Research findings involving mothers and fathers interacting with babies shows a mixed picture. Some studies, involving children aged from 9 to 24 months, find differences between mothers and fathers. Thus, in contrast with mothers, fathers observed in free-play, were less sensitive and often intrusive, for example, introducing questions or requiring information that may interfere with play (Leaper, 2000; Volling et al., 2002; Lovas, 2005; Kwon et al., 2012; Hallers-Haalboom et al., 2014; Fuertes et al., 2016). Likewise, Feldman and Klein (2003) found that fathers interacting more through contact and physical play, were usually less positive, more unpredictable, and characterized by sudden peaks of emotional intensity. Fathers used more stimulation and exploratory play and less emotional support behaviors (Grossmann et al., 2008).

Other studies, involving a wider range of child ages, from 0 to 36 months, find no differences between fathers and mothers in the quality of interactions with their children (e.g., Goossens and van IJzendoorn, 1990; Braungart-Rieker et al., 2001; Lewis and Lamb, 2003; John et al., 2012; Yago et al., 2014) or in the intensity of their negative affect (Ekas et al., 2011).

These studies involved infants of different ages from very young infants to toddlers (Braungart-Rieker et al., 2001; Yago et al., 2014) and different measures, from event-based schemes to rating scales (Volling et al., 2002; Ekas et al., 2011). Some of these studies compared mother and father with the same child (e.g., Yago et al., 2014) which could be clouding possible differences, as it is plausible that a partner influences the quality of parent–infant interaction. In fact, some research indicates that partners can become similar through the process of marital life (Easterbrooks and Goldberg, 1984; Osnat and Bonnie, 1995; Lundy, 2003). Especially during infancy, parents can rely on each other in searching and implementing successful strategies of interaction with their infant, leading to bidirectional modeling (Braungart-Rieker et al., 1998; Schoppe-Sullivan et al., 2007). Additionally, Barnett et al. (2008) found that perceived high level of marital quality was associated with interdependence of sensitive parenting behaviors in mother–infant and father–infant interactions. This could explain the high correlations between the scores obtained by couples of fathers and mothers in sensitivity and intrusiveness (Braungart-Rieker et al., 1998; Volling et al., 2002; Tamis-LeMonda et al., 2004; Hallers-Haalboom et al., 2014). Finally, most of the studies did not consider infant gender as a factor (Braungart-Rieker et al., 2001; Kwon et al., 2012).

Two theoretical frameworks describe some mechanisms regarding differential parenting of boys and girls. The biosocial theory proposes that the parents use gender-differentiated parenting as a means of gender-role socialization (Eagly and Wood, 2002; Wood and Eagly, 2012) and gender schema theories (Bem, 1981; Markus et al., 1982) proposes that parenting would be affected by parents’ gender-role stereotypes.

Considering these two theories, Endendijk et al. (2016), conducted a meta-analysis of 126 observational studies, involving 15,034 families to examine parental differences with their sons and daughters. They used ‘autonomy-supportive strategy’ in parental behavior, that is, child-centered responding and promoting autonomy through support, conceptually similar to the construct of parental sensitivity as formulated within Attachment Theory (Bowlby, 1969/1982; Ainsworth et al., 1978) and controlling strategies, similar to parenting practices described within Coercion Theory (Patterson, 1982; Eddy et al., 2001). Contrary to their expectations, no overall gender-differentiated effect was found in autonomy-supportive strategies, and they found very small effects (d = 0.08) of child gender on parents’ use of control after excluding outlying effect sizes by which parents used more controlling strategies with boys than with girls.

