As we define matters here, coding schemes are a central defining characteristic of sequential observational methods. Sometimes it useful to use the phrase systematic observation to distinguish the sorts of methods we are talking about from simply looking at behavior or producing narrative, journalistic reports. Then a brief definition of systematic observation might be the application of predefined coding schemes to sequences of live or recorded behavior (or transcripts of behavior) based on rules and with attention to observer reliability.
It is also important to define what observation is not. In the definition of observational methods just given, no mention was made of the context in which observation occurs. It could be either a field or a laboratory setting and, in either setting, experimental manipulation might or might not be used (although usually experimental manipulations are far more frequent in laboratory settings). Thus systematic observation, which is often thought of as a naturalistic technique, is inherently neither correlational nor causal; it depends on context. Second, no element of psychological theory is present in the definition, and in fact, observation can serve many different theories providing specific contents to categories. However, if the definition of observation is context- and contentfree, it is not free of epistemological assumptions: As you might deduce from the definition itself, it is based on Stevens' (1951) theory of measurement and on the belief that human behavior can be quantified and formalized in models.
Coding schemes can be thought of as measuring instruments, something like rulers or thermometers. However, unlike rulers and thermometers, which measure length and temperature on interval scales, coding schemes usually make categorical or nominal (or at most ordinal) distinctions. They consist of sets of predefined behavioral categories representing the distinctions that an investigator finds conceptually meaningful, often explicitly theory based, to check important psychological hypotheses or to answer important research questions. One classic example is Parten's (1932) coding scheme for preschool children's play. She defined six categories—unoccupied, onlooker, solitary, parallel, associative, and cooperative—and then asked coders to observe children for 1 minute each on many different days and to assign the most appropriate code to each minute.
Examples of other coding schemes can be found in Bakeman and Gottman (1997), but most share this in common: Like Parten's scheme, they consist of a single set of mutually exclusive and exhaustive codes (there is a code for each event, but in each instance only one applies), or of several such sets, each set coding a different dimension of interest.
For example, when interacting with her mother, an infant's gaze (to mother, to object, to other), vocalization (neutral/pleasure, fuss/cry, none), and body movement (active, still) might be coded, using three sets of mutually exclusive and exhaustive (ME&E) codes. In the simplest case, a set could consist of just two codes, presence or absence of a particular behavior; thus if observers were asked to note occurrences of five different behaviors, any of which could co-occur, this could be regarded as five sets with each set containing two codes, yes or no. As a general rule, it is useful to structure codes into ME&E sets; it eases exposition, aids recording, and facilitates subsequent analysis.
The objection is sometimes raised that coding schemes are too restrictive and that predefined codes may allow potentially interesting behavior to escape unremarked. Sometimes a more open stance is recommended, similar to that of a participant observer or a qualitative researcher. We assume that such qualitative, unfettered observation occurs while coding schemes are being developed and will influence the final coding schemes. However, once defined, coding schemes have the merits of replica-bility and greater objectivity that they share with other quantitative methods. Even so, coders should remain open to the unexpected and make qualitative notes as circumstances suggest. Further refinement of even well-developed coding schemes is a possibility to which investigators should always remain open. We could go even further and claim that a qualitative stance is important in other phases of observational research, not just when developing coding schemes, because such a stance often provides deeper insight into phenomena, which is useful when generating and defining hypotheses and when interpreting results in natural contexts.
Coding schemes are presented to behavioral observers, not participants. Participants may be aware that an observer is present or that a video image is being recorded, but they don't interact with the measuring device itself in the way they do, for example, with a questionnaire that they fill out, nor is their behavior constrained as with a structured interview. They are free to simply behave, sometimes restricted only by the instructions the researcher provides them, the structure of the experimental session, or the features of the environment (i.e., novelty, artificiality). True, their behavior may be altered by the presence of an observer, although most investigators report that participants rapidly habituate, whether observers are recording live or using video. As a result, the behavior captured by observational methods often seems more natural and less constrained than it is with other methods. Although not absolute, in general we think that the ability to capture relatively naturally occurring behavior is perhaps one of the major advantages of observational methods.
A second advantage is the ability to capture nonverbal behavior. Again, the coding scheme resides with the observer; there is no presumption that participants need to be verbal (or able to read), as is the case with many other methods. Thus it is not surprising that, historically, observational methods have been developed primarily by investigators studying animals (e.g., S. Altmann, 1965) and nonverbal humans, that is, infants (e.g., Tron-ick, Als, Adamson, Wise, & Brazelton, 1978). Of course, verbal behavior can be captured explicitly by observational methods, for example, when coding transcripts of couples' conversation (e.g., Gottman, 1979).
A third, and perhaps major, advantage is the way observational methods can be used to study process. Although Parten coded 1-minute samples from different days, this is the exception. More typically observational methods are used to capture a more or less continuous record of behavior as it unfolds sequentially in time. Thus the book that Bakeman wrote with Gottman (1997), titled Observing Interaction, has as its subtitle, An Introduction to Sequential Analysis, understanding that sequential analysis can be a general approach that takes into account both sequences and co-occurrences of events ordered in time. For example, Bakeman and Brownlee (1980), using codes similar to Parten's (their codes were unoccupied, solitary, together, parallel, and group play), recorded sequences of children's play states, which allowed them to discover that parallel play acted as a bridge to group play (because solitary often preceded parallel play, and parallel often preceded group play, but solitary rarely preceded group play).
Not all investigators who use observational methods to capture records of behavior in time are interested in sequential (or concurrent) associations among behaviors. Some may be interested primarily in time-budget information, that is, in what proportion of time an animal foraged or slept, or what proportion of time, on average, 3-year-old children spent in parallel play. Still, investigators interested in one, the other, or both of these uses of observational data will experience what may be the primary disadvantage of these methods, which is the voluminous amounts of data that can be generated. Thus issues of data management, and especially data reduction, although not unique to observational methods, often demand considerable attention when observational methods are used.
We began this section with the statement that coding schemes are a defining characteristic of sequential observational methods. Although this chapter follows this definition, the definition itself is arguably somewhat narrow. Other, very useful possibilities exist and are worth mentioning. One is the use of rating scales. Although the terms coding and rating are sometimes used interchangeably, it seems clearer to maintain that coding relies on categorical scales and rating on at least ordinal scales. Ratings could be applied sequentially. For example, raters might be asked to rate successive 10-second intervals for emotional intensity (e.g., 1 = very negative, 2 = somewhat negative, 3 = neutral, 4 = somewhat positive, 5 = very positive). More typically, raters might be asked, for example, to rate an entire 5-minute mother-infant interaction session for maternal warmth, maternal responsiveness, infant responsiveness, and so forth. The two strategies can also be combined. For example, coders could code mother and infant behaviors throughout the session and then rate various characteristics at the end.
In a number of ways, problems, techniques, statistics, and other matters are different for coding compared to rating. Coding is usually more labor intensive and time consuming, but it provides a level of concrete detail and exploration of process (e.g., moment-by-moment changes and effects) that rating typically does not. Moreover, reliability approaches can be quite different (see Hox & Mass, chap. 19, this volume, for the intraclass correlation, which is used with ratings). In this chapter we have chosen to focus on coding and its particular problems and techniques because we believe that the more, different approaches investigators know about, the more likely multimethod approaches become. There are many reasons to choose between, for example, detailed moment-by-moment coding and summary ratings, but lack of knowledge about a particular approach should not be one of them.
Was this article helpful?