Participants

Researchers recruited four 4–5-year-old individuals diagnosed with autism spectrum disorder (ASD) to participate in this study. The participants had previously received face-to-face applied behavior analysis (ABA) services, including instruction via DTI, from a university-based early intervention (EI) program. Additionally, researchers observed that all participants had an established echoic repertoire (i.e., participants echoed complete sentences consisting of at least five words), and caregivers indicated that participants had no prior exposure to formal instruction that used IF. Eligible participants had access to a stable internet connection, and a caregiver was present for each session. Prior to the initial baseline session, each participant and caregiver met with the primary researcher who certified that all participants met the following inclusion criteria: (1) attended (i.e., eye gaze directed to relevant materials) to digital materials for at least 12 consecutive trials and (2) produced a vocal tact of previously mastered targets, presented through a tablet, for at least 10 out of 12 trials.

Board Certified Behavior Analysts (BCBAs) that oversaw eligible participants completed the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP; Sundberg, 2008) prior to the participant’s acceptance in the study (see Table 1 for VB-MAPP scores associated with each targeted verbal operant). Jose was a 5-year-old white, European American boy enrolled in a public-school kindergarten classroom. Jose previously received two years of one-on-one DTI and natural environment teaching (NET) instruction. Jose displayed an emerging basic conversation repertoire, and before each session, he infrequently engaged in reciprocal conversations. Elmer was a 4-year-old white, European American boy enrolled in a half-day EI program at a university-based preschool. Elmer previously received one year of one-on-one DTI and NET structured instruction. At the time of the study, Elmer attended a university-based preschool for 12 hours a week and received NET structured, small-group instruction. Elmer displayed an established conversation repertoire and frequently engaged in reciprocal conversations. Sabrina was a 5-year-old white, European American girl enrolled in a public-school kindergarten classroom. Sabrina previously received two years of one-on-one DTI and small group NET structured instruction. Sabrina displayed an emerging basic conversation repertoire and infrequently engaged in reciprocal conversations. Stacy was a 5-year-old white, European American girl. Stacy was homeschooled by her mother. Previously, Stacy received two years of small-group NET. Stacy displayed an established conversation repertoire, and before each session, she frequently engaged in reciprocal conversations.

Table 1 Total and targeted verbal operant VB-MAPP milestones scores across participantsSetting and Materials

The first and third authors acted as instructors throughout the study. Instructors conducted all sessions on the ZoomTM Video Communications, Inc. (Zoom) platform. Instructors accessed Zoom calls from their homes or a private office at a university-based preschool, and participants’ caregivers connected to Zoom calls from their homes. Jose and his caregiver completed their sessions either at their kitchen table or in their home office. Elmer and his caregiver completed their sessions in their dining room, living room, or bedroom. Sabrina and her caregiver completed all their sessions exclusively at their kitchen table, whereas Stacy and her caregiver conducted their sessions in their living room. Two participants connected to Zoom calls through an electronic tablet (e.g., iPad), and two participants connected via home computers. To protect each participant's privacy, instructors used a HIPAA-compliant Zoom account. Additionally, instructors agreed to end research sessions if a third party (i.e., an individual not affiliated with the study) entered the instructional space within the participant or instructor’s setting.

All digital stimuli were organized and presented in trials according to procedures described by Mattson et al. (2020)—a protocol for developing DTI procedures via Google Slides (Google LLC, 2006). The slide decks that instructors presented during probe sessions included a final slide that displayed a variety of preferred videos, and participants selected one to watch following the session. Prepared materials were presented using Zoom’s “Share Screen” feature. During all calls, one caregiver sat with the participant and delivered preferred edible items.

