TABLE 4

Ratios of Typical to Atypical Behaviors

Operational DefinitionsaTypical:Atypical Occurrence Ratio
Typical BehaviorAtypical BehaviorAutismLanguageTypical
RespondingTaking offered toys, eye contact or directed facial expressions in response to social overtures, laughing or vocalizing in response to social games, catching a ball, or following verbal or gestured directionsAbsence of any typical behaviors within 3 s of a clear opportunity presented by the adult8:1b,c51:1b63:1c
VocalizationBabbling, crying, laughing, talking, with typical prosodyStereotyped or repetitive (3 times in succession) vocalizations, or vocalizations with odd prosody6:131:113:1
PlayAppropriate moving or holding of toys, objects, or body partsUnusual examination, stereotyped or repetitive use of toys, objects, or the body (eg, identical action, such as banging, in more than 3 time intervals)13:1659:1d88:1
InitiatingSharing attention or excitement, engaging others in play, requesting something, or initiating a turn in a back-and-forth gameNo sharing, requesting, or initiating back and forth games despite a clear opportunity; odd overtures, such as using another’s hand as a tool18:1e,f67:1e136:1f
RTNOrienting or vocalizing to the speaker within 3 s of name being calledNo response within 3 s of name being called1:1g,h5:1g4:1h
  • a Raters were allowed to consider the subsequent interval to determine response to a bid that was presented at the end of the 10-s interval. The response was coded in the interval in which it was observed.

  • b Kruskal-Wallis of total Responding behaviors (opportunities): χ2 (2) = 14.39; P = .001; Mann-Whitney U Autism (70) < Language (88); U = 161.5; z = 2.921; P = .002.

  • c Autism < Typical (92); U = 174.5; z = 3.518; P < .001.

  • d Ratios are calculated on aggregate behaviors within the group. In the Language group, only 2 intervals were coded with atypical play, compared with 1319 intervals with typical play behavior.

  • e Kruskal-Wallis of total Initiating behaviors (opportunities): χ2 (2) = 12.447; P = .002 (Autism [10] < Language [19]; U = 161; z = 2.987; P = .003).

  • f Autism < Typical (19); U = 167; z = 3.172; P = .001.

  • g Kruskal-Wallis of total RTN behaviors (opportunities): χ2 (2) = 10.720; P = .005 (Autism [19] > Language [10]; U = 36; z = −2.857; P = .004.

  • h Autism > Typical (11); U = 40.5; z = −2.654; P = .007.