In addition to categorizing objects and single events, we generalize and categorize entire physical situations and temporal sequences of events. When a number of dif-ferent situations occurring at difdif-ferent times seem to have aspects in common, they are eventually averaged together into an abstract memory framework. This is the process of formation of semantic memory, which has been described previously.
Built up out of the commonalities shared by different experiences, these frameworks are referred to as “schemas”. Like conceptual categories, schemas are thought to be central structures of semantic memory.1
The distinction between categories and schemas is of course not absolute. Schemas are a sort of metacategory; indeed, the elements or “slots” of which a schema is composed are categories.2 Both schemas and categories are sets of long-term memory associations. Schemas are larger sets of associations. The internal structure of schemas and categories may be somewhat different. Categories are usually arranged hierarchically in levels, whereas schemas may be organized purely in terms of the structure of the situation (spatial or temporal) they represent (Mandler, 1979).
Schemas are organized sets of memories about sequences of events or physical scenes and their temporal and spatial characteristics, which are built up as we notice regularities in the environment. When we encounter similar situations repeatedly, we do not remember every detail of each encounter. As with categories, this would require enormous amounts of memory and would be very wasteful. Rather, we form an abstract model of the situation, based on the invariant aspects our repeated encounters have in common.3
Schemas function as norms or sets of ideas about how things usually are, and allow us to move through situations without having to repeatedly consciously eval-uate every detail and its meaning: they operate unconsciously to contextualize
current experience. They are an important part of the semiactivated memory con-texts mentioned in chapter 1. The operation of schematic memory concon-texts during perception is what makes the world seem familiar. Extremely rapid processing through schematic connections between groups of neurons and neural maps is thought to be an important aspect of the selection of the perceptual information that enters short-term memory. Schemas provide frameworks within which to eval-uate novelty and thereby guide attention (Bregman, 1990: 398–399).
Schemas are large patterns of generalized associations in memory that determine how whole situations are processed. Our initial scanning of a situation reveals fea-tures that then cause particular higher-level schematic connections to be selected. In this sense, situations are processed through schemas. Selecting the correct schema to process a situation is the basis for the process of understanding. This happens very quickly—usually within milliseconds of our seeing or hearing something and usually outside our conscious awareness: we deal quite well with many types of sit-uations without ever consciously thinking about how to do it. Note that the term understanding metaphorically refers to a process that takes place “underneath” the conscious mind—in the unconscious.
If most of the details of a situation fit reasonably well with a schema, our attention immediately moves to the details that do not—to the novel details that stand out against a background of the familiar. (This is a point at which “direct awareness” in figure 1.1 might be activated.) If many of the details of the situation do not fit with the currently evoked schema, a search for a new schema—known as a “double take”—will usually cause us to focus consciousness on the unusual details of the situation.
Thus schemas are large networks of memories with potential associative connec-tions. When particular scenes or events in the environment trigger our expectations, some of these memory networks become semiactivated; these semiactivated memo-ries may enter our peripheral consciousness as a “feeling” of what is about to happen. Schemas in the form of musical patterns and styles are largely responsible for our feelings of expectation while listening to a piece of music. This feeling usually stays on the fringes of the focus of consciousness. In some instances, however, we may see or hear what we expect, rather than what is “really” there.4 While our expectations usually do not intrude into our conscious present as hallucinations, the very possibility of hallucinations reminds us that a sizable part of our experi-ence of the outside world does not come directly from that world (Dennett, 1991:
3–18).
96 Chapter 8. Schemas: Frameworks for Experience and Memory
Schemas may be of physical scenes or of temporal event sequences. Because music consists of acoustical event sequences, we shall be primarily concerned with temporal schemas.
Schematic Organization
Schemas are based on what similar situations have in common; because no two sit-uations are ever exactly alike, schemas must be somewhat flexible: their elements, that is, the categories of objects, single events, actions within a scene or event, are variable within certain limits. This flexibility makes a schema somewhat like an equation, with abstract variables that can be filled in with different values. These variables, in turn, are like “slots” into which various particular features can be fitted, provided they do not violate the basic nature of the schema. This flexibility is one of the things that make schemas so useful, because they can be adapted to many different situations.
An example of a temporal schema would be eating in a restaurant (Schank and Abelson, 1977: 42, 153). This schema would have a relatively stable sequence of events, such as ordering, eating, and paying the bill, as its components. Note that in order to correctly deal with the restaurant schema, not only do we have to be familiar with the temporal organization of the schema itself, but we have to recog-nize instances of categories (slots) relevant to the schema. This means that we must recognize instances of the categories of table, chair, waiter/waitress, cash register, and so on, and that we must know what to do in response to these instances. All of these have a role in the schema, and all of these can differ considerably in detail, and still evoke the restaurant schema.
