At this point in the class, you should know the proper way to set up a title page, headings, etc. Correct APA format for the title page and body of the study with headings, page numbers, and content where it belongs is worth 4 points Any error in format will cost this pts Introduction 1) State what is known about your topic clearly -2pts 2) State what is unknown (the question which your study addresses – 2pts 3) State your hypothesis in a simple single sentence- 2pts Methods Using full sentences explain the following What type of study is this (prospective, retrospective, correlational, experimental, survey, etc. – 2pts Describe the subjects in this study (Demographics- tell me age, gender or other important characteristics (e.g If you are working with dementia patients you may want to say at what stage of dementia and what type (there are different types). Also, state from where you recruited them and HOW (e.g. advertisement, clinic sample, etc.) -3pts What was the procedure (how were the subjects tested or measured? What instruments, tests, or other methods were used to measure them? If you are doing a true experiment (and perhaps a quasi-experiment you should have a control group. A single-subject design 3pts What kind of data does the study show (nominal, ordinal, interval, or ratio)?-2pts What kind of analysis was used (t-Test, Chi-Square, ANOVA, correlation, etc.)-2 pts 

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Social skills interventions for preschoolers with Autism Spectrum
Disorder: A description of single-

subject design studies

Jennifer M. Gillis, Ph.D., BCBA1 & Robert C. Butler, B.S.

Abstract
Social skill development is one of the primary areas of intervention for young children with Autism
Spectrum Disorders (ASD). The purpose of this article was to conduct a retrospective review of social
skills intervention research for preschool children with ASD. A review of 17 single-subject design studies
from twelve journals (1999-2006) was conducted. We assessed information concerning the features of
social skills interventions, the elements of single subject designs utilized across studies, and the overall
success of interventions for social behaviors. A comparison with a review conducted by Vaughn et al.
(2003) revealed some important common elements of interventions such as reinforcement, modeling and
prompting, providing converging evidence from group design studies and single subject studies.
Keywords: Autism Spectrum Disorders, Social Skills, Intervention, Preschool

The term, Autism Spectrum Disorder (ASD), is commonly used to identify a family of disorders,
including, Autistic Disorder, Asperger’s Disorder, or Pervasive Developmental Disorder Not Otherwise
Specified, in the Diagnostic Statistical Manual–IV, Text Revision (DSM-IV TR; American Psychiatric
Association, 2000). An individual with ASD exhibits deficits in core areas including social development
and social skills, language and communication skills, and repetitive, ritualistic, stereotyped behaviors.
Across the ASD spectrum, the expression of these deficits ranges from mild to severe.

Social Skills Deficits in ASD

The primary deficit of ASD is social impairment (Romanczyk, White, & Gillis, 2005; Weiss,
2001; Weiss & Harris, 2001a). We use the term, social impairment to refer to any deficit or limitation or
delay in social awareness, social competence, and social development. We define social skills as
behaviors each person learns to facilitate awareness of his/her social environment and social
contingencies, to be able to solve social problems (i.e., demonstrate social competence), and other
behaviors that are developmentally appropriate.

Social skills deficits are common to all individuals with an ASD, are pervasive, and typically

manifest at a very young age. The DSM-IV-TR (APA, 2000) lists the impairments in social interaction as:
1) deficits in nonverbal behaviors (e.g., eye-to-eye gaze, recognition of facial expressions, use of gestures
to regulate social interaction), 2) failure to develop peer relationships appropriate to the child’s
developmental level, 3) lack of spontaneous seeking to share enjoyment and interests (e.g., failure to
show, bring, or point out objects of interest), and 4) lack of social or emotional reciprocity (e.g., unable to
or does not respond to emotions or social interactions from others).

ASD is a heterogeneous disorder, meaning that one individual with ASD will have differing areas

of social impairment with differing levels of severity from another individual with ASD.

1 Author Notes-The authors would like to thank Trina L. Butler for her assistance in data collection for
this literature review. The authors wish to acknowledge the helpful feedback and comments of the two
anonymous reviewers.

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Additional examples of social impairment observed in children with ASD include difficulties
initiating social interactions, responding to the social initiations of others, initiating or responding to joint
attention, and recognizing emotions in self. Areas of social impairment frequently observed in preschool
age children with ASD include social play, dramatic play, friendship-seeking behavior, and cooperative
play. Poor motivation to learn social behaviors or to engage in social activities is also commonly observed
in children with ASD. These comprise only a fraction of social skills observed in individuals with ASD.

