Infant Behavior & Development 37 (2014) 258–267

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Infant Behavior and Development

Mutual touch during mother–infant face-to-face still-face interactions: Influences of interaction period and infant birth status Irene Mantis ∗ , Dale M. Stack ∗ , Laura Ng, Lisa A. Serbin, Alex E. Schwartzman Department of Psychology, Centre for Research in Human Development, Concordia University, Canada

a r t i c l e

i n f o

Article history: Received 22 February 2013 Received in revised form 31 January 2014 Accepted 8 April 2014

Keywords: Mother–infant interactions Prematurity Mutual touch Psychosocial-risk Still-face procedure Nonverbal communication

a b s t r a c t Contact behaviours such as touch, have been shown to be influential channels of nonverbal communication between mothers and infants. While existing research has examined the communicative roles of maternal or infant touch in isolation, mutual touch, whereby touching behaviours occur simultaneously between mothers and their infants, has yet to be examined. The present study was designed to investigate mutual touch during face-toface interactions between mothers and their 5½-month-old fullterm (n = 40), very low birth weight/preterm (VLBW/preterm; n = 40) infants, and infants at psychosocial risk (n = 41). Objectives were to examine: (1) how the quantitative and qualitative aspects of touch employed by mothers and their infants varied across the normal periods of the still-face (SF) procedure, and (2) how these were associated with risk status. Mutual touch was systematically coded using the mother–infant touch scale. Interactions were found to largely consist of mutual touch and one-sided touch plus movement, highlighting that active touching is pervasive during mother–infant interactions. Consistent with the literature, while the SF period did not negatively affect the amount of mutual touch engaged in for mothers and their fullterm infants and mothers and their infants at psychosocial risk, it did for mothers and their VLBW/preterm infants. Together, results illuminate how both mothers and infants participate in shaping and co-regulating their interactions through the use of touch and underscore the contribution of examining the influence of birth status on mutual touch. © 2014 Elsevier Inc. All rights reserved.

During early mother–infant interactions, non-verbal communication is paramount given that infants are largely prelinguistic during the first year of life. Nonetheless, past studies examining social interactions during early development (e.g., first year of life) have primarily focused on the examination of the distal behavioural indices of gaze and affect, while neglecting to investigate the specific contribution of contact behaviours such as touch. Yet, caregivers commonly employ touch during face-to-face interactions and play, along with their vocal and facial expressions (Stack, 2010). The Still-Face procedure (SF; Tronick, Als, Adamson, Wise, & Brazelton, 1978), an adaptation of the face-to-face interaction, is a popular and valid paradigm to study mother–infant exchanges. The conventional SF procedure consists of two normal periods of

∗ Corresponding authors at: Centre for Research in Human Development, Department of Psychology, Concordia University, 7141 Sherbrooke Street West, PY-170, Montreal, Quebec H4B 1R6, Canada. Tel.: +1 514 848 2424. E-mail addresses: [email protected] (I. Mantis), [email protected] (D.M. Stack). http://dx.doi.org/10.1016/j.infbeh.2014.04.005 0163-6383/© 2014 Elsevier Inc. All rights reserved.

