Janet E. Frick

The Still Face: A History of a Shared Experimental Paradigm

When faced by a suddenly unresponsive social partner, young infants typically react by sobering and gazing away. This still-face reaction has intrigued researchers for several decades. In this article, we present a history of the still-face paradigm in which we locate early observations of the still-face effect, describe the formalization of a procedure that reliably produces it, and discuss how this procedure has been used to investigate a broad range of questions about early social and emotional development. In addition, we reflect on the heuristic value of shared experimental paradigms.

Visual pop-out in infants: Evidence for preattentive search in 3- and 4-month-olds

The present experiment tested for preattentive visual search in 3- and 4-month-old infants using stimulus features described by Treisman and Souther (1985) as producing visual “pop-out” effects in adults. Infants were presented with two visual arrays to the left and right of midline. One array comprised homogeneous elements, while the other had a discrepant element embedded in it. On the basis of previous research, we expected infants to fixate the array containing the embedded discrepant element. The pattern of fixation indicated detection of the embedded discrepant element for both age groups, but only with stimuli shown to elicit visual pop out in adults. This asymmetry in detection is consistent with the presence of preattentive visual search in infants as young as 3 months.

Do Infants Show a Cortisol Awakening Response

Upon awakening from sleep, combined processes of deactivation of the hippocampus and activation of suprachiasmatic nucleus result in a marked increase in cortisol release from structures within the hypothalamic-pituitary-adrenal axis. This phenomenon, termed the cortisol awakening response (CAR), has been studied extensively in adults. In the current study, we examine this phenomenon for the first time in infancy. Saliva samples were collected by 32 mothers from themselves and their infants (13 males; 7.8-17.4 months of age) at the infants AM waking (and 30 min later), and upon waking from the infants first nap (and 30 min later). In contrast to what has been observed with the CAR in adults, cortisol levels declined from AM waking to 30 min post-waking. Moreover, cortisol levels did not significantly rise or fall following naps. Consistent with prior research, both group-level and dyadic-level analyses showed that cortisol levels for mother-infant dyads were associated.

Autonomic correlates of individual differences in sensitization and look duration during infancy

Patterns of infant visual attention have been attributed to both the processes of habituation and arousal. Previous research has linked individual differences in arousal (sensitization) with measures from habituation that have been associated with the efficiency of stimulus encoding (look duration). The aim of current study was to validate individual differences in these realms with a convergent measure of attention based on heart rate (HR) that might presumably reflect autonomic function and arousal. In contrast with previous work, neither habituation nor look durations differed significantly as a function of the presence of sensitization. HR variables did not differentiate infants who showed sensitization from those who did not. HR analyses on individual differences in look duration, however, yielded two significant findings: short-looking infants maintained higher levels of HR variability than long-looking infants across the session, and long-looking infants had greater HR accelerations to stimulus onsets than did short-looking infants.

Individual differences in the cortisol and salivary α‐amylase awakening responses in early childhood: Relations to age, sex, and sleep

Recent studies have examined post-waking changes in cortisol as a marker of HPA functioning, but questions remain about the stability of this response, as well as its relation to sleep and other ANS markers. The purposes of this study were to a) examine the presence and developmental changes in the cortisol awakening response (CAR) and salivary α-amylase awakening (sAA-AR) in a toddler sample and b) determine whether and how sleep relates to these responses in this age group. We measured cortisol and sAA upon awakening (and 30 min post-waking) and sleep characteristics using actigraphy (e.g., total sleep time, sleep efficiency, number of awakenings) in toddlers (N = 47; 36% female, ages 12-24 months). Forty-six percent of toddlers demonstrated a CAR and 52% demonstrated a sAA-AR. Strength of either response did not change linearly with age. Additionally, likelihood of demonstrating the CAR and sAA-AR was unrelated to age, sex, awakening time, time between samples, and time since feeding. Higher waking cortisol levels were associated with a shorter total sleep time and an earlier awakening. No associations were observed between sleep characteristics and the sAA-AR, ps > .05. Our findings suggest that these awakening responses function independently of sleep in toddlers. Additionally, the lack of change in percentage of children showing a CAR or sAA-AR across these ages suggests that these responses are stable and not emerging reliably across the second year of life.

Look Here! The Development of Attentional Orienting to Symbolic Cues

Although much research has examined the development of orienting to social directional cues (e.g., eye gaze), little is known about the development of orienting to nonsocial directional cues, such as arrows. Arrow cues have been used in numerous studies as a means to study attentional orienting, but the development of childrens understanding of such cues has not previously been examined. It remains unclear to what extent the social nature of a cue is important for directing attention; further, it is unknown whether symbolic understanding is necessary for young children to be cued by symbols such as arrows. The present investigation explored when and how arrows cue childrens attention. Our results suggest that children younger than 5 years of age orient their attention using the perceptual properties of arrows, and it is not until sometime after 5 years of age that children use the conceptual meaning of arrows to orient their attention. Understanding of the directional meaning of arrows may develop through both exogenous and endogenous orienting; we discuss possible contributions of the compression-based and selection-based learning systems.

Cross-Task Stability in Infant Attention: New Perspectives Using the Still-Face Procedure

Infant visual attention has been studied extensively within cognitive paradigms using measures such as look duration and reaction time, but less work has examined how infant attention operates in social contexts. In addition, little is known about the stability of individual differences in attention across cognitive and social contexts. In this study, a cross-sectional sample of 50 infants (4 and 6 months of age) were first tested in a look duration and reaction time task with static visual stimuli. Next, their mothers participated with the infants in the still-face procedure, a mildly distressing social interaction paradigm that involves violation of expectancy. Individual differences in looking and emotion were stable across the phases of the still-face task. Further, individual differences in looking measures from the visual attention task were related to the pattern of looking shown across the phases of the still-face procedure. Results indicate that individual differences in attentional measures show...

One Still Face, Many Visions

Tronick, Cohn, and Muir and Lee have strengthened and extended our history of the still-face procedure by reflecting on important theoretical and methodological issues in the current literature, and by looking to the future of how the still face can inform and guide further investigations. These commentaries provide a wonderful illustration of how the use of a shared, if not fully standardized, paradigm can continue to inspire ever more sharing of ideas.

The Development of Facial Identity Discrimination Through Learned Attention

Learned attention models of perceptual discrimination predict that with age, sensitivity will increase for dimensions of stimuli useful for discrimination. We tested this prediction by examining the face dimensions 4- to 6-month-olds (n = 77), 9- to 12-month-olds (n = 66), and adults (n = 73) use for discriminating human, monkey, and sheep faces systematically varying in outer features (contour), inner features (eyes, mouth), or configuration (feature spacing). We controlled interindividual variability across species by varying faces within natural ranges and measured stimulus variability using computational image similarity. We found the most improvement with age in human face discrimination, and older participants discriminated more species and used more facial properties for discrimination, consistent with learned attention models. Older infants and adults discriminated human, monkey, and sheep faces; however, they used different facial properties for primates and sheep. Learned attention models may provide insight into the mechanisms underlying perceptual narrowing.

Developmental changes in inhibition of return from 3 to 6 months of age

The development of inhibition of return was examined in 3-6-month-olds using varied stimulus onset asynchronies. The 300 ms SOA condition revealed particularly interesting findings as it elicited facilitation in 4.5-month-olds, but inhibition in 6-month-olds. Implications for understanding the development of IOR are discussed.