Response Measurement

The primary dependent variable was the percentage of correct independent primary target responses emitted during each training session. The primary target responses for Jose, Elmer, and Stacy were vocal textual responses that corresponded to the presented word, letter, or letter blends (e.g., reading the word), and the primary target responses for Sabrina were vocal intraverbal responses that corresponded to the presented instruction (see Table 2). For each trial, observers scored a correct independent response if the participant produced the target vocal response within 5 s of the initial target stimulus presentation or an incorrect response if the participant did not produce the target vocal response. Following each session, researchers calculated the percentage of correct independent primary target responses by dividing the total target independent responses by the total trials and multiplying the quotient by 100. The mastery criteria for all primary target stimulus sets was two consecutive sessions with correct independent responses above 90% or five consecutive sessions above 80%.

Table 2 Assigned responding across participants

The secondary dependent variable was the percentage of correct secondary responses emitted during each probe session (see Table 2). The secondary target responses for all participants were intraverbal responses that corresponded to novel targets (i.e., primary and secondary targets shared no relation). Similar to primary target responses, observers scored a correct independent response if the participant produced the target vocal response within 5 s of the secondary target. Researchers used probe sessions to evaluate the emergence of all secondary target responses.

Interobserver Agreement (IOA) and Procedural Integrity

Instructors recorded the DTI, DTI with IF, and probe conditions through Zoom. Secondary independent observers collected data on all dependent variables and procedural integrity for at least 30% of the recorded sessions. Researchers randomly selected sessions from a list of saved session recordings. Across all observed sessions, researchers defined an agreement as any trial in which the instructor and independent observer coded matching responses. Researchers calculated trial-by-trial interobserver agreement (IOA) by taking the number of agreements, dividing them by the total number of trials, and multiplying the quotient by 100. Mean IOA across all participants was 99.3% (range, 83.3-100% [see Table 3]).

Table 3 Interobserver agreement across conditions

Independent observers recorded the instructor’s implementation of condition-specific variables (see Table 4). Researchers calculated procedural integrity by dividing the sum of condition-specific variables implemented correctly by the total condition-specific variables per session and multiplying the quotient by 100. Mean procedural integrity across all conditions was 99.7% (range, 91.8–100% [see Table 5]).

Table 4 Breakdown of the component specific procedural integrityTable 5 Treatment integrity scores across conditionsExperimental Design

Researchers employed an adapted alternating treatments design (i.e., AATD [Sindelar et al., 1985]) embedded in a non-concurrent multiple baseline design across participants. Researchers utilized a non-concurrent multiple baseline design to compare the effects each teaching procedure (i.e., DTI or DTI with IF) had on the acquisition of their respective primary target responses. Additionally, researchers employed the adapted alternating treatments design to compare the effects of the teaching procedures on the acquisition of the secondary targets.

Stimulus Sets

Researchers emailed each participant’s caregivers to identify appropriate targeted responses for primary and secondary targets. Researchers requested that caregivers identify potential targets that had not been directly taught to the participant and that might meet the participant’s current academic/behavioral goals (i.e., assessed skill deficit needing to be trained). Potential targets required participants to engage in either textual or intraverbal responding. Once researchers identified a list of potential targets, researchers requested that the caregivers not teach the selected targets outside of the study, and instructors probed the potential targets and assessed each participant’s responding. Researchers listed all potential stimuli that did not evoke a correct response and paired potential stimuli according to their topographical features and corresponding response topography (Cariveau et al., 2021). Researchers measured topographical features as the corresponding appearance of the stimuli (e.g., “G” and “C”). Response topography was measured according to the required number of syllables and phonemic production associated with the correct response (e.g., nail and tail). After pairing potential stimuli, researchers assigned one of each stimulus pair to each training condition. For example, if “nail” and “tail” were paired as potential stimuli, researchers assigned “nail” to the DTI with IF condition and “tail” to the DTI condition. This process for equating stimuli was repeated across all sets of stimuli until both training conditions consisted of four primary targets and untrained conditions consisted of four secondary targets. All participants received training on a single set of assigned targets in each condition, except Jose, who received training on two sets of assigned primary targets in training conditions and one set of assigned secondary targets in the probe condition. Table 2 lists target stimuli and responses for primary and secondary targets.