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social interaction (typically providing vocal, visual, and tactile stimulation to their infants) between a caregiver and an infant, separated by a perturbed period of interaction, the SF period. During the SF, mothers assume a neutral, unresponsive “still face” and provide neither vocal nor tactile stimulation to their infants while gazing at their infants. A large body of evidence suggests that the SF period can be challenging for infants since they have to cope with the sudden loss of their mothers’ availability and responsiveness, modulate their own emerging negative emotions, while at the same time attempt to reengage their caregiver into mutual regulation (Manian & Bornstein, 2009). By exhibiting changes in their behaviours during the SF period, infants reveal themselves to be active participants during mother–infant interactions, and show their sensitivity to changes in their mothers’ behaviour (e.g., Stack & LePage, 1996; Tronick, 2003; Weinberg & Tronick, 1996). Although still in its early stage, significant advancements have contributed to our understanding of tactile stimulation as an integral component of the mother–infant communicative system (Stack & Jean, 2011; Weiss, 2005). During mother–infant interactions, touch has been shown to be an influential channel through which mothers and their infants convey emotion and affection, and establish a strong connection (Stack, 2010). Maternal touch is pervasive during interactions, occurring between 33% and 99% of the time during brief interaction periods (e.g., Field, 1984; Jean, Stack, & Fogel, 2009; Stack & Muir, 1990; Symons & Moran, 1987). Results from a number of studies suggest that mothers communicate with their infants through the use of touch (Feldman, 2011; Field, 2003; Hertenstein, 2002; Jean & Stack, 2009; Stack, 2010), which aids in modulating and regulating infants’ displays of emotion (Hertenstein, 2002). However, much of the research that has examined touch during mother–infant face-to-face interactions has focused on maternal tactile behaviours, yet touch is also an important modality of communication for infants. Infants are active and competent participants during their early social encounters (e.g., Adamson & Frick, 2003; Cohn, 2003; Moszkowski & Stack, 2007; Moszkowski, Stack & Chiarella, 2009), and mother–infant interactions are a two-way process involving influences from both interactive partners. Existing research has focused on examining the important communicative role of maternal touch or of infant touch from a more unidirectional perspective and has examined touch in the context of other behaviours. Yet, the investigation of mutual touch, whereby both mothers and infants are active agents in shaping their interactions, has been largely overlooked. We define mutual touch as simultaneous touch whereby both mothers and infants are engaged in continuous and dynamic touching behaviours. Just as with mutual gaze and mutual affect, mother–infant dyads may be touching one another simultaneously during their early interactions, and mutual touch likely serves several functions, such as communicating infants’ and mothers’ states and affect. The present study’s rationale was to examine mutual touch in order to achieve a more comprehensive understanding of the communicative roles of touch during early mother–infant social exchanges. The objectives were to document: (1) whether the qualitative (types) and quantitative (duration) aspects of touch employed by mothers and their infants varied across the normal periods of the SF procedure (given that the first normal period of the SF procedure is the baseline preceding the perturbation period, where the mother is emotionally unavailable); and, (2) how these were associated with risk status. Few studies have examined the relationship between co-regulation and touch, and this study takes an important first step in this direction. As such, mothers and their 5½ month old fullterm infants, very low birth weight preterm (VLBW/preterm) infants, and infants at psychosocial risk were included in our sample in order to broaden our understanding of the communicative properties underlying nonverbal communication during mother–infant interactions in at-risk groups. With regard to the types of touch under investigation, the goal was to examine how mutual touch occurs in different interaction periods in relation to other types of touch behaviours, such as one-sided touch (i.e., touch eliciting no response from the member of the dyad being touched) and one-sided touch plus movement (i.e., touch eliciting movement but not touch from the member of the dyad being touched). According to the dynamic systems perspective, mother–infant interactions form a mutually regulated bi-directional system (Fogel & Garvey, 2007; Fogel, 1993; Hsu & Fogel, 2001). Thus, it is not the mother or the infant alone, but the relationship between the two that contributes to the development of infants’ communicative abilities during the first year of life. Working to achieve their mutual goal of coordinated states of interaction, mothers and infants jointly regulate their interactions by modifying their affective states according to changes in their social partner’s behaviour (Fogel, 1993; Gianino & Tronick, 1988). Thus, both mothers and infants modify their behaviours at various times through their interactions, contributing to the creation of a shared dialogue. Complementary to this perspective, the transactional model highlights that just as mother–infant interactions can be a context for fostering healthy development, they can also be a context through which risk can be transferred (Sameroff, 2009). Thus, the co-regulation that is considered normative between mothers and infants may be impaired, particularly in interactions of at-risk dyads (Crockenberg & Leerkes, 2005). Examining touch through a bidirectional process, could add to our understanding of the communicative properties underlying non-verbal communication during mother–infant interactions. Despite an abundance of studies involving interactions of mothers and their infants, research on touch is sparse, and particularly with at-risk dyads. In the present study, two types of risk were examined (infants born prematurely and infants at psychosocial risk). In very low birth weight preterm infants (VLBW/preterm), several factors (e.g., restricted opportunities for physical contact following birth, modified experiences with touch early in life, maternal stress) may alter their abilities to process and/or reciprocate tactile-gestural stimulation in the same way as normal birth weight fullterm infants. Similarly, interactions may also be altered during interactions between mothers and their infants at psychosocial risk due to disadvantage and problematic patterns of social behaviour and peer relations in their mothers’ childhood histories. A number of investigations have suggested that preterm infants have less efficient self-regulatory strategies than fullterm infants, as infants born prematurely demonstrate greater reactivity and sensitivity to distress, lower thresholds for displaying

