Category Archives: consciousness

Another look at consciousness

Judith Copithorne image

Judith Copithorne image

There is an interesting new paper with a proposed model of consciousness (Michael H. Herzog, Thomas Kammer, Frank Scharnowski. Time Slices: What Is the Duration of a Percept? PLOS Biology, 2016; 14 (4): e1002433 DOI: 10.1371/journal.pbio.1002433). It reviews various theories and experiments in the literature on the subject. Their model is similar to how I have viewed consciousness for a few years, but with important and interesting differences.

They view consciousness as non-continuous, like the frames of a movie, which has seemed the only way to look at consciousness that fits the knowledge that we have of what appear to happen in the brain. They are not dealing with the neurology though and give space to reasons why people have resisted discrete frame and clung to continuous consciousness.

Another aspect of their theory that I like to hear is that the heavy lifting of perception is done unconsciously. The final product of the unconscious processing is a ‘frame’ of consciousness. This fits with the notion that there is not a conscious mind in the sense that we think of a mind. There is only the unconscious mind or simply the mind. Consciousness is a presentation, a moment of experience to remember, a global awareness of a percept.

I have in the past thought of a best-fit-scenario end point of perception, the stable point that would end the iterations of a complex analog computation and be the perception on which consciousness is based. The authors talk of Bayesian statistical computations stopping when they reach an ‘attractor’. This seems the same basic idea but more amenable to experimentation and modeling.

During the unconscious processing period, the brain collects information to solve the ill-posed problems of vision, for example, using Bayesian priors. The percept is the best explanation in accordance with the priors given the input. … One important question is how the brain “knows” when unconscious processing is complete and can be rendered conscious. We speculate that percepts occur when processing has converged to an attractor state. One possibility is that hitting an attractor state leads to a signal that renders the content conscious, similarly to, for example, broadcasting in the global workspace theory. … Related questions are the role of cognition, volition, and attention in these processes. We speculate that these can strongly bias unconscious processing towards specific attractor states. For example, when viewing ambiguous figures, a verbal hint or shifting attention can bias observers to perceive either one of the possible interpretations, each corresponding to a different attractor state.

The most interesting idea (to me) is that the conscious precept is not a snap shot in a series of snap shots but a constructed slab or slice of time in a series of slices. The frames are of short duration but represent slices of time rather than moments. The implication is that we do not, in any sense, have a direct experience of the world, but a highly processed and codified one.

All features become conscious simultaneously, and the percept contains all the feature information derived from the various detectors. Hence, (a green line) is not actually consciously perceived as green during its actual (sensual stimulus) but later when rendered conscious. The same holds true for temporal features. The stimulus is not perceived during the 50 ms when it is presented. The stimulus is even not perceived for a duration of 50 ms. Its duration is just encoded as a “number,” signifying that the duration was 50 ms in the same way that the color is of a specific hue and saturation.

I hope this paper stimulates some ingenious experimentation.

 

Get rid of the magic

I have difficulty with the reaction of many people to the idea that consciousness is a process of the brain. They say it is impossible, consciousness cannot be a physical process. How can that vivid subjective panorama be the product of a physical process? They tend to believe either some variety of dualism – consciousness is not physical but spiritual (or magical), or consciousness is a natural primitive – a sort of state of matter/energy that objects possess more of less of (another sort of magic). Or they fudge the issue by believing it is an emerging aspect of physical processes (kind of physical but arising by magic). I find explanations like these far more difficult than a plain and simple physical process in the brain (with no magic).

My question is really, “what would you expect awareness to be like?” “Have you a better idea of how to do awareness?” It would certainly not be numeric values. It would not be word descriptions. Why not a simulated model of ourselves in the world based on what our sensory organs can provide? Making a model seems a perfectly reasonable brain process with no reason to reject it as impossible. It sounds like what we have. But does it need to be a conscious model? (Chalmers’ idea of philosophical zombies assumes that consciousness is an added extra and not needed for thought.)

But it seems that consciousness is an important aspect of a shared simulation. It is reasonable to suppose that all our senses, our memory, our cognition, our motor plans, our emotional states, all contribute to create a simulation. And it is reasonable to assume that they all are responsive to the simulation, use it to coordinate and integrate all the various things going on in the brain so making our behaviour as appropriate as possible. If a model is going to be created and used by many very different parts and functions of the brain it has to be something like a conscious model – a common format, tokens and language.

