Schema theory & mental models

Why do we need schema theory?

Suppose you overheard the following conversation between two college-age apartment-mates:

A: Did you order it?
B: Yeah, it will be here in about 45 minutes.
A: Oh... Well, I've got to leave before then. But save me a couple of slices, okay? And a beer or two to wash them down with?

Do you know what the roommates are talking about? Chances are, you're pretty sure they are discussing a pizza they have ordered. But how can you know this? You've never heard this exact conversation, so you're not recalling it from memory. And none of the defining qualities of pizza are represented here, except that it is usually served in slices, which is also true of many other things.

The other theories we've looked at in this course would have a difficult time explaining how we can comprehend this conversation. Schema theory would suggest that we understand this because we have activated our schema for pizza (or perhaps our schema for "ordering pizza for delivery") and used that schema to comprehend this scenario.

In our discussions of CIP and Ausubel, it may have seemed as if the learner was relatively passive. New knowledge gets "slotted" somewhere in the brain, but neither theory seems to emphasize how that knowledge gets used. Schema theory, on the other hand, attempts to address specifically how we actively make meaning of information.

What is a schema?

A schema (plural schemata) is a hypothetical mental structure for representing generic concepts stored in memory. It's a sort of framework, or plan, or script. According to Stein and Trabasso (1982), schemata are thought to have these features:

Schemata are composed of generic or abstract knowledge; used to guide encoding, organization, and retrieval of information.
Schemata reflect prototypical properties of experiences encountered by an individual, integrated over many instances.
A schema may be formed and used without the individual's conscious awareness.
Although schemata are assumed to reflect an individual's experience, they are also assumed to be shared across individuals [in a culture?].
Once formed, schemata are thought to be relatively stable over time.
We know more about how schemata are used than we do about how they are acquired.

Driscoll suggests that a schema is analogous to:

A play, in that it has a basic script, but each time it's performed, the details will differ.
A theory, in that it enables us to make predictions from incomplete information, by filling in the missing details with "default values." (Of course, this can be a problem when it causes us to remember things we never actually saw...)
A computer program, in that it enables us to actively evaluate and parse incoming information.

How are schemata created and modified?

Schemata are created through experience with people, objects, and events in the world. When we encounter something repeatedly, such as a restaurant, we begin to generalize across our restaurant experiences to develop an abstracted, generic set of expectations about what we will encounter in a restaurant. This is useful, because if someone tells you a story about eating in a restaurant, they don't have to provide all of the details about being seated, giving their order to the server, leaving a tip at the end, etc., because your schema for the restaurant experience can fill in these missing details.

Not all of the information we have about restaurants necessarily gets added to our schema. For example, there's a restaurant in Indianapolis where the seating booths are little jail cells. After you're seated, the server closes your cell doors. (Of course, you can escape any time you want, as long as you've paid your bill.) Even though I've been to this restaurant several times, I don't think my restaurant schema includes tables as miniature jail cells. This information is simply an outlier; it is too unlike my experience at other restaurants.
Three processes are proposed to account for the modification of schemata:

Accretion: New information is remembered in the context of an existing schema, without altering that schema. For example, suppose I go to a bookstore, and everything I experience there is consistent with my expectations for a bookstore "experience." I can remember the details of my visit, but since they match my existing schema, they don't really alter that schema in any significant way. (Note that this is analogous to Ausubel's derivative subsumption.)
Tuning: New information or experience cannot be fully accommodated under an existing schema, so the schema evolves to become more consistent with experience. For example, when I first encountered a bookstore with a coffee bar, I probably had to modify by bookstore schema to accommodate this experience. (Note that this is analogous to Ausubel's correlative subsumption.)
Restructuring: When new information cannot be accommodated merely by tuning an existing schema, it results in the creation of new schema. For example, my experience with World Wide Web-based bookstores may be so different from my experience with conventional ones that I am forced to create a new schema. (Note that this is analogous to Ausubel's superordinate learning.)

What are mental models?

Mental models goes beyond schema theory to include perceptions of task demands and task performances. Mental models researchers are interested in how people perform tasks and solve problems in school settings and in the real world. (You can think of problem-solving as including both knowledge of schemata and knowledge of procedures.) This kind of research has been most prevalent in the sciences and mathematics.

Why are schema theory and mental models important in teaching and learning?

It's important to understand that schemata are powerful forces in learning. In an article on the role of schemata in story comprehension, Stein and Trabasso (1982) noted that:

Schematic knowledge has a significant effect on organization of ambiguous or disorganized stories.
Narrative schemata specify expected components of a story, such as the time sequence of events, and causal relations that should connect the events; during encoding or retrieval of a story, missing events may be inferred to fill in omitted information, and events may be reordered to correspond to a real-time sequence.
Many studies have shown that the use of schematic knowledge is so powerful that listeners have little control over the retrieval strategies used during recall of narrative information; even when listeners are instructed to reproduce texts verbatim, they cannot do so when the text contains certain types of omissions or certain sequences of events.

For example, consider the following excerpt from a story:

The girl sat looking at her piggy bank. "Old friend," she thought, "this hurts me." A tear rolled down her cheek. She hesitated, then picked up her tap shoe by the toe and raised her arm. Crash! Pieces of Piggo?that was its name?rained in all directions. She closed her eyes for a moment to block out the sight. Then she began to do what she had to do.

If you have a well-developed schema for "piggy banks", this story should be readily comprehensible. You would understand that traditional piggy banks were usually made of some fragile, brittle material, that they contained a slot for inserting and saving coins, and that the money could only be removed by breaking them.

On the other hand, if you have no schema for piggy bank, the story probably makes little sense.

What are some implications of schema theory and mental models research for instruction?

Schema theory:

Provide unifying themes for content, since information that lacks no theme can be difficult to comprehend, or, worse, the learner may "accrete" the information to the wrong schema.
Choose texts with "standard" arrangement so that it conforms to student expectations.
Encourage students to read titles and headings.
Point out the structure of particular kinds of texts; e.g., what are the common features of published research articles?
Ask questions to determine what students' current schemata might be.
Pay attention to student answers and remarks that may give clues about how they are organizing information; i.e., what schemata are they using?

Mental models (particularly from mathematics):

Identify students' current "theories" or algorithms.
Use student errors as a source of information about their mental models.
Use "think aloud" activities, since these help to uncover current models.
Model real problem-solving for students. Students need to see that solving problems is not just a matter of plugging numbers into an algorithm; rather it is a matter of determining the kind of problem so that an algorithm can be successfully applied.
Explicitly teach problem-solving strategies.
Focus on processes, structures, and decisions, not answers.
Provide a mix of problem types, rather than grouping problems of one type; otherwise, students won't develop skill at determining problem type.

Last Updated: Sept 1999