Thin Slice Sampling of Video Footage for Mother/Child Interaction: Application to Single Cases

Abstract

The purpose was to test the reliability of short samples of parent/child interaction for use in single-subject research. Four variable pairs of mother/child behaviour were coded for seven mother/child play sessions. Each session lasted 20 min and 18 min of the session was behaviourally coded using frame-by-frame analysis. The co-occurrence of the mother/child behaviours within a given time window was computed and an odds ratio was calculated for the co-occurrence of the targeted behaviours. The play session was divided into shorter segments (3, 6 and 9 min) and odds ratios of the variable pairs from the shorter segments were compared to the odds ratios from the entire session. Segments of 3 and 6 min did not yield the same pattern of results as the entire session. In single-subject research, evidence of the reliability of the time segment for behavioural coding should be reported in the methods section of original research manuscripts.

Comparing thin slices of verbal communication behavior of varying number and duration

“…In Roter’s study [16] of patient-provider communication among medical students, the thin slice sample comprised of three slices was more strongly correlated with the entire encounter than any 1-minute thin slice. James et al [15] found “thicker” slices, those nine minutes in duration representing 50% of the 18 minute interaction, accurately represented mothers and infants dyads’ eye gaze and vocalizations but shorter slices of three and six minutes were discrepant from patterns observed in the full interaction.…”

“…In their discussions, both Murphy [4] and James et al [15] indicate the frequency of the target behavior is a critical issue. Thin slices sampling might not accurately detect and, therefore, might not be appropriate for behaviors with a very low base rate.…”

“…The literature suggests a high degree of accuracy when using thin slices to make global assessments [e.g., 5, 6–14], but only three studies have examined the accuracy of thin slices to identify and characterize specific behaviors [i.e., 4, 15, 16]. The purpose of the present study is to examine the extent to which thin slices accurately represent verbal communication behaviors between adolescent patients and MI counselors engaged in weight loss counseling.…”

“…James and colleagues [15] tested the utility of thin slices to code interactions between mothers and infants (gaze and verbalizations). Each 18-minute encounter was divided into six 3-minute segments, three 6-minute segments and two 9-minute segments.…”

“…Specifically, we investigated both how many thin slices are needed and how thin can slices be to accurately characterize key communication behaviors relative to fully coded sessions? Based on the work of Murphy [4], Roter [16], and James et al [15], we expected to find greater accuracy when a greater proportion of the encounter was extracted. In other words, we expected greater accuracy when a greater number of thin slices were extracted (six versus four slices) and when “thicker” slices were extracted (2-minute versus 1-minute slices).…”