These results provide detailed information regarding the deficits seen in the conversational skills of speakers with ASD. When compared with age-mates with TD, difficulties of young people with ASD are not found across all PRS items, but are focus on approximately one-third of the items rated. Differences are largest in the areas of intonational and gaze abnormalities (See ). In terms of pragmatic behaviors, the aspects of conversation most significantly impacted are the amount of information provided in conversation to satisfy listener needs, the degree to which topics are managed and reciprocated, the ability to respond to partner cues and engage in reciprocal exchanges. Other areas affected include the ability to clarify and repair conversational breakdowns, and to initiate appropriate, spontaneous discourse. These pragmatic difficulties can be conceptualized into three broad categories: (1) topic management, specifically, the ability to produce a comment pertinent to the topic introduced by the partner and the ability to introduce topics of shared relevance and interest (PRS 8, 10); (2) information management, specifically, providing the appropriate amount and type of information based on listener needs (PRS 7, 17, 18, 19); and (3) reciprocity (PRS 11, 12), the ability, in both verbal and nonverbal ways, to maintain a balanced, back-and-forth conversational exchange.
The difficulties identified here in topic management and information management can be seen to be related to what linguists refer to as presuppositional skills (Ward and Horn 2004
). Presupposition involves the ability to predict what listeners already know and are thinking about, as well as what they wish to know, when choosing what information to convey in conversation. Competent conversationalists use presuppositional skills to adhere to what the linguistic philosopher (Grice 1975
) called the “maxim of quantity.” That is, they say just enough to tell the listener what s/he needs to know without expressing information s/he neither wants nor needs. Adhering to this maxim requires a good deal of “mind reading;” i.e., knowing what the listener already knows, has in the forefront of his/her mind where it can easily be related to what is being said, and what the listener’s goals, intentions and desires for this conversation are. Thus, apart from their significant issues in use of intonation and gaze in conversation, speakers with ASD differ from those with TD primarily in their difficulty in determining what topics and information are necessary for a cooperative, mutually engaging conversation to proceed.
Difficulties in reciprocity—including being unresponsive to verbal and nonverbal cues for floor-shifting and turn-exchange, as well as inappropriate timing and latency of turn-taking—may reflect a more basic failure of attention and sensitivity to others. That is, a history of neglecting to attend to the cues of others can be implicated in a failure to form hypotheses about and understand the intentions behind those cues.
The description of pragmatic skills that emerges from this study, then, adds weight to the notion that difficulties in computing others’ states of mind in real-time exchanges play an important role in the conversational deficits of speakers with ASD. Although performance on structured ToM experimental tasks has been shown to be highly related to verbal IQ in previous studies (e.g., de Villiers 2000
), the correlation between verbal IQ and total PRS score in this study does not reach significance (r
= .09). This finding lends support to Klin’s hypothesis (Klin et al. 2000
) that in real-world activities, performance is affected not only by general verbal cognition, but also by the ability to “[seek and detect] salient aspects of a social situation to [react] quickly to fast-changing emotional expressions” (p. 382).
Gaze management problems, as well, can perhaps be traced to early-emerging differences in prelinguistic interaction. That is, the neural mechanisms that dictate preferences for looking at faces from early in development (Klin 2003
; Klin et al. 2002
) may differ in individuals with ASD; such differences could develop into aberrant gaze patterns as the information gained through looking at faces is less abundant and less salient for children with ASD, and as gaze becomes more coordinated and integrated with conversational turn-taking and the monitoring of interpersonal cues in conversation.
Thus, many of the major deficits seen in the conversational skills of speakers with ASD can be construed to relate to core indices of social disability present in the first years of life, including failures of joint attention and attention to face and voice, and to the integration of these abilities, as they develop into linguistic presuppositional skills. One major area of deficit remains to be explained however: the deficit in intonation. Neither presupposition nor early difficulties in joint attention seem obviously related to the difficulty in modulating vocal production and integrating it with underlying intention. Studies underway in our laboratory are attempting to address this puzzle by using neuroimaging to explore the roots of intonational difficulties in brain structure and function.
A caveat should be mentioned regarding these results. Even for items on which there were significant differences between participants with ASD and TD, participants with ASD received, on average, only 12–16% of the possible points for aberrant behavior. Subjects who were rated more than one standard deviation above the mean for the ASD group received 30% of the possible points for aberrant behavior in any of the categories rated. The maximum percentage of possible points for aberrant behavior ever assigned to any subject in any category was 42%. Thus, although there were differences between participants with TD and ASD, those with ASD did not produce aberrant conversational behaviors consistently, and were NOT, in fact, rated as aberrant on a majority of the observations. This suggests that a proportionally small amount of atypical conversational behavior characterizes this population. However, it is important to note that these adult–child interactions are those in which speakers with HFA and AS are often seen to be least handicapped. Interactions with peers typically constitute more difficult situations for these individuals. In fact, Communication and Socialization scores on both the Vineland and ADOS in , indicate that others’ perceptions of these subjects’ interactive skills are highly impacted by this relatively small amount of atypicality.