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reactions to negative stimuli, and increased difficulty soothing and regulating negative arousal (Feldman, 2009; Korja et al., 2008; Als, 1995; Field, 1982; Lester, Boukydis, & LaGasse, 1996). In addition, the quality of the dyadic interaction has been described as less optimal in preterm infant–mother dyads, as interactions are typically characterized by less mutually synchronous and co-regulated exchanges (Feldman & Eidelman, 2007). Given that preterm infants place different demands on their caregivers, the development of sensitive and co-regulated interactions that are typical in mother–infant dyads and are characterized by an intimate interchange, is often hindered in preterm infant–mother interactions (Feldman, 2007). While the significance of touch for VLBW/PT infants’ cognitive and physical development has been established and comprehensively investigated (Field, 2011; Vickers, Ohlsson, Lacy, & Horsley, 2004), the impact of touch on the quality of dyadic exchanges is still warranted. Touch may be serving different needs or be especially important in preterm infant–mother dyads and may be used in different ways compared to fullterm dyads. Similarly, touch may be working differently during interactions between mothers and their infants at psychosocial risk. Problematic behavioural styles during childhood have been shown to impact the conditions under which parents raise their offspring, and these conditions affect their ability to nurture their children’s development and growth (Stack, Serbin, Mantis, & Kingdon, in press; Stack et al., 2012). Disadvantaged backgrounds and maladaptive behaviour in childhood (such as aggression and social withdrawal) are linked to a sequence of problematic events and conditions that contribute to later disadvantaged child-rearing conditions (e.g., low education, early parenthood, single parenthood, family poverty) in parenthood. These conditions then place subsequent generations at risk for a wide variety of developmental, social, academic, economic, and health problems (Serbin et al., 2011). Taken together, touch has been found to be an essential component of mother–infant exchanges. Nonetheless, research on touch remains sparse, particularly in at-risk dyads, and the examination of the communicative properties of touch through a bi-directional process has yet to be examined. Given the two aforementioned objectives, it was hypothesized that “mutual touch” and “one-sided touch plus movement” would dominate interactions, in comparison to “one-sided touch” and no touching. Further, it was anticipated that results would provide a better understanding as to whether mothers’ and infants’ mutual touching episodes change (i.e., whether they increase or decrease) following a SF perturbation (i.e., maternal emotional unavailability in the SF period). Mutual touch may be serving different functions in at-risk dyads and it was expected that touch would be used in different ways compared to fullterm and not at-risk dyads. For example, it was hypothesized that mothers and their fullterm infants would engage in similar amounts of mutual touch in the two normal periods of the SF procedure, while mothers of VLBW/preterm infants would engage in less mutual touch in the reunionnormal period (following a perturbation period, the SF). Given that the SF period can be more challenging for preterm infants, it was hypothesized to culminate in affecting the amount of mutual touch engaged in during the reunion-normal period.

1. Method 1.1. Participants The final sample consisted of three groups of 5½-month-old fullterm (n = 40) infants, VLBW/preterm (n = 40) infants, and infants at psychosocial risk (n = 41) and their mothers drawn from a longitudinal project. All dyads were tested in their homes when infants reached 5½ months of age. The fullterm, VLBW/preterm, and psychosocially at-risk (described next) dyads were matched on infant sex, maternal age (within 5 years) and maternal education. Table 1 provides demographic and medical information for the final sample.

Table 1 Demographic and medical information.

Maternal age at birth (years) Maternal education at birth Infant birth weight (g) Infants gestational age (weeks) Infant weight at 5½ months (g) Infant height at 5½ months (cm) Race White Hispanic Asian Black Middle Eastern Other

Fullterm (n = 40; 20 females)

VLBW/PT (n = 40; 22 females)

At psychosocial risk (n = 41; 24 females)

