Infant Effects on Experimenter Behavior

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Beginning in the late 1960's (e.g., Bell, 1968), a considerable literature has emerged documenting the impact of children's characteristics on their own care and biopsychosocial outcomes. Yet, surprisingly little research has focused on the impact of the child on the experimental setting. It is well known in the infant literature that infant emotional states contribute to their own attrition, and even cognitive performance (e.g., Fagen et al., 1991). Less well known is the extent that infant characteristics contribute to experimenter social engagement. In the present investigation, we explored whether two experimenters responded to infants differently as a function of infant temperament. Sixty- 334 five infants (37 girls) visited the lab at M = 15.38 months (SD = 1.99). Mothers completed the Infant Behavior Questionnaire - Revised (IBQ-R) and a demographic assessment. Temperament measures derived from the IBQ-R were reduced to three overarching superdimensions (negative affectivity, effortful control, and surgency) from 14 subdimensions. Infants participated in a Brooks and Meltzoff (2005) type gaze-following procedure. On Trial 1, either of two experimenters sitting directly across from the infant established eye-contact by calling the child's name, said "Look!", then turned their head to look at a target object on the infant's left for 8 seconds. On Trial 2, experimenters followed the same procedure but looked to the infant's right. Trial 3 was the same as Trial 1. On Trials 4-6, experimenters followed a right-left-right pattern, with the exception that an Elmo videotape played on a monitor behind and above the experimenter as soon as the experimenter looked at the target object. Trials 4-6 were designed to test gazefollowing under conditions of distraction. The two experimenters did not differ statistically from one another in looking to the target object on any trial (see Table 1; t's <= 1.60, p's => .12); although, due to procedural requirements looking time for both experimenters differed as a function of distraction condition [F(1, 57) = 98.53, p = .000; see Table 1]. Nevertheless, during a procedural fidelity check, and despite both experimenters being blind to children's temperamental status, we found that experimenter looking time to the target objects in the control condition was correlated with both effortful control and surgency (see Table 2). These correlations were carried primarily by the subdimensions of duration of orientation and perceptual sensitivity, respectively. Evaluating the correlations separately by experimenter showed that both experimenters appeared to be susceptible to infant temperament. These results raise the possibility that even highly trained experimenters, blind to child temperament status, may be responsive to child characteristics when implementing experimental protocols. Obviously, in the present case, when experimenters remained visually engaged with target objects for longer periods of time for certain children, those children had greater opportunity to demonstrate gazefollowing. In principle, children high in effortful control and surgency could demonstrate longer gaze-following not as a direct effect of their temperament, but as an indirect effect of their temperament mediated through an experimenter. Future experimental researchers may wish to include temperament instruments as standard protocol to test for experimenter fidelity.


Philadelphia, PA

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