In considering the comparisons between conversational behaviors in speakers with AS and those with HFA/PDD-NOS, we see, first, a similar picture of generally low levels of aberrant conversational behavior in both ASD groups (See ). Significant differences between the two groups with ASD on individual PRS items are relatively rare, primarily in the use of overly formal language style in the group with AS, and in significantly more difficulties with gaze management in the group with HFA/PDD-NOS. Both the group with AS and with HFA/PDD-NOS were significantly more impaired on PRS item 8 (out of sync) than the group with TD; however, they were not significantly different from each other on this item. The same pattern was seen on PRS item 23 (unusual intonation). This finding supports those of Shriberg et al. (2001)
, who reported that AS and HFA groups showed similar impairments in prosody. Our findings also support observations of a more formal, pedantic speech style in speakers with AS than in those with HFA/PDD-NOS (Ghaziuddin and Gerstein 1996
For the other items on which significant differences were seen in the three-way comparison (PRS 7 [inappropriate detail], 10 [topic preoccupation], 11 [unresponsive], and 12 [little reciprocal exchange]), only the group with AS was significantly different from that with TD. The large standard deviations within the AS and HFA/PDD-NOS groups are factors likely to contribute to a reduced power to find pair-wise differences, despite significant findings in the three-way comparison. Still, these results support the suggestion of Tager-Flusberg et al. (2005)
that, unlike other speakers with other communication problems, speakers with ASD show more marked impairment the more they talk. That is, the speakers with AS who, as Shriberg et al. (2001)
reported, tend to be more verbose than those with HFA/PDD-NOS, show larger differences from typical speakers.
The finding that speakers with ASD show aberrations on a minority of their conversational turns suggests that they do have some conversational skills that can be built on in intervention. Carefully analyzing conversational behaviors with a tool like the PRS may help clinicians to identify not only the deficits, but also the adaptive conversational behaviors within an interaction, and help the speaker extend their use to a greater number of contexts. Thus, in some sense, these speakers may not need to learn “how” to converse, but may need additional cues to “when” their successful conversational behaviors should be applied. Our discussion of the possible roots of these pragmatic difficulties in early-emerging failures to “tune in” to appropriate social cues suggest that one way to help speakers with ASD respond more appropriately in conversation may involve prompts to attend to cues present in the interaction (presented in instructional contexts in exaggerated form, at first) and recognize them. Once cues are recognized more consistently, strategies for responding may be addressed.
The study also suggests the broad areas in which conversational strengths and weaknesses are most likely to be seen in speakers with ASD. On the PRS Speech/Prosody and Paralinguistic scales, only intonation and gaze items showed between-group differences. Other areas of difficulty seen in younger and more severely impaired individuals, included scripted speech, poor use of gesture, and problems with volume, rate or timing are infrequent in these high-functioning adolescents. In the Pragmatic domain, usages easily misinterpreted as rude, such as excessive bluntness and informality, are also rare. Areas of significant deficit center on management of topics and information, related to difficulties in presuppositional skills, and achievement of reciprocity related to attention and sensitivity to partner verbal and nonverbal cues. Although individual assessment will be necessary to establish the conversational difficulties in a particular student, these data suggest promising areas in which treatment programs that will have broad applicability for high-functioning speakers can be developed.
Such programs would focus, as suggested earlier, on increasing the awareness of interlocutor cues to turns and topics in conversation and learning adaptive ways to respond to these cues, helping students identify topics likely to be of interest to peers, finding ways to comment reciprocally on topics introduced by others, adding new, relevant ideas to a given topic, avoiding irrelevant and tangential contributions, monitoring the success of contributions and learning strategies for conversational repair. Several methods reported in recent literature on social skills training could be adapted to address these foci, including video modelling (Charlop-Christy and Milstein 1999
; Charlop-Christy et al. 2000
; Corbett and Larsson 2001
), social thinking (Paul 2007
; Wiig and Wilson 2002
; Winner 2005
), think-aloud protocols (Brinton et al. 2004
; Camp and Bash 1981
), and cognitive-behavioral approaches (Bock 2001
; Timler et al. 2005
; Timler et al. 2007
The data also suggest that, although students with AS are more likely than others with ASD to use an overly formal speech style, other areas of conversational deficit are likely to be shared among all speakers on the spectrum who function at this level. Since scores on PRS items that were significantly different from speakers with TD were not significantly different between the AS and HFA/PDD groups, it is likely that most goals and strategies discussed above will be relevant for high functioning speakers with all diagnoses within the autism spectrum. These findings can guide clinicians as they attempt to address the persistent conversational difficulties faced by these otherwise able individuals.