Progressive Time Delay Research Articles

Modeling Alphabet Skills as Instructive Feedback Within a Phonological Awareness Intervention.

This study evaluated the efficacy of an instructive feedback strategy for modeling letter names and sounds during presentation of positive feedback within a small-group phonological awareness intervention for preschoolers. Two experiments were conducted using multiple-baseline designs across children and behaviors. Letter name and sound identification and performance on a phonological awareness fluency measure served as the primary outcome variables. Six children completed Experiment 1. A progressive time delay was added to instructive feedback to elicit a response from the 9 children in the second experiment. In the first experiment, 6 children demonstrated gains on phonological awareness but not alphabet knowledge. With the addition of progressive time delay in the second experiment, all 9 children demonstrated gains on letter name and sound identification as well as phonological awareness skills. Progressive time delay to prompt children's responses appears to bolster the effects of instructive feedback as an efficient strategy for modeling alphabet skills within a broader early literacy curriculum. Modeling alphabet skills did not detract from, and may have enhanced, phonological awareness instruction for preschoolers.

Massed Trials Versus Trials Embedded Into Game Play: Child Outcomes and Preference

Limited data are available regarding how response prompting procedures should be used in early childhood settings. The purpose of this study was to compare the efficiency of progressive time delay instruction presented via two trial arrangements: massed and embedded. During massed trial sessions, a short instructional session was conducted, followed by game play. During embedded trial sessions, trials were conducted during game play. Across 12 participants with and without disabilities, efficiency and preference data were mixed. Preference data suggested most participants preferred the instruction type that resulted in most efficient learning. Social validity data suggest inservice and preservice practitioners may be equally likely to use the procedures, but some respondents indicated they might be less willing to use embedded trial arrangements due to increased effort in materials preparation. Implications include the possibility that faster learners may learn better in embedded contexts and that children may prefer instructional contexts that are most efficient for them.

Increasing Social Behaviors in Young Children with Social-Communication Delays in a Group Arrangement in Preschool

Abstract Young children with disabilities are less likely to display age-appropriate social behaviors than same-age peers with typical social development, especially children who display social-communication delays. In this study, two concurrently operating single case designs were used to evaluate the use of progressive time delay (PTD) to teach children with disabilities to share and to name peer preferences during dyadic instruction. PTD was effective for teaching children to share and to identify peer preferences. All participants generalized 50 to 100% of peer preference targets to typical classroom activities (e.g., selecting their peer's preferred snack before mealtime), with mixed results regarding sharing during an art activity. Keywords: systematic instruction, sharing, peer preferences, preschool, young children ********** Pro-social behaviors influence the development of friendships beginning in early childhood (Odom, Schertz, Munson, & Brown, 2004), potentially impacting long-term success in academic and social settings (Lane, Stanton-Chapman, Jamison, & Phillips, 2007). High-quality preschool programs focus on increasing pro-social behaviors in young children with and without disabilities (Division for Early Childhood [DEC] and National Association for the Education of Young Children [NAEYC], 2009; Wolery, 2005), providing numerous opportunities for interactions (Grisham-Brown, Hem meter, & Pretti-Frontczak, 2005). However, young children with disabilities are more likely to display social delays that impede appropriate peer interactions, potentially leading to rejection from peer groups (Guralnick, 1999). Young children with disabilities may require structured opportunities for peer-to-peer interactions to recognize the potentially "complex discriminative stimuli" that set the occasion for age-appropriate social behaviors (Ledford & Wolery, 2013, p. 440). Increasing age-appropriate pro-social behaviors in young children with disabilities requires practitioners to select target behaviors common in peer-to-peer interactions. Pro-social behaviors, such as initiating conversations (e.g., commenting on a peer's preferred interest), helping behaviors (providing assistance or aid), and sharing items with peers (giving an item so a peer can engage in or have the same or similar materials during an activity), are behaviors young children with typical social development commonly demonstrate in preschool classrooms (e.g., Babcock, Hartle, & Lamme, 1995). In addition, young children are more likely to identify peers who help and share items as "nice" and as "friends" (Tisak, Holub, & Tisak, 2007), potentially leading to increases in meaningful peer-to-peer interactions. Young children with social-communication delays (SCD), such as autism spectrum disorder (ASD), are less likely to initiate and attend to peers' social initiations than children with intellectual disability or typical development (Bregman & Higdon, 2012) and may display difficulties taking the perspective of others (known as Theory of Mind Impairments [ToM]; Millward, Powell, Messer, & Jordan, 2000; Mundy & Thorp, 2006; Zager, Wehmeyer, & Simpson, 2012), indicating a need for evidence-based interventions that directly teach pro-social behaviors with peers (Reichow & Volkmar, 2010; White, Keonig, & Scahill, 2007; Wolery & Hemmeter, 2011). Direct instruction regarding peer preferences may increase pro-social behaviors by providing contextual support when teaching helping and related behaviors (e.g., conversation skills). One study assessed learning a peer's preferences by presenting this information as instructive feedback during small group academic instruction; all participants learned some of the information without direct instruction, but generalization was not assessed (Lane, Gast, Shepley, & Ledford, 2015). Although knowing a peer's preferences may set the occasion for pro-social behaviors (e. …