There have been a number of good and interesting attempts to explain how consciousness might work as the physical process; and there have been a number of attempts to show that such an explanation is impossible. They pass one another like ships in the night. Agreement is not getting any closer. There is not even the start of a concensus and the reason is that one group will not accept something is a valid explanation if it include the magic and the other group will not accept an explanation that loses the magic. The hard question is all about the magic and not about anything else. The question boils down to how can consciousness be explained scientifically while including the magic? I hope that more and more science throws out the magic and the hard question and gets on with explaining consciousness.

REM sleep and saccades

When we sleep we pass through a cycle of types of sleep. One of these types is REM (rapid eye movement) sleep and if we are awqkened during REM sleep we report dreaming. During REM sleep movement of the body is suppressed (except of sleep-walkers). Only the eyes are moving under the eye lids. These eye movements resemble the regular rapid movement of the eyes from one fixation to another when awake, called saccades.

A recent paper (Thomas Andrillon, Yuval Nir, Chiara Cirelli, Giulio Tononi, Itzhak Fried. Single-neuron activity and eye movements during human REM sleep and awake vision. Nature Communications, 2015; 6: 7884 DOI: 10.1038/ncomms8884) compares REMs and saccades. The research was carried out on epileptic patients being prepared for surgery by having electrodes implanted deep in the brain for 10 days. In this case there were 9 patients with electrodes in the medial temporal lobe. The MTL is thought of as a bridge between vision and imagining visual scenes on the one hand and memory on the other. As well as recording activity from neurons, the researchers also recorded movement of the eye muscles and conventional EEC from various parts of the scalp.

They found the REMs and saccades were very similar in their pattern of activity in the brain. This says something very interesting about consciousness. When the eyes move in a saccade there is saccadic suppression of the information arriving via the optic nerve from the eyes. There are signals arriving and they affect brain activity but they do not register in consciousness; the gap in visual information is also hidden from consciousness. We are, in affect, as when watching a movie, viewing a series of still images and creating a continuous effect. So saccades are associated with creating a continuous effect from a train of discrete, discontinuous signals. (At least that is one theory.)

The type of dreaming that is associated with REM sleep can be seen as a very similar process, a form of consciousness that is cut off from actual sensory input and from control of skeletal muscles. The purpose of these dreams is unclear but it probably involves some aspect of memory processing. So perhaps the dreams are a series of discontinuous images divided by REMs, leaving no trace of the gaps during the eye movement, as in awake consciousness.

But why would the eye movement by required to create the conscious process during sleep? Perhaps it drives it, or controls it, or times its components, or perhaps it is not required but cannot be eliminated. What interesting questions! They may help to understand conventional consciousness as well as dreams.

Here is the abstract: “Are rapid eye movements (REMs) in sleep associated with visual-like activity, as during wakefulness? Here we examine single-unit activities (n 1⁄4 2,057) and intracranial electroencephalography across the human medial temporal lobe (MTL) and neocortex during sleep and wakefulness, and during visual stimulation with fixation. During sleep and wakefulness, REM onsets are associated with distinct intracranial potentials, reminiscent of ponto-geniculate-occipital waves. Individual neurons, especially in the MTL, exhibit reduced firing rates before REMs as well as transient increases in firing rate immediately after, similar to activity patterns observed upon image presentation during fixation without eye movements. Moreover, the selectivity of individual units is correlated with their response latency, such that units activated after a small number of images or REMs exhibit delayed increases in firing rates. Finally, the phase of theta oscillations is similarly reset following REMs in sleep and wakefulness, and after controlled visual stimulation. Our results suggest that REMs during sleep rearrange discrete epochs of visual-like processing as during wakefulness.

Making sense of the sense of smell

This is another post on Morsella’s ideas.

In developing the Passive Frame theory of consciousness, the group uses olfaction as the sensory source to focus on. This seems surprising at first, but they have good reasons for this.

First, it is an old system from an evolutionary viewpoint. As in this quote from Shepherd: “the basic architecture of the neural basis of consciousness in mammals, including primates, should be sought in the olfactory system, with adaptations for the other sensory pathways reflecting their relative importance in the different species”.