General Procedures

Instructors conducted sessions with the participants one to three times per week. During each Zoom meeting, participants experienced at least one session of all conditions (described below). The DTI and DTI with IF conditions were presented in a randomized order. Instructors conducted probes every third session—after the participant received one exposure to both the DTI and DTI with IF conditions. Lasted for 1 to 5 min, and a 1 to 10 min break followed. During sessions with primary targets, instructors presented the four primary targets three times in a semi-randomized order, yielding a total of 12 trials. During probes, instructors presented all eight secondary targets (i.e., four in the DTI condition and four in the DTI with IF condition) twice in a semi-randomized order, yielding 16 trials.

At the start of each Zoom call, caregivers conducted an informal preference assessment of available edible items. Each preference assessment consisted of caregivers identifying available preferred edible items (e.g., mini chocolate chips), vocally listing various preferred edible items that were available to the child, and the child selecting one item. Researchers requested that caregivers provide small edible items because we anticipated that participants would take less time to consume smaller items. Additionally, researchers asked caregivers to provide edible reinforcers to ensure that caregivers would not require additional training on reinforcement systems (e.g., token economies) and participants would not be required to relinquish access to the preferred item multiple times throughout the session (e.g., accessing the item for 20 s and then handing the item to the caregiver).

Prior to implementing treatment sessions, researchers directed each caregiver to provide edible items if the participant emitted a correct response. Throughout treatment sessions, caregivers provided the selected item as the contingent consequence for correct responses.

Baseline and Secondary Target Probes

Instructors initiated each trial by presenting the target and the instruction (e.g., the screen displayed the letter, “A,” and the instructor said, “What sound?”). Instructors then allowed up to 5 s for the participant to respond, and no programmed consequences were delivered contingent on incorrect responding. In addition, instructors provided noncontingent, non-specific praise (e.g., “Thanks for sitting.”) in between every three to four trials. Finally, participants received contingent access to preferred video clips for completing every third session (i.e., probe sessions).

General Treatment Conditions

Instructors initiated trials by presenting the primary target and the instruction (see the top panel of Fig. 1). Then instructors allowed up to 5 s for the participant to respond. If the participant correctly responded (i.e., engaged in the primary target response), the participant received praise paired with a preferred edible item. If the participant responded incorrectly or did not respond to the presentation of the primary target, instructors removed the stimulus and provided feedback (e.g., the screen displayed “Try again” and the instructor said, “Try again.”). Then instructors re-presented the trial and provided an immediate (i.e., 0-s prompt delay) echoic prompt. If the participant incorrectly echoed the response, instructors continued to re-present the trial with the corresponding prompt until the participant correctly echoed the response. After a correct prompted response, instructors re-presented the original training trial without an echoic prompt. Instructors repeated the error correction sequence if the participant erred in the re-presented trial. When the participant correctly responded, the participant received praise paired with a preferred edible item.

Fig. 1

Flowchart of all teaching procedures. Note. This figure depicts a flowchart of each teaching condition

DTI

During the consequent event, instructors presented the secondary target (e.g., a picture of a cow) and withheld the presentation of the secondary target response (see the top panel of Fig. 1). Caregivers did not orient participants toward the presentation of the secondary target, and instructors did not provide consequences if participants manded for information that related to the secondary target or engaged in a tact of the secondary target. Researchers included this presentation of the secondary target to control for simple exposures to the stimulus as a potential controlling variable. Secondary targets were presented an equal number of times each session, and stimulus presentation occurred in a semi-randomized order.

DTI with IF

Following the delivery of the preferred edible item, instructors presented a secondary target (e.g., a picture of a dog) and presented the secondary target response (e.g., “A dog is an animal” [see the bottom panel of Fig. 1]). Similar to DTI procedures, caregivers did not orient participants toward the presentation of the secondary target, and instructors did not provide consequences for manding or tacts of the secondary target.