Teaching Young Children With Social-Communication Delays to Label Actions Using Videos and Language Expansion Models

Young children with autism spectrum disorder (ASD) and related social-communication delays may display difficulties commenting on actions that occur in their natural environment. One method for increasing early conversation skills is direct instruction. Using video examples of actions may increase the salient features of instructional targets and, as such, may be an effective stimulus for presenting actions during instruction. The present study used a multiple-probe design across participants replicated across behaviors to evaluate the effectiveness of a 0- to 4-s progressive time-delay (PTD) procedure using video presentation of actions to teach three preschool-aged children with ASD and related social-communication delays to label actions. In addition, the teacher provided language expansion on all instructional targets, as well as assessed generalization to novel stimuli (videos and pictures or photographs). Results indicate that all participants acquired action labels. Two of the three participants generalized responses to novel videos and pictures while expanding their responses without direct instruction. Implications for teachers targeting action labels in early childhood settings are provided.

Photonic True-Time Delay Beamforming Using a Switch-Controlled Wavelength-Dependent Recirculating Loop

A photonic true-time delay beamforming network to provide tunable progressive time delays for phased array beamforming is proposed and demonstrated. In the proposed system, a microwave signal is modulated on multiwavelength optical carriers and sent to an optical dispersive recirculating loop that contains a linearly chirped fiber Bragg grating (LCFBG) to provide a wavelength-dependent round trip time. As the microwave-modulated optical signals recirculate in the loop, the microwave signals carried by different wavelengths will experience different time delays at the output of the loop. By controlling the number of round trips, tunable progressive true-time delays are achieved, which are required for true-time delay phased array beamforming. The proposed true time delay beamforming network is experimentally evaluated. Two dispersive loops that can introduce a single-round-trip true-time delay difference of 2.5 ns and 160 ps are designed, which are implemented by using two LCFBGs with two different dispersion coefficients of 2500 and 200 ps/nm. The progressive time delays for beam steering achieved by the two dispersive loops can cover a beam scanning range from –60° to 60°.

Peer Modeling of Commenting During Small Group Direct Instruction for Academic Behaviors

During small group instruction, two groups of children—each group comprised of one child with a disability and two without disabilities—were taught to read words using a progressive time delay procedure (PTD). Apart from the children with disabilities, two typically developing peers in each group were taught to comment on tokens given for correct responding. Academic responding was similar to that in previous studies including older children, but observational learning of peers’ words was variable within and across participants. Although adequate baseline comparisons were not possible and experimental control was not demonstrated, peers and one participant with a disability exhibited variable but increasing levels of commenting over time. Commenting increased over time in one generalization context (generalization across adults) and remained at low levels in the other (generalization across materials).

