Perovic Et Al 2013 Applied Psycholinguistics

Applied Psycholinguistics 34 (2013), 813835doi:10.1017/S0142716412000033

Comprehension of reflexiveand personal pronouns in childrenwith autism: A syntacticor pragmatic deficit?ALEXANDRA PEROVICUniversity College London

NADYA MODYANOVA and KEN WEXLERMassachussetts Institute of Technology

Received: April 25, 2010 Accepted for publication: July 22, 2011

ADDRESS FOR CORRESPONDENCEAlexandra Perovic, Developmental Science Department, Division of Psychology and LanguageSciences, University College London, Chandler House, 2 Wakefield Street, London WC1N 1PF, UK.E-mail: [email protected]

ABSTRACTAlthough pragmatic deficits are well documented in autism, little is known about the extent to whichgrammatical knowledge in this disorder is deficient, or merely delayed when compared to that oftypically developing children functioning at similar linguistic or cognitive levels. This study examinesthe knowledge of constraints on the interpretation of personal and reflexive pronouns, an aspect ofgrammar not previously investigated in autism, and known to be subject to differential developmentalschedules in unimpaired development. Fourteen children with autism (chronological age = 617 years,M = 11) showed some difficulties comprehending personal pronouns, no different from those observedin two groups of younger controls matched on nonverbal IQ or receptive grammar, but in line with thereported pragmatic deficits and general language delay in this population. However, their interpretationof reflexives was significantly worse than that of the control children. This pattern is not evidencedat any stage of typical development, revealing an impaired grammatical knowledge in our sample ofchildren with autism, and is argued not to be due to a general language delay or cognitive deficits.

Deficits in language and communication are known to be one of the definingcharacteristics and diagnostic criteria of autism (American Psychiatric Associ-ation, 2000). Individuals with autism form a rather heterogeneous group withrespect to their language abilities, which range from mutism and little functionalcommunication to relatively well-developed language. A common characteristicof these individuals, however, is that they all share impairments in pragmatic andconversational skills.

Less is known about grammatical development in this population. It has beenargued that it follows the same path as that in typically developing (TD) children Cambridge University Press 2012 0142-7164/12 $15.00

Applied Psycholinguistics 34:4 814Perovic et al.: Comprehension of reflexive and personal pronouns in children with autism

matched on mental age (MA), although at a slower rate (Lord & Paul, 1997; Tager-Flusberg, 1981; Tager-Flusberg et al., 1990). However, some results reported inboth early and very recent research seem to suggest otherwise. Early studies re-vealed difficulties in the use of grammatical morphology in spontaneous speech ofchildren with autism, not dissimilar to those seen in children with developmentaldysphasia, or specific language impairment (SLI; Bartolucci, Pierce, & Streiner,1980; Churchill, 1972). Difficulties with grammatical morphemes marking tense(e.g., John goes, where the verb is correctly marked for tense vs. the incor-rect John go) and present progressive (John is going) have been confirmedmore recently (Eigsti & Bennetto, 2009; Roberts, Rice, & Tager-Flusberg, 2004).Using a computational measure introduced in accounts of the optional infinitivestage (difficulties in marking the finiteness of verb; Wexler, 1993) in TD andSLI children, Roberts et al. (2004) reported that performance of children withautism was poorer than expected for their general level of both linguistic andcognitive development, indicating a specific morphosyntactic deficit in this pop-ulation. Note that difficulty with tense marking is argued to be a reliable clinicalmarker of SLI (Rice & Wexler, 1996). These findings are particularly interestingin view of reports suggesting a genetic link between autism and SLI (Fombonne,Bolton, Prior, Jordan, & Rutter, 1997; Tomblin, Hafeman, & OBrien, 2003; Verneset al., 2008), as well as a recent claim that the two disorders could even be ona continuum (Bishop, 2003a). Mapping out a detailed linguistic profile in thepopulation with autism is crucial to both establishing reliable differences betweenautism and other developmental disorders, such as SLI, as well as understand-ing the heterogeneity of the grammatical abilities of individuals on the autismspectrum.

