What are Stimulus Classes and Response Classes?
It’s important to understand the distinction between what a stimulus class is and what a response class is in applied behavior analysis. A stimulus is any change in the environment. A stimulus class is defined as a group of antecedent stimuli that have a similar effect on responses and behavior. Stimuli in a stimulus class typically evoke or abate the same responses. There are several type of stimulus classess including: formal stimulus class, temporal stimulus class, and a functional stimulus class. A response is one occurrence of behavior. Response and behavior are used interchangeably but there is a distinction. A response class is a group of behaviors that serve the same function.
Types of Stimulus Classes
There are three types of stimulus classes: formal, temporal and functional. Stimuli in a formal class share physical features with one another. In other words, the topography of the stimuli are similar. Some examples of formal similarities are size, shape, weight, color, magnitude, intensity, and general appearance. Stimuli in a temporal class exist in a similar temporal space as one another. In other words, the temporal class refers to time in relation to the behavior of interest. There are antecedent temporal stimuli and consequence temporal stimuli. Antecedent temporal stimuli have a similar evocative or abative effect as one another such as an instruction or a signal. Consequence temporal stimuli appear after a certain response or behavior like a certain item or toy. Finally, stimuli can exist in a functional class. Stimuli in a functional stimulus class are commonly identified through a functional analysis. The stimuli in this class share a similar effect on behavior. For example, when you hear music, you start to dance, regardless of what type of music you hear.
Two More Ways to Identify Stimulus Classes
In addition to the big three, there are two more ways to identify potential stimulus classes. Feature stimulus classes are more conceptual and typically involve stimulus generalization. If you start to generalize one response to multiple stimuli, those stimuli might be part of a feature stimulus class. An arbitrary stimulus class are stimuli that evoke or abate similar responses but stimuli that do not share common features. Categories of items like meat and vegetables are common arbitrary stimulus classes.
More on Response Classes
Response classes are not broken down in the same way stimulus classes are broken down. Response classes often make up a repertoire. A repertoire is a collection of behaviors that an individual can perform. These can be positive behaviors or maladaptive behaviors. We use different repertoires in different scenarios. You should also consider response differentiation when thinking about response classes as it relates to ABA. Response differentiation is a behavior change where reinforced members of one response class occur more often than unreinforced members of the response class. If you want someone to fist bump instead of handshake you might teach response differentiation.