Stacks Image 15

11. Functional Assessment & Functional Analysis

Measurement is important in any science and in the previous chapter we looked at how to measure various dimensions of behaviour. Given that the occurrence of a behaviour is dependent on the context in which it is observed, the behaviour is classified as a ‘dependent variable’, i.e., its occurrence depends on the occurrence of another, independent, variable. Putting that science speak in everyday terms, this means that if you can identify aspects of the environment (independent variable) that are responsible for the behaviour that was observed (dependent variable), you will have explained the reason for your observation. In effect, explanations for behaviour boil down to statements describing the relations between dependent and independent variables, what we call functional relations.

Once functional relations have been identified, the mystery surrounding the occurrence of a behaviour disappears. This sounds fairly logical and straightforward, but it is not always as easy as it sounds. First, we have to contend with the conceptual traps caused by mentalism in the search for these functional relations. Second, we might not always know how to collect the appropriate data. It’s all very well looking at simple behaviours in a laboratory, but what about the real world where behaviours are more complicated and contingencies of reinforcement and punishment are also more complicated?

Functional assessment is the general term used for a range of methods that can be used to help address issues on data collection. Functional relations are uncovered by procedures that systematically examine the antecedents and consequences that lead to and maintain a behaviour. This information can then be used to develop individually tailored interventions. In this chapter we examine some of the procedures that have been devised.
There are three main methods in functional assessment:

  1. Direct observation
  2. Indirect or informant based methods
  3. Functional Analysis

Direct Observation

In Movie 11.1, we first see a snapshot of a child kneeling and stretching her arms forward against a white background. If you were asked about what she was doing, you would have to take a wild guess. Maybe she is stroking a dog or fixing a bike.

The next picture adds a background image. You can see that she is actually kneeling on a chair and leaning on a table. If you were asked what she is doing, your guess would be a little more informed. There is no dog and no bike, so the previous guess is not right. You see papers and pens on the table, so she may be drawing a picture or writing something.

The next slide adds some motion and you can see that she is doing her homework and talking to someone. As the scenario unfolds in subsequent slides you observe the normal routine of a child being given homework by her teacher, being told by her mother to do her homework, doing her homework, being praised after finishing it, and then being praised by the teacher after she brings it to school.

The focal segment in this sequence is the child doing her homework. This scene was chosen simply because it provided an opportunity to show visually that the concept of the behavioural stream is not a fanciful abstraction invented by academics in their ivory towers. Rather, it is a simple statement of fact, and one that provides a framework that helps us to understand how components of the behavioural stream are interrelated. The graphics merely help us to visualise the kinds of data that could be obtained from direct observation of relations that can exist between antecedents, behaviour, and consequences.

When it comes to applied research with children who are not doing their homework, it makes sense to examine components of the typical stream shown here with Kalinka to see whether the problem lies with the antecedents or consequences of the behaviour. This is exactly what was done by Millar and Kelley (1994). They used goal setting (antecedent changes) and contingency contracting (changes of consequences) to improve homework performance and on-task behaviour of children. Parents of these children were actively involved and consumer satisfaction for the procedures was high.

Movie 11.1 has an example of another behavioural stream. With ‘Jean’, we see an older woman receiving a visitor and together they reminisce about the ‘good old days’. We have identified examples of the distal and proximal antecedents and distal and proximal consequences. There are more of course, but as in all these examples, we have merely highlighted those that ‘tell the story’ around a focal behaviour, which in this instance is reminiscing, i.e., on-topic self-initiated conversation.

Bourgeois (1993) examined the behavioural stream of older participants who were diagnosed with dementia and lived in day-care and nursing-home settings. She examined ways of helping these participants to engage in on-topic self-initiated conversations. Using a prosthetic memory aid (antecedent) had a positive effect on the frequency of productive utterances, length of conversational turns, appropriate relinquishing of conversational dominance, and increasing acknowledging or affirmative comments (reinforcing consequences).

Finally, in Movie 11.1 we see a mother bathing her baby. Clearly, Martina’s childcare skills are well developed. She comes from a large family, had lots of experience with babies as she grew up herself, and Ellen is her second child. She had plenty of chances to practice bathing a baby and seems quite relaxed. However, childcare skills do not come naturally; young parents usually learn from others. Seeing Martina engaged in these skills offers a starting point for helping a parent who has difficulties caring for their baby. Green at al. (1995) worked with two families in which parents had intellectual disabilities and children were in foster care. Both families were instructed in childcare skills. One mother readily acquired and applied these skills and the child’s phased return home was implemented. However, the other parent did not acquire the skills and the child remained in care.

The Behavioural Interview

So far, we have looked at the notion of behavioural measurement in situations where the behavioural scientist could directly observe the behaviour of another person. There are, however, many occasions when this is not possible. For example, the behaviour of interest might be private (as in the case of feelings and thoughts), or it might occur in the privacy of someone's home. In such cases we have to rely on the verbal or written reports of others who are in a position to observe the behaviour directly.

All too often, however, the lay person reports their own interpretation of events rather than a precise description of the behaviour in question. This problem with verbal reports was outlined earlier when we discussed summary labels and mentalistic thinking. We also came across a particular example when students were asked to describe Adam's behaviour. Their reports included: "He was rude", "He was cheeky", "He was romantic".