M

SD

M

SD

M

SD

30.62 14.75 3476 39.74 6800 64.18

5.13 1.92 395 1.08 0.89 4.41

32.86 13.12 1092 28.51 6750 62.65

5.68 2.11 237 2.29 1.04 3.54

29.12 13.07 3324 39.22 7114 63.68

3.09 1.95 635 1.92 1.2 6.87

92.5% 5%

2.5%

60% 5% 2.5% 20% 10% 10%

100%

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Fullterm. Mothers and their infants were recruited from birth records from a major community hospital in the Montreal (Quebec, Canada) area. Following a letter outlining the general research, mothers were contacted by telephone and asked to voluntarily participate. Participants consisted of 48 mothers and their healthy, fullterm infants born between 37 and 41 weeks gestation, and weighing more than 2750 g (6 lbs) at birth. Eight dyads were excluded from the current study based on various exclusion criteria including: mothers touching their infants for less than 10% of the time during the first normal period (n = 2), mothers not following instructions (n = 1), infant’s gaze obstructed (n = 2), dyads taking a break between the SF and reunion-normal periods (n = 2), and excessive infant crying (n = 1). The final sample consisted of 40 infants (20 males, 20 females). The mean age of infants at the time of the study was 5 months and 12 days (SD = 6.70). Very low birth weight preterm. Subsequent to ethics approval and in collaboration with the chief neonatologist, VLBW/preterm infants were pre-screened for medical status variables by the nurse in charge of the follow-up clinic of a major community teaching hospital (Montreal, Quebec) during their 3–4 month clinic visit. These infants were recruited from the same hospital as the fullterm infants in order to ensure similarity in socio-economic status (SES) and ethnic backgrounds. Caregivers of these infants who met inclusion criteria were provided with a letter outlining the general description of the study and if interested, were contacted by telephone for participation. The VLBW/preterm group consisted of 63 mothers and their infants with gestational ages ranging from 26 to 32 weeks, and birth weights between 800 and 1500 g (approximately 1 lbs, 12 oz–3 lbs, 5 oz). Additional selection criteria limited the study population to healthy infants who were living with their biological mothers and excluded infants who suffered from any serious medical problems (e.g., infants diagnosed with a congenital abnormality or major congenital defects; infants who suffered GRADE IV (or III) intraventricular haemorrhage or other major medical complications, illnesses or syndromes, such as hydrocephalus, severe neurological impairment, or those with hearing loss, retinopathy). Further exclusion criteria included infants who had a prolonged hospitalization since the neonatal period, and mothers at psychosocial risk due to a history or inadequate prenatal care, drug abuse, and mental illness. Thus, our VLBW/preterm sample was composed of healthy infants who met rigorous inclusion/exclusion health criteria. Corrected age (i.e., postnatal age minus the number of weeks the infant was premature) was used to correct for prematurity. Twenty-three mother–infant dyads were excluded due to: mothers touching their infants for less than 10% of the time during the first normal period (n = 2), mothers’ failure to follow instructions (n = 9), procedural error (n = 6), and SF period repeated more than once due to infants’ excessive crying (n = 6). The final sample consisted of 40 infants (18 males, 22 females). The mean corrected age of the VLBW/PT infants at the time of the study was 5 months and 14 days (SD = 8.21). Psychosocial risk. The dyads at psychosocial risk constituted a sub-sample of the Concordia Longitudinal Risk Project (Concordia Project), a prospective, longitudinal, intergenerational study that began in 1976–1978 (Schwartzman, Ledingham, & Serbin, 1985; Serbin et al., 1998). These infants are considered at-risk due to disadvantage and problematic patterns of social behaviour and peer relations in their mothers’ childhood histories. Offspring (between the ages of 5 and 6 months) born to participants of the initial sample were recruited for the current sample. The current sample is considered a “community based” sample, as no selection criteria (e.g., no clinical referral or other assessments) was used to identify possible participants. However, it is also a “risk” sample, in that the original participants came from communities where levels of socio-economic status and other demographic characteristics were below the population means. Mothers associated with the Concordia Project who were pregnant or who had recently given birth were contacted to participate in the study. Fifty-six mothers participated in this phase of the project, however, fifteen mother–infant dyads were excluded based on the various exclusion criteria including: mothers’ failure to follow instructions (n = 11), procedural error (n = 1), and SF period repeated more than once due to infants’ excessive crying (n = 3). The final sample constituted 41 (17 males, 24 females) normal, healthy fullterm infants having gestational ages ranging from 37 to 41 weeks. The mean age of the at-risk infants was 5 months 8 days (SD = 0.86) and that of mothers was 29.5 years (range = 21–36 years, SD = 3.13). 1.2. Apparatus All sessions took place at the participants’ homes and were video-recorded for subsequent coding purposes. Testing was carried out in a spacious and well-lit room, usually the kitchen, and outside distractions were minimized (e.g., televisions and radios were turned off, siblings or pets remained outside of the room). Infants were securely fastened in an infant seat without toys or pacifiers. Mothers and infants were seated facing each other at eye-level, with a distance of approximately 70 cm between them. A stopwatch was used to time the duration of each period. A Sony video camera was positioned on a tripod in order to simultaneously capture a full view of the infant’s face and body and their mother’s hands. To capture the mother’s face on the video recording, the set-up included a mirror that was strategically placed at an angle beside the infant seat on the table. Following the testing session, a time line was added to each 8 mm cassette using a Video Timer. Video records were later coded second-by-second using a Sony VTR/TV remote control with slow speed shuttle function for the starting and stopping of the tape and slow motion viewing. 1.3. Procedure During the home visit, mothers received information on the purpose of the study, and were given a consent form to read and sign. Before beginning the study, mothers were reminded that they could withdraw from the study at any given moment. Each dyad participated in the face-to-face SF procedure (Tronick et al., 1978), which consists of three 2-min face-to-face interaction periods (normal, Still-Face, and reunion-normal) between the mother and her infant. Each of these periods was

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separated by a transition period of 20–30-s, where mothers received instructions for the subsequent period. During this transition period, the dyads were free to interact with one another. During the first and third (i.e., reunion) normal periods, mothers were instructed to play with their infant as they normally would at home. During the second period, the SF, mothers were instructed to gaze at their infant with a still, neutral facial expression, and refrain from speaking to and touching their infant. That is, mothers were unresponsive and emotionally unavailable to their infants. The normal interaction periods and the SF period were each two minutes in duration, and the experimenter knocked on the wall to mark the beginning and end of each period. If infants fretted for 20 s or mothers wished to stop the session, the session was interrupted. At the end of the testing session, mothers from all three infant-dyad groups were asked to complete a demographic questionnaire and answer questions in relation to their infants’ developmental and medical histories. Mothers were thanked for their participation and given an “Infant Scientist Award” for their infant, as a symbol of appreciation for their participation in the study.