However, there is little consistent data on the comprehension of complex syntac-tic structures. Research on grammar in autism traditionally entails investigationsof spontaneous speech and analyses of results obtained by standardized tests oflanguage abilities. Although these methods generate a wealth of important data,contexts in which complex grammatical structures are produced are often limited,thus failing to give a reliable picture of an individuals competence. In additionto the studies reporting difficulties with verb inflection mentioned earlier, thefew experimental studies of complex grammar suggest that passives (Perovic,Modyanova, Hanson, Nelson, & Wexler, 2007; Tager-Flusberg, 1981) and relativeclauses (Riches, Loucas, Charman, Simonoff, & Baird, 2009) also seem suscepti-ble to impairment, as well as some operations at the syntactic/semantic/pragmaticinterfaces, such as marking of definiteness (Modyanova, 2009).

The lack of consensus on the issue of whether grammar in autism is simply de-layed or also deviant, coupled with a scarcity of studies implementing experimentalmethods, calls for investigations of formal aspects of grammar in this population inmore depth. The aim of our study is to investigate binding in children with autism.Binding is the area of grammar that concerns constraints on the distribution ofpersonal and reflexive pronouns. There is no previous experimental research inthis area in the population with autism; however, difficulties with using personalpronouns in spontaneous speech have been reported (Lee, Hobson, & Chiat, 1994).Like young TD children, children with autism have been found to interpret youas I, and vice versa. This phenomenon, termed pronoun reversal, is argued tobe due to their difficulties with shifting reference and to general problems with


pragmatics. Nothing is known about how children with autism interpret personalversus reflexive pronouns. Experimental research on typical development reportsspecific difficulties in the interpretation of personal but not reflexive pronouns:even after 6 years of age, TD children frequently interpret sentences involvingpersonal pronouns such as Mary washes her to mean Mary washes herself. Thisrobust phenomenon, termed the delay of Principle B effect (DPBE; to be discussedin more detail in the following section) has been explained by appealing to thedistinct nature of the principles that guide the interpretation of reflexive as opposedto personal pronouns: reflexives are interpreted by relying on constraints that arepurely syntactic in nature, whereas personal pronouns are regulated by both syn-tactic and extrasyntactic (i.e., pragmatic) constraints. Syntactic constraints are inplace early, but the development of pragmatic constraints takes time (Thornton &Wexler, 1999; Wexler & Chien, 1985); thus, the pattern in typical developmentis understood as being due to TD childrens prolonged maturation of pragmaticand not syntactic principles. In view of reported errors in production of personalpronouns and general difficulties in pragmatics and understanding of intention inautism, an in-depth investigation of the knowledge of constraints regulating theinterpretation of both reflexive and personal pronouns in this population seemsparticularly pressing. If language in autism is delayed, but develops in a fashionparallel to typical development, a similar, or even more exaggerated, pattern ofdifficulties with pronouns is expected, in line with reported pragmatic deficits inthis population. However, if syntactic knowledge is also affected, children mayshow difficulties interpreting reflexives that cannot be accounted for by a simplelanguage delay. The following section outlines the theory of binding, its acquisitionin the typical populations, and spells out the predictions for children with autism,thus providing a rationale for our study.

CONSTRAINTS GOVERNING PERSONAL AND REFLEXIVEPRONOUNS IN TYPICAL ACQUISITIONOur implicit knowledge of the constraints involved in assigning reference leads usto interpret the reflexive pronoun, herself, as referring to only one of the femalecharacters mentioned in sentence (1a) below: Susan. To be interpreted as herself,the noun phrase (NP) Susan (its antecedent), has to be nearest to the reflexive.The index next to an NP refers to the referent of the NP.

(1) a. Maryi says that Susanj likes herselfj.b. Maryi says that Susanj likes heri.

The personal pronoun her, in (1b), is interpreted as referring to Mary, the NPfurthest away from the pronoun.

The facts of the distribution of reflexive and personal pronouns have beencaptured in structural terms by the binding principles of Chomsky (1986),1 givenin (2).

