Poster #30 - Heart Rate Variability Predicts Standardized Test Performance But Is Mediated By Inhibitory Control

• In Event: 3-003 - Poster Session 09
  In Poster Session: PS 09 Section - Cognitive Processes

Integrative Statement

Background and Aims: When individuals attend to stimuli, their heart rate, along with the variability in this heart rate, falls (e.g., Richards & Casey, 1991). Variability in heart rate is associated with parasympathetic activity and attention (Porges, 1976, 1980), and it relates in children to performance on cognitive tasks (Marcovitch, Leigh, Calkins, Leerks, O’Brien, & Blankson, 2010; Staton, El-Sheikh, & Buckhalt, 2009). Inhibitory Control (IC), an executive function and aspect of temperament that allows children to inhibit dominant responses, also relates to many important childhood cognitive outcomes (e.g., Blair & Razza, 2007 ; Carlson & Moses, 2001; Miyake, Friendman, Emerson, Witzki & Howerter, 2000). However, little work has been done to show the unique and overlapping influence of these two characteristics in early childhood. Therefore the purpose of this investigation was to determine the influence of both heart rate variability (HRV) and IC on one particular cognitive outcome so as to investigate the potential for a mediated model.

Participants and Measures: Sixty-nine 4-year-old children (mean age: 4 years, 3 months; 39 boys, 30 girls) participated in an investigation of early childhood IC and its antecedents and consequences. Before the appointment, mothers reported on children’s IC using the Children’s Behavior Questionnaire (Rothbart et al., 2001). Then, at the appointment, children completed the Peabody Picture Vocabulary Test (PPVT-IV, L.Dunn & D. Dunn, 2007) as a measure of their receptive language. Soon after, children watched a two minute clip from the film, Finding Nemo (turtles in the East Australian Current) while baseline heart rate was measured using disposable electrocardiogram electrodes placed in the modified lead II alignment (right collarbone and lower left rib; Stern, Ray, & Quigley, 2001) with a ground on the scalp. HRV was computed as variability in inter-beat interval, using a process similar to that described by Patriquin, Lorenzi, Scarpa, Calkins, and Bell (2014).

Results and Discussion: As expected, the three variables of interest were significantly associated with one another, as can be seen in Table 1. With this assumption met, regression analysis was used to investigate the hypothesis that IC mediates the effect of HRV on PPVT score. As can be seen in Figure 1, HRV was a significant predictor of IC (b = -.105, SE = .043, p = .018) and IC was a significant predictor of PPVT score (b = .443, SE = .181, p = .018). Also shown in Figure 1, HRV was no longer a significant predictor of PPVT score after controlling for the mediator, IC (b = -.110, SE = .065, p = .094). These results support a mediational hypothesis. Approximately 17% of the variance in PPVT score was accounted for by the predictors (r2 = .168). Percent mediation was calculated as .296, meaning that IC mediates approximately 30% of the effect of HRV on PPVT score (see Preacher & Kelly, 2011 for calculation). Results imply that though HRV influences PPVT score, this association can be partially explained through the effect of IC on language. Implications of these results will be discussed.

Authors

• Amanda Watson Joyce, Murray State University
  Presenting Author

• Martha Ann Bell, Virginia Tech
  Non-Presenting Author