"Imagination is what makes our sensory experience meaningful, enabling us to interpret and make sense of it, whether from a conventional perspective or from a fresh, original, individual one. It is what makes perception more than the mere physical stimulation of sense organs. It also produces mental imagery, visual and otherwise, which is what makes it possible for us to think outside the confines of our present perceptual reality, to consider memories of the past and possibilities for the future, and to weigh alternatives against one another.Thus, imagination makes possible all our thinking about what is, what has been, and, perhaps most important, what might be" (Nigel J. T.
Thomas). To the individual, conscious mental experiences like imagery are more than just an epiphenomenon but are central to being a living human being. Thus, research on mental imagery has presented a challenge for mainstream cognitive psychology by generating new kinds of theory concerning potential mental representations and new methods for investigating those representations.One central question in the research is how mental imagery compares to and interacts with the ordinary perception in the view of different modalities. One interesting effect can be reported while performing the following task: call up before your imagination objects and concepts linked to different sense modalities e.
g. whistle of a railway for sound, tobacco for smell, silk for touch, fatigue for sensation, etc (these items appeared in Galton's "breakfast-table questionnaire") and consider your mental representation of them.My introspective account is that I can imagine those easier and faster if I have a visual image of some object, place or event before my mind's eye right before I recall the sensation itself (almost simultaneously). The "pictures" appear briefly and are very faint and abstract, probably because characteristics like shape, colour, etc are irrelevant for the task (modalities other than visual).Nonetheless, I am aware of some sort of visualization, as if the compartments in long-term memory where all things are conceptualized, or "drawers" for each something with all the information about it inside, are labeled with pictures and not with words. In order to extract certain knowledge about a stimulus presented linguistically, the word seems to be associated with an image first and then the right "drawer" is easily found.
Can this account suggest a certain hierarchical organization within different kinds of mental imagery unlike within perception?While all the modes of perception are equally valuable for us and independent of each other, the visual imagery seems to be the dominating means for mental representation. Is visual imagery primal in some way that makes it a highly effective heuristic for finding information in memory and possibly managing its recourses? In contrast, why it does not seem to be useful to answer a question like "how many dimes make up a dollar? " To what extent the processes underlying the quasi-linguistic and the quasi-pictorial representations are different and how these processes allow the interplay between the two?Intuitively as well as according to many studies, it appears that visual imagery is effective for many kinds of problem solving, especially spatial and kinesthetic tasks, because most of the trivial, sensual knowledge about the physical world is encoded and retrieved from the memory implicitly. Finke (1989) characterized this property of mental imagery as the "implicit encoding principle": "Mental imagery is instrumental in retrieving information about the physical properties of objects, or about physical relationships among objects, that was not explicitly encoded at any previous time" (p. ).Plus mental images are catching-all in the sense that they are relatively easy to manipulate voluntarily in mind-zoom in and out, rotate, transform, add or omit details, etc-so they appear as more concrete entities than words. It is possible that an abstract stimulus such as linguistic information has to be translated into images, concrete instances to be stored and accessed in memory implicitly.
From developmental perspective, the language i. e. the verbal representation is more limited due to its abstractedness.The set of symbols that constitutes a language has to be learned through experience in childhood and thus the names of mental states can be learned and used to describe only those states that coincide regularly with evidence available to others. For example, pains coincide with burns and cuts so that is easy to know when it is appropriate to speak of them to describe a wide range of similar experiences. However, names cannot be taught for mental experiences, which are not so connected with some reliable external signs.
That is why it is very hard to compare the nature of experiences, which people call by the same name, in general and in particular for the purposes of psychological research. Imagery itself provides a notorious example. Some people (about 10% of population, according to Thomas) claim that they do not experience imagery ever. Do they actually not experience any "quasi-perceptual experiences" or they simply understand the concept in a somewhat idiosyncratic fashion-deny that what they do experience is predominantly visual or that it involves inner pictures?Either way the results of inquiry into this phenomenon would be useful for understanding the role of imagery as a form of mental representation. The abstract nature of verbal representation might provide clues as to why imagery occurs and about the functional architecture of its processes. So mental images are distinct from the internal talk in that they are very concrete for the person who experiences them on the one hand but sometimes very hard to express with known vocabulary because of their personal and implicit nature on the other hand.