1.4. Measures and observational coding Following the testing sessions, behavioural coding was carried out in the research laboratory. Maternal compliance with instructions was verified prior to coding by previewing the video records and observing maternal behaviour during the normal and SF interaction periods. Each touch behaviour (i.e., one-sided touch; one-sided touch plus movement; mutual touch) was mutually exclusive and was assigned a code for each second of the interaction (i.e., behaviours were coded for 1-s intervals). The summed percent duration of each dependent measure (type of touch) was defined as the duration of time in seconds that a touch occurred out of the total time of the period (120 s) computed as a percentage (multiplied by 100). This was calculated for each of the two periods. Touch behaviours. The mother–infant touch scale (MITS; Mantis, Ng, & Stack, unpublished) was used to code mother and infant behaviours second-by-second. The MITS is a behavioural coding scheme designed to code touching behaviours between caregivers and their infants. Three types of touch were operationally defined and measured: one sided touch, onesided touch plus movement and mutual touch. One-sided touch was coded when one member of the dyad was actively or passively touching the other, while the latter remained passive (i.e., did not respond with movement). An example is a mother resting her hands on the legs of her infant who does not move. One-sided touch plus movement was coded when one member of the dyad was stimulated by another’s active or passive touch, and he/she responded with a movement but not a touch. The movement did not involve actively/intentionally touching the other member and was not necessarily performed by the body part touched. Given that behaviours take time to unfold, touching bouts (i.e., a period of time spent in one of the touch categories) had to occur for a minimum of three seconds in order to be included in our analyses. An example of one-sided touch plus movement is when mothers tickle their infants’ torsos and infants bring their hands to their mouths. Finally, mutual touch was defined as a continuous and dynamic touching behaviour between both members of the dyad. Of note, mutual touch was coded when mothers and infants were touching at the same time, and although the touching did not need to be the same behaviour from both members of the dyad, the inclusion criteria required that the behaviours were on the same plane or direction (i.e., neutral to positive) in order to be classified as mutual touch. An example of mutual touch is when mother–infant dyads are swinging their interlocked hands from side to side. Of note, the initiator of the mutual touching was also coded. Specifically, initiation was coded as the member of the dyad who first touched the other member of the dyad. A small percentage of mutual touch was initiated by the infants, while most of the mutual touch was initiated by mothers. At 5½ months old, touch is primarily mother directed, given that infants have more limited fine motor skills at this age and as a result, less breadth in touching behaviours as compared to more distal communicative modalities, such as gaze and affect. Two coders were involved in the coding of the videotapes, the second of whom was blind to the hypotheses. A graduate student completing her master’s degree was the primary coder and an undergraduate honours student was trained to doublecode 30% of randomly chosen video records of mother–infant interactions. Prior to initiating the coding, the two coders had to attain reliability with an overall kappa coefficient (rk; Cohen, 1960) of 0.80 or higher for each of the touch categories. Cohen’s kappa calculates the inter-observer agreement as a proportion of potential agreement following a correction made for chance agreements (Kaplan & Saccuzzo, 2001). The overall kappa coefficient for this study was rk = 0.94, indicating high inter-rater reliability. Kappa coefficients for the touch behaviours were all good to very good, and indicated high inter-rater reliability (Cohen, 1968); rk = 0.98 for no touch, rk = 0.83 for one sided touch, rk = 0.97 for one-sided touch plus movement, and rk = 0.98 for mutual touch. Description of analytic approaches. Data screening procedures were undertaken to evaluate the integrity of the data. The data was normally distributed and did not reveal any outliers, skewness or kurtosis, thus no transformations were necessary. All statistical analyses were conducted using the Statistical Package for the Social Sciences for Macintosh (SPSS, version 18.0). For all the ANOVA analyses, significant main effects were followed with post hoc-t-tests and when ANOVAs revealed significant interactions, Bonferroni post hoc pairwise comparisons were used to isolate the source of the significance. The between-subjects factor was group and the within-subject factors were the interaction period and types of touch. The dependent variable was the percent duration of each touch behaviour. Results were considered statistically significant at a critical alpha level of .05 and partial eta-squared (Áp 2 ) are reported as a measure of effect size (Kline, 2004; Olejnik & Algina, 2003).

