Kategoriarkiv: Kognitiv teori

Understanding Basic Vision

Contemplation of Basic Vision, according to the famous philosopher Descartes (1637)

Contemplation of Basic Vision, according to the famous philosopher Descartes (1637)

This is a little report on what we have been doing the past weeks in the Visual studies program. We now start every academic year in English, and with perception. As the title of our course book Basic Vision says, the perception course is really about the very basics of vision and brain. ”Why do you need vision science in visual studies?” some people ask, believing that visual studies is not a scientific field.

They are partly right, if we use the word ”science” in its more limited sense, meaning hard and objective science. Visual studies is a continuation of programs in Cultural Studies and ”Visual Culture Studies”, beginning in Britain in the Sixties as a part of sociology and cultural history – disciplines that some proponents of hard science would associate with witchcraft rather than science. Some people have grown tired of the one-sided ”culturalism” of these circles and proposed that Visual studies should learn less from Cultural studies and more from for example Medicine and Computer Systems.

There is a growing awareness that our conceptions of Nature and the Universe are now increasingly based on scientific images that are very different from those we know from earlier times. These images are visualizations of highly complex sets of data, and it is not possible to understand the principles and processes behind them if you don’t have access to some specialized knowledge. Thus, the divide between the ”two cultures” at universities (i.e. the scientific and the humanistic) tends to widen even more. If populated with open-minded people with a broad range of knowledge, Visual studies might help the two cultures talk again.

A very basic phonomenon of basic vision. The two lines are exactly the same length. Why don't they look like they were?

A very basic phenomenon of basic vision. The two lines are exactly the same length. Why don't they look like they were? (In fact, vision science is still struggling with this question.)

The first priority would be that we learn to talk about our own field of study – images and vision – in a scientific way, if only on a very basic level. This is what we do in the course Image Perception and Cognition. Our participants represent a wide range of interests and fields – some are from the humanistic field, some study computer science, and some are in the master’s program of the Bioimaging group in Turku. These bioimaging students will soon work independently with scientific imaging. Maybe they will end up in a research group studying the brain, and then contribute to bringing new knowledge to the field of vision science! Image Perception and Cognition is our most popular and successful course this far – mainly, I think, because it is basic and inter-disciplinary.

Tarja Peromaa (Image source: Visual Science Group)

Tarja Peromaa (Image source: Visual Science Group)

Being essentially ”culturalists”, me and my colleagues here at the faculty of arts must of course adopt a quite humble attitude in these contexts. How lucky we are that we have an experienced vision scientist and brilliant teacher to handle this course – Tarja Peromaa of the Visual Science Group at Helsinki University! Under her guidance, we have now read the first four chapters of Basic Vision and started to orient ourselves at ”the first steps of vision”. We are starting to understand that vision is both dynamic and selective, and we are beginning to remember the names of the different pathways, regions and cells involved in the visual system. It is like learning to talk a language. Before you know the basic terms and structures in a language, it is impossible to form sentences or to understand them. Soon, we will all know the meaning of terms such as ”cornea”, ”fovea”, ”retina”, ”ganglion cell” and ”lateral geniculate nucleus”, and understand a bit of what vision scientists are talking about when they are describing perceptual processes that art critics have been talking about all the time, but in a much more intuitive and everyday manner.

The eye as a camera (before the camera), according to Descartes.

The eye as a camera (before the camera), according to Descartes.

