Introduction
Welcome to this CEU based on a talk by Dr Douglas Greer, a leading figure in the field of behaviour analysis whose work has reshaped how we understand teaching, verbal behaviour, and the functions of reinforcement.
In this session, Dr Greer draws on decades of research and applied experience to distinguish between two critical but often conflated functions of reinforcement: strengthening and selecting. This distinction is not just theoretical. It has real consequences for how we teach, how we train, and how we support meaningful learning for individuals with and without developmental disabilities.
Dr Greer reflects on the evolution of our science, from Skinner’s early focus on strengthening behaviour through consequences, to a more complex understanding of how reinforcement selects operants over time within natural environments. This shift, from thinking about behaviour as something to be repeated, to something shaped by contingencies of social significance, underpins much of the work done in CABAS and in contemporary verbal behaviour development.
Drawing on examples from experimental analysis, classroom practice, and the history of behaviour science, Dr Greer explores concepts such as establishing operations, learn units, developmental cusps, prosthetic reinforcers, and the transition to natural reinforcement. He explains how certain learners must first acquire the capacity to be reinforced by teacher attention, voices, and faces before they can benefit from correction procedures, or be taught verbal operants like mands and tacts.
This talk is both a conceptual and practical guide to a more refined, ethical, and effective application of behaviour analysis. It invites practitioners to think carefully about what we reinforce, how we do it, and whether we are truly teaching or merely training.
As you begin, consider how your own practice reflects these ideas. Are your interventions building enduring, functional repertoires, or simply momentary performances? This talk offers a framework for answering that question, and for moving our science forward.
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Video Presentation (Subtitles Recommended)
Glossary
Bidirectional Naming (BiN)
A verbal developmental capability in which a learner can acquire both speaker and listener responses to a stimulus from a single experience. For example, after hearing the name of an object and seeing it, the learner can later name the object (tact) and identify it when named (listener response) without separate instruction.
CABAS (Comprehensive Application of Behavior Analysis to Schooling)
A systems-based model of schooling that applies behaviour analytic principles to all aspects of education, including curriculum design, instruction, teacher training, and organisational management. CABAS schools use learn units as the basic unit of instruction, measure teaching effectiveness using the TPRA, and focus on inducing verbal developmental cusps and capabilities.
Capability
A type of developmental milestone that changes the way a learner acquires future behaviour. Capabilities such as Bidirectional Naming or Observational Learning allow learners to acquire new skills more efficiently, without requiring direct instruction for each new response.
Cusp
A behaviour change that exposes the individual to new environments, reinforcers, and contingencies, thereby significantly expanding the learner’s access to learning opportunities. The acquisition of a cusp often leads to rapid developmental progress.
Delayed Bidirectional Naming (Delayed BiN)
A form of Bidirectional Naming where the listener or speaker response emerges after a delay, without continuous reinforcement or recent exposure, indicating a more stable and generalised repertoire.
Echoic
A verbal operant in which the learner repeats what they have just heard. Echoics require point-to-point correspondence and formal similarity between the model and the response (e.g., hearing “ball” and saying “ball”).
Intraverbal
A verbal operant that involves responding to another person’s verbal behaviour without point-to-point correspondence. This includes answering questions, completing phrases, or engaging in conversation (e.g., “What do cows drink?” – “Water”).
Learn Unit
A complete instructional episode consisting of two interlocking three-term contingencies: one for the teacher and one for the student. The student experiences an antecedent, a behaviour, and a consequence (reinforcement or correction), while the teacher observes the behaviour, delivers the consequence, and records the outcome. Learn units serve as the basic unit of teaching and measurement in CABAS.
Learn Unit in Context
A learn unit only functions effectively when embedded within the learner’s broader behavioural and developmental context. This includes their instructional history (both prior teaching experiences and verbal developmental cusps), setting events (such as motivational conditions or competing stimuli), phylogenetic and trauma history, and the instructional behaviours of the teacher. Together, these factors determine whether a presented antecedent will evoke a functional operant, and whether the consequence will successfully select and maintain the behaviour. Teaching occurs not by delivering isolated learn units, but by arranging conditions under which operants can be selected and sustained by meaningful consequences.
Listener Literacy
The ability to respond accurately to spoken language without relying on visual cues. Listener literacy reflects abstract stimulus control by vocal stimuli alone and is foundational for higher-order verbal capabilities such as reading comprehension, conversation, and reasoning.
Mand
A verbal operant controlled by a motivating operation and reinforced by a specific consequence. It typically functions as a request (e.g., saying “water” when thirsty and receiving water).
Motivating Operation (MO)
An environmental event or condition that temporarily alters the value of a reinforcer and changes the likelihood of behaviour that has been reinforced by that stimulus in the past. Includes both establishing operations (which increase reinforcer value) and abolishing operations (which decrease it).
Prosthetic Reinforcement
A contrived or substitute reinforcer used when a natural consequence is not yet effective in maintaining behaviour. Examples include tokens, exaggerated praise, or artificial rewards. These are used temporarily to condition a behaviour until it can be maintained by natural reinforcement.
Reinforcement
A process by which a consequence increases the future probability of the behaviour it follows. Reinforcement can be delivered deliberately in teaching or occur naturally in the environment. It may function to either strengthen a response or select a behaviour over time.
Selection Function of Reinforcement
The process by which reinforcement shapes behaviour over time by selecting those behaviours that are most effective within a given environment. This function is analogous to natural selection and results in the development of stable operant repertoires.
Strengthening Function of Reinforcement
The immediate effect of reinforcement in increasing the likelihood of a behaviour occurring again under similar conditions. This function was the focus of early operant research by B. F. Skinner.
Tact
A verbal operant controlled by a non-verbal stimulus and maintained by social reinforcement. It functions as a label (e.g., seeing a dog and saying “dog,” followed by a response such as “Yes, that’s right”).
Three-Term Contingency
The foundational unit of operant behaviour: antecedent, behaviour, and consequence. It describes how environmental events evoke behaviour and how consequences influence whether that behaviour occurs again.
Four-Term Contingency
An expanded model of behavioural control that includes the motivating operation along with the antecedent, behaviour, and consequence. This allows for a fuller analysis of why a behaviour occurs under certain conditions.
TPRA (Teacher Performance Rate and Accuracy Scale)
An observation tool used in CABAS to assess how accurately and consistently a teacher delivers learn units. It tracks whether instructional antecedents are presented, whether student responses are correct or incorrect, and whether the teacher provides the appropriate reinforcement or correction. TPRA scores are used to improve instructional fidelity and student outcomes.
Training vs Teaching
Training refers to producing accurate responses through prompting or reinforcement, often using prosthetic reinforcers and sometimes without lasting change or generalisation. Teaching, in contrast, involves selecting and establishing verbal operants that are maintained by natural reinforcement and generalise across people, settings, and time. Teaching builds repertoires; training builds performances.
Incidental Bidirectional Naming (Inc-BiN)
A form of Bidirectional Naming where the speaker and listener behaviours are acquired without direct instruction, often as a result of shared activities such as reading or play. It reflects a more natural and generalised form of verbal learning.