Endendijk et al. (2016) in their meta-analytic study included boys and girls from 0 to 18 years. Although biosocial theory does not explicitly consider child age, it is plausible to expect some gender-specific parenting related with developmental level. With older children expressing their demands more clearly, parents would be more effective in adjusting their behavior to their demands. Hallers-Haalboom et al. (2014) reported that mothers responded in a more sensitive and non-intrusive way to their older children (between 2.5 and 3.5 years) compared to younger ones (12 months) without being influenced by infant gender. Likewise, in the area of parental control some meta-analytic evidence supports this, for example, the findings reported by Leaper et al. (1998) by which gender differences in the mother’s directive speech was more evident with older children than with younger ones. In contrast, other studies found that parental control decreases with the child’s age in favor of child self-control (Lytton and Romney, 1991). The combined effect size reported by Endendijk et al. (2016) for the differences in parental controlling: more with boys than with girls was largest in the youngest age group (0–2 years: d = 0.16). The findings for that age group were coming mainly from studies involving toddlers, because in the pool of 126 studies, 16.67% (21 studies) included children averaging in age from 1 to 2 years and only one study (Huber, 2012) included children whose average age was under 12 months.

Research suggests that parent–infant interaction can be affected, not only by the gender of children but also the parent’s gender. However, Endendijk et al. (2016) testing only differential controlling of boys and girls in those studies which included fathers and mothers, found no effect of parental gender on the extent of their differential treatment of boys and girls.

In summary, there is no consensus about the extent to which parents treat their sons and daughters differently. Moreover, there are other factors, like the setting of the interaction, which may interact with the gender factor. Thus, in meta-analytic studies it has been found that differences of gender on interaction are often lower in relatively unstructured settings, such as free-play, than in structured tasks such as problem-solving (Leaper et al., 1998; Endendijk et al., 2016).

Therefore, the heterogeneity of measures, age, and settings, across studies in this field can prevent potential gender-differences being detected. However, even the existence of parental differences in the treatment of their children may be reflecting differences in parental practices which may be due to factors other than gender, like birth order (Lovas, 2005; Hallers-Haalboom et al., 2014). Some studies showed that fathers and mothers are more sensitive to the first child than to later ones. These differences were especially pronounced when the second born was the same gender as the firstborn, and fathers were more likely to show differential treatment than mothers (Van IJzendoorn et al., 2000; Furman and Lanthier, 2002; Hallers-Haalboom et al., 2014).

Although studies on dyadic interaction show that the gender of parents and children may affect parental behavior, the direction of those influences is not yet conclusive (Hallers-Haalboom et al., 2014). Nor is it conclusive that the level of parental sensitivity depends, exclusively at least, on the combinations of parent–child gender (Lovas, 2005; Schoppe-Sullivan et al., 2007; Hallers-Haalboom et al., 2014; Endendijk et al., 2016).

The area of caregiver–infant interaction has been influenced by the Sensitivity construct, referred to as ‘Maternal Sensitivity’ because it has been regarded as one of the most important mediators of attachment patterns (Ainsworth et al., 1978). This construct consists of awareness of the child’s cues and demands, his/her appropriate interpretation, and the ability to respond quickly and accurately (Ainsworth et al., 1978). This central feature of maternal behavior was originally assessed with a global rating scale: Ainsworth’s Maternal Sensitivity Rating Scale (Ainsworth et al., 1974). This strategy has been the most influential and common in this field (for a review of the Global Interaction Scales, see Leclère et al., 2014).

One of the most important features of rating-scale approaches is that they do not capture the temporal dimension of the interaction. Research has highlighted that infants develop an early procedural representation of the world before they develop symbolic forms of representation (Beebe et al., 2010). In addition, the infant’s procedural form of representation is based on his perception of contingency and the predictability of events: infants develop ongoing expectations of sequences of events, within the self, within the ‘other’ and between the two (Tarabulsy et al., 1996; Beebe and Lachmann, 2002; Gergely, 2004). This unfolds during the process of interaction over time. Therefore, to examine these central aspects of parent–infant interaction requires a real time sequential coding approach.