Second, its connections are simple compared to vision and hearing. Olfactory signals go straight to the cortex rather than arriving in the cortex via the thalamus and they enter an old part of the cortex, the paleocortex rather than the neocortex (which has primary processing areas for the other senses). The processing of smell is more or less confined to one area in the frontal region and does not extend to the extensive areas at the back of the brain where visual and auditory processing occurs. The sense of smell is much easier to track anatomically than the other ‘higher’ senses. To understand minimal consciousness, it is reasonable to use the least elaborate sense as a model.

Third, looking at what lesions interfere with olfactory consciousness, it seems that connections outside the cortex are not needed for awareness of odours. This implies that at a basic level consciousness does not require the thalamus or mid-brain areas (although consciousness of other senses does require those areas). Some links to the thalamus and other areas may be involved in further processing smell signals but not in being conscious of them.

Fourth, the addition of a smell into the contents of consciousness has a sort of purity. The sense is only there when it is there. We are aware of silence and of complete darkness but we are not aware of a lack of odour unless we question ourselves. If odours are at very low concentrations or if we have habituated to them because they are not changing in concentration, we are not conscious of those odours and also not conscious of their absence. “The experiential nothingness associated with olfaction yields no conscious contents of any kind to such an extent that, absent memory, one in such a circumstance would not know that one possessed an olfactory system.” So addition of a smell to the contents of consciousness is a distinct change in awareness and can of itself focus attention on it.

Fifth, olfaction is not connected with a number of functions. There are no olfactory symbols being manipulated and the like. It is difficult to hold olfactory ‘images’ in working memory. Also “olfactory experiences are less likely to occur in a self-generated, stochastic manner: Unlike with vision and audition, in which visually-rich daydreaming or ‘ear worms’ occur spontaneously during an experiment and can contaminate psychophysical measures, respectively, little if any self-generated olfactory experiences could contaminate measures.

As well as these reasons given by Morsella in justifying the choice of olfaction in developing the Passive Frame theory, it occurs to me that there is a significant difference in memory. There is a type of recall prompted by smell that seems instantaneous, effortless and very detailed. For example, when you enter a house that you have not been in since childhood and the house has changed in so many ways over the years, the first breath gives a forgotten smell and a vivid sense of the original house along with many images from memories you know you could not normally recall. There seems to be some direct line between the memory of a ‘place’ and the faint odour of that place.

This olfactory approach to consciousness does cut away much of the elaborations and fancy details of consciousness and allows the basic essentials to be clearer.

Content generation for passive frame consciousness

This is a continuation of posts on Morsella’s passive frame theory of consciousness.

Content is generated by modules that have input from bottom-up sensory paths, and from top-down paths. The generators are sensitive to context – a picture of a snake and a real snake are different. And they are unconscious – we cannot unsee a visual illusion even if we have knowledge of the real presentation.

The contents enter consciousness in an automatic manner. They are pushed in unconsciously not pulled in consciously – they just seem to happen, to ‘pop up’. The contents are under the control of unconscious associations – a word presented as a purely visual stimulus can be a phonetic representation in consciousness.

As well as sensory content generators, there are generators of action-related urges. Morsella uses the example: “when one holds one’s breath while underwater, or runs barefoot across the hot desert sand in order to reach water, one cannot help but consciously experience the inclinations to inhale or to avoid touching the hot sand, respectively. Regardless of the adaptiveness of the expressed actions, the conscious strife triggered by the external stimuli cannot be turned off voluntarily.

Thus the sensory presentation and the urges are generated in a way that is insulated or encapsulated from voluntary control. “Thus, although inclinations triggered by external stimuli can be behaviorally suppressed, they often cannot be mentally suppressed. One can think of many cases in which externally triggered conscious contents are more difficult to control than is overt behavior.

