Can integrated information theory explain the psychedelic experience?

In our last blog post “Are we living in a conscious universe?” we looked at a new theory of consciousness called “integrated information theory”. IIT was developed in an attempt to understand the link between the physical world and our experience of consciousness.

In trying to understand what physical systems give rise to our experience of consciousness, IIT makes a basic assumption; that consciousness is part of the basic fabric of the universe. At first this may sound unscientific… but in fact we assume many fundamental laws in science. In physics we assume a fundamental link between matter and gravity without being able to see examine the link directly. James Maxwell had to assume some fundamental electromagnetic laws to develop a theory of electromagnetic fields. And in a similar way, IIT assumes that consciousness arises from physical systems due to some fundamental laws of the universe.


The details of IIT are complex, and involve quite a bit of computational neuroscience. Overall, the basic idea is that any physical system that contains feedback systems has at least some level of consciousness. IIT predicts that our brains, with their highly connected and complex feedback systems, are highly conscious – which we can confirm from our own experience.

So what does IIT predict about the psychedelic state? What changes in the way that information is organised in our brains during the psychedelic experience, and how does that fit in with IIT’s model of consciousness?

Last year, the computational neuroscientist Andrew Gallimore attempted to describe what IIT predicts about the psychedelic state. Matched up with the results of recent brain imaging studies, IIT tells us some interesting things about how the psychedelic experience changes the way we see the world.


Psychedelics and IIT

When we ingest psychedelic compounds like psilocybin or LSD, we experience many changes in our perceptions. We may see colours as being brighter or with increased saturation. We may hear sounds we’ve never heard before in familiar music, or see motion in stationary objects.

As well as all these changes in perception, we also notice dramatic changes in consciousness. We may become more aware of our own emotions. We may find ourselves making connections we would never have made before. Basically, we start thinking in a totally new, unique way.

Recent neuroimaging studies have given us the first detailed views inside the brain during these dramatic changes in perception and consciousness. Robin Carhart-Harris and his group took images of people’s brains during a psilocybin-induced psychedelic experience. They found that psilocybin caused the brain to enter a state of ‘high entropy’. Basically, the brain makes lots of unique connections between areas that don’t usually talk to each other, and our normal patterns of thought are dissolved. In other words, the brain had become highly disordered.

Does this mean that the psychedelic experience is random, disordered and chaotic? Sometimes it can be… but most people will tell you that the psychedelic experience can produce moments of brilliant intuition and creativity, by opening up new ways of seeing the world.

IIT seems to confirm this idea. When we look at the highly disordered, entropic brain that we see in Carhart-Harris’ neuroimaging studies through the lens of IIT, we see a beautiful picture of an expanded consciousness…

IIT proposes that a single consciousness is made up of a large collection of ‘concepts’, which themselves are created by specific structures of integrated information. The concept of an apple, for example, is created by specific groups of interconnected neurons in your brain.


IIT suggests that consciousness is made up of many concepts, connected in various ways. Figure from Gallimore (2015).

Concepts are connected to each other through ‘cause-effect repertoires’ – basically all the possible ways that your systems of concepts can be connected. For example, the colour orange (cause repertoire) connects to the thought of an orange (concept), which may connect to the thought of an apple (effect repertoire). This is a basic train of thought, and the concept here (an orange) could have many different causes, and many different effects, producing a large range of different possible trains of thought (or cause-effect repertoires).

In normal consciousness, our cause-effect repertoires are set in stone (part A, below). Thinking of an apple probably won’t make you think of too many other things, because the systems of concepts in your brain are not connected in that way. But in the psychedelic state, our cause-effect repertoires become expanded: it’s possible to make more connections between concepts (part B, below). In the words of Gallimore, a concept becomes “about more things” in the psychedelic state.


Cause-effect repertoires. Concepts (black dots) are thoughts that you are having right now. They can be caused by various states in your brain (blue dots). A concept can then cause new states (red dots), producing a train of thought. During a psychedelic experience (B), your concepts are linked to more states than in normal consciousness (A), meaning that concepts can be “about more things”. Figure from Gallimore (2015).

So the psychedelic state allows us to make more connections between concepts than normal. This makes sense, as experienced psychonauts will know that the normal lines between ideas become blurred during the psychedelic experience (supported also by recent research).

Although we make more connections and think in unique patterns during psychedelia, creating a “richer” form of consciousness, that doesn’t necessarily mean that it’s a better form of consciousness. IIT is still at an early stage, so can’t predict exactly ‘how much’ consciousness is present in the psychedelic state compared to normal thought. But what it does tell us is that the psychedelic state processes less information. Because the ‘reality cone’ of conscious experience is expanded during psychedelia (see below), our thoughts become less focussed and we can’t engage in simple tasks as effectively.