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Table 2 Mean percent duration and standard deviations of touch variables in the normal and reunion-normal periods. Normal period M (SD)

Reunion-normal period M (SD)

No touch Fullterm VLBW/preterm Psychosocial risk

20.48 (18.84) 15.87 (16.25) 23.31 (23.68)

21.74 (24.48) 13.99 (15.32) 19.63 (22.25)

One-sided touch Fullterm VLBW/preterm Psychosocial risk

8.48 (8.49) 10.65 (13.84) 6.30 (12.78)

7.44 (8.03) 9.05 (14.61) 4.10 (8.21)

One-sided touch plus movement Fullterm VLBW/preterm Psychosocial risk

32.47 (19.97) 19.16 (13.72) 30.85 (22.16)

33.93 (20.78) 32.65 (20.71) 30.65 (21.14)

Mutual touch Fullterm VLBW/preterm Psychosocial risk

38.56 (24.70) 54.31 (22.22) 39.37 (25.81)

36.87(25.07) 44.33 (24.69) 45.88 (26.98)

2. Results Overall duration. Descriptive statistics indicated that the mean percent duration of mutual touch for the fullterm group in the normal period was 38.56 (SD = 24.70), whereas in the reunion-normal period, it was 36.87 (SD = 25.07). The mean percent duration of mutual touch for the VLBW/preterm group in the normal period was 54.31 (SD = 22.22), whereas in the reunion-normal period, it was 44.33 (SD = 24.69). Finally, the mean percent duration of mutual touch for the group at psychosocial risk in the normal period was 39.37 (SD = 25.81), whereas in the reunion-normal period, it was 45.88 (SD = 26.98). The means and standard deviations for types of mother–infant touch, including no touch, are found in Table 2. The total time that touch (overall duration) occurred during each normal period was obtained by grouping the types of touch from the mother–infant touch scale (one-sided touch, one-sided touch plus movement, and mutual touch) into one total touch category. This analysis was conducted in order to ensure that differences obtained for types of touch were not the result of an overall difference in the total amount of touch provided across period. A paired-samples t-test revealed that collapsed across group, there was no significant difference in the amount of touch being provided across the two normal periods, t(120) = .79, p = .43 (normal period: M = 80.02%, SE = 1.81; reunion-normal: M = 81.63%, SE = 1.90), indicating that there was a consistent amount of touch occurring during both normal periods. Subsequent differences found for types of touch were therefore not the result of an overall difference in the amount of touch occurring across interaction periods. Following descriptive statistics, 3 (Group: fullterm, VLBW/preterm, infants at psychosocial risk) × 2 (Period: normal, reunion-normal) × 4 (types of touch: one-sided touch, one-sided touch plus movement, mutual touch, and no touch) repeated measures Analysis of Variance (ANOVA) were conducted. 2.1. Objective 1: the investigation of normal interaction periods Results from the ANOVA indicated that a statistically significant main effect of touch was found, F (3, 354) = 82.34, Áp 2 = 0.41, p < .001. Post-hoc t-tests revealed that, collapsed across the two normal periods, dyads were most likely to engage in mutual touch (M = 43.22%, SE = 1.81), followed by one-sided touch plus movement (M = 29.95%, SE = 1.42), no touch (M = 19.18%, SE = 1.55), and one-sided touch (M = 7.67%, SE = .83). No main effect was found for Period, thus, no significant differences were found for the types of touch between the two normal periods. 2.2. Objective 2: the investigation of infants’ birth status on touch An interaction between Touch and Group, F (6, 354) = 2.64, Áp 2 = 0.04, p < .05, indicated that the amount of time dyads engaged in the various types of touch varied according to group. Mothers and their fullterm infants engaged in significantly more mutual touch (M = 37.72%, SE = 3.15) than one-sided touch (M = 7.96%, SE = 1.44) and no touch (M = 21.12%, SE = 2.70). Mothers and their VLBW/preterm infants engaged in significantly more mutual touch (M = 49.95%, SE = 3.15) than one-sided touch plus movement (M = 25.90%, SE = 2.48), one-sided touch (M = 9.85%, SE = 1.44) and no touch (M = 14.94%, SE = 2.70). Mothers and their infants at psychosocial risk engaged in significantly more mutual touch (M = 42.63%, SE = 3.12) than one-sided touch (M = 5.20%, SE = 1.43) and no touch (M = 21.48%, SE = 2.66). Comparing touch between groups, mothers and their VLBW/preterm infants engaged in significantly more mutual touch than did mothers and their fullterm infants (mean difference = 11.61, SE = 4.45, p < .05). In addition, a trend was observed in that VLBW/preterm dyads tended to engage in more one-sided touch than dyads at psychosocial risk (mean difference = 4.65, SE = 2.03, p = 0.07). A significant 3-way interaction between Period, Touch and Group was revealed F (6, 354) = 2.372, Áp 2 = 0.39, p < .05. Bonferroni pairwise comparisons revealed that mothers and their VLBW/preterm infants engaged in significantly more mutual touch in the normal period (M = 54.31, SE = 3.85) than in the reunion-normal period (M = 44.33, SE = 4.05). In addition, mothers and their VLBW/preterm infants engaged in significantly less one-sided touch plus movement (M = 19.16, SE = 3.00) in the normal period than did mothers and their fullterm infants (M = 32.48, SE = 3.003) and mothers and their infants at psychosocial risk (M = 30.86, SE = 2.97). Furthermore, mothers and their VLBW/preterm infants engaged in significantly more mutual touch (M = 54.31, SE = 3.84) in the normal period than did mothers and their fullterm infants (M = 38.56, SE = 3.84) and mothers and their infants at psychosocial risk (M = 39.37, SE = 3.78). Fig. A.1 illustrates the percent duration of touch in the normal and reunion-normal periods for fullterm dyads, VLBW/preterm dyads, and dyads at psychosocial risk. 2.3. Follow up analyses Given that mutual touch may have been distributed differently within each of the normal periods, a more precise and accurate representation of its occurrence was warranted in order to observe whether there were differences that were not being detected by use of an average mutual touch score for the entire period. In order to obtain such a representation of mutual touch during the periods of the SF procedure, 30-s segments were compared. That is, a 2 × 4 repeated measures ANOVA was conducted for each group to evaluate: (1) the first 30-s of the normal period with the first 30-s of the reunion-normal