Because these diverse summary labels of the same carefully choreographed scene are open to individual interpretation, they are not appropriate for the precision required by a natural science approach to behaviour. What, then, is the scientist to do? In order to obtain an accurate assessment of events that transpired during the scene, a behaviour analyst would rely on information obtained from a
Behavioural Interview. In such an interview the client is asked for a precise description of the behaviour in question, along with the context in which it occurs. So-called "W" questions are the key to this procedure: What exactly did he do? Who did he do it to? How did he do it? Where did he do it?

Let us look at a typical example from childcare practice. Meranda (age 22) is the single mother of two children. Paul is 2 1/2 years old, and Lucy is 9 months old. Meranda states that Paul "is often very cheeky'" and she "has to hit" him at times.

Parents in Meranda's situation are usually told not to worry too much: "Paul is at the 'terrible two' stage and will grow out of it". Meranda may even be labelled an ineffective parent, in danger of physically abusing her child. In order to help Meranda manage Paul's behaviour effectively, we need to find out exactly what she means by "cheeky". His behaviour could be the same as that of Adam, who was also labelled "cheeky", or it could be totally different. In the behavioural interview, the first task is to establish the topography of Paul's behaviour (Movie 11.2).

From this animation we have now established that when Meranda said that Paul was cheeky, she meant that he hit his little sister with his fist on the head. Quite a difference to Adam's behaviour, isn't it! This is possibly not the only behaviour that Meranda labels "cheeky" and we will have to ask her for equally precise descriptions of other behaviours. We must also ask her about the frequency, duration, and latency of these behaviours. If she is unable to give us precise information, the first step of any intervention would be to ask her to record the behaviour accurately.

The next step in the behavioural interview is an analysis of the context in which the behaviour occurs (Movie 11.3). Where does it occur? What happens immediately before it? Who is present at the time? The aim of these questions is to identify possible Antecedents to the behaviour.

We now know in much more detail what Meranda means when she says Paul is 'cheeky'. We know that she means that he hits his little sister with his fist on the head, that this happens in the kitchen after mealtimes when his father is present. The next set of questions in the interview is concerned with the consequences of Paul's behaviour. What happens after he hits (Movie 11.4).

We have noted earlier that consequences influence behaviour. For a full analysis of Paul's behaviour, then, it is crucial that we ascertain the consequences of Paul's hitting behaviour. If particular consequences are responsible for the maintenance of Paul's behaviour, we will be able to identify them with this line of questioning.
We have now conducted an analysis of Paul's behaviour that is much more precise than the summary label 'cheeky' given by Meranda. With this information we can develop a possible explanation for Paul's behaviour that includes reference to the roles of important antecedents and consequences. Once these events are known, it becomes a relatively straightforward task to change Paul's behaviour. The first step would be to specify a desired 'target behaviour'. That is, working with Meranda, the behaviour analyst specifies exactly what it is that she wants Paul to do. Thereafter, the intervention involves changing either the antecedents or consequences that maintain his problem behaviour. At all times during the intervention, records are kept for monitoring the effects on Paul's behaviour. These records help ensure that decisions can be quickly made if changes to the intervention are required.

Functional Analysis

The examples of the functional assessment that we used here were fairly simple and obvious (see also Movie 11.5), but of course there are many times when behaviour is much more complex and it is difficult to be clear about which antecedents and consequences bracket a focal behaviour.

In more scientific terms, we say that it may be difficult to identify which antecedents and/or consequences play a key role in maintaining the behaviour; i.e., the variables of which the behaviour is a function. We say this because we know that some antecedents have acquired discriminative control over the behaviour (e.g., the antecedent is a S
) and some consequences have reinforcing or punishing effects on the behaviour. But we may not know which. Consider, for example, a very complex behaviour, such as self-injurious behaviour (SIB). The effect of this behaviour is damage to a person’s own body. Typical examples include hitting, scratching, or biting oneself or banging one’s head against a wall or other hard object which often leads to bruises or cuts. Extreme cases may also include the behaviour of gouging out one’s own eyes. Self-injurious behaviour is a serious issue not only for the individuals who engage in it but also for everyone around them. SIB reduces the ability to focus on education, and depending on severity, physical injury may require medical attention. For family and staff, it is very upsetting to watch a loved one hurting him/herself and in trying to help you can end up in the line of fire yourself. Traditionally, interventions have relied mainly on medication or physical restraint, such as arm braces or head gear
If we are not clear about which antecedents and consequences play key roles in maintaining SIB, we will not be in a position to help the person change this behaviour. Simply trying a variety of treatment approaches might eventually achieve the desired treatment outcome. However, this would neither be very efficient nor very ethical. Furthermore, the possible success of this kind of approach would be by default rather than by design. Even if you are successful with one person, you cannot guarantee that repeating a successful intervention with other clients would be equally successful.

A Functional Analysis is a systematic approach that has been developed to help identify, on an individual basis, the role of antecedents and consequences in maintaining behaviour.