Vision science is not a new thing – in Europe it has been going on at least since Leonardo da Vinci tried to figure out a way to inspect the ”picture” projected inside an eye from a dead cow, hoping to see the world in the same way as a cow does. This idea was based on the same kind of misunderstanding as the diagram by Descartes that I show details of here. What misunderstanding? Well, the misunderstanding that Consciousness (of a cow or a human) is like a small person sitting somewhere inside our heads, looking at the pictures of our retinas (the ”screen” at the back wall of our eyes) like someone visiting a movie theater. The philosopher Antony Fredriksson will discuss the history of this idea in our course about moving images. Modern brain research gives ample proof that visual perception or any perception doesn’t work like that at all. In fact, there is no picture to be seen on some inner movie screen, but only a myriad of light-sensitive cells – the so called photo-receptors of the retina – each picking up a certain wavelength and intensity of light from a certain point in the environment, then sending it upwards through the numerous crossroads of the visual pathway. Somewhere – but definitely not in one place only – all these isolated signals are finally ”computed” together to form a part of our current field of consciousness. In this way, the digital camera with its receptive screen of isolated sensors is a better metaphor for vision than the traditional analogue camera.

Modern picture of the basic visual pathway. The blue patches at the center are the LGNs (Lateral Geniculate Nucleae)

Modern picture of the basic visual pathway. The blue patches at the center are the LGNs (Lateral Geniculate Nucleae)

Most people know that we have two kinds of photo-receptors in the retina – rods and cones, rods being responsible for night-time vision and cones for color perception. What happens further along the road is less common knowledge. All the different signals from the photo-receptors are ”cabled” through the two optical nerves that meet at the first crossroad – called the ”optical kiasm”. That is what you see in upper half of this picture. Then the signals from the left side of the field of vision (of both eyes) are cabled to the right side of the brain, and vice versa. This happens in the ”cables” known as the visual tracts. The signals arrive at the small nucleae with the difficult name – the Lateral Geniculate Nucleus, or LGN. They are located deep inside the brain, within each side of the central region called Thalamus. The LGNs consist of at least two types of cellular layers, responsible for transmitting different kinds of information to different parts of the cortex (the cortex is the outer, ”wrinkled” parts of the brain). In this way, high-contrast information and most color information is sent through the parvo-cellular layers, while low-contrast information about movements is sent through the magno-cellular layers. It is believed that some problems with reading and writing could be due to deficiencies of the magno-cellular system.

In the lower half of the picture above, it is shown how numerous axons forward most information to the main visual center of the cortex, which is located at the very back of your head, in the region that we call the occipital lobe. And this is where we were in the course this week, learning how different cells at this ”station nr 1” (or V1) of the visual cortex are responsible for decoding specific kinds of information, for example the orientation and position of edges.

Akiyoshi Kitaokas "ormar".

Basic Vision, 2006 edition with Akiyoshi Kitaokas "snakes".

Probably our students are already busily reading the chapters for next week’s lecture, dealing with depth perception, color perception, and movement. Then, we will learn more about other visual cortex regions apart from V1 – Vision science discovers new regions all the time! Of special importance are V4 and V8 (centers for color perception) and V5 (movement perception). Look at this cover from the 2006 edition of Basic Vision. It is a popular perceptual illusion that was created by the Japanese artist and researcher Akiyoshi Kitaoka. It is basically a pattern of striped circles-within-circles, but the illusion that they are moving and the addition av small red tongues makes it easy to interpret them as snakes. Why do they seem to move? It is actually because of the division of different signals at LGN and the fact that green-black and blue-white contrast is higher than blue-black or green-white contrast. Still unclear? The exact answer is in Chapter six in Basic Vision, and in the next post on this blog.

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Perception, Imagology and Visualization this year

Professor Anthony Johnson

Professor Anthony Johnson

After the student’s texts last week, I will now publish some posts in English, due to our current courses in English and all the positive interest that we receive from exchange students!

On this Thursday two of our courses in Visual Studies will start, and both are given in English. The first one is simply called Image Perception and Cognition, and it explains the basics in current neurological and psychological knowledge about the human visual system. You will learn some anatomy of the brain and the mechanisms at different stages in its processing of visual information. It will be a mind-boggling and exciting journey, all the way from the ”simple” registration of light at the retina, up to the cognitive job of consciously interpreting what we see!