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Fig. A.1. Percent duration of touch during the normal and reunion-normal periods for fullterm dyads, VLBW/preterm dyads, and dyads at psychosocial risk.

period, (2) the last 30-s of the normal period with the last 30-s of the reunion-normal period, and (3) the last 30-s of the normal period with the first 30-s of the reunion-normal period. No statistically significant differences in mutual touch were found.

3. Discussion The present study was designed to examine mutual touch during face-to-face interactions between mothers and their 5½ month old fullterm infants, VLBW/preterm infants, and infants at psychosocial risk. The first objective was to investigate how the quantitative (duration) and qualitative (type) aspects of touch employed by mothers and their infants varied across the normal periods of the SF procedure. With regard to the types of touch, the goal was to compare mutual touch with the other touch behaviours (one-sided touch and one-sided touch plus movement) during the two normal periods, keeping in mind that the two normal periods were separated by a perturbation period (the SF). In line with what was hypothesized, the amount of touch was found to be consistently high across both normal periods of the mother–infant interaction. Specifically, mutual touch and one-sided touch plus movement were found to dominate interactions, in comparison to one-sided touch and no touch. This is consistent with previous literature suggesting that active types of touch are prominent in mother–infant face-to-face still-face interactions (Jean, Stack, Girouard, & Fogel, 2004; Kaye & Fogel, 1980; Stack & Muir, 1990, 1992). The low levels of ‘no touch’ found are also consistent with previous studies investigating touch duration during the still-face procedure; in general, these have revealed that maternal touch occurs between 33% and 99% of brief interaction periods (Jean et al., 2009; Symons & Moran, 1987) and infant touch occurs 85% of the time (Moszkowski & Stack, 2007). This finding further supports the accumulating evidence that touch is an important form of interaction and a central communicative channel within mother–infant face-to-face still-face interactions. The second objective was to investigate how the quantitative (duration) and qualitative (type) aspects of touch employed by mothers and their infants varied according to risk status. In line with expectations, mothers and their fullterm infants engaged in similar amounts of mutual touch in both the normal and reunion-normal periods of the SF procedure while mothers and their VLBW/preterm infants engaged in higher levels of mutual touch in the normal period compared to the reunion-normal period. Thus, the SF period did not appear to reduce the amount of mutual touch mothers and their fullterm infants engaged in, while it did for mothers and their VLBW/preterm infants. Such a carry-over effect from the Still-Face to the reunion-normal period is consistent with previous literature indicating that preterm infants have less efficient self-regulatory strategies than fullterm infants. Specifically, infants born prematurely demonstrate greater reactivity and sensitivity to distress, lower thresholds for displaying reactions to negative stimuli, and more difficulty soothing and regulating negative arousal (Als, Duffy, & McAnulty, 1988; Field, 1982; Lester et al., 1996). The SF period can potentially be more challenging for preterm infants since they need to cope with the sudden loss of their mothers’ availability and responsiveness, modulate their own emerging negative emotions, while at the same time attempt to reengage their caregiver into mutual regulation.