Comparison of Simultaneous Prompting and Constant Time Delay Procedures in Teaching Children with Autism the Responses to Questions about Personal Information

AbstractThe aim of the current study was to compare simultaneous prompting (SP) and constant time delay (CTD) in terms of their effectiveness and efficiency in teaching children with autism how to respond to questions about personal information. The adapted alternating treatments model was used in the study. Three male students with autism aged 4, 6, and 9, respectively, were included in the study. The findings of the study did not indicate any significant difference in two students with respect to the effectiveness of SP and CTD procedures. On the other hand, SP was observed to create more positive results and lead to a higher level of learning for the third participant. According to the findings, SP was more effective for one participant with respect to all the parameters studied. While SP was more efficient in the other two subjects in terms of incorrect responses, the difference regarding the instructional time to criterion for these two subjects was at a minimal level in favor of SP.Keywords: Autism spectrum disorder * Errorless teaching * Simultaneous prompting * Constant time delayDespite the fact that scientific studies on the autism spectrum disorder (ASD) have been conducted for half a century, there are still various topics that have not yet been explained. A huge variety of researchers from diverse fields such as medicine, psychology, and education have studied ASD. As a result of these studies, individuals that are diagnosed with ASD have been provided with various services with diverse characteristics. However, many of the studies conducted in this field unfortunately lack a scientific basis (Kurt, 2012a). This has created the need to identify procedures that are proven through experimental studies in terms of their effectiveness. With the aim of determining effective procedures used in the field of ASD, experimental studies published in this field have been analyzed and the results of research compilation studies have been published (National Autism Center [NAC], 2009; Wong et al., 2013).One of the procedures that has been proven in terms of its effectiveness through various studies, and identified to be evidence-based in research compilation study reports, is prompting (Odom, Collet-Klingenberg, Rogers, & Hatton, 2010; Wong et al., 2013). The CTD and SP are listed among the effective procedures that are frequently used in teaching various skills to the individuals with ASD and developmental disabilities with the aim of presenting them prompts in a systematic way.The CTD is a teaching procedure that consists of two phases, which are 0-second delay trials and constant delay trials. In the first phase of this teaching procedure, there are sessions where 0-second delay trials are performed. In these sessions, a target stimulus and controlling prompt are presented simultaneously. Following the 0-second delay procedure that is performed as many times as planned, the controlling prompt is presented upon waiting for a certain period following the target stimulus. A delay period is presented in order to provide the child with the opportunity to respond to the target stimuli independently (Browder & Snell, 2000; Kurt, 2009; Tekin-Iftar, Kurt, & Cetin, 2011). There are two types of time delay teaching procedures: constant time delay (CTD) and progressive time delay (PTD). In the constant time delay procedure, a constant time period (i.e. 4 seconds) of wait is allowed for the individual to respond after the target stimulus is presented. In the progressive time delay procedure, the delay period is progressively increased. For instance, a 2 second time delay is allowed at the beginning after the target stimulus is presented, which is followed by 4 and 6 seconds of delay periods, respectively, in order to present the prompt (Kurt, 2102a; Tekin, 1999; Wolery, Bailey, & Sugai, 1988).There are various studies that have indicated the effectiveness of the CTD procedure in teaching the individuals from various age and disability groups including individuals with autism. …

Educating Children with Autism Spectrum Disorders (ASDs) to Delay Gratification in the Contet of Temper Tantrums

Temper tantrums among young children are common, especially those with autism spectrum disorders. Delay of gratification is an essential component of temper tantrums. Teachers and parents seek management strategies for temper tantrums that are efficient, effective and ethical. The purpose of this applied behavioral analysis research was to compare various types of functional communication training with three children in the three and a half year old age range. In Phase One, to determine the misguided goal or function of each child’s temper tantrum, functional behavioral assessment was undertaken. In Phase Two, a reward menu was used to determine preferred rewards for the treatments. In Phase Three, a multiple baseline across participants design was used to reduce temper tantrums and increase appropriate communication that was identified through functional communication training (FCT). In Phase Four, fixed time delay (FD), progressive time delay with verbal praises (PDVP) and progressive time delay with visual cues (PDVC) were employed to represent three intervention conditions to teach delay of gratification. In Phase Five, parents were surveyed to determine the social validity or acceptability of the interventions with parents. Two independent observers counted frequency of temper tantrums, frequency of alternative communication behaviors, and length of wait time in each of these three children. Results showed that progressive time delay with visual cues (PDVC) increased wait time and reduced temper tantrums the most. Implications for teachers and parents working with young children prone to temper tantrums are discussed.