The extant literature suggests that early social impairments greatly impact future relationships,

employment, independent living, and other mental health issues (e.g., anxiety, depression) (Bellini, 2004;
Strain & Scwartz, 2001; Tantam, 2000). Thus, there should be an emphasis for intervention to occur early
and to focus on the development of social skills in order to build social interactions and relationships.
Unfortunately, it remains unclear as to which social skills are important to teach that will lead to better
outcomes in areas related to social impairment for children with ASD. An issue that remains elusive and
is of equal importance is to determine the specific types of interventions that effectively teach social
skills.

Normal Social Skills Development in Preschoolers

Typical social development in preschool age children (i.e., ages two through five) involves the
development of social interactions with peers and development of play behaviors. For all children, play
begins with nonsocial or solitary play, when a child is content to play alone with toys/objects with or
without the engagement of others in the same play activity. Children then develop parallel play, which is
when a child plays with the same toys as another child, but does not necessarily interact with the other
child (Rubin, Fein, & Vandenberg, 1983).

Children begin to form their first friendships between three and four years of age. At this age,

children begin to increase cooperative and interactive play with peers and develop increased self-
regulation (a necessary skill in order to play well with others). Children begin to understand turn-taking
and simple rules to games in small groups. By the age of five, a child’s social communication skills are
more complex, for example, children will tell jokes, share a variety of experiences with others, and take
turns in conversations (American Academy of Pediatrics, 1999).

Social skills interventions for children in the preschool age range focus on the improvement of

behaviors related to social interactions with peers, including play skills (e.g., engaging in pretend play,
sharing, turn-taking, etc). Other examples include, social communication skills (e.g., initiating and
responding to others verbally or nonverbally), socio-emotional skills (e.g., affect recognition, empathy),
and friendship skills. For children with ASD, focusing on age-appropriate skill development is important,
but becomes difficult given the limited skill repertoires and difficulty in learning for children with ASD.

Recent Review of Literature

In a review of social interventions by Strain and Schwartz (2001), conclusions are made
suggesting that there is plentiful research demonstrating the efficacy of teaching children with ASD
specific social behaviors, including initiating and responding to social interactions. These authors identify
the need to examine issues related to generalization and maintenance of social behaviors. In addition, the
authors propose the use of eco-behavioral assessments (i.e., examining the behavior in applied contexts
such as the classroom). Strain and Schwartz also emphasize the importance of social validity, in terms of
evaluating the acceptability of an intervention by family members/caregivers and teachers and whether
these interventions would be sustainable outside of the research setting.

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There is a literature base to provide potential targets for social skills interventions (Terpstra,
Higgins, & Pierce, 2002; Weiss & Harris, 2001a; Koegel & Koegel, 1995). However, the specific
interventions that are successful for preschool children with ASD have not been fully confirmed nor
endorsed by the majority of professionals across disciplines.

In an effort to examine key features of social skills interventions for preschool children with

developmental disabilities, including ASD, Vaughn, Kim, Morris Sloan, Hughes, Elbaum, and Sridhar
(2003) reviewed 23 group design studies from 1975 to 1999. Vaughn et al. (2003) found 10 categories or
features important in social skills interventions. These included prompting (i.e., verbal or physical
prompting of a social skill), rehearsal/practice, play-related activities (to elicit social skills), free-play
generalization, reinforcement of appropriate social skills, modeling of social skills, social skills-related
storytelling, direct instruction of social skills, imitation, and time-out (to decrease inappropriate
behaviors).

Vaughn et al. (2003) calculated effect sizes for the studies reviewed and found that the studies

with the greatest effect sizes included the following four features in the interventions: modeling, play-
related activities, rehearsal/practice and/or, prompting procedures. It should be noted that the other
categories listed in the previous paragraph were not necessarily associated with negative outcomes. For
the 23 studies reviewed, there was an average of 3.4 categories of interventions included in each study.
The authors stated that incorporating a free-play generalization phase is helpful in determining whether
the above categories of intervention facilitated the generalization of the targeted social skills to new
settings, peers, and social-related activities.

Single Subject Research

Behavioral science not only aims to understand the nature of the determinants of behavior, but
also how to apply these principles in order to change dysfunctional behavior through intervention.
Interventions derived from empirical findings traditionally have been evaluated using two types of
research designs. The two major types of research designs that meet the standards of scientific research
methodology are single subject and group designs.

Single-subject and group designs provide valuable information. Both designs examine functional

or causal relationships between an independent variable (e.g., an intervention) and a dependent variable
(e.g., behavior) and to control for threats to internal and external validity. Operational definitions of the
intervention and the targeted behavior(s) are also fundamental aspects of both designs.