In this view, it would be plausible to assume that imagery is to some extent primal, deeper level of representation in our mind and its sharing of the same processes with perception and verbal representation is limited to the regions where back-and-forth communication between them must occur in order to process information. Empirical evidence consistent with this view can be found in multiple experiments of Shepard et al. mental rotation of objects, scanning mental maps, etc), which showed that "imagined transformations and physical transformations exhibit corresponding dynamic characteristics and are governed by the same laws of motion"(Finke p. 93).
In light of this conclusion, Shepard has speculated about these constraints of mental imagery from evolutionary perspective: "The constraints that have evolved in the perceptual system as an internal reflection of the most pervasive, enduring, and (often) abstract constraints in the external world have subsequently become to some extent liberated from the preemptive control of sensory input.The wisdom about the world ... may thus have become available for the internal modeling of hypothetical situations .
.. According to this viewpoint, the purely linguistic apparatus, though in some ways still more abstract and versatile, if forced to operate without the benefit of the powerful constraints incorporated in the perceptual system, would fail to deal effectively with the physical realities of this particular world. ...
The conceptual-linguistic system may itself have evolved as an abstract extension of the spatial-perceptual system. .. The view to which we are led differs from the traditional empiricist view in ..
. that a major part of this knowledge has been internalized through biological evolution and so, for each individual, is pre-wired rather than acquired and ...
it reflects very abstract and general constraints governing, for example, the projection and transformation of objects in three-dimensional Euclidean space. "(p. 321-324)The research of Friedman at al. n mental comparison also suggests that the "principle of transformational equivalence" described above not only does underlie comparison of physical objects but also of abstract semantic dimensions.
For example, Friedman obtained a symbolic distance effect (response times as function of the magnitude of the difference between two named objects) when subjects were asked to compare pairs of low-imagery words (abstract notions) in terms of which made them feel better or worse. Piavio investigated the assumption that imagery should be evoked more readily by pictures of objects than by the names of objects.His findings were: both pictures and words produced a symbolic distance effect and, as were predicted, reaction times were substantially faster with pictures than with words (Richardson p. 47). More empirical evidence comes from the study of brain injuries. De Renzi and Nichelli (1975) studied patients with long-term visuo-special memory deficits and with verbal short-term memory impairments but intact short-term visuo-spatial memory.
They concluded that the mechanisms responsible for verbal and visuo-spatial working memory are functionally dissociable (p. 61).Studies using brain-imaging technologies suggest that structures in both hemispheres may be involved in imagery, including those within the superior and lateral occipital lobes but apparently not the primary visual cortex (Richardson, p. 33). The interpretation of these findings consistent with the view presented above would be that the representation of objects and concepts in the form of mental images evolved on the basis of some cognitive mechanisms that are involved in perception since imagery is modeled upon the real world and is implicitly governed by the same physical principles.
However, it also must involve many other mechanisms, possibly some specializing in imagery per se and some involved in other cognitive functions. It is a complex, flexible system to allow us to use imagery as a heuristic in problem solving of various sorts, whose parts are orchestrated to work in parallel or even independently of each other, depending on the task at hand, in order to produce fast and reliable results.In this sense mental images are much like somatic markers proposed by Damasio to account for the role of emotions in cognition. So what the components of this system might be and how they interact? Most of the proposed models include working memory specializing for imagery and perception or "visuo-spatial working memory" that interacts with phonological loop or verbal system through Central Executive (Baddeley's model of working memory)(Richardson, p. 2) or directly (dual-coding model of Paivio)(p.
82). (The competition for resources of visuo-spatial working memory may explain why it is difficult to perceive and imagine simultaneously in the same modality. ) Kosslyn adopted a more elaborated "protomodel" with seven basic components, which can account for how the visual system works to solve different problems in trying to identify physical objects and also constructs and manipulates images.He argued that images consisted of two components: the "surface" representation of quasi-pictorial nature, held in some form of active memory, and underlying it was "deep" representation in propositional format, stored in the long-term memory, from which the surface representation derived (p. 54).
