By Matt Harrington, BCBA · Behaviorist Book Club · April 2026 · 12 min read

Conditioning Novel Items as Preferred Stimuli: Expanding Reinforcer Options for Autistic Learners

Overview & Clinical Significance

Identifying effective reinforcers is foundational to every ABA program. Without access to potent reinforcers, behavior analytic interventions lose their primary mechanism: reinforcement cannot produce its characteristic effects on behavior if the putative reinforcers are not actually functioning as such. For autistic individuals who demonstrate limited object preferences — a restricted range of items that function as reinforcers — this creates a significant practical constraint on programming. When the available reinforcer pool is narrow, behavioral satiation occurs rapidly, reinforcer efficacy declines, and the efficiency of instruction suffers.

This course describes a study in which researchers conditioned novel items to become preferred stimuli for three autistic individuals through observational procedures. The clinical significance of this finding is substantial: if novel items can reliably be conditioned to acquire reinforcing functions through observation — without direct pairing with a known reinforcer or direct delivery to the target learner — BCBAs have access to a procedure that can expand the reinforcer pool for clients with restricted preferences at relatively low cost.

Dr. Leaf presents the study procedures, results, and clinical implications in a format that makes this finding directly accessible to practitioners. For BCBAs who have experienced the clinical frustration of working with clients for whom the available reinforcer pool is insufficient to sustain programming, this course provides both a specific procedural approach and a conceptual framework for understanding how reinforcing functions can be acquired through observational mechanisms.

Background & Context

The behavior analytic literature on reinforcer identification and development has grown substantially over the past two decades. Classical approaches to reinforcer identification rely on preference assessments — paired choice, multiple stimulus with replacement, free operant — to identify stimuli that a client will select or contact with high frequency under conditions of relative deprivation. These assessments are valuable but limited: they can only identify items that already function as reinforcers, not create new ones.

Conditioned reinforcement is an established behavioral process through which a neutral stimulus acquires reinforcing functions by being paired with an existing reinforcer. This process is foundational to understanding how complex reinforcers — social approval, tokens, money, grades — acquire their behavioral effects. The study described in this course applies conditioning principles to expand the reinforcer pool for autistic individuals with restricted preferences, but through an observational rather than direct-pairing mechanism.

The observational conditioning procedure draws on the literature on observational learning and vicarious conditioning. Research has documented that autistic individuals can acquire reinforcer preferences through observation — watching another person interact with and be reinforced by a novel object can condition that object to become preferred for the observer. The specific procedures required for this conditioning effect to occur — including the model's behavior, the contingency between the model's behavior and the consequences, and the observer's attending — are critical variables that the study illuminates.

Limited object preferences in autistic individuals have been associated with a range of behavioral and developmental factors, including restricted sensory experiences, limited exploratory behavior, and reduced social referencing. Understanding the specific functions that the restricted preference pattern serves — or the learning history variables that produced it — is relevant to selecting the most appropriate procedure for expanding the reinforcer pool.

Clinical Implications

The clinical implications of successfully expanding the reinforcer pool through observational conditioning are broad. More reinforcers mean less satiation within sessions, greater flexibility in program design, improved maintenance of instructional behavior across settings, and more opportunities to use naturally available reinforcers rather than exotic items that require specialized management. For clients whose restricted preferences have been a significant barrier to programming, even modest expansion of the available reinforcer pool can produce meaningful improvements in instructional efficiency.

The procedure described involves having the target participant observe a model interacting with novel objects and receiving reinforcement. BCBAs implementing this procedure must attend carefully to the attending behavior of the observer — the conditioning effect depends on the observer actually processing the model's interaction with the item, not merely being physically present. Establishing and verifying adequate attending before proceeding with conditioning trials is an important procedural prerequisite.

Probe procedures for assessing whether the novel item has acquired preference are equally important. After observational conditioning trials, BCBAs should conduct formal preference assessments using the conditioned items alongside previously preferred and neutral items to determine whether the conditioning was effective. Documenting preference before and after conditioning trials provides the data needed to evaluate the procedure's effectiveness for a specific client.

The clinical implications also extend to the selection of conditioning models. Research on observational learning suggests that models who are perceived as similar to the observer, who demonstrate engagement and enthusiasm with the target item, and who receive clear, observable reinforcement are more effective conditioning stimuli. In practical terms, this may mean selecting peer models rather than adult models for some clients, or ensuring that the model's engagement with the item is expressive and reinforced in a way that is clearly visible to the observer.

