Table 2.

Descriptions of Scoring Measures

Sample	4 month Visit	14 month Visit	21 or 24 Month Visit
Sample 1 Thistle	Motor Reactivity: Total # of movements of both arms, both legs, and hyperextension of the arms or legs; (1 pt. each); Bursts: Total # of occurrence of bursts of both arms or legs (two or more movements in quick succession) (2pts each) Negative Reactivity: Crying: Total # of seconds the child cried across the battery Fretting/Fussing: Total # of trials on which these two occurred Other Coded Reactivity: Arching: Total occurrences of arching of the back (2pts each); Fret/Fuss: # of trials on which these two responses occurred. Positive Vocalizations: # of trials on which response occurred; Smiling # of trials on which response occurred. Final Scores: Sum of frequencies for both Motor Reactivity and Negative Reactivity.	Total number of fears (including fretting or crying, or reluctance to approach) to an unfamiliar event or procedure.	Total number of fears (including fretting or crying, or reluctance to approach) to an unfamiliar event or procedure. (Seen at 21 months)
Sample 2 Cohort 1: Thistle	Motor Reactivity: Total # of movements of both arms, both legs, and hyperextension of the arms or legs; Can be one or two in succession; Bursts: Total # of occurrence of bursts of both arms or legs (three or more movements in quick succession) (1 pt. each) Arching: Total occurrences of arching of the back (1pts each) Negative Reactivity: Crying: Total # of seconds the child cried across the battery; Fret/Fuss: # of trials on which these two responses occurred. Positive Reactivity: Positive Vocalizations: # of trials on which response occurred; Smiling # of trials on which response occurred. Final Scores: Sum of frequencies for Motor Reactivity, Negative Reactivity, and Positive Reactivity.	Composite score of the following measures: Latency to touch Toy (free play), Latency to vocalize (free play), Time spent in proximity to mother (free play), Latency to vocalize to stranger, Latency to approach stranger, Latency to vocalize to approach robot, Latency to approach robot, Time spent in proximity to mother (robot), Time spent in proximity to mother (truck).	Composite score of the following measures: Time spent in proximity to mother (free play), Time spent in proximity to mother (truck), Time spent in proximity to mother (robot), Time spent in proximity to mother (tunnel), Latency to approach/touch truck, Latency to approach/touch robot, Latency to pass through tunnel. (Seen at 24 months)
Cohort 1 Likert	Motor Reactivity: movements of both arms, both legs, and hyperextension of the arms or legs; Can be one or two in succession Bursts: of occurrence of bursts of both arms or legs Arching: Total occurrences of arching of the back (three or more movements in quick succession) (all scored on a Likert Scale from 1 to 7) Negative Reactivity: Crying: seconds the child cried across the battery; Fret/Fuss:(scored on a Likert Scale from 1 to 7). (all scored on a Likert Scale from 1 to 7) Positive Reactivity: Positive Vocalizations; Smiling (all scored on a Likert Scale from 1 to 7). Final Scores: Composite score of Likert scores for Motor Reactivity, Negative Reactivity, and Positive Reactivity.
Cohort 2 Likert	Motor Reactivity: movements of both arms, both legs, and hyperextension of the arms or legs; Can be one or two in succession Bursts: of occurrence of bursts of both arms or legs Arching: Total occurrences of arching of the back (three or more movements in quick succession) (all scored on a Likert Scale from 1 to 7) Negative Reactivity: Crying: seconds the child cried across the battery; Fret/Fuss:(scored on a Likert Scale from 1 to 7). (all scored on a Likert Scale from 1 to 7) Positive Reactivity: Positive Vocalizations; Smiling (all scored on a Likert Scale from 1 to 7). Final Scores: Composite score of Likert scores for Motor Reactivity, Negative Reactivity, and Positive Reactivity.	Composite score of the following measures: Latency to touch Toy (free play), Latency to vocalize (free play), Time spent in proximity to mother (free play), Latency to vocalize to stranger, Latency to approach stranger, Latency to vocalize to approach robot, Latency to approach robot, Time spent in proximity to mother (robot), Time spent in proximity to mother (truck).	Composite score of the following measures: Time spent in proximity to mother (free play), Time spent in proximity to mother (truck), Time spent in proximity to mother (robot), Time spent in proximity to mother (tunnel), Latency to approach/touch truck, Latency to approach/touch robot, Latency to pass through tunnel. (Seen at 24 months)
Sample 3	Motor Reactivity: movements of both arms, both legs, and hyperextension of the arms or legs; Can be one or two in succession Bursts: of occurrence of bursts of both arms or legs Arching: Total occurrences of arching of the back (three or more movements in quick succession) (all scored on a Likert Scale from 1 to 7) Negative Reactivity: Crying: seconds the child cried across the battery; Fret/Fuss:(scored on a Likert Scale from 1 to 7). (all scored on a Likert Scale from 1 to 7) Positive Reactivity: Positive Vocalizations; Smiling (all scored on a Likert Scale from 1 to 7). Final Scores: Composite score of Likert scores for Motor Reactivity, Negative Reactivity, and Positive Reactivity.		Composite z-score of the following measures: Time spent in proximity to mother (free play), Time spent in proximity to mother (truck), Time spent in proximity to mother (robot), Time spent in proximity to mother (tunnel), Latency to approach/touch truck, Latency to approach/touch robot, Latency to pass through tunnel. (Seen at 24 months)