(2) a. Principle A: a reflexive must be locally bound.b. Principle B: a pronoun must be locally free.2


As stated above, the binding principles describe the complementary distribution ofreflexives and pronouns. This is illustrated in (3a) and (3b): Principle A forces thereflexive to corefer with Mary in (3a), whereas Principle B excludes coreferenceof pronoun and Mary in (3b).

(3) a. Maryi adores herselfi/jb. Maryi adores heri/j

Being part of the computational aspects of our linguistic knowledge, compliancewith binding principles is expected to be seen early on. Knowledge of Principle A,which demands that a reflexive have a local antecedent in the sentence, is acquiredby TD children at least by age 4 (Chien & Wexler, 1990; Jakubowicz, 1984; Wexler& Chien, 1985). In Wexler and Chien (1985), structure (4) was tested with the aidof a two-choice picture task in 129 children, aged 2 years, 6 months (2;6) to 6;6(and adult controls). Their performance grew with age; 6-year-olds gave greaterthan 90% correct performance (chance is 50%).

(4) Cinderellas sister points to herself.

Note that when tested on the constructions above, young children also show theirunderstanding of the c-command component of binding, as possessives allow fortwo potential antecedents of the relevant pronominal element: one c-commanding(the entire NP, Cinderellas sister), the other non-c-commanding (the genitive NPCinderella). Possessive NPs are argued to appear early in typical development(Tomasello, 1998), at least by age 4 (Bannard & Matthews, 2008; Golinkoff &Markessini, 1980); thus, any difficulties with these constructions should to bedue to childrens incomplete mastery of the binding principles, and not of thepossessive NP.

In contrast, at around the same age, TD children have a great deal of troublewith constructions that involve personal pronouns:

(5) Cinderellas sister points to her.

In the context of a forced-choice task (where one picture shows the sister point-ing to Cinderella, and the other picture shows the sister pointing to herself), thesentence in (5) cannot mean that Cinderellas sister pointed to the sister, but mustmean that she pointed to Cinderella. Wexler and Chien (1985) report that in thetwo-choice picture task, children 5.5-year-old children (the same children who dovery well in reflexives) were still around chance, and performance increased to lessthan 60% for the 6-year-olds. This robust pattern, termed DPBE, has been repli-cated in a number of studies for English (Avrutin & Thornton, 1994; Boster, 1991;Chien & Wexler, 1990; Thornton & Wexler, 1999) and has also been observedcrosslinguistically (e.g., Dutch: Philip & Coopmans, 1996; Hebrew: Friedmann,Novogrodsky, & Balaban, 2010; Icelandic: Sigurjonsdottir, 1992; Russian: Avrutin& Wexler, 1992). Acquisition of binding has been one of the most fertile areas inthe field of language acquisition (for a review, see Guasti, 2002) and the famous


phenomenon of DPBE is still debated in the literature, two decades on. It has beennoted that very young children may not show the difference in their performanceon reflexives versus pronouns (such as 2.5-year-olds in Wexler & Chien, 1985,or the 3-year-old Hebrew speakers in Ruigendijk, Friedmann, Novogrodsky &Balaban, 2010), and that the pattern may be more robust in comprehension thanin production (Bloom, Barss, Nicol, & Conway, 1994; Hendriks & Spenader,2005/2006; but see Ruigendijk et al., 2010, for data in Hebrew and German thatpresent an argument against the asymmetry in comprehension and production).

What is it that children do not know about the principles that constrain the use ofpronouns? Chien and Wexler (1990, followed by other researchers) argued that thisresult is due to the different nature of constraints governing personal pronouns,as opposed to reflexives. Binding principles, as given in (2), regulate syntacticbinding only, where the bound item is a bound variable. Reflexives are subjectto syntactic binding only. Pronouns can be ambiguous between a coreferentialand a bound variable reading3: when a bound variable, they are regulated byPrinciple B, but when interpreted coreferentially, they are subject to constraintsthat are nonsyntactic in nature (pragmatic, according to Chien & Wexler, 1990,or subject to a special rule of coreference, as argued by Grodzinsky and Reinhart,1993).4 Children thus have the knowledge of Principle B, the constraint governingthe bound variable interpretation, but their difficulties with pronouns are due tolimitations in implementing nonsyntactic constraints that govern illicit corefer-ence. Chien and Wexler (1990) argue that the high rate of errors in accepting thecoreferential reading of (5) should be interpreted as a pragmatic error (failure ofPrinciple P).5 It is important that the same study reports additional experimentaldata confirming that children are sensitive to the distinction between binding andcoreference. In contexts where a coreferential reading is not available, that is,when pronouns are bound by quantified antecedents, children show no difficultiesrejecting an ungrammatical sentence such as (6).