Despite some methodological similarities, single-subject and group designs posses several

important differences. First, group design studies measure dependent variables (DVs) before and after the
intervention, whereas single subject design studies measure the DV(s), continuously and over time,
including before (i.e., baseline) during, and after the intervention. This is especially helpful when a timely
assessment of the effects of an intervention is warranted (e.g., determining the precise dosage of a
medication).

Second, group designs require random or quasi-random assignment of participants to

experimental and control conditions (to help control for threats to internal validity). Single subject
designs, however, do not require the random assignment of participants. In other words, there are no
“participant requirements”, per se, in single subject design studies. Single subject designs typically
include between three to eight participants, on average, with each participant serving as his/her own
control. This latter characteristic of single-subject designs eliminates the need for experimental and
control groups. This is a major advantage when a social skills training intervention occurs in a classroom

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of preschool children with ASD. As these children present with a heterogeneous skill set and, most likely,
varying levels of functioning, it is difficult to obtain an adequate control sample.

Third, group design studies allow for statistical analyses that yield estimates of the causal effects

of the intervention (e.g., Analysis of Variance). These analyses are not possible with single subject design
studies. Rather, visual inspection of the data is utilized, which also permits inferences to be drawn about
causal relationships between the independent IV(s) and DV(s). There are specific criteria established to
guide the visual inspection process.

Single-subject designs can be particularly useful when conducting research in applied settings,

which is often the case in the evaluation of interventions for individuals with ASD. As mentioned above,
single-subject research provides for the examination of the effects of an intervention at the individual
level. Important aspects of single subject research designs include: a) the demonstration of a functional
relationship between treatment and behavior change; b) DVs are operationally defined; c) repeated
measurement of the DVs over time; d) the illustration of social validity of the intervention; e) the use of
methods for evaluating procedural fidelity and external validity; f) a description of the baseline phase
with sufficient data collected to evaluate effect of the IV; and g) a thorough description of the participants
and setting, to allow for replication (Horner, Carr, Halle, McGee, Odom, & Wolery, 2005). For a more
comprehensive description of single subject research designs used in special education research, please
see Horner et al., (2005).

Current Review

In this paper, we utilized the categories identified by Vaughn et al. (2003) in their review of
group design studies to determine whether these categories were also included in single subject design
studies. Vaughn identified modeling, play-related activities, rehearsal/practice and prompting as the
features associated with the largest effect sizes and, thus positive results. Effect sizes were not calculated
for this review, as this statistic is not typically utilized in single subject research studies due to the low
number of participants.

The primary purpose of this review was to examine the state of the single subject research over
the past five years for social skills interventions for preschool age children with ASD. A second purpose
of this review was to assess whether the features of social skills intervention packages were similar in
Vaughn et al’s (2003) review of group design studies. A synthesis of the single subject research at this
time is helpful in order to examine the status of interventions for social skills interventions and to identify
areas that warrant attention for future research.

Method

We selected journal articles from PsychInfo and the search engine on the website for the Journal

of Applied Behavior Analysis. Studies included in this publication were published between June 1999 and
December 2006. Keywords utilized for this search included autism, ASD, Asperger’s, handicapped,
special education, language impairment, communication impairment, developmental
delay, mentally retarded, social skills, joint attention, social referencing, imitation, friendship, and
approach. Terms were entered alone and in conjunction with other terms, truncating the keywords when
appropriate, i.e., autis* and dev*. We reviewed each article to determine if it met the inclusion criterion
for this review, resulting in 17 studies. Articles came from many different journals (i.e., Behavioral
Interventions, Early Education and Development, Education and Treatment of Children, Educational
Psychology in Practice, Development and Education, Focus on Autism and Other Developmental
Disabilities, International Journal of Disability, Journal of Applied Behavior Analysis, Journal of Autism

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and Developmental Disorders, Journal of Positive Behavior Interventions, Topics in Early Childhood
Special Education, and Topics in Language Disorders).

The criteria for inclusion used to select articles for review are presented below:

1. Preschool Age. At least half of the participants in each study were between the ages of

2 and 5.
1.2. Design. Only studies utilizing single subject designs were included. Group

designs were excluded.
1.3. Peer Review. We only used articles that had been peer reviewed for this study in

an attempt to include higher quality research.
1.4. Social Skills. Studies were included if they focused on increasing beneficial

social behaviors or skills (e.g., joint attention, communication, appropriate eye
contact, cooperative play, sharing, sociodramatic play, imitation, self-management,
complimenting, initiating play, expressing sympathy, showing disapproval
appropriately, showing appreciation, pretend play, group interactions, verbalizing
requests).