Progressive time delay to remediate letter discrimination difficulty.

A b st r A c t reading is hindered when students have difficulty discriminating letters. given their visual similarity, the letters b and d can be challenging for some individuals. Progressive time delay (ptd) was used to teach two first-grade students to discriminate between the letters b and d. During the procedure, a problem was presented and a prompt immediately provided. As students correctly responded to the problem, the delay between the problem and the prompt was gradually increased. student 1 mastered the discrimination after four sessions and skills were maintained. student 2 showed gradual improvement but continued to make some errors. implications for practice are discussed.

Peer Modeling of Academic and Social Behaviors during Small-Group Direct Instruction

The authors describe an intervention for 3 preschoolers with disabilities who had low peer-related social competence. The intervention taught academic skills tailored to the need of each target student in small groups (triads) with two typically developing peers, using a progressive time delay procedure. Prior to instruction and separate from the students with disabilities, typical peers learned to provide reinforcers for correct responses, and to say “thank you” when a group mate shared. The authors assessed the acquisition of sharing and thanking behaviors during instructional sessions by the preschoolers with disabilities and generalization of these social behaviors to contexts similar to classroom activities for all participants. Results were (a) all participants learned targeted academic behaviors; (b) all participants learned some academic behaviors taught to their peers; (c) participants without disabilities modeled sharing with high fidelity but modeled thanking with lower fidelity; (d) all participants with disabilities shared and less frequently said “thank you” during instructional sessions (although they were never prompted to do so); and (e) participants with and without disabilities shared in art and picnic activities and said “thank you” to a lesser extent, although they were not prompted to share or thank in these contexts.

Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy)

Abstract. Adding to the on-going debate regarding vegetation recolonisation (more particularly the timing) in Europe and climate change since the Lateglacial, this study investigates a long sediment core (LL081) from Lake Ledro (652 m a.s.l., southern Alps, Italy). Environmental changes were reconstructed using multiproxy analysis (pollen-based vegetation and climate reconstruction, lake levels, magnetic susceptibility and X-ray fluorescence (XRF) measurements) recorded climate and land-use changes during the Lateglacial and early–middle Holocene. The well-dated and high-resolution pollen record of Lake Ledro is compared with vegetation records from the southern and northern Alps to trace the history of tree species distribution. An altitude-dependent progressive time delay of the first continuous occurrence of Abies (fir) and of the Larix (larch) development has been observed since the Lateglacial in the southern Alps. This pattern suggests that the mid-altitude Lake Ledro area was not a refuge and that trees originated from lowlands or hilly areas (e.g. Euganean Hills) in northern Italy. Preboreal oscillations (ca. 11 000 cal BP), Boreal oscillations (ca. 10 200, 9300 cal BP) and the 8.2 kyr cold event suggest a centennial-scale climate forcing in the studied area. Picea (spruce) expansion occurred preferentially around 10 200 and 8200 cal BP in the south-eastern Alps, and therefore reflects the long-lasting cumulative effects of successive boreal and the 8.2 kyr cold event. The extension of Abies is contemporaneous with the 8.2 kyr event, but its development in the southern Alps benefits from the wettest interval 8200–7300 cal BP evidenced in high lake levels, flood activity and pollen-based climate reconstructions. Since ca. 7500 cal BP, a weak signal of pollen-based anthropogenic activities suggest weak human impact. The period between ca. 5700 and ca. 4100 cal BP is considered as a transition period to colder and wetter conditions (particularly during summers) that favoured a dense beech (Fagus) forest development which in return caused a distinctive yew (Taxus) decline. We conclude that climate was the dominant factor controlling vegetation changes and erosion processes during the early and middle Holocene (up to ca. 4100 cal BP).