(6) Every beari is washing heri.

This is because quantifiers, like other operators, have no definite referents andaccidental coreference is not an option: there is no ambiguity and no chance forchildren to fail. The same 5- to 6-year-old children in Chien and Wexler who showa chance performance on structures where the pronoun refers to the referentialantecedent, reached 84% correct performance on constructions involving a quan-tified antecedent. These findings have been confirmed in other languages (Russian:Avrutin & Wexler, 1992; Dutch: Philip & Coopmans, 1996) where children havebeen shown to accept illicit coreference between a pronoun and a local referentialantecedent.6

PREDICTIONS FOR CHILDREN WITH AUTISMThe result that TD children as old as 6 are still missing some crucial pragmaticabilities (while the related aspects of grammar have been acquired) provides an


important opportunity to test hypotheses concerning language abilities in autism.We formulate these hypotheses as follows:

1. If only pragmatic, but not syntactic knowledge is affected in autism, childrenwith this disorder will show difficulties in interpreting personal but not reflexivepronouns, displaying a pattern parallel to unimpaired development. An even moreexaggerated pattern of difficulties with personal pronouns might be expected inautism compared to unimpaired development, in view of reported language delaysin this population.

2. If, however, syntactic knowledge is also affected in autism, children may showdifficulties interpreting reflexives, because interpretation of these elements isguided by principles that are purely syntactic in nature. A pattern of a worseperformance on reflexives as opposed to, or in addition to pronouns, would be asign of deviance, and cannot be accounted for by a simple language delay becauseit is not evidenced in the course of typical acquisition.

In the ensuing sections, we present a study of the knowledge of binding inchildren with autism, aged 617. This age range was chosen to account for anyinitial delays in language development in this population. Following Wexler andChien (1985), whose task was successfully used with over 100 English-speakingTD children, we aim to also test the knowledge of the c-command part of PrinciplesA and B in our participants, by using a possessive subject that introduces botha c-commanding and a non-c-commanding local antecedent to the reflexive orpersonal pronoun in question. Testing c-command is important because failuresof interpretation could be due to failures in calculating c-command or to moregeneral binding principle failures. To examine any effects of verbal as opposed tononverbal abilities in the population with autism, our participants were carefullymatched to TD controls on standardized measures of verbal and nonverbal abilities.Binding principles have never been investigated in children with autism before,nor have the possessive structures; thus, we hope that our investigation will fill animportant gap in the literature with respect to comparing the grammar in autismto that of TD children.

METHODParticipantsForty-five children, 18 clinically diagnosed with autism and 27 TD controls, wererecruited for the study. The children with autism, aged 6;617 (M = 11;6), wererecruited with the help of Childrens Hospital Boston and autism parent supportgroups in Massachusetts. Four autistic children (7- to 10-year-olds) were excludedfrom this group as they were unable to complete the test battery; thus, the completeset of data was obtained from 14 participants with autism (of which 3 were girls).Their overall IQ, as measured by the Kaufman Brief Test of Intelligence (KBIT;Kaufman & Kaufman, 1990), ranged from 40 to 98 (M = 64.38, SD = 20.55; cf.Table 1). Their scores on different standardized measures reveal some disparity


Table 1. Ages and mean (standard deviation) scores on standardized tests oflanguage and cognition for the group with autism and two control groups

Group

Autism KBIT-TD TROG-TD(n = 14) (n = 13) (n = 14)

Age (months) 133.63 (43.36) 71.31 (20.12) 49.79 (6.93)Age range (months) 78206 48112 4060KBIT

Composite SS 64.38 (20.55)Vocabulary SS 67 (22.59)Matrices SS 65.93 (20.37) 100.00 (6.76)Matrices RS 15.93 (5.86) 16.85 (4.58)