Ethical Considerations

The ethical dimensions of reinforcer expansion procedures involve both the process and the goals. Code 2.09 requires behavior analysts to use the least restrictive procedures, and expanding the reinforcer pool through observational conditioning — a procedure that involves observation of naturally occurring interactions rather than imposing stimulation on the client — is consistent with this principle. It avoids more intrusive approaches to reinforcer development while addressing a genuine clinical need.

Code 2.08 requires that behavior analysts assess and account for the functions of behavior and the environmental variables maintaining them. Restricted preferences may serve functions — they may be associated with reduced sensory overload, reduced social demand, or other aversive stimulation. BCBAs should consider whether expanding the reinforcer pool might inadvertently create conditions that are aversive to the client, and whether the client is showing assent-consistent responses during the conditioning procedure.

Data collection and honest reporting of outcomes are ethical obligations under Code 3.01 and Code 6.01. When implementing conditioning procedures, BCBAs should design data systems that allow accurate evaluation of whether the procedure is working for a specific client, rather than assuming success based on general research findings. Individual variability in response to conditioning procedures is real, and honest data allow clinical decisions to be responsive to individual outcomes.

The goal of expanding the reinforcer pool — making more stimuli functionally reinforcing — is ethically justified by its service to client welfare and instructional effectiveness. BCBAs should be prepared to articulate this rationale to families and team members who may be unfamiliar with the procedure, ensuring that informed consent includes an explanation of why reinforcer development is clinically relevant.

Assessment & Decision-Making

Assessing the need for reinforcer expansion begins with a comprehensive preference assessment and reinforcer analysis. BCBAs should document the current reinforcer pool through multiple preference assessment formats (not relying on a single assessment method), identify the degree of satiation that occurs within sessions with current reinforcers, and evaluate whether restricted preferences are significantly limiting programming. If the reinforcer pool is sufficient for current programming demands, reinforcer expansion may not be an immediate priority. If satiation is frequent, instructional efficiency is compromised, or new programming domains require reinforcers not currently available, expansion becomes a clinical priority.

Decision-making about which conditioning procedure to use should be guided by the client's current repertoire. Observational conditioning requires adequate attending to the model's behavior. If a client does not reliably attend to others' interactions with objects, the observational conditioning procedure may require prerequisite work on attending before it can be effective. Alternative reinforcer expansion approaches — such as pairing neutral items with existing reinforcers through direct association — may be more appropriate for clients with significant attending deficits.

For clients where observational conditioning is feasible, BCBAs should specify the procedure precisely: the model, the item, the contingency, the number and distribution of conditioning trials, and the probe design for assessing preference acquisition. Replicating the published procedure with as much procedural fidelity as feasible increases the probability of obtaining outcomes consistent with the research findings, while documented variations allow for analysis if outcomes diverge.

Post-conditioning preference assessment should use a design that controls for the passage of time: pre-conditioning preference for the conditioned item should be established, conditioning trials implemented, and post-conditioning preference assessed with the same or equivalent procedure. This comparison provides the data needed to attribute any preference change to the conditioning procedure rather than to spontaneous experience with the item.

What This Means for Your Practice

Reinforcer poverty — too few effective reinforcers to sustain efficient programming — is a common clinical problem that this course addresses with a specific, empirically evaluated procedure. The practical implications for BCBA practice are direct.

First, conduct a reinforcer inventory for your current clients with restricted preferences. Document what items are currently functioning as reinforcers (not just what items are offered), how quickly satiation occurs with each, and how many separate reinforcers are available for a typical programming session. For clients where this inventory reveals genuine reinforcer poverty, develop a reinforcer expansion plan that includes observational conditioning as an option alongside other approaches such as stimulus-stimulus pairing and direct exposure with graduated contact.

Second, assess whether your clients have the attending prerequisites for observational conditioning. If attending to others' behavior with objects is not a reliable repertoire, treat this as a programming target before attempting observational conditioning. The procedure depends on genuine observational processing — it is not sufficient for the client to be physically present during modeling.

Third, design your implementation with prospective data collection. Establish the current preference status of the items you intend to condition, document conditioning trial procedures and outcomes, and conduct formal post-conditioning preference assessments using the same structured format as pre-conditioning assessment. This data trail allows you to evaluate the procedure's effectiveness for your specific client and to make data-based decisions about continuation, modification, or discontinuation.