Concurrent fNIRS and fMRI processing allows independent visualization of the propagation of pressure waves and bulk blood flow in the cerebral vasculature

Blood Oxygen Level Dependent (BOLD) functional magnetic resonance imaging (fMRI) measures changes in blood oxygenation, which is affected by physiological processes, including cardiac pulsation, breathing, and low frequency oscillations (LFO). It is challenging to identify spatial and temporal effects of these processes on the BOLD signal because the low sampling rate of BOLD leads to aliasing of higher frequency physiological signal components. In this study, we used concurrent functional near infrared spectroscopy (fNIRS) and fMRI on 6 subjects during a resting state scan. To reduce aliasing, the BOLD fMRI acquisition was repeatedly performed on a set of sequentially acquired slice stacks to lower the TR to 0.5s while retaining high spatial resolution. Regressor interpolation at progressive time delays (RIPTiDe) method was used, in which physiological signal acquired by fNIRS (without aliasing) and its temporal shifts were used as regressors in the fMRI analysis to determine the magnitude and timing of the effects of various physiological processes on the BOLD signal. The details of the timing of the passage of the cardiac pulsation wave and of the cerebral blood itself were mapped. The result suggests that the cardiac signal affects the voxels near large blood vessels (arteries and veins) most strongly, while LFO mostly affected the drainage veins. We hypothesize that this could be the result of differences in the cerebral blood path lengths, and differences in the dynamics of the propagation of the signals. Together these results validate and extend a novel imaging technique to dynamically track the pulse-wave and bulk blood flow with concurrent fMRI and fNIRS.

Physiological denoising of BOLD fMRI data using Regressor Interpolation at Progressive Time Delays (RIPTiDe) processing of concurrent fMRI and near-infrared spectroscopy (NIRS)

Confounding noise in BOLD fMRI data arises primarily from fluctuations in blood flow and oxygenation due to cardiac and respiratory effects, spontaneous low frequency oscillations (LFO) in arterial pressure, and non-task related neural activity. Cardiac noise is particularly problematic, as the low sampling frequency of BOLD fMRI ensures that these effects are aliased in recorded data. Various methods have been proposed to estimate the noise signal through measurement and transformation of the cardiac and respiratory waveforms (e.g. RETROICOR and respiration volume per time (RVT)) and model-free estimation of noise variance through examination of spatial and temporal patterns. We have previously demonstrated that by applying a voxel-specific time delay to concurrently acquired near infrared spectroscopy (NIRS) data, we can generate regressors that reflect systemic blood flow and oxygenation fluctuations effects. Here, we apply this method to the task of removing physiological noise from BOLD data. We compare the efficacy of noise removal using various sets of noise regressors generated from NIRS data, and also compare the noise removal to RETROICOR+RVT. We compare the results of resting state analyses using the original and noise filtered data, and we evaluate the bias for the different noise filtration methods by computing null distributions from the resting data and comparing them with the expected theoretical distributions. Using the best set of processing choices, six NIRS-generated regressors with voxel-specific time delays explain a median of 10.5% of the variance throughout the brain, with the highest reductions being seen in gray matter. By comparison, the nine RETROICOR+RVT regressors together explain a median of 6.8% of the variance in the BOLD data. Detection of resting state networks was enhanced with NIRS denoising, and there were no appreciable differences in the bias of the different techniques. Physiological noise regressors generated using Regressor Interpolation at Progressive Time Delays (RIPTiDe) offer an effective method for efficiently removing hemodynamic noise from BOLD data.