The contents of consciousness are independent of one another whether they are memories, stimuli from the environment are whatever, and this is adaptive. Cross contamination would interfere with successful behavior. The safer influence by context-sensitivity is unconscious, not the result of a conscious whim. This is an important point of difference with some other theories. “This view stands in contrast to several influential theoretical frameworks in which both the activation of, and nature of, conscious contents are influenced by what can be regarded as over-arching goals or current task demands. Because of the principle of encapsulation, conscious contents cannot influence each other either at the same time nor across time, which counters the everyday notion that one conscious thought can lead to another conscious thought. In the present framework, not only do contents not influence each other in the conscious field, but as Merker concludes, content generators cannot communicate the content they generate to another content generator. For example, the generator charged with generating the color orange cannot communicate ‘orange’ to any other content generator, for only this generator (a perceptual module) can, in a sense, understand and instantiate ‘orange.’ Hence, if the module charged with a particular content is compromised, that content is gone from the conscious field and no other module can ‘step in’ to supplant that content. As Merker notes, in constructing the conscious field, modules can send, not messages with content, but only ‘activation’ to each other. This activation, in turn, influences whether the receiver module will generate, not the kind of content generated by the module from which it received activation, but rather its own kind of content (e.g., a sound). Because messages of content cannot be transmitted to other content generators, the neural correlates of the content for X must include activation of the module that generates X, for a content cannot be segregated from the process by which it was engendered, as stated above.” Thus it seems that the contents of consciousness are not marshalled onto a stage or theatre but rather a network is formed connecting the original generators or modules.

The mosiac of independent content is discontinuous and arises in each conscious moment which quickly follow one another. What is watching this content? The passive frame theory says: “ “Importantly, the collective influence of the combination of contents in the conscious field is not toward the conscious field itself; instead … the conscious field is apprehended by the (unconscious) mechanisms comprising the skeletomotor output system. Thus, the conscious contents of blue, red, a smell, or the urge to blink are the tokens of a mysterious language understood, not by consciousness itself (nor by the physical world), but by the unconscious action mechanisms of skeletomotor output system. Why do things appear the way they do in the field? Because, in order to benefit action selection, they must differentiate themselves from all other tokens of the field—across various modalities/systems but within the same decision space.”

I have to add that this may indeed be the original evolutionary reason for consciousness and it may be the over-riding determinant of the mechanisms involved. However, it seems to me that having created a moment of consciousness the brain is loath to throw it away. It is somehow saved and used to form an episodic memory.

Lingua Franca of the brain

Ezequiel Morsella has been kind enough to send me more information on the Passive Frame theory of consciousness. So here is another posting on ideas from that source.

From time to time I encounter notions of there being a ‘language of the brain’ or a brain coding system. Although I would not say that there was no extra language layer (who knows?), I have never seen the necessity for it. The idea seems a product of thinking of the brain in the context of software algorithms, digital transmission, information theory, universal Turing machines and the like rather than in biological cell to cell communication.

Look at forming and retrieving episodic memories: they are conscious experiences before they are stored and conscious experiences when they are retrieved. Awareness is in the form of consciousness and so is the access of various parts of the brain to information from other parts. We understand movement of ourselves and others in similar terms. The Passive Frame proponents talk of perception-like tokens – “they represent well-crafted representations occurring at a stage of processing between sensory analysis and motor programming” and are presumably accessible to both. Here we can have a lingua franca for sensory-motor interaction.

Of course for both sensory and motor processing we need a space and viewpoint for the perception-like tokens. This is often thought of as a stage or a sensorium, but I like to think of it as a model of the environment with the organism active in it. In this ‘space’ the objects we perceive can be placed and our actions can be simulated.

Passive Frame Theory

ScienceDaily has an item (here) on a paper by Morsella and others on the Passive Frame Theory of consciousness. This theory is one of my favorites!!

The passive frame presents information but does not create or act on that information. This consciousness is like an interpreter Morsella says, “the information we perceive in our consciousness is not created by conscious processes, nor is it reacted to by conscious processes. Consciousness is the middle-man, and it doesn’t do as much work as you think.” It is intuitive to think that consciousness is in control of the things it reports (actions, thoughts, feelings, perceptions). But really consciousness simply passively presents these things.

Morsella also says that consciousness is not a connected stream. “One thought doesn’t know about the other, they just often have access to and are acting upon the same unconscious information. You have one thought and then another, and you think that one thought leads to the next, but this doesn’t seem to be the way the process actually works.

This theory also puts action at a more central place in the function of consciousness than perception.