In general, rating-scale and temporal sequential approaches, referred to as macro- and micro-analytic approaches, respectively, have tended to favor different contexts. The macro-analytic one has traditionally used naturalistic situations, such as free-play and the most frequent setting for micro- analytic studies has been face-to-face interaction with the mother on a chair, facing the infant, who is secured in a baby seat. In the latter context, the coding of mother–infant interaction states is done in minor units, for example, units of 1 s. These constraints on the mother–infant interaction and the fragmentation of the analysis have been criticized (Mesman, 2010). In fact, free-play offers greater ecological validity because the mother, or caregiver, has no restrictions on their behavior with their child.

In this context, there is a third way: the observational strategies of sequential coding in real time in a free-play situation (Cerezo et al., 2008). Indeed, the interaction during free-play can be sequentially coded as it unfolds, with mutually exclusive and exhaustive defined categories for infant and mother. Thus, the recorded data can be read as a sort of abbreviated text, reflecting the stream of behavior. The analyses can provide important information, not only about “what” the parent responds to, but also “with what” and “when,” in that stream of social exchange (Cerezo et al., 2012, 2016). Therefore, micro-analytic approaches, that is to say, approaches including the temporal dimension, may be a further step in the understanding of sensitivity and “appropriateness” of parental responses because they look at parental matching/contingent behavior to the child’s behavior, which fosters synchrony and mutual emotional regulation in the interaction (Sroufe, 1995; Feldman, 2007; Woodhouse, 2010).

Consideration of the temporal dimension in the measurement of parent–infant interaction allows for the examination of the dynamic process in dyadic interaction. In this context, the non-linear dynamic systems (NDS) framework and its principles that account for properties of dynamic, complex, adaptive, open systems, offer an instrument to examine these processes (Prigogine and Stengers, 1984; Thelen and Smith, 1994, 1998). This approach has led to a paradigm shift in multiple fields (Fogel, 2011), including that of dyadic interaction. Indeed, by accepting the dyad as a dynamic system, then the NDS principles can account for dyadic behavioral patterns that emerge and stabilize through the system’s internal feedback processes (Hollenstein et al., 2004; Hollenstein, 2007; Dishion, 2012). The State Space Grid (SSG) analysis, a graphical tool based on a dynamic system approach (Hollenstein, 2013) allows visualizing the content, temporal and affective flow of the interactions (Sravish et al., 2013) and relevant structures and dimensions of that interaction (Feldman, 2007; Beebe et al., 2010).

Few studies have used NSD and SSG indices in early parent–child interaction. Sravish et al. (2013) have used this paradigm to study the dynamic regulation behaviors between the child and his caregiver through the face-to-face Still-Face paradigm. Cerezo et al. (2012) used the SSG for the study of dyadic flexibility, in the context of interactions. In that study, dyadic flexibility was an index of sensitivity, a precursor of attachment. However, all these studies have focused on mother–infant dyads.

The present study is part of a research program focusing on detecting precursors of attachment in which the central character has been the mother (Cerezo et al., 2006, 2008, 2012, 2016). The present development of the research program addresses father–infant interaction, compared with mother–infant dyads, using the same observational methodology, the NDS approach and tools of previous studies and, additionally, it considers the factor of the infant’s gender in the interactive process. The general purpose was to progress the understanding of paternal behavior using systematic observation, so the study of precursors of attachment can include fathers when they are caring for their infants, including the potential infant gender effects on that parent–infant interaction.

Given the lack of studies, using this approach for this specific topic, the overall purpose of the current study was exploratory. Specifically, the purpose was twofold: on the one hand, to compare the interactive profile of dyadic temporal organization of fathers with their babies and mothers with theirs and, on the other hand, to examine the effect of the baby’s gender on the interaction.

The participants in this study were 52 infants: 26 children interacting with their mothers and 26 children interacting with their fathers. Boys and girls were equally represented (50%) in both groups.