A musical example of a schema slot would be the category of the downbeat in music that is organized metrically. The organization of musical time into repeating cycles of meter works in a schematic way (see Chap. 11). The downbeat is a very important type of category in metrical structure. It is a beat that marks the beginning of a metrical cycle, and functions to maintain the cyclical grouping standard of meter. The downbeat is like a schema slot, in that many different kinds of musical events may occupy the downbeat position in the measure and still function as downbeats. The category of downbeat actually has a graded structure, with some types of events being more prototypical or better examples of the downbeat than others. (More will be said about the schematic nature of meter in chapter 12.)
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The categories that comprise a schema may also have “default values” (Barsalou, 1992: 160). Details of a situation that are not noticed as unusual quickly drop out of awareness and their slots are assigned default values in memory. Default values fill in typical or average instances in memory for variables not attended to at a par-ticular time—creating a kind of generic reality. In our memories of things that have taken place outside, for instance, the sky is usually there, although we may not have looked at it at all. The sky slot may therefore have a default value. Based on the category prototype effects mentioned earlier, schema default values are probably responsible for many episodic memory distortions. When recalling a particular episode, we often do not remember which parts of the experience we were actually paying attention to, therefore we do not know which parts of the memory may be our own default values and which parts “really” happened. We have filled in the unattended-to parts of the memory with our own previously established prototyp-ical values. In this way, different generations of memories can get conflated. In the very long term, this probably causes the details of episodic memories to slowly drift in the direction of default values (J. Mandler, 1984: 104–105): our memories slowly modify themselves to become more and more like the most prototypical instances of our own categories and schemas. Because our categories and schemas themselves are evolving or being updated based on new experiences and expectation failures, this means that subsequent experience can actually modify our older memories (see Linton, 1982).
Schemas and Normalcy
We are most likely to notice and remember things when they do not fit exactly within our schemas, and these novel episodic memories will tend to be connected by association with a relevant schema. This means that noticing and remembering are most likely to take place when our expectations fail (see Schank, 1982).5A wait-ress in a gorilla suit, for example, would not be a part of our restaurant schema, and would be immediately noticed as being unusual, as would a loud, dissonant chord in the middle of a piece of music that was quiet and consonant. We would tend to remember these types of events, and would also tend to be reminded of these episodes when something in a later situation evoked the same schema.
From the perspective of biological adaptation, when our expectations fail is when we most need a specific (episodic) memory of another failure of the same expecta-tion to help us figure out what to do. That is, we notice and remember things when 98 Chapter 8. Schemas: Frameworks for Experience and Memory
expectations fail because these types of situations could eventually require that a schema be modified, or in more extreme circumstances, that a new schema be formed. If a particular set of expectations fails a number of times, the schema for that particular situation will need to be updated. Hence specific episodic memories representing the failure of particular expectations (schemas) are connected to those expectations by association: they are available to remind us at the relevant moment when we might need to consider updating a schema (Schank, 1982: 37–40).
All of our schemas taken together form a kind of averaged model of how the world usually is, a kind of generic reality. Without this complex of frameworks, the world would be always strange and unfamiliar, and we would spend all of our time trying to figure out where we were and what was going on. Most of the time, this model works so well that we do not need to pay much attention to many details of our lives. When something deviates sufficiently from the normal, it receives our attention; it is remembered and this memory is associated with the relevant schema in memory.
Because they are part of semantic memory, different levels of schemas may be hierarchically arranged, moving from schemas about generalized aspects of reality to very specific schemas about particular kinds of objects or events (remember, however, that the internal organization of a particular schema is usually based on the organization of the scene or event it represents). For instance, in addition to the previously mentioned restaurant schema, we might have more general schemas about dinners, food, or eating in general, and we might have more detailed schemas about which kinds of food are served in which kinds of restaurants. The actual restaurant schema itself, however, would derive its time sequence from the sequence in which the events typically happen. In relation to a particular piece of music, we might have more general schemas about the large-scale organization of a piece or its musical style, and we might have more detailed schemas about the local arrangement of sections, particular types of patterns in those sections, and so forth.
The disadvantage of a generalized, schema-driven recognition system is that over time, because they are always undergoing the process of being slowly generalized, particular episodic memories of experiences that are similar and fit the same schemas tend to become confused. That is, when we have any type of experience repeatedly, we have great difficulty remembering the details of any particular occurrence, unless they are fairly unusual. This is referred to as an “interference effect” and is based on the idea that similar memories interfere with each other. Interference effects are Schemas and Normalcy 99
a direct result of the limits of categorization: we simply cannot retain all of the minute differences between different but very similar experiences. Music that uses repeated, highly similar patterns is designed to produce this effect.
Because a schema has been defined here as a higher-level categorization of expe-rience, and because categories create boundaries, an interesting question arises.