PPVT-IIISS 56.57 (15.81)RS 67.50 (16.26)

TROG-2 99.91 (9.92)SS 56.50 (4.05)RS 3.57 (2.76) 3.64 (2.71)

Note: The scores for the measures on which participants with autism were matchedto controls are in bold. KBIT, Kaufman Brief Test of Intelligence; TD, typicallydeveloping; TROG, Test for Reception of Grammar, Second Edition; SS, standardscore; RS, raw score; PPVT-III, Peabody Picture Vocabulary Test, Third Edition.

between nonverbal and verbal abilities, but these differences did not prove tobe statistically significant: on the Matrices subtest of KBIT, which measuresnonverbal IQ, their mean standard score (SS) was 65.93 (SD = 20.37); on thePeabody Picture Vocabulary Test, Third Edition (PPVT-III; Dunn & Dunn, 1997),the test of receptive vocabulary, the mean was 56.57 (SD = 15.81); and on theTest for Reception of Grammar, Second Edition (TROG-2; Bishop, 2003b), theirmean score was 56.50 (SD = 4.05). It may be noted that these childrens scoresappeared uniformly poorer on TROG as opposed to PPVT: 12 out of 14 childrenwere at floor on TROG, whereas 4 out of 14 children were at floor on PPVT.

Unimpaired controls, aged 39, were recruited from day care centers and schoolsin Boston, Massachusetts, and were individually matched to children with autismon the raw scores of one of the two measures: the matrices subtest of KBIT (nomore than 1 point off), and TROG-2 (no more than 1 point off), thereby formingtwo control groups: KBIT-TD and TROG-TD, respectively. The inclusion of thetwo different measures of nonverbal and verbal abilities allowed us to factor outthe influence of general cognition and of general grammar ability on participantsperformance on the particular syntactic structures under investigation. The TROG-TD control group consisted of 14 children, whereas the KBIT-TD group had 13: 1child with autism scored particularly low on KBIT; thus, no match could be foundfor him among our typical controls. Independent sample t tests confirmed that therewere no statistically significant differences between the raw scores of the group


with autism and either of the two control groups on the relevant matching measure.Participants were closely matched for gender: this match was exact in the autismversus KBIT control group, and fairly close in the autism versus TROG group,where 11 out of 14 autistic participants were matched with controls for gender.All participants were native speakers of standard American English dialect.

ProcedureComprehension of personal and reflexive pronouns was investigated with the aidof a two-choice picture selection task, adapted from Wexler and Chien (1985). Tomake sure that all participants understood the procedure, great care was taken tointroduce the task, the characters used in the experimental pictures (the Simpsonsfamily: Mom, Dad, Bart, Lisa, and Maggie), and the verbs depicting differentactions used in the experimental sentences (dress, wash, point to, and touch).

The task was first piloted with two children with autism and two children withWilliams syndrome, aged 36, all with varying degrees of intellectual impairment.A similar version of this task, with the identical procedure but testing a differentsyntactic construction, was successfully used in another experiment in our lab,with 198 TD children, aged 314. The pictures of the five cartoon characters wereintroduced on the laptop screen individually, for example, This is Mom, this isDad, this is Lisa, etc., followed by practice items that tested the childs familiaritywith each one: the child would be asked to point to the character that matches thename uttered by the experimenter (e.g., Lisa, while the screen shows two pictures,one of Lisa, one of Marge, Lisas mom). This was followed by the introductionof four verbs used in the experimental pictures: dress, wash, point to, and touch,and finally, by two practice items involving simple transitive constructions: Momkisses Dad and Bart holds Lisa. The correct answers to all the practice itemsand experimental items alternated between pictures presented on the left and rightside of the screen, to control for any visual bias. The task was administered toten unimpaired adults whose performance was at ceiling. All the controls and the14 participants with autism (excluding the aforementioned four participants withautism who were for this reason excluded) were able to follow the task instructionsand successfully completed the introductory items, before the experimental probewas presented to them.