The parents came from the general population who joined a community-based program provided on a universal basis to support parenting during the first 2 years of life. The Program comprised six trimestral visits over a period of a year and a half. As part of the service, parent and infant are videotaped in a free-play situation, with parental consent, to analyze their interaction and provide parents with individual guidance (for a description: Cerezo and Pons-Salvador, 1999; for a summary of evaluation studies: Pons-Salvador et al., 2014). The first time they attend, parents do not receive any information after they have finished the free-play and for more specific and personalized feedback, they need to wait until their second visit when their free-play has been analyzed.

The criteria to select the cases were:

For the parents: to be (a) the biological mother or father, (b) involved with childcare, (c) to be the first visit to the Program; so no previous intervention received and this visit should be before the child was 12 months old. For the infants: (a) absence of congenital anomalies or neurological diseases, all the children’ development was appropriate for their chronological age, assessed by the Developmental Scales of Knobloch et al. (1980) and (b) gender with 50% of girls in each group.

The selection procedure was the following: First, the infants interacting with their fathers were selected. Although the program is offered to both parents, about 15% of fathers attended at least one visit (out of the six Program visits). The initial pool of data comprised 980 families. There were 145 cases of infants interacting with their fathers at least once. From these there were thirty-five who met the criterion of having their first visit to the program on their own and, of those, 29 dyads met the criterion of the child’s age. There were 13 girls in that group; to balance the gender factor thirteen out of the sixteen cases involving interaction with a male infant were randomly selected for the final group. Secondly, to select the group of infants interacting with their mothers, 13 girls were randomly selected from those cases in which mother attended the first visit, so had no prior intervention and then 13 boys to comprise a similar group to the one of infants with their fathers.

In both groups, mothers’ and fathers’ interaction was assessed when their children were, on average, 36.47 weeks of age (SD = 2.85), ranging from 26 to 44 weeks. No significant differences in infants’ age (t = 3.37, df = 48, p = 0.71) with mothers: M_age = 36.62, SD_age = 2.46 and with fathers: M_age = 36.32, SD_age = 3.22. The second half of the first year shows important advances for the child’s social and emotional development. From the neuro-relational approach, regarding adjustment and interaction, Lillas and Turnbull (2009) point to the age range 6 to 10 months as being the one where children display bi-directional intentional communication (child–adult) interaction.

The mean age of the 26 mothers in the study was 28.35 years (SD = 6.09), ranging from 17 to 41 years. As for the 26 fathers, the mean age was 32.48 years (SD = 6.76), with a range between 21 and 48 years. The two groups had a similar average number of children: 1.58 (SD = 1.03) in the group of mothers and in the group of fathers, 1.73 (SD = 1.18). The birth order for infants was similar in both groups. Thus, the majority of the infants were first or second born: 84.61% and 88.46%, in father and mother groups, respectively, 11.53 and 7.69% were third or fourth born, and only 3.84% in both groups were children in fifth or sixth position. The comparison between mother and father groups in the number of dyads with first child vs. second child vs. third child plus, showed no significant differences. In the father–infant group, all the fathers, except one, came from two-parent families and there were three single-mothers in the mother–infant group.

The participants were all resident in Ireland. In the fathers group 84.61% were Irish or from other European countries, like Poland, and the rest, 15.39%, were from the United States, the Philippines, Libya, and Turkey. With regard to the mothers, 76.92% were Irish or from other European countries. There were 7.69% mothers from South-American countries, 11.53% from African countries and 3.8% from India.

Regarding educational levels, 69.23% mothers and 42.3% fathers had only Secondary School education (Intermediate/Junior Cert level: 26.92% of mothers and 7.69% of fathers; Leaving Certificate level 42.31% mothers and 34.61% fathers). Studies at third level: 23.10% of mothers and 34.61% of fathers, finally 7.69% of mothers and 11.53% of fathers reported post-graduate studies. One father reported only having Primary school studies (3.84%) and two fathers did not provide this information (7.69%).

