Poster #163 - Examining 3.5- and 7-month-old infants’ ERP responses to mom and stranger expressing different emotions

• In Event: 1-169 - Poster Session 04
  In Poster Session: PS 04 Section - Perceptual, Sensory, Motor

Integrative Statement

Being able to recognize faces and understand different emotions is critical to infants’ developing understanding of their social world. Young infants can discriminate between familiar and unfamiliar faces (Bushnell, 2001) and differentiate between emotional expressions (Quinn et al., 2011). Despite extensive research into the development of identity and emotion recognition, few studies investigate their interaction. A few studies have found that infants recognize emotion more readily when expressed by caregivers (e.g., Walker-Andrews et al., 2011). No one has yet investigated the neural underpinnings of this phenomenon. In the current study, we aim to understand the neural mechanisms underlying how infants process information regarding face familiarity, emotion, and their interaction.
Infants were tested at 3.5 and 7 months as part of a larger longitudinal study. Forty-nine infants have completed the 3.5-month assessment; 34 of these infants have completed the 7-month assessment (testing is ongoing). Infants viewed familiar (mom) and unfamiliar (female stranger) faces expressing happy and fearful expressions one at a time while their brain activity was recorded using high-density electroencephalography (EEG).
We examined three components: the Nc over frontocentral leads (reflects attention – Courchesne et al, 1981) and the N290 and P400 over occipitotemporal leads (reflects face-sensitive processing – de Haan et al, 2003). We hypothesized differential processing of emotion and familiarity for all three components (de Haan & Nelson, 1996; 1997; Swingler et al, 2010). Given behavioural work (Walker-Andrews et al 2011) suggesting better recognition of emotion when expressed by mom, we also predicted an interaction between emotion and familiarity. However, we were unsure how this interaction would unfold, therefore conducted exploratory analyses on both latency and mean amplitude for each component.
Preliminary analyses found no main effects of emotion or familiarity for Nc mean amplitude or latency in either 3.5- or 7-month-old infants. Preliminary analyses of the N290 found that latency was faster for mom’s face than stranger’s face for 3.5-month-old but not 7-month-old infants (Figure 1). Analyses of the P400 found that latency was significantly faster for mom’s face than stranger’s face in 7-month-old infants but not 3.5-month-olds (Figure 2). There were no main effects of familiarity or emotion on N290 nor P400 mean amplitudes. Due to the small number of infants that completed enough trials in all four conditions (mom happy, mom fearful, stranger happy, stranger fearful), we are not yet able to examine the interaction between familiarity and emotion.
In sum, both 3.5- and 7-month-old infants show faster processing of their caregiver’s face compared to that of a stranger’s, but potentially during different time frames. We found no main effect of emotion, which is surprising given that past research has found neural responses to fearful are faster and larger in amplitude compared to happy and neutral (e.g., de Haan & Nelson, 1996). We were not yet able to examine the interaction between familiarity and emotion due to small sample size. This study is one of the first to examine this interaction and understand how emotion development may be facilitated via face familiarity at the neural level.

Authors

• Alexandra R Marquis, Ryerson University
  Presenting Author

• Xiaomei Zhou, Ryerson University
  Non-Presenting Author

• Maire L. O'Hagan, Ryerson University
  Non-Presenting Author

• Shira Segal, Ryerson University
  Non-Presenting Author

• Margaret Moulson, Ryerson University
  Non-Presenting Author