I do not have access to the original paper (Morsella, Godwin, Jantz, Krieger, Gazzaley; Homing in on Consciousness in the Nervous System: An Action-Based Synthesis; Behavioral and Brain Sciences 2015). But here is the abstract:

What is the primary function of consciousness in the nervous system? The answer to this question remains enigmatic, not so much because of a lack of relevant data, but because of the lack of a conceptual framework with which to interpret the data. To this end, we developed Passive Frame Theory, a internally-coherent framework that, from an action-based perspective, synthesizes empirically supported hypotheses from diverse fields of investigation. The theory proposes that the primary function of consciousness is well-circumscribed, serving the somatic nervous system. Inside this system, consciousness serves as a frame that constrains and directs skeletal muscle output, thereby yielding adaptive behavior. The mechanism by which consciousness achieves this is more counterintuitive, passive, and ‘low level’ than the kinds of functions that theorists have previously attributed to consciousness. Passive Frame Theory begins to illuminate (a) what consciousness contributes to nervous function, (b) how consciousness achieves this function, and (c) the neuroanatomical substrates of conscious processes. Our untraditional, action-based perspective focuses on olfaction instead of on vision and is descriptive (describing the products of nature as they evolved to be) rather than normative (construing processes in terms of how they should function). Passive Frame Theory begins to isolate the neuroanatomical, cognitive-mechanistic, and representational (e.g., conscious contents) processes associated with consciousness.

 

A weird model

A while ago Tiny Buddha site had an article by Lisa Esile. I often like Tiny Buddha articles but not those of this sort: “7 Secrets Your Mind Doesn’t Want You to Know”. My reaction is to wonder what is the ‘you’ that does not include ‘your mind’. There is the type of dualism that we have been encountering for many years, since Descartes’ time, and then there is this other new kind of dualism. A ‘you’ have can know things but is not ‘your mind’ seems a crazy idea. What exactly is this ‘you’ thinking with?

The article starts with, “Our mind is inherently scared. That’s its job, to be cautious; to keep us alive, to have us cross roads safely, and not get eaten by a lion. But left unchecked, it can become paralyzed with fear and meaner than a cornered crocodile.” Who says that we are likely to be paralysed with fear or mean? What sort of mind is being envisaged here? So we are careful and do not endanger our lives but that does not make us paralysed or mean. The idea is that a power struggle between ourselves and our minds is going on, with ourselves having the better judgement. Apparently judgement is some magical gift that does not require a mind to produce it. “We feel anxious, fearful, sad, or resentful when we give our mind too much power, when we follow all of its dopey ideas against our better judgment.”

There is a hint to what she means by mind. “Your mind is smart. Not wise smart, but computer smart.

Your mind isn’t into all that woolly intuition jazz. It wants facts. It likes making calculations. Running the odds.” Perhaps she is calling ‘mind’ the conscious mind and ‘you’ the unconscious mind, although this is not a very accurate description of type 2 thought. I have a big problem with her idea in that I do not see two minds any more than I see a separate mind and you. I see one mind and it is aware of only part of its functioning through consciousness. And … it is that consciousness that gives us the concept of ‘self’.

Esile goes on to describe the various fights between two sets of ideas, one ascribed to ‘mind’ and the other to ‘self’. It is almost impossible to imagine having the disagreements described. They may be descriptions that ring true to others. But I cannot shake the idea that divided our sense of self into different compartments is not helpful; having those compartments oppose one another is positively unhealthy. We have a brain and it functions as a whole not as separate parts – one of its functions is ‘mind’ or thought/memory/action/awareness/volition/emotion – ‘mind’ includes the creation of a world and ourselves in that world and a partial awareness of this creation that we experience as consciousness – so we are self-aware of a model of the world and a model of ourselves. There is absolutely no reason or advantage in modelling ourselves as two entities, ‘mind’ and ‘self’, that carry on a power struggle. Rather than struggle and fight, we can learn to think and act in ways that satisfy us and add to our confidence and happiness. We don’t do this be giving ourselves orders but by asking ourselves ‘how’, ‘why’, ‘which way’ questions.

A new way to parse language

For many years I have followed EB Bolles’ blog Babel’s Dawn (here) while he discussed the origin of human language. He has convinced me of many things about the history and nature of language. And they fit with how I thought of language. Now he has written a chapter in a book, “Attention and Meaning: The Attentional Basis of Meaning”. In his chapter, “Attentional-Based Syntax” (here), Bolles re-writes the mechanics of parsing phrases and sentences. He uses new entities, not nouns and verbs etc., and very different rules.