What constitutes the boundaries of a temporal schema? One answer to this ques-tion that has been proposed is that schemas are bounded by the achievement of goals (Schank, 1982: 86–98). This means that schemas are groups of memories orga-nized around particular goals, and that once a particular goal is achieved (or dis-carded, for that matter), a new set of expectations directed toward a new goal goes into effect. This is a kind of high-level grouping of real-life experience. Certainly, in real life, these schemas and goals are nested, and there can be a number of both short- and long-term goals in operation at the same time. In linear, goal-directed music, which is far less complex than real life, there may still be a number of hier-archical levels of goals operating at a particular time. It is often the case in such music that the arrival at a goal of some sort signals the end of a section—in essence, a temporal category boundary. (More will be said about this in chapter 13.)
Schemas and Music
With regard to our mental representation of a piece of music, all of the foregoing has several implications. First of all, on first hearing a piece, we do not remember all or even most of its details. What we remember is a rather abstract “gist” of what went on (see Schank, 1990: 170–176).6 This gist might consist of defaults, based on our ideas of what is normal (schemas) for this type of work. This generalized semantic memory model might be peppered with more vivid and specific episodic memory fragments of details that in some way did not fit our expectations and were somehow remarkable, and hence were remembered. As we listen to the piece repeat-edly, we build up a more and more detailed model of specific events in it, although it takes many listenings before we literally know in detail what is coming next throughout the entire piece. In the early stages of listening, our fragmented episodic memories may be quite different from what is actually in the piece—indeed, they may tend to be more like other fragments of similar music which we already remem-ber. A comparison of the actual piece with what we remember, especially if made after a considerable time, may be startling in the depth of its “errors.” As we build up our mental representation through repeated listening, it slowly becomes more 100 Chapter 8. Schemas: Frameworks for Experience and Memory
“accurate,” that is, in closer conformance with the original. If we listen repeatedly to the extent that we learn to know exactly what is coming next at any point, we might say that we have exhausted the piece because our mental representation is practically equivalent to the piece itself, and we do not notice what we already know.
This generally takes a very large number of repetitions, however, because of the dif-ficulty of remembering nuances. (This argument is being made in relation to a fixed performance such as a recording because live performance nuances would always produce many microsurprises.)
Compositional strategies can have profound influence on the process described above, making it anywhere from relatively easy to very difficult to form a complete schematic (mental) representation of a piece. Examples of ways to make pieces dif-ficult to represent schematically would be 1) building a piece with virtually no rep-etition so that schemas would be difficult to form (it would be hard to develop a gist); 2) building a piece so that there appears to be only one repeating schema with variations so slight that comparisons of pattern differences are very difficult because of memory interference effects or; 3) building a piece out of indefinite and uncate-gorizable events such as indistinct pitches, slides, noises, etc. These compositional strategies will be discussed further in the chapter on musical form.
Schemas as Musical Frameworks
Schemas in music generate expectations about the kinds and order of musical events;
they serve as frameworks for memory, increase chunkability, and help us form rep-resentations in long-term memory. There is a kind of reciprocal relation between schemas and some kinds of musical experience. While we derive schemas from musical experiences, we can also construct musical experiences so that they will be easier to schematize. On the highest level, this would include many kinds of rela-tively stable musical forms or genres, such as symphony, raga, jazz improvisation on chord changes, and variations. Indeed, the classical version of the European form known as “variations” is an almost perfect model of how a schema works: basic musical material is introduced in the first section, then varied in different ways in subsequent sections, usually retaining some recognizable relation to the original, prototype section. Other examples of obviously schematically based music are struc-tured improvisational styles such as mainstream jazz and North Indian raga, where understanding the improvisation requires constant comparison with a schematic archetype. These styles are purposely constructed so that we can have relatively Schemas as Musical Frameworks 101
stable expectations (subjective set) about the general type of events which will happen. Also, particular styles, cultures, or historical periods of music structure our expectations schematically on a very general level.
On a lower level, systematic and categorical aspects of music that relate to details of the music within particular pieces, such as tuning systems, metrical organization, scales of duration, and organization of instrumental sounds into families of instru-ments, would also qualify as schemas. (We shall examine each of these in detail in later subsections dealing with particular musical parameters.) We also develop expectations within a particular piece, based on previous events in that piece (objec-tive set). This would have to do with the nature of the actual patterns encountered in that piece. All such musical schemas serve as frameworks for our expectations:
they allow us to have some idea of “where we are” and possibly “where we are going” in the music (see Francès, 1988: 188).
Schemas and Musical Culture
Most of our discussion has involved the representation of music in the mind of the individual listener. There are, however, aspects of the mental representation of music
Most of our discussion has involved the representation of music in the mind of the individual listener. There are, however, aspects of the mental representation of music