where it could reach consciousness and it the other case it appears to reach that level but for some reason is not included in the contents of consciousness. The two explanations can be examined by starting with yellow and moving to red and then jumping back to yellow. Is the jump noticed (implicit updating has happened) or not (freezing has happened)? In general the answer is implicit updating. But…

Incidentally, freezing of stationary color changes has been found to last for approximately 200ms, which corresponds to a -10 degrees change in hue in our reversion test. Though the data rule out the possibility that temporal freezing explains silencing, they leave open the possibility that freezing persists within a local window, such that the perceived color consistently lags a bit behind the actual color; this would explain the observed, though not statistically significant, lag.

This is about the time that it would take for a change to be able to reach consciousness. Activity occurring up to 200ms seems not to be distinguishable between conscious and unconscious processing, past that approximate duration the activity builds to reach consciousness at about 300ms or remains unconscious. Thus there is a somewhat paradoxical situation where a perception seems to have been formed and reached (or almost reached) consciousness and yet is not consciously reported although is in some sense it is remembered. Is it only the addition of being suddenly the focus of attention that makes the difference?

ResearchBlogging.org
Suchow, J., & Alvarez, G. (2011). Motion Silences Awareness of Visual Change Current Biology DOI: 10.1016/j.cub.2010.12.019

Time travel

What is the difference between remembering an event, imagining it in the future or experience it in the present? Is the completeness and vividness of the present the only difference? A recent paper by L. Nyberg and others has examine the question. The article is behind a pay wall but a good review is available at Physorg (here). Below is the paper’s abstract:

“Mental time travel” refers to conscious experience of remembering the personal past and imagining the personal future. Little is known about its neural correlates. Here, using functional magnetic resonance imaging, we explored the hypothesis that mental time travel into “nonpresent” times (past and future) is enabled by a special conscious state (chronesthesia). Well-trained subjects repeatedly imagined taking one and the same short walk in a familiar environment, doing so either in the imagined past, present, or future. In an additional condition, they recollected an instance in which they actually performed the same short walk in the same familiar setting. This design allowed us to measure brain activity correlated with “pure” conscious states of different moments of subjective time. The results showed that the left lateral parietal cortex was differentially activated by nonpresent subjective times compared with the present (past and future > present). A similar pattern was observed in the left frontal cortex, cerebellum, and thalamus. There was no evidence that the hippocampal region is involved in subjective time travel. These findings provide support for theoretical ideas concerning chronesthesia and mental time travel.

It has to be stressed that all the sessions where imagined whether they were placed in the past, present or future and so there should be very little difference in the content of consciousness, only the time associated with the content changed.

The strongest difference is between the present and not present time. There is much less difference between past and future. It also is interesting that the effect of time travel is so widespread in the brain – at number of processes must have to be aware that this is not a ‘now’ conscious content.

Alien hand

A recent study of a Parkinson patient with alien hand syndrome has been published by Schaefer, Heinze and Galazky (citation below). This patient offered an interesting opportunity because his left hand made both involuntary and voluntary (but with effort) movements. What is more, a particular sort of involuntary movement could be triggered in a predictable manner. Blocks of fMRI scans were made under 4 conditions and rest.

  1. left handed triggered to move without volition by pushing it slightly resulting in a counter movement (Gegenarbeiten) – it gave activity as compared with 2 in primary motor cortex, left premotor cortex, precuneus, right inferior frontal gyrus, and cerebellum;

  2. a similar trigger on the right hand that does not result in any movement – it gave no significant activity compared to 1;

  3. a voluntary movement of the left hand which took extra effort to achieve – it gave activity as compared with rest in primary motor cortex, supplementary motor area, ventromedial prefrontal cortex, precuneus and cerebellum;

  4. a voluntary movement of the right hand – similar activity to 3 compared to rest except for inactivity in the precuneus and inferior frontal gyrus.

  5. motionless rest.

A difference between conscious and unconscious movement was found in the precuneus, where it would likely be due to conflicts of agency.

“Similar to the precuneus, the IFG is not typically activated in motor paradigms. This brain area has also been reported to be uniquely activated during alien movements in the fMRI study by Assal et al. Recent lesion studies discuss a role for the right IFG in inhibitory control over motor responses. Since the IFG was active only in the condition when we elicited involuntary movements, involvement of this brain region may reflect attemptions to control and inhibit movements of the alien hand. Thus, we argue that both precuneus as well as the IFG may reflect conflicts of agency in unconscious and unwanted movements.”

So the main difference between conscious and ‘alien’ movement seems to be attempting and/or resisting the sense of agency or ownership of the movement and attempting/resisting inhibition of the movement. There appears to be no difference in the planning, specifying and execution of the movement.

ResearchBlogging.org
Schaefer, M., Heinze, H., & Galazky, I. (2010). Alien Hand Syndrome: Neural Correlates of Movements without Conscious Will PLoS ONE, 5 (12) DOI: 10.1371/journal.pone.0015010

Decline effect

A writer to the Less Wrong discussion page (here) commented on the New Yorker article by J Lehrer (article) about why some effects start out with positive results and with time the results become negative.

The comment is by a physicist, name unknown:

A summary of explanations for this effect:

  • “The most likely explanation for the decline is an obvious one: regression to the mean. As the experiment is repeated, that is, an early statistical fluke gets cancelled out.”
  • “Jennions, similarly, argues that the decline effect is largely a product of publication bias, or the tendency of scientists and scientific journals to prefer positive data over null results, which is what happens when no effect is found.”
  • “Richard Palmer… suspects that an equally significant issue is the selective reporting of results—the data that scientists choose to document in the first place. … Palmer emphasizes that selective reporting is not the same as scientific fraud. Rather, the problem seems to be one of subtle omissions and unconscious misperceptions, as researchers struggle to make sense of their results.”
  • “According to Ioannidis, the main problem is that too many researchers engage in what he calls “significance chasing,” or finding ways to interpret the data so that it passes the statistical test of significance—the ninety-five-per-cent boundary invented by Ronald Fisher. … The current “obsession” with replicability distracts from the real problem, which is faulty design.”

Things sort themselves out – this is not a huge problem to those in the particular field where a ‘decline effect’ happens. Where the problem is serious is outside the field involved. Where a original result piques the public’s interest, especially where it is reported without needed context and very especially where it touches a controversy, there is a problem.

There are a lots of people who hold metaphoric bets on how the brain works and particularly how consciousness works. Although it is not as controversial as, for example, global warming, people still would like certain things to be true and others to be false. It would help keep results in perspective if people knew that unusual results often fade away with time as more studies are done, that this is normal and not scandalous.

I will say it again and hope that my readers are not bored by this repeated message – do not put your trust in individual results or even chains of results which depend on their weakest link, but trust strong webs or fabrics of evidence.