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Such difficulties likely carried over into the reunion-normal period and may have culminated in affecting the amount of mutual touch engaged in. Fullterm infants may have better coping responses and self-regulating abilities during maternal unavailability than VLBW/preterm infants. Mothers and their infants at psychosocial risk engaged in significantly more mutual touch than one-sided touch and no touch, collapsed across periods. In addition, similar to fullterm infant–mother dyads, mothers and their infants at psychosocial risk used similar amounts of mutual touch across both the normal and reunion-normal interaction periods. Of note, the mother infant-dyads at psychosocial risk are considered a “community based” at-risk sample, which may explain the similar finding found among the fullterm and the at psychosocial risk groups. The original participants at psychosocial risk came from disadvantaged communities where levels of socioeconomic status and other demographic characteristics were below the population means and there were problematic patterns of social behaviour and peer relations in their mothers’ childhood histories. Within this context, risk is probabilistic and should be viewed on a continuum. Although some families still come from disadvantage, some have been able to circumvent adversity over the years. However, it is important to note that there is likely more taking place during these mother–infant interactions (e.g., functional components of touch, gaze, vocalizations, affect, behaviours during the transition periods), particularly as they relate to the quality of the mother–child relationship. Therefore, an examination of what is accompanying the touch behaviours during mother–infant face-to-face interactions when they occur, as well as what is occurring during such interactions while touching is absent, is warranted in future studies. Further, infant age has been found to influence both the duration of touch as well as the types of touch utilized by mothers (Jean et al., 2009). Examining touch interactions at various ages would allow for an examination of the evolving nature of the mother–infant interaction over time. Moreover, while a number of studies have examined touch in typically developing infants, few if any, have examined nonverbal behaviour in at-risk infants and particularly in the type of risk group considered in the present study (i.e., infants at psychosocial risk due to disadvantage and problematic patterns of social behaviour and peer relations in their mothers’ childhood histories). Yet it has been shown that maternal characteristics such as sensitivity and hostility affect infants’ engagement in touching behaviours (Moszkowski et al., 2009). This suggests that levels of engagement, and most probably other characteristics of interactions, vary within mother–infant social exchanges. While results from our study made a number of contributions, there are a few limitations. First, even though interactions were filmed in the participants’ homes, the ecological validity is somewhat limited. Specifically, the interaction setting was controlled in that infants were constrained to the infant seat, consequently limiting their range of movement. Furthermore, only four minutes of interactions were coded per mother–infant dyad. Given that four minutes is relatively short in duration, it may not be truly representative of the daily interactions between mothers and their infants. However, two-minute interaction periods are consistent with the majority of studies utilizing the Still-Face procedure, while some have used shorter (60–90 s) or longer (three minutes) periods. This study was the first to explore mutual touch. Consequently, there are several potential avenues for future research that would significantly add to the limited body of knowledge on touch and nonverbal communication between mothers and their infants. First, studies should be designed to examine the functional components of mutual touch, as well as the patterns and quality of mutual touch during the SF procedure. It would also be of importance to examine mutual touch in the aforementioned regard, across various interaction contexts, such as play or feeding. Moreover, although the literature on the role of touch in father–infant interactions is growing (Feldman, 2003; Jean, Moszkowski, Girouard, & Stack, 2005; Weiss & Goebel, 2003), it is nonetheless still limited. Fathers are sensitive and important partners in the development of children’s emotion regulation and control (Pougnet, Serbin, Stack, & Schwartzman, 2011). It may be that mutual touching surfaces differently and serves some different functions during father–infant interactions. While further work is required to gain a more complete understanding of the role of mutual touch in mother–infant interactions, the present study was an important first step in examining mutual touch in fullterm, healthy and at-risk infants. Results support existing evidence that touch is an integral part of the mother–infant relationship and that mother–infant dyads adjust their tactile behaviour to the period of the interaction. Importantly, results highlight that touch during mother–infant early exchanges is not solely one-sided and that mutual touch is prominent, and illuminate how both mothers and infants participate in shaping and co-regulating their interactions through the use of touch. With additional research in the area of mutual touch, results could provide further support for the contention that different forms of mutual touch may communicate different meanings and serve different functions. Further work is certainly needed in order to explore mutual touch and the mechanisms of self-regulation in premature infants. Understanding such mechanisms and their parents’ positive influence may have direct implications for supportive programmes aimed at improving infants’ socio-emotional outcomes. In the long run, findings could be used to educate mothers on the roles of touch and how to foster attunement in their abilities to sensitively adjust their touch to their infants’ affect and distress. Ultimately findings have implications for the design of preventive interventions and programmes of early touch stimulation for at-risk and biologically compromised infants. Acknowledgments This research was conducted by the authors in the Department of Psychology and the Centre for Research in Human Development, Concordia University. Portions of this research were presented at the International Conference of Infant Studies in Minneapolis in 2012. The research described in this paper was partially supported by grants from the Conseil

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´ ecois ´ ´ ´ e´ et culture, and the Social Sciences and Humanities Queb de la Recherche, Fonds de recherche du Quebec – Societ Research Council of Canada. The Concordia Project originated in 1976 under the direction of Jane Ledingham and Alex E. Schwartzman. The intergenerational project is currently directed by Lisa A. Serbin, Dale M. Stack, and Alex E. Schwartzman. We extend our deepest gratitude to Joleen Coirazza, Joelle Bélisle-Cuillerier, Sabrina Basso, Kristen Boyle, Marisa Mercuri, and Bianca Panarello for their help with various tasks towards the preparation of this manuscript. We also thank Nadine Girouard, Claude Senneville, and the Concordia Project team for their assistance in data collection. Finally, we are most indebted to the participants in the study. References Adamson, L. B., & Frick, J. E. (2003). The still face: A history of a shared experimental paradigm. Infancy: 4., 451–473. Als, H. (1995). The preterm infant: A model for the study of fetal brain expectation. 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