This image shows Danny engaged in self-injurious behaviour. He tends to pull his own hair until it comes out in big tuffs and he punches his own eyes until they are bruised. His parents say that “He does it all the time!”. He usually wears a helmet and sometimes his arms are restrained. He also takes medication. This kind of behaviour obviously prevents him from leading a fulfilled and happy life.


Imagine that you were charged with helping him to stop engaging in such destructive behaviours and trying to take him off physical as well as chemical restraints. Where would you begin? Well, one of the most important things you have learned to date from the study of schedules of reinforcement is that a discrete behaviour observed at any point in time may be part of a more general pattern of behaviour. The explanation for the observed behaviour, then, is to be found by making repeated observations until the pattern is uncovered. Data collection would involve details of his interactions with the environment, including details of various antecedents and consequences to his behaviour.

Sometimes, though, the antecedents and consequence of a behaviour are not readily identified. If that is the case, then we need to devise a specific strategy to determine which antecedents (distal and proximal) occasion his behaviour and the role that consequences play in maintaining it. We call this approach an ‘experimental’ or functional analysis.

In a functional analysis you would design a variety of test conditions in which you could observe Danny’s behaviour. The purpose of these tests would be to systematically assess different conditions until you identify the functional relations between his SIB and specific antecedents and consequences that cause and maintain it. In other words, by using the scientific method you would be able to determine which conditions reliably produce his SIB. You would then use the results of your investigation to design a treatment package that is specifically tailored for him.

Let’s now have a look at a few of things we could do. Here are four different test conditions that are typically used in the search for functional relations:

We have seen that when we want to understand the reasons why a behaviour occurs and why it is maintained we may need to use carefully crafted test conditions. In Danny’s case, this approach helps us to identify precisely those circumstances in which his SIB is likely to occur, and they can identify those events that function as reinforcers for either the presence or absence of SIB.

Functional analysis is discussed in detail in a special edition of JABA (1994) devoted to behaviour assessment. In this issue, Brian Iwata and colleagues report how they carried out a range of functional-analytic tests with individuals with developmental disabilities who displayed self-injurious behaviour. They describe how the detailed functional analysis of self-injurious behaviour led to focused and effective interventions.

The conclusion from all test conditions is that Danny’s SIB is a function of a number of different variables. Decisions regarding appropriate intervention are based on the identification of these variables. In Danny’s case, here are some suggestions for interventions based on the findings in each condition.

Condition 1: Attention
When Danny was reprimanded for SIB and continued to engage in it, we concluded that social disapproval and reprimand did not function as ‘punishers’. In fact, we also drew attention to the possibility that this kind of social attention could function as a reinforcer. If Condition 1 had been the only condition in which Danny engaged in SIB, it would follow that the intervention should involve the replacement of social disapproval and reprimand with non-contingent attention or access to material of food. An intervention should also involve differential reinforcement of other or alternative behaviours (DRO and DRA respectively) in order to replace SIB with less aberrant behaviours that serve the same function, i.e., gaining social attention.

Condition 2: Demand
If Danny stopped engaging in SIB after the termination of a demanding task, we would conclude that escape from the task functioned as a negative reinforcer for SIB. Had this been the only condition in which Danny engaged in SIB there are a number of ways in which in which he could be helped:
1 - The difficulty of the task demand could be reduced.
2 - He could be taught the necessary skills to accomplish the task.
3 - He could be taught to ask for a break appropriately to allow for time off-task or for access to leisure activities.
As part of the general effort to individualise an intervention and generate motivation for task completion, positive reinforcement for appropriate behaviour should be provided frequently.

Condition 3: Play
When Danny was praised for the absence of SIB while at the same time SIB was ignored, he did not engage in SIB. We concluded that praise functioned as a positive reinforcer for the absence of SIB. We also concluded that ignoring SIB may function as a ‘punisher’ for it. To increase the likelihood of him not engaging in SIB, we should use praise for appropriate behaviour more often and continue to ignore SIB.

Condition 4: Low stimulation
When Danny was left alone and engaged in SIB, we concluded that the sensory stimulation produced by this behaviour functioned as an ‘automatic’ reinforcer. If this had been the only test condition in which Danny engaged in SIB, it would follow that an intervention should involve substitute sensory stimulation.

It can be difficult to identify substitutes, though, because some topographies of SIB produce multiple sources of sensory stimulation. Alternative sources of stimulation may include leisure materials. Availability of these should be combined with keeping Danny occupied with preferred tasks.


To sum up, functional analysis offers an experimental tool to help assess the function of a behaviour in a way that goes beyond simple direct observation in natural environments. Functional analysis was first published in a review of 152 cases when Iwata et al. (1994; reprinted from 1982) noted the following;

“All of these interventions when applied to the function of SIB for which they were designed, reduced behavior to below 10% of baseline in over 80% of cases. More importantly, uniformly positive results were obtained in spite of the fact that reinforcement-based interventions were used two to three times more often than punishment” (p. 233).

Since then, functional analysis has become the key methodology for the assessment of severe problem behaviours, including SIB and many others. It has been used in experimental settings, but also in schools and in the home (Movie 11.5).

Additional Video Resources