The second course to start this Thursday is very different from the first one, so this way you really have a chance to get a clue of how broad and open the field of Visual studies really is! It is a course in arts and literature, given by our professor in English language and literature, Anthony Johnson, whom you see a picture of here. He is a legendary lecturer, and a jazz musician too.

The subject of his course is not so far away from psychological concerns as one might believe, because it is really about Imagology – a research field created by scholars who want to understand the mental images we form, for example when we read a certain text. In some respect, imagology was founded almost 100 years ago, when the American journalist and scholar Walter Lippmann developed his theory on the stereotypes we use when we describe members of certain nations or groups.

Anthony’s course is called Cultural Imagology – An introduction, and because it is about cultural imagology, he will not only talk about national and social stereotypes but also about the way people conceive of literature, geography and music. In the first lecture this Thursday, he will however begin with defining what an image is, or could be.

For those of you registered in the Image Perception and Cognition course, I will give an introduction on this Thursday, September 5th at 2 PM, in the Arken building of human sciences and languages here in Turku, room E201 (Camera Obscura). Then there is a one hour pause, and at 4 PM Anthony Johnson’s lecture starts in the same room. It will last for two hours.

Maybe you are a biologist or a student of computer systems who is also interested in art and literature, or maybe you are a student of literature who wants to know how the brain works? Then you are welcome to attend both courses!

Screen-Ddump from looking at tissue layers in BioImageXD.

Screen-dump from looking at tissue layers in BioImageXD.

In October and November I will myself give a course on Comics together with Folkloristics and Sociology. Further information in English is here. At the end of January a fourth Visual Studies course in English starts. Its name is Visuality and Visualization of Information.

This course will really give rich opportunities of combining arts with knowledge of the brain, because it is about why certain design strategies are better than others. We will use a textbook by the American psychologist Colin Ware, who is currently one of the internationally most acclaimed scientists in the expanding field Visualization.

This is a field in which neurological research, which may seem technical and abstract to many, is really put to practise in the form of effective strategies for visualization. It could be of use for marketers and web designers, but not the least for students and scholars who want to communicate research visually. There is a joint Master’s program in Bioimaging between Åbo Akademi University and Turku University, and many of our perception students have been from there. The Turku Bioimaging center (se link at top right here) has generously given all of us an opportunity to see how modern visualization works. They have created the free image processing tool BioImageXD that anyone can download at the BioImageXD page.

After downloading and opening the program, you can experiment yourself with multi-layer microscope images that you download as a free sample package at the SourceForge download page (see links at the bottom of the BioImage XD download page). The image that I show here is from a session that me and one of my students had with the program. We noticed that the possibility of generating views in 3D really added a lot to the precision of the visualization. In the Visuality and Visualization of information course we will study both simple and complex visualizations, ranging from comic books to medicine and physics, and at the end you will have the opportunity to realize a new visualization yourself.

For more inspiration, see:

”Genes to Cognition” page with an interactive 3D brain (very good for training at the Image Perception and Cognition course)

A short text defining Imagology

A Vimeo lecture on visualization by Colin Ware


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Tecknade serier och mentala strukturer

Första sidan i Mari Ahokoivus "Talviunta" (vinterdröm), 2013

Första sidan i Mari Ahokoivus "Talviunta" (vinterdröm), 2013

Förra gången jag gjorde ett inlägg här på bloggen var i juni, och då med löfte om mer information om våra kurser om visualisering av data och om ämnet Imagologi. Sedan blev tiden för knapp, och sommaren är inte heller en tid då folk förväntas läsa inlägg om kurser och forskning. Det är också något som har märkts på statistiken över antalet besökare på bloggen i sommar. Därför har jag väntat tills nu med att önska gamla och nya läsare välkomna tillbaka. Jag befinner mig just nu i Helsingfors där konferensen ”Imagined Worlds” har pågått från onsdag till fredag – en konferens som samlat deltagare från konsthistoria, litteraturstudier och filosofi kring frågan om fiktionens betydelse nu och då. Den amerikanske filosofen Nelson Goodman och hans idéer om ”worldmaking” och fiktionernas påverkan på den verkliga världen har stått i fokus i de flesta av presentationerna på konferensen. Från Åbo Akademi deltog förutom jag själv också forskarna Marie-Sofie Lundström och Jenny Wiik från ämnet konstvetenskap, Freja Rudels från litteraturvetenskap och Petter Skult från engelska språket och litteraturen.