Regarding occupations, there were 11.53% mothers working full time at home. In the two groups, 53.84% of mothers and 46.15% of fathers reported being unemployed, 11.53% mothers and 7.69% of fathers worked in unskilled occupations, while 15.38% of mothers and 30.76% fathers were in semi-skilled jobs, and, finally, 11.53% in each group were in qualified occupations.

In the context of the visit to the Program, the professional left the parent with the infant in a room for the free-play. This session took place in a room with a table and a chair and there were some toys appropriate for the child’s age. The parent was told to play with his/her child the way she/he normally did and if she/he wanted, she/he could use the toys. The systematic observation was carried out on 4–5 min free-play session. An average of 5 min play is sufficient, according to studies in this area by Kemppinen et al. (2005). On the table there was a matt and in all cases parents played with their child on the table or on their lap. The session was videotaped for coding as part of the routine of the Program. Consequently, the protocol for the staff was that the parent and child play between 4 and 5 min, with flexibility. The final duration did not have to do with any parental/infant characteristic. Sometimes, the play was closer to 4 min and sometimes a bit longer, depending on the circumstances (i.e., staff may have been momentarily busy when the timer rang went off).

The parents were informed consent to be videotaped. Additionally, they gave written consent for the anonymous use of their data for research purposes. This study was approved by the Research Ethics Committee of the University of Valencia.

The SSG analysis (Lewis et al., 1999; Hollenstein, 2013) allows visualizing the content, temporal, and affective flow of the interactions (Sravish et al., 2013) and relevant structures and dimensions of the interaction (Peck, 2003; Feldman, 2007; Beebe et al., 2010).

The parental and infant gender factors on parent–infant interaction were examined by conducting a two-way MANOVA (Multivariate analysis of variance) for the data obtained with the SSG regarding ‘Diversity,’ ‘Dispersion,’ ‘Event rate,’ ‘Transition rate,’ and ‘Events per Visit’ ratio. The assumption of homogeneity was tested by computing variance Levene’s Test.

To study the magnitude of the relationships between the variables analyzed significance level value of 0.05 was considered, and the effect size statistic (η²) was computed. The statistical package SPSS v.21 for Windows was used for the analyses.

As part of the analysis plan, if the SSG variables showed differences between groups, it was planned to analyze the 54 possible potential dyadic states for those particular variables, to predict father–infant dyads vs. mother–infant dyads. For this purpose a Linear Discriminant Analysis was chosen with a stepwise variable selection method, applying the Wilks Lambda method, and the verification criteria associated with the F values by default, in SPSS program.

The duration of the Free-play ranged from 240.05 to 348.60 s. As a preliminary step, the observation time was analyzed in relation to parental and infant gender using ANOVA. The dependent variable was the duration of the free-play.

The results showed that there were statistically significant differences in the observation time between the groups of dyads. The free-play from the father–infant dyads was shorter (M = 267.58, SD = 13.69) than the one involving mothers and infants (M = 321.07, SD = 13.69), (F(1,51) = 7.83, p = 0.008, η² = 0.14). No differences were found for the infant’s gender (F(1,51) = 0.70, p = 0.40, η² = 0.015), or parental gender by infant gender (F(3,153) = 0.02, p = 0.90, η² = 0.00). Consequently, for subsequent analyses the number of events and transitions, based on the number of visits, were divided into the observation time in seconds for each dyad, using the rate per second.

The two-way MANOVA to test parental gender and infant gender on the parent–infant interaction measures showed no interaction effect between the two factors: parental and infant gender on the combined dependent variables. There was a multivariate effect for parental gender on the parent–infant interaction measures (F(5,44) = 6.52, p = 0.00, Wilk’s λ = 0.563, η² = 0.43) (Figure 3).