These propositions do try to account for differences and relationship between quasi-linguistic and quasi-pictorial representations and perception but miss out at least one component that seems to be very important if not central to understanding those differences and relations.Episodic and semantic memory might be the key. In "Toward a Theory of Episodic Memory: The Frontal Lobes and Autonoetic Consciousness", Wheeler, Stuss, and Tulving define episodic memory in terms of autonoetic consciousness: "According to James (1890), 'remembrance is like a direct feeling; its object is suffused with a warmth and intimacy to which no object of mere conception ever attains' (p. 239).
... It is a unique mental experience, not confusable with the awareness of an 'object of mere conception,' which corresponds to something simply known.The latter type of knowledge does not possess any personal veridicality or pastness and represents retrieval from semantic memory.
... We label the types of awareness associated with episodic and semantic retrieval as autonoetic (self-knowing) and noetic (knowing) awareness, respectively" (p.
333). Imagery also seems to exhibit such autonoetic quality whether we re-experience actual events from our past or the imaginary events. For example, consider the experience when imagining a dancing person and following his or her movements.This must involve some retrieval from semantic memory for the general outlines-how a human looks like and what dance is. But once this is done and the imaginer is filling in the details, following the movements of the imagined dancer, he might feel like he himself is dancing as if the imagined person and he were one.
After all, isn't our imagined person doing what we want him/her to do, although we might be not conscious of this fact? Such imagined events if they are remembered are, too, expected to be stored in episodic memory.Thus, there must be some "tag" that would say whether the remembered experience has happened in reality or in imagination since most of the time we can distinguish between the two. When we are aware that we are viewing pictures in our imagination, the tag is activated and the mental event is encoded under appropriate "entree". This process would also fall under domain of autonoetic consciousness.
So episodic memory might actually be a repository of such tags for our memories.In this view, imagery might require retrieval from semantic memory through the tags of episodic memory and that is why it feels more concrete and personal, whereas verbally encoded mental events need not follow this channel, although they can. According to Wheeler, Stuss and Tulving, "there is no known method of readily encoding information into an adult's semantic memory without putting corresponding information in episodic memory or vice versa"(p. 333)-this explains why when learning a new word, we have an image associated with its meaning in our mind.But "it is possible for a learner to know that he or she personally witnessed an event, such as the appearance of a word in a studied list, without consciously recollecting the event.
... Episodic memory need not play any role in the actualization of this kind of knowledge"(p.
349). "Consciously recollecting" or employing autonoetic consciousness would involve mental images while the noetic consciousness would be supervising the processes during imageless activity such as perception.In this view of the two kinds of consciousness as a system tracking our mental processes, we have to redefine what we usually mean by the absence of consciousness while dreaming, daydreaming and experiencing other types of imagery. After all, can we ever see with the mind's eye (or hear with the mind's ears, etc) if we are not aware of the experience unless we mistaken it for perception? Imagery, consciousness and personality seem to be intimately related and the research on each can help to understand the other.
I think, more clues would be found if we looked more liberally into psychological functions of imagery. Just to give one example of research that suggests involvement of imagery in our mental life in the ways we would not expect: In "The Paradox of Sleep: The Story of Dreaming", Michel Jouvet generates an intriguing hypothesis about the function of the REM sleep and dreams-seemingly a phenomenon without function; nonetheless, "dreams are necessary, for if they are suppressed they tend to return automatically, and the brain tries to make up the lost dream time. (p. 8).Driving on the evidence from studies of REM-like states during ontogenesis and neurogenesis (genetic programming of the brain in immature mammals) and studies of twins, raised completely apart since birth, who often report having identical dreams, Jouvet proposed that dreams are there to restore individuality because "genetic reprogramming occurs during paradoxical sleep, that is, during dreaming"(p. 15) Since function defines structure, further investigation of theories like this one could illuminate cognitive mechanisms of imagery.