An improved method for mapping cerebrovascular reserve using concurrent fMRI and near-infrared spectroscopy with Regressor Interpolation at Progressive Time Delays (RIPTiDe)

Cerebrovascular reserve (CVR) reflects the compensatory dilatory capacity of cerebral vasculature to a dilatory stimulus. Blood oxygen-level dependent (BOLD) fMRI has been proven to be an effective imaging technique to obtain CVR maps when subjects perform CO2 inhalation or a breath-holding (BH) task. Here we propose a novel way to process the fMRI data obtained during a blocked BH task by using simultaneously collected near-infrared spectroscopy (NIRS) data as regressors to estimate the vascular contribution to the BOLD signal.Six healthy subjects underwent a 6min 30s resting state (RS) fMRI scan, followed by a scan of the same duration with a blocked BH task (5 breath holds with 20s durations separated by ~50s of regular breathing). NIRS data were recorded from a probe over the subjects' right prefrontal area. For each scan, the time course of changes in total hemoglobin (Δ[tHb]) was calculated from the NIRS data, time shifted by various amounts, and resampled to the fMRI acquisition rate. Each shifted time course was used as regressor in a general linear model analysis. The maximum parameter estimate across all time shifts was calculated at all voxels in both the BH and RS scans, and then converted into signal percentage changes. The ratio of these signal changes generates a CVR map of the BH response, normalized to the resting state. The NIRS regressor method makes no assumptions about the shape (or presence) of the BH response, and allows direct, quantitative comparison of the vascular BOLD response to BH to the baseline map obtained in the resting state.

Isolating the sources of widespread physiological fluctuations in functional near-infrared spectroscopy signals

Physiological fluctuations at low frequency (<0.1 Hz) are prominent in functional near-infrared spectroscopy (fNIRS) measurements in both resting state and functional task studies. In this study, we used the high spatial resolution and full brain coverage of functional magnetic resonance imaging (fMRI) to understand the origins and commonalities of these fluctuations. Specifically, we applied a newly developed method, regressor interpolation at progressive time delays, to analyze concurrently recorded fNIRS and fMRI data acquired both in a resting state study and in a finger tapping study. The method calculates the voxelwise correlations between blood oxygen level dependent (BOLD) fMRI and fNIRS signals with different time shifts and localizes the areas in the brain that highly correlate with the fNIRS signal recorded at the surface of the head. The results show the wide spatial distribution of this physiological fluctuation in BOLD data, both in task and resting states. The brain areas that are highly correlated with global physiological fluctuations observed by fNIRS have a pattern that resembles the venous system of the brain, indicating the blood fluctuation from veins on the brain surface might strongly contribute to the overall fNIRS signal.

Small Group Instruction for Students With Autism

A multiple-probe design across response chains and students was used to evaluate the combined instructional effects of progressive time delay, general case training, and observational learning on the food and drink preparation skills of three children with autism. All instruction was delivered in a group learning arrangement. The data suggested that these students acquired and maintained the targeted skills through the use of these instructional techniques. In addition, students were able to acquire response chains by observing the other student in the group and appeared to generalize the acquired skills to similar response chains. The implications for future research are discussed.

A comparison of within- and across- session progressive time delay procedures for teaching sight words to individuals with cognitive delays.