1.5. Diagnosis. The majority of participants were required to have a diagnosis of an
autism spectrum disorder (e.g., Autistic Disorder/Autism, Asperger’s Disorder, PDD-
NOS or pervasive developmental disorder.) Studies utilized various methods to
diagnose the participants. Further information on diagnoses is available in Table 1.

Results & Discussion

Seventeen studies met criteria for inclusion in this study. Each of these studies used single subject

research designs, however, the specific type of design used varied. The median age was 50 months. There
were 41 males and 9 females in this study. This reflects a similar ratio to that of male to females in ASD.
The total number of participants included in all of the reviewed studies was 50. Table 1 shows the
participant demographics across the studies, including diagnoses, gender, and age.

TABLE 1, NEXT PAGE

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Social Skills Interventions in Single Subject Design Studies

We examined aspects of interventions included in single subject design studies and compared
them to the data obtained in Vaughn et al.’s review (2003) of group design studies. Specifically, we
examined the following aspects of social skills interventions: 1) who implemented interventions; 2) the
length of the interventions; and 3) the categories of interventions most commonly used.

Implementation of the interventions. Vaughn et al. (2003) reported that mostly teachers

implemented interventions, followed by researchers, therapists, parents, and one study with a peer who
implemented the intervention. The studies we reviewed utilized several sources to implement the
intervention as well. These include: peers (n=5), video (n=5), researcher/research assistant (n=4),
teacher/tutor (n=3), parent (n=2), and therapist (n=1). In some studies, more than one person (or source)
implemented an aspect of the intervention, hence the total number of sources that implemented the
intervention is more than 17. In the studies reviewed, the interventions were mostly implemented by peers
and with a video, which is different from Vaughn et al.’s findings. Based on our review of these studies,
there did not appear to be a relationship between the person/source that implemented the intervention and
the results of an intervention.

Length of the interventions. The length or duration of an intervention was measured differently

across the reviewed articles including: number of sessions, number of observations, and total time
commitment (i.e., hours, months). Thirteen of the 17 studies reviewed reported the length of intervention
in terms of sessions conducted. In this review we utilized the authors report on number of sessions in the
intervention phase. When the authors did not report the number of sessions in the intervention phase, we
assumed that each data point reported in the X-Y graphs of the studies correlated with one session, unless
the article indicated that this was an inappropriate interpretation. The number of sessions utilized in the
intervention phase ranged between 1 and 80 with an average of 34.19 sessions per intervention. In two of
the studies the length of intervention was reported in total number of hours required to implement the
intervention. The intervention described by Dauphin, Kinney, and Stromer (2004) required 8-10 hours.
The intervention by Symon (2005) required 25 hours. Two studies measured the length of intervention in
terms of numbers of observations recorded. Arntzen, Halstadtrø, and Halstadtrø (2003) reported 118-120
trials across fifteen days. Tarbox, Ghezzi, and Wilson (2006) measured 300 observations in a one-day
period. Across the reviewed studies, the overall length of intervention varied greatly, ranging from one
day to 7 months.

Table 1.
Participant demographics across studies.

Reported Diagnoses n

Autism 33
AspergerÕs Disorder 5
PDD-NOS 3
PDD 3
Developmental Disability/Delay 3
Comorbid Autism and PDD 2
Comorbid ASD with ADHD 1

Gender n

Male 41
Female 9

Age months

Mean ( Standard Deviation ) 53 (15)
Median 50
Range 29-90
Note. Two of the participants were diagnosed as having
comorbid Autism and PDD. It is important to note that
according to the DSM-IV TR the diagnosis of autism excludes
the diagnosis of comorbid PDD and Autism (American
Psychiatric Association, 2000). It is unclear as to why one article
utilized this diagnosis.

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In comparison to the review by Vaughn et al. (2003), similar results are found. We acknowledge

that a the comparison of our findings to those of Vaughn et al.’s is an approximate and conservative
comparison given that the authors presented the data differently. Considering this limitation, it appeared
that the group design studies reviewed included for some social skills interventions, a range from 5 to 60
sessions was reported, others reported between 10-60 minutes for each session length. The group design
studies reported intervention length by different time periods (e.g., weeks, months, etc).