Specifically, significant differences were found in the Event rate (F(1,39) = 12.34, p = 0.001, η² = 0.20) and in the Transition rate (F(1,39) = 23.23, p < 0.001, η² = 0.33), in both of those the father–infant dyads showed a higher rate per second than the mother–infant dyads. Moreover, the two groups showed significant differences in the Events per Visits ratio (F(1,39) = 7.09, p = 0.010, η² = 0.13). The mother–infant dyads showed a higher value than the father–infant dyads (Table 2). Taken together the results indicated that dyads with fathers changed more frequently from state-to-state and engaged in more events per second, while mothers were more repetitive than fathers when interacting with their infants (Figure 4).

Regarding exploratory examination about the possible differences in interaction with infant boys and girls, no significant differences were found in relation to infant gender (F(5,44) = 0.93, p = 0.47, η² = 0.09). Therefore, in terms of the measures examined in this study, parent–infant interaction was similar with boys and girls.

In summary, both mother and father dyads showed similar diversity in their interaction, in terms of the number of different dyadic states they went through, and similar levels of dispersion. Additionally, paternal dyads were more ‘active’ than maternal dyads: they were faster in the rate of Events and in the rate of Transitions (per second). In contrast, maternal dyads were more repetitive than paternal ones because they engaged in more events once they visited a particular dyadic state. There were no differences between girls and boys.

Discriminant analyses were used to determine the linear combination of SSG variables that best classified the 52 dyads into each of the two groups: with fathers and with mothers. We established regarding previous probabilities that all groups were equal. Therefore, based on a discriminant analysis of ‘Events rate,’ ‘Transitions rate,’ and ‘Events per Visit’ ratio, functions were derived for the total grid. These variables were selected because they showed significant differences, and the purpose was to examine, in terms of content, what state or states (dyadic behaviors) could potentially distinguish the two type of dyads. The Eigenvalues, relative variance, canonical correlations and significance tests are shown in Table 3.

As Table 3 shows, overall the Wilks Lambda value is moderately high (0.68), and the Lambda transformed value showed a statistically significant level [χ²(2,N = 52) = 18.44, p = 0.000], which supported the rejection of the null hypothesis. Therefore, the means of the father–infant dyads and mother–infant dyads on the discriminant function –the centroids, were significantly different. Likewise, the variance in the dependent variable accounted for by this model was 46%.

The stepwise discriminant analysis included two variables out of the three analyzed in the following order: ‘Transitions rate’ for the dyadic behavioral state ‘Child Social Approach, neutral-Sensitive Approach neutral’ (TR-AS) and ‘Events per Visit’ ratio for ‘Child Play-Sensitive Approach neutral’ (ER-JS).

The standardized discriminant function coefficients indicated the relative importance of the independent variables in predicting group membership. This function was marked by a positive coefficient for TR-AS and negative weight for ER-JS. Thus, the lower the TR-AS and the higher the ER-JS the less likely it was that the dyad was from the father–infant group and more likely to belong to the mother–infant group (Figure 5).

This study presents some limitations. Firstly, the groups who came from nonclinical populations included a proportion of individuals from diverse cultures; about 20% were from India, Turkey, Libya, or African countries. As caregiving behavior may be influenced by cultural factors in both fathers and mothers, some caution needs to be taken in generalizing the reported findings of the present study. Secondly, about half of the mothers and the fathers in this study reported being unemployed. No assessment of factors like depression or depressive mood, due to economic stress, was done, and this might have an effect on their interaction with their infants.

This study also presents some strength. It involved fathers and mothers, each interacting with their own infant, this controls for possible interdependence effects between the parents. The age of the infants was between 6 and 10 months, which reduces the possible interference of using a wide age range. Moreover, this age is very relevant to study interactive patterns that can be antecedents to the quality of child attachment. The number of girls and boys was the same in both groups of dyads with fathers and mothers. The participants came from a general population who joined a community-based program provided on a universal basis. Finally, the analytical approach using SSG methodology with dyadic variables allows for the characterization of different temporal features of father interaction with quantitative measures that can shed light on the paternal sensitivity construct.