Time delay procedures have been used for teaching skills such as sight words (Gast, Wolery, Morris, Doyle, & Meyer, 1990), sign language (Browder, Morris, & Snell, 1981), social studies and health facts (Wolery, Cybriwsky, Gast, & Boyle-Gast, 1991), spelling (Coleman-Martin & Heller, 2004), instruction following (Striefel, Bryan, & Aikins, 1974), spontaneous speech (Charlop, Schreibman, & Thibodeau, 1985; Ingenmey & Van Houten, 1991; Taylor & Harris, 1995), vocational assembly tasks (Walls, Haught, & Dowler, 1982), gross motor skills (Zhang, Horvat, & Gast, 1994), word identification (Browder, Hines, McCarthy, & Fees, 1984; Lalli & Browder, 1993) and a variety of other skills (Walker, 2008, Wolery, Ault, & Doyle, 1992). Time delay procedures typically involve the presentation of a discriminative stimulus (e.g., a flashcard with the word LAUNDRY on it) followed by the delivery of an instructional cue (e.g., What word is this?) followed by the provision of the controlling prompt (i.e., stating the correct response; e.g., laundry). In cases where the delays of 0 s (i.e., no delay) are employed the teaching method is often termed as errorless learning (Touchette, 1971, Touchette & Howard, 1984), whereas delays of longer than 0 s are termed as delay. In both procedures the controlling prompt cues the student to engage in the correct response (i.e., a prompted correct response). However, once a delay for providing the controlling prompt is introduced the student has the ability to respond to the salient features of the stimulus independent of the controlling prompt which is the goal of any instructional strategy (i.e., providing independent correct responses). Two typically utilized time delay procedures are constant time delay and progressive time delay procedures (Walker, 2008). Both procedures are similar in implementation: the presentation of the discriminative stimulus, paired with the delivery of an instructional cue with a specified delay to the controlling prompt. The procedures differ on how the delay to when the provision of the controlling prompt is provided. In constant time delay, an arbitrary delay is often selected (e.g., 5 s; Coleman-Martin & Heller, 2004; Lalli, Casey, Goh, & Merlino, 1994), however in progressive time delay, the delay is typically faded in increments (e.g., 1-2 s) based on preset number or percentage of correct responding criteria (e.g., correct responses in 3 consecutive trials; Taylor & Harris, 1995). The effectiveness of both versions of these time delay procedures have been documented through literature reviews regarding time delay procedures (Handen & Zane, 1987; Walker, 2008). However, it has been reported that constant time delay procedures have been associated with slightly more errors and longer delays in the transfer of stimulus control (i.e., correct responding no longer being cued by the controlling prompt; Walker, 2008). Thus, progressive time delay procedures appear to have some advantages over constant time delay procedures. Progressive time delay procedures typically proceed from 0 s to some delay contingent upon a set criterion of correct responding being met. For example, a 0 s delay will be faded to a 2 s delay, then to a 4 s delay and so on until some ceiling limit is reached (e.g., 10 s delay; Taylor & Harris, 1995). In most applications of progressive time delay, delays are typically increased across sessions based on correct responding. However, Touchette's (1971) original procedure consisted of within-session increases to the onset of the controlling prompt for the next trial by 0.5 s following a correct response, and reducing the delay on the next trial by 0.5 s following an incorrect response. Such changes can be burdensome in community based settings, especially when this criterion for increasing/decreasing the delay is applied to stimuli being trained concurrently. …

Constant and Progressive Time Delay Procedures for Teaching Children with Autism: A Literature Review

A review of 22 empirical studies examining the use of constant (CTD) and progressive (PTD) time delay procedures employed with children with autism frames an indirect analysis of the demographic, procedural, methodological, and outcome parameters of existing research. None of the previous manuscripts compared the two response prompting procedures. This review suggests that the effectiveness of the two procedures is similar on some variables. However, the CTD procedure resulted in more errors to criterion, a greater magnitude of procedural modifications, and in a delayed moment of transfer of stimulus control than in the PTD studies. Conclusions may influence clinical and educational practices and indicate a need for research.

The Taped-Problems Intervention

ABSTRACT A multiple-probe across-tasks design was used to determine if the taped-problems intervention, a variation of the taped-words interventions (Freeman & McLaughlin, 1984), could be used to enhance division fact fluency in a fourth-grade student. During the taped-problems intervention, the student was given a list of problems on a sheet of paper and instructed to attempt to complete each problem before the answer was provided by an audiotape player. On the tapes, problems were read followed by their answers. Progressive time delay procedures were used as intervals between the problem and answer were adjusted. Initially, the interval between the problem being read and the answer was 1 second. During each session, as problems were repeated, the interval was gradually increased and then reduced. Results showed clear increases in division fact fluency after the intervention was implemented. This enhanced performance appeared to be maintained. Discussion focuses on future research related to the taped-problems intervention.

EFFECTIVE INSTRUCTIONAL PROCEDURES FOR TEACHING INDIVIDUALS WITH SEVERE DISABILITIES IN MOTOR SKILLS

The purpose was to describe effective instructional procedures used to teach motor skills to individuals with severe disabilities. Five effective instructional procedures supported with experimental data in adapted physical education are identified through the review of literature: (a) response shaping, (b) increasing prompt hierarchy, (c) decreasing prompt hierarchy, (d) constant time delay, and (e) progressive time delay. The characteristics, documentations, guidelines, and recommendations for application of these procedures are described.