Number of categories used in each intervention study. Unlike the group design studies reviewed

by Vaughn et al. (2003), which averaged 3.4 categories of interventions in each study, the review of
single subject design studies indicated that an average of 2.6 categories of interventions were used in each
study. This difference may be due to the differences of how we defined categories of intervention
compared to Vaughn et al. (2003).

Vaughn et al. (2003) described play-related activities and storytelling as categories of

intervention because these types of activities might have solicited social behavior and social skills. We
chose to not include these intervention categories because it is difficult to separate the effects of a context
that includes play-related activities from another intervention category (e.g., prompting or imitation in a
play activity context). There were no comparative studies that addressed this issue. We did find, however,
that 5 of the studies included play-related activities as part of the intervention. We also excluded
rehearsal/practice, because all but one of the single subject studies reviewed included multiple sessions
that provided opportunities for the participants to practice social skills.

Figure 1. The frequency of different categories of interventions used to teach social skills across the
reviewed articles are displayed.

Figure 1 shows the most commonly utilized interventions in the articles reviewed. The most
frequently used categories of interventions were modeling, prompting, and reinforcement. For studies

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utilizing modeling, there were three major types of models used. These included peer modeling (n=4),
adults (n=1), and video modeling (n=4). The next most frequently used categories of interventions
included imitation and peer training. Other categories of interventions used in at least one study included,
parent training, priming, social communication acquisition, fading, naturalistic teaching strategies, and
token economies. None of the studies reviewed implemented time-out.

The categories of reinforcement, modeling and prompting were used in both reviews and were

present in many studies. The ubiquitous nature of these categories provides convergent evidence of the
potential necessity of including these categories of intervention in social skills interventions for preschool
children with ASD. In this review, we make a distinction between the different types of modeling that are
used in interventions. These include adult models, peer models and video models for teaching social
behavior.

State of Single Subject Design Studies

As part of our review, we examined the single subject designs of the reviewed studies in order to
assess the quality of the social skills interventions across studies. An excellent article by Horner et al.
(2005) provides descriptions of quality indicators of single subject design research and provides
guidelines for evaluating such designs. The quality indicators that we evaluated and summarized below
included demonstration of a stable baseline, description of participant characteristics and intervention
setting, behavior that was measured, measurement of social validity, demonstration of procedural fidelity
(which is related to evaluation of the independent variable or intervention), and external validity (i.e.,
maintenance and generalization). Please see Horner et al., (2005) for a thorough review of these and other
quality indicators of single subject design research.

Baseline. One of the quality indicators is the presence of baseline data. In single subject designs,

there needs to be a presence of stable baseline data. Horner et al., (2005) suggest five data points or more.
According to Kazdin (2003), two or more baseline data points are sufficient prior to implementing an
intervention. Considering these differing reports and other issues related to the stability of the data in the
baseline phase (i.e., slope, variability, steady state), we decided that a baseline phase needed to consist of
at least three data points and the baseline needed to be described as stable.

It is our opinion that in 38% of the studies reviewed stable baseline data was not included for at

one or more participants prior to implementation of the intervention. Variability of baseline data or less
than three baseline data points were present in these studies. Specifically, 22% of studies included at least
one participant with no baseline data or less than three points of data in the baseline phase. Therefore,
without stable baseline data, it is difficult to determine whether the intervention had a functional
relationship with the change in behavior.

Participants and setting. A description of participants is an important characteristic of single

subject research with respect to determining if an intervention is appropriate and might be effective for
other participants with similar characteristics. The manner in which the participants were described in the
reviewed studies greatly varied. All of the studies reviewed indicated that the majority of participants
were diagnosed with or stated as having an ASD (see Table 1). Information related to how participants
received a diagnosis varied from participants receiving a diagnosis from an independent psychologist
(47% of studies), to the authors only stating that the participants met the criteria listed in the DSM-IV TR
as a basis for diagnosis (12% of studies), to a diagnosis based on a review of records (12% of studies), to
simply stating that the participants had an ASD, but not reporting how the diagnosis was obtained (29%
of studies). Standardized assessments that measure domains of functioning, such as social skills, cognitive

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abilities, language/communication skills, adaptive skills, etc, were greatly underutilized. Many of the
reviewed studies contained descriptions of participant characteristics by stating strengths and weaknesses
of participants or reporting observations of the participants’ abilities and levels of functioning in different
domains. Some studies reported a combination of standardized assessment scores and descriptions of
characteristics. In some studies, there was not enough information about participants to determine the
level of functioning and skill set of the participant(s), presenting a challenge for the reader in determining
whether the intervention is applicable to other children with ASD

From our review of the description of …