StimuliThe probe consisted of two experimental conditions involving reflexive (namereflexive [NR]) and personal pronouns (name pronoun [NPr]) and two controlconditions involving no pronouns but just proper names (control possessive [CP]and control name [CN]). The complete list of sentences is provided in Table 2.

Possessive subjects (Barts dad) were chosen over simple noun phrases(Homer), because possessive structure allows for two potential antecedents ofthe reflexive or pronoun in the experimental conditions: the possessor NP Bart,and the entire subject NP consisting of the possessor and possessee, Barts dad.This way, the child has the choice of two local antecedents, one c-commandingthe dependent, the other not.


Table 2. The complete list of sentences in each test condition

1. Name reflexive Barts dad is touching himself.Lisas mom is touching herself.Barts dad is pointing to himself.Lisas mom is pointing to herself.Barts dad is washing himself.Maggies mom is washing herself.Maggies mom is dressing herself.Lisas mom is dressing herself.

2. Name pronoun Barts dad is touching him.Lisas mom is touching her.Barts dad is pointing to him.Lisas mom is pointing to her.Barts dad is washing him.Maggies mom is washing her.Maggies mom is dressing her.Lisas mom is dressing her.

3. Control name Bart is pointing to Dad.Lisa is touching Mom.Bart is washing Dad.Mom is dressing Maggie.Dad is pointing to Bart.Mom is touching Lisa.Mom is washing Maggie.Mom is dressing Lisa.

4. Control possessive Barts dad is licking a lamp post.Lisas mom is waving a flag.Barts dad is petting a dog.Maggies mom is petting a dog.Lisas mom is driving a car.Lisas mom is playing with blocks.Barts dad is eating an ice cream.Maggies mom is eating an ice cream.

Participants were asked to point to one of the two pictures presented on thelaptop computer that matched the sentence uttered by the experimenter. Thus,a sentence Barts dad is washing him (NPr) would be accompanied by twopictures: Picture A, depicting Homer, Barts dad, washing himself, with Bartstanding by, and Picture B, the correct answer, where Homer is washing Bart.

The same two pictures would be used for the reflexive sentence (NR), Bartsdad is washing himself, where the correct answer is the aforementioned Picture A.In the control condition CP, which contained no pronominal elements, a sentencesuch as Barts dad is petting a dog would be accompanied by two pictures:Picture A showing Bart petting a dog, and Picture B showing Homer, Barts dad,petting a dog (the correct answer). CP sentences tested whether children knewthe structure of possessive NPs: whether they knew that the structure Barts dadrefers to Barts dad and not, say, to Bart, which is the first NP in the sentence.


If children did well on this control condition, then any problems they have withbinding could not be the result of misunderstanding the possessive structure.Furthermore, as is also the case for control condition CN (to be described next), ifchildren did well on this control condition, it shows that they can perform well inthis experiment when binding is not involved. Control condition CN contained nopossessive structures and no pronominal elements: for example, the sentence Dadis pointing to Bart would be accompanied with Picture A showing Homer, Bartsdad, pointing to Bart (the correct answer), and Picture B showing Bart pointing toHomer, his dad.

There were eight sentences in each condition (two for each of the four verbs inthe experimental conditions), thus totaling 32 sentences. The order of sentenceswas automatically randomized for each participant. The test took about 10 min tocomplete.

The majority of the participants with autism were tested in their homes, butseveral were tested in their schools. TD controls were all tested at their daycarecenters or after school clubs.

RESULTSBecause the outcome variable was binary, and involved repeated measures for eachparticipant in each of the three groups, the data were analyzed using the generalizedlinear mixed model function with a logit link (Gelman & Hill, 2007). Mixedlogistic regression models have been argued to be more suitable for analyzing datain psycholinguistic research than commonly used repeated measures analyses ofvariance (e.g., Jaeger, 2008; Quene & van den Bergh, 2008).

The fixed effects built into the model were Group (autism group and the twocontrol groups: KBIT-TD and TROG-TD), sentence (NPr, NR, CP, and CN), andGroup Sentence interaction.7,8

The model revealed significant main effects of group, F (2, 152) = 16.62, p

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Perovic Et Al 2013 Applied Psycholinguistics