Rate Per Minute of Child Communication
Descriptive statistics and results of the LMM comparing child communication across interaction contexts are displayed in
Tables 2 and
3, respectively. Main effects of diagnostic group,
F(2, 228.61) = 31.30,
p < .001, and context,
F(7, 219.96) = 23.90,
p < .001, were significant, while the interaction term was not,
F(14, 207.70) = 1.74,
p = .05. Across contexts, model estimates indicated that children in the TD group communicated at significantly higher rates than autistic children and those with DD (autism–TD mean difference ±
SE = 2.02 ± .26,
p < .001, 95% CI [1.40, 2.63]; DD–TD = 1.47 ± .31,
p < .001, 95% CI [0.74, 2.21; autism–DD = −0.55 ± .25,
p = .09, 95% CI [−1.15, 0.06]).
For the entire sample, on average, children communicated at significantly higher rates per minute during book sharing and play with people compared to all other interaction contexts (all ps < .001). Rates of communication during book sharing and play with people did not differ (mean difference ± SE = −0.7 ± .24, p = 1.00, 95% CI [−0.83, 0.70]). In contrast, children communicated at significantly lower rates during transitions between activities than all other interaction contexts except play with props (all other ps < .05). Rates of communication among the contexts of caregiving, chores, meals and snacks, play with props, and play with toys did not differ significantly for children in this sample (all ps > .18).
Communicative Functions Expressed
Average proportions of communicative functions used during interaction contexts for the entire sample are shown in
Figure 1. Descriptive statistics and results of planned contrasts within contexts are displayed in
Table 4. Communicative acts for all three functions were represented in each interaction context. The effect of communicative function was significant within each of the eight interaction contexts examined. Notably, more than half of all communicative acts were for behavior regulation during caregiving, family chores, meals and snacks, as well as transitions between activities. Proportions of communicative acts for this function were significantly larger than those for social interaction and joint attention in each of these contexts (see
Table 4; all
ps < .001). Play with toys followed a similar trend, with proportionally higher child communicative acts for behavior regulation (42%) compared to the other two functions,
F(2, 205) = 36.93,
p < .001, η
p2 = .27. Fifty-nine percent of acts for social interaction occurred during play with people, which was significantly larger than proportions of communication for behavior regulation (27%) and joint attention (13%),
F(2, 167) = 115.84,
p < .001, η
p2 = .58. Finally, 53% of child communication during book sharing was for joint attention, which was significantly more than both behavior regulation and social interaction,
F(2, 154) = 150.46,
p < .001, η
p2 = .66.
PVR
Descriptive statistics for PVR to child communication across interaction contexts for the entire sample are presented in
Table 5 and by diagnostic group in
Supplemental Material S4. All PVR types were represented in each interaction context. Parents responded with follow-in verbal comments 20% or less of the time in all activities except for book sharing (30%). Approximately 40% of PVR during chores and 36% of PVR during transitions were follow-in directives. Follow-in nonverbal comments accounted for about 56% of PVR during play with people.
Results of the three LMMs comparing PVR across two contexts (i.e., book sharing/play and necessary activities) are presented in
Table 6. For the model comparing parents' use of follow-in verbal comments, main effects of group and interaction context were statistically significant,
F(2, 208.06) = 12.83,
p < .001, and
F(1, 204.24) = 7.25,
p < .01, respectively. The interaction term was nonsignificant,
F(2, 204.27) = 1.01,
p = .37. Across interaction contexts, parents of children with TD responded using proportionally more follow-in verbal comments than those of autistic children and children with DD (TD–autism mean difference ±
SE = .10 ± .02,
p < .001, 95% CI [.05, .15]; TD–DD = .11 ± .03,
p < .001, 95% CI [.05, .18]). Parents of autistic children and those with DD did not differ in their use of follow-in verbal comments (mean difference ±
SE = .01 ± .02,
p = 1.00, 95% CI [.04, .06]). On average, parents of children in all groups responded using proportionally more follow-in verbal comments during book sharing/play compared to necessary activities (mean difference ±
SE = .03 ± .01,
p = .008, 95% CI [.01, .04]).
Turning to follow-in directives, the main effect of interaction context was significant, F(1, 216.60) = 12.96, p < .001. The main effect of group and the interaction term were nonsignificant, F(2, 225.30) = 0.90, p = .41, and F(2, 216.63) = 0.14, p = .87, respectively. Parents of children in all diagnostic groups, on average, responded using proportionally more follow-in directives during necessary activities than during book sharing and play (mean difference ± SE = .04 ± .01, p < .001, 95% CI [.02, .06]).
Finally, regarding follow-in nonverbal comments, significant main effects for group and interaction context were observed, with the interaction term remaining nonsignificant, group: F(2, 208.64) = 4.10, p = .018; context: F(1, 204.95) = 18.94, p < .001. Parents of children on the autism spectrum and those with DD used follow-in nonverbal comments more often than those of children with TD (autism–TD mean difference ± SE = .07 ± .03, p = .044, 95% CI [.01, .13]; DD–TD = .09 ± .03, p = .025, 95% CI [.01, .17]). Parents of children across groups also used follow-in nonverbal comments significantly more often during book sharing/play than during necessary activities (mean difference ± SE = .05 ± .01, p < .001, 95% CI [.02, .07]).