Poster #45 - Motivational Responses to Emotional Infant Faces in Mothers and Non-mothers

• In Event: Poster Session 18

Abstract

Infant emotions are expressed through facial expressions and vocalizations in order to capture the caregiver’s attention, and to motivate the caregiver to attend to the infant’s needs. Infant cues are efficient in activating mothers’ brain areas related to motivation and reward-processing (Strathearn et al., 2008). With a reward value paradigm, motivational responses to infant cues can be studied on a behavioral level. In earlier studies, motivational responses to infant cues have been associated with salivary testosterone (Hahn, DeBruine, Fisher, & Jones, 2015), and self-reported maternal tendencies in nulliparous women (Hahn, DeBruine, & Jones, 2015). It is unclear whether becoming a parent alters the way infant emotions trigger the motivational systems to approach or withdraw from infant cues. In this study we investigated whether first time mothers and non-mothers differ in motivational responses to emotional infant faces and whether the motivational responses are associated with salivary oxytocin, estradiol, testosterone, or cortisol.

The data were collected from 96 participants: 42 non-mothers (age 26.35 years) and 54 new mothers of 6-month-old infants (age 29.91 years). The motivational responses to infant emotions were evaluated with a simple key press task. The participants were shown either a happy or a sad infant face on each trial (10 individual stimuli in each condition) and they could decide how long they wanted to see each face on the screen. Participants were asked to press keys 7 and 8 repeatedly to prolong the viewing time or alternatively shorten it by pressing keys 1 and 2 repeatedly. Hormone samples were collected in the beginning of the laboratory visit by asking the participants to chew a Salivette® swab for one minute. The data were analyzed with a linear mixed model. The number of key presses was the dependent variable. Trial was the repeated factor, infant emotion, age of the participant, and the four hormonal levels were added as level 1 variables. Parity was the grouping (Level 2) variable.

The LMM showed that both groups viewed happy infant faces longer (p < .001). Parity had no significant main effect, but there was an interaction between parity and emotion (p < .001, Figure 1). This indicates that mothers had a relatively larger difference in viewing times between the two emotions. Mothers viewed the happy faces longer and the sad faces shorter when controlling for age and hormonal levels. In addition, there was a main effect of testosterone; higher testosterone levels were related to more effort to shorten the viewing times of both emotions (p = .001). Estradiol also had a significant main effect (p = .016); women with higher estradiol levels exerted more effort to lengthen the viewing times for both infant emotions.

Happy infant faces are more motivating than crying infant faces for both mothers and non-mothers, but there seems to be a larger difference in the effort to view happy versus crying infant faces in mothers. Happy infant faces may be particularly motivating to new mothers. Furthermore, testosterone and estradiol seem to have individual associations with the motivation towards babies.

Authors

• Hanneli Sinisalo, Tampereen yliopisto (Tay)
  Presenting Author

• Amanda C. Hahn

• Lisa M. DeBruine

• Benedict C. Jones

• Marian J Bakermans-Kranenburg, ISPA Lisbon

• Mikko Peltola