På en sådan här konferens är det tydligt hur stort intresse det finns idag för kognitiv psykologi och mentala strukturer bland forskare från de mest skilda fält. Kognitiv psykologi kan hjälpa oss förstå hur en värld byggs upp i läsarens eller betraktarens medvetande och hur händelser och skeenden byggs upp i olika genrer. På konferensen presenterades forskning om allt ifrån rekonstruktionen av städer som Los Angeles i videospel till föreställningen om Orienten i det sena 1800-talets finska bildkonst. Intressanta samband blev tydliga, till exempel hur konstnärer i 20-talets Europa (som den holländska gruppen De Stijl) tänkte sig ett universellt språk med abstrakta visuella tecken – något som förebådade mycket av kommunikationen med diagram och visualiseringar idag. En forskare som litteraturvetaren Merja Polvinen i Helsingfors vill veta hur olika typer av fiktion (t.ex. Fantasy) aktiverar visuella mentala funktioner. Detta har en klar klar koppling till både visualiseringar och Imagologi – ämnet Imagologi skulle man kunna definiera som studiet av världsbilder.

Själv valde jag att inte ta upp Nelson Goodman och hans ”worldmaking” men däremot en filosof som på många sätt var Goodmans motsats – Charles Sanders Peirce, en av den moderna semiotikens (teckenteorins) grundare. Peirces tänkande handlade inte bara om enstaka tecken och hur de uttrycker ett innehåll (eller refererar till en grupp av ”verkliga” föremål) utan också om mentala strukturer i en väldigt vid bemärkelse. Hans teori om interpretanter har haft stor betydelse för nutida kognitiv psykologi, trots att Peirce skrev sina texter för mer än hundra år sedan. Det är inte så lätt att i korta ord förklara vad ett tecken eller en interpretant är enligt Peirce. Jag har försökt att förklara Peirces teckenbegrepp med hjälp av den svenske konstnären Elis Erikssons märkliga tecknade serie Pavan, som jag presenterade på konferensen.

Jag är också intresserad av hur Peirces interpretanter kan hjälpa oss förstå vad som händer – mentalt – när vi läser tecknade serier. Trots att hans formuleringar kunde vara krångliga handlar Peirces teorier till stor del om vardagliga handlingar och praktiskt förnuft. Det är ingen tillfällighet att han själv kallade sin filosofi ”pragmaticism” och att hans efterföljare blev kända som ”pragmatiker”. Jag tror att anledningen till att tecknade serier är så populära är att deras struktur påminner om hur vi bearbetar och reagerar på den ständiga strömmen av intryck i vardagen. Med andra ord hur vi ständigt formar interpretanter. På konferensen för serieforskning i Helsingfors i maj försökte jag förklara det här med hjälp av bland annat tre mycket olika seriesidor av olika tecknare. Den finska serietecknaren Mari Ahokoivu valde jag som exempel på serier som drastiskt avviker från vad som ses som ”mainstream” i serier. Mari har en hemsida där man kan läsa mer om hennes produktion:

Mari Ahokoivus hemsida

Tack vare vårt Lärcentrum i Åbo och deras redskap för undervisning via Nätet har jag kunnat spela in min presentation om serier och interpretanter så att den är tillgänglig för alla. Presentationen är gjord i programmet Camtasia Studio och är 25 minuter inklusive abstract i början. Välkomna att höra och se mina argument via den här länken som öppnas i ett nytt fönster:

Fred Andersson: The Level of the Interpretant – Towards an Extended Use of Peircean Typology in Comics Analysis (Helsinki May 24th 2013)

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