The reason I like this approach so much is the same reasons that I cannot accept Chomsky’s view of language. I see language from a biological point of view, a product of genetic and cultural evolution, and continuous with the communication of other animals. It is a type of biological communication. I imagine (rightly or wrongly) that Chomsky finds biology and especially animals distasteful and that he also has no feel for the way evolution works. I on the other hand, find a study of language that seems to only deal with complete written sentences on a white board, not of much interest. Instead of a form of biological communication, Chomsky gives us a form of logical thought.

Bolles summarizes his chapter like this. “The commonsense understanding of meaning as reference has dominated grammatical thought for thousands of years, producing many paradoxes while leaving many mysteries about language’s nature. The paradoxes wane if we assume that meaning comes by directing attention from one phenomenon to another. This transfer of meaning from objective reality to subjective experience breaks with the objective grammatical accounts produced by many philosophers, lexicographers, and teachers through the ages. The bulk of this paper introduces a formal system for parsing sentences according to an attention- based syntax. The effort proves surprisingly fruitful and is capable of parsing many sentences without reference to predicates, nouns or verbs. It might seem a futile endeavor, producing an alternative to a system used by every educated person in the world, but the approach explains many observations left unexplained by classical syntax. It also suggests a promising approach to teaching language usage. ”

The key change of concept is that words do not have meanings, nor do they carry meaning from a speaker to a listener – instead, they pilot attention within the brain. Or in other words they work by forcing items into working memory and therefore attention (or attention and therefore working memory). This makes very good sense. Take a simple word like ‘tree’: speaker says ‘tree’, listener hears ‘tree’ and memory automatically brings to the surface memories associated with ‘tree’. The word ‘tree’ is held in working memory and as long as it is there, the brain has recall or near recall of tree-ish concepts/ images/ ideas. The meaning of tree is found within the listener’s brain. No one thing, word or single element of memory has meaning; the meaning is formed when multiple things form a connection. It is the connections that gives meaning. I like this because I have thought for years that single words are without meaning. But words form a network of connections in any culture and a word’s connections in the network is what defines the word. Because we share cultural networks including a language, we can communicate. I also like this starting point because it explains why language is associated with consciousness (an oddity because very little else to do with thinking is so closely tied to consciousness). Consciousness is associated with working memory and attention, and the content of consciousness seems to be (or come from) the focus of attention in working memory.

Bolles uses a particular vocabulary in his parsing method: phenomenon is any conscious experience, sensation is a minimal awareness like a hue or tone, percept is a group of sensations like a loud noise, bound perception is a group of percepts that form a unified experience. We could also say phenomenon is another word for subjective consciousness. Then we have the process of perception. Perception starts with primary sensory input, memory and predictions. It proceeds to bind elements together to form a moment of perception, then serial momentary perceptions are bound into events. It matters little what words are used, the process is fairly well accepted. But what is more, it is not confined to how language is processed – it is how everything that passes through working memory and into the content of consciousness is processed. No magic here! No mutation required! Language uses what the brain more-or-less does naturally.

This also makes the evolution of language easier to visualize. The basic mechanism existed in the way that attention, working memory and consciousness works. It was harnessed by a communication function and that function drove the evolution of language: both biological evolution and a great deal of cultural evolution. This evolution could be slow and steady over a long period of time and does not have to be the result of a recent (only 50-150 thousand years ago) all powerful single mutation.

So – the new method of parsing is essentially to formulate the rules that English uses to bind focuses of attention together to make a meaningful event (or bound perception). Each language would have its own syntax rules. The old syntax rules and the new ones are similar because they are both describing English. But… it is not arbitrary rules any more but understandable rules in the context of working memory and attention. Gone is the feeling of memorizing rules to parse sentences on a white board. Instead is an understanding of English as it is used.

I have to stick in a little rant here about peeves. If someone can understand without effort or mistake what someone else has said then what is the problem? Why are arbitrary rules important if breaking them does not interfere at all with communication? With the new parsing method, it is easy to see what is good communication and what isn’t; it is clear what will hinder communication. The method can be used to improve perfectly good English into even better English. Another advantage is that the method can be used for narratives longer than a sentence.

I hope that this approach to syntax will be taken up by others.

 

A video on self

Thomas Metzinger is a favorite philosopher of mine. Deric Bownds has a post that includes a video of Metzinger talking about the self (here). Have a look. He deals with consciousness, the self model, transparency, identification and some experimental illusions. It’s great.