The Reality Cone. Being in a psychedelic state means that your current conscious experience is connected to more potential past and future states than normal. This means that your thoughts are more creative and flexible, but you are less able to focus on a single idea or problem. Figure from Gallimore (2015).

This has an interesting implication for the potential benefits of psychedelics. We’ve evolved to have brains that focus our attention on tasks, while still allowing a certain amount of entropy that produces a flexible form of thought. We’re capable of being creative, while still being productive and focussed (this is the ‘entropic brain’ theory of conscious states). Psychedelics tip our consciousness over the carefully balanced pattern of normal thought, making us more creative, but at the cost of practical focus.


Figure form Carhart-Harris et al (2014).

According to IIT, psychedelics might not help us process lots of information; but they may hold huge potential in being used as a tool for creativity. Psychedelics change the way the systems of our brains connect, allowing us access to new concepts and ideas.

The creative state of mind produced by psychedelics could help us in many ways. Maybe it could even help us reach an understanding of the fundamental laws of consciousness that govern the physical requirements of experience…

…understanding our own existence is surely something worth striving for.

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Carhart-Harris et al. (2014) The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs. Front. Hum. Neurosci. 8:20

Gallimore AR (2015) Restructuring consciousness – the psychedelic state in light of integrated information theory. Front. Hum. Neurosci. 9:346

Oizumi, Albantakis & Tononi (2014) Integrated information theory 3.0. PLOS Comp. Biol. 10(5)

Tononi & Koch (2015) Consciousness: here, there and everywhere? Phil. Trans. R. Soc. B. 370

Integrated Information Theory on Scholarpedia

4 thoughts on “Can integrated information theory explain the psychedelic experience?

  1. I think it’s absolutely great that people are investigating psychedelics. And your descriptions of what psychedelics do our mostly accurate I think. I’m a little concerned at describing psychedelic states in an objective manner; for one because that’s with the scientist tried to do from the beginning and the people who were on psychedelics could see right through them.

    But in particular what came to mind for me is it’s not just that the mind makes these connections or that perceptions get changed or linkages in the mind are multiplied or or any of those types of descriptions; it is more I think that only in the initial stages of taking psychedelics does not happen. I think that psychedelics do you do that they tend to disrupt or disorganize what could be called a normal pattern of mind functioning. But I think that repeated use will be shown to settle in a particular pattern.

    I know it’s very modern of us and scientists to want to say that there are multifocality and multi realities multi worlds all these types of postmodern multi things.

    I think it would be more productive and I think the science on psychedelic states will be lacking until we take a single subject a single person -but I think this might be unethical maybe- and then also a small group of people, and measure or somehow record their brain activity before they ever took psychedelics and then measure it over time as they continue to take psychedelic substances over say five years 10 years.

    I myself spent a good solid two years on psychedelic specifically but drugs of all sorts. And very honestly speaking, I was not insane by any observable means; I worked I was pretty functional part normal human being so to speak. But I had to stop taking it because of a particular type of consciousness that I did not enjoy about myself. In the end I would take psychedelics more and more occasionally thinking that somehow it would rectify itself. But the repeated taking the drug in order to rectify what does kind of mental itch was in a manner of speaking, only served to make it itch more.

    There is something to say about leary and I forget the other author take on psychedelics in the Tibetan book of the dead. There is something to say about let it flow.

    But there is also something to say as to what occurs when that is not happening.

    I would think any science neuroscience chemical science mind science will always be lacking excepted so much as we want to control people along a certain line , until we take in all these variables, which might be exceedingly difficult.

    Again honestly speaking from the time I took my last dose of LSD it took 15 years before that it was gone and I considered myself a “normal” human being. But it is not so much that I hated myself or that I was insane or anything negative at all really, it was just there were some type of mental “itch” that I couldn’t scratch anymore that psychedelic drugs would not reproduce and not get rid of.

    So I’m a little concerned with the investigation into psychedelics that does not see the sheer number of variables that go into some sort of analysis of it . But I also realize we got to start somewhere.


  2. You know I’m glad I found your website or your blog I mean. I too am interested in psychedelics but more on the experience side. I feel part of the science that you are talking about at least in this post should also be accompanied by a kind of anthropology of experience sites. And what I mean by this is not the short term individual psychedelic experiences of like say hey I went to the Grateful Dead and they played the songs and it made so much sense to me– these should be taking to account — but I am more interested in the long term affects of long-term psychedelic use including smoking pot.

    For it seems to me that we could learn a lot and find out just what psychedelics do to people or just what types of experiences occur if we could get people to talk about their lives in a very candid way how they think about things what their spirituality is what spirituality they don’t have things like that.

    Thx so much. Keep it up.

    Liked by 1 person

  3. I just read it again. It does appear that it is dealing with initial, or preliminary, or what we could call ‘real-mediant’ states. The surfacial aspect that occurs with real ontological knowledge, philosophically speaking. Which i would say occupies about 15% of phychedelic affect.


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