Attentional control is key to the development of executive functions. Previous studies have indic... more Attentional control is key to the development of executive functions. Previous studies have indicated that individual differences in attentional control behaviour may be stable from 6 months. Here, we analyse electroencephalogram data collected from 59 6-month-olds to gain insights into the neural processes underlying attentional control in infancy. Firstly, we examine the neural activity preceding distinct looking behaviours in a task designed to elicit attentional control. Secondly, we test whether those neural markers show predictive associations to behavioural measures of attentional control (Freeze-Frame task) and executive function (A-not-B task) in the same infants at 9 months. Whilst our data do not show evidence that 6-9Hz power is implicated in attentional control at 6 months, or that the P1 ERP component plays a role in our attentional control task, we do find evidence that corroborates and extends research linking 3-6Hz power to attentional control. At the group level, f...
Past research has focused on infants’ visual preference for the mother’s face, however it is stil... more Past research has focused on infants’ visual preference for the mother’s face, however it is still unknown how these responses change over time and what factors associate with such changes. A longitudinal study (N ~ 60) was conducted to investigate the trajectories of infant visual preference for the mother’s face and how these are related to the development of emotional reactivity in the first year of life. Two face stimuli (i.e., the infant’s mother and a consistent stranger face) were used in a visual preference task at 2 weeks, 4, 6, and 9 months of age. At each time point, mothers were asked to complete a measure of infant temperament via standardised questionnaires. Our results show that while at 2 weeks, 4 months and 9 months of age infants looked equally at both faces, infants at 6 months looked significantly longer at their mother’s face. We also observed prospective associations with emotional reactivity variables so that infants who looked longer at the mother’s face at 6...
This longitudinal study investigated the associations between mother-infant interaction character... more This longitudinal study investigated the associations between mother-infant interaction characteristics at 9 months of age with maternal mental health and infant temperament in the first year postpartum, and with child behaviour at 3 years of age. The infants (N = 54, 22 females) mainly had White British ethnic backgrounds (85.7%). Results showed that 1) mother-infant dyadic affective mutuality correlated positively with infant falling reactivity, suggesting that better infant regulatory skills are associated with the dyad’s ability to share and understand each other’s emotions; and 2) maternal respect for infant autonomy predicted fewer child peer problems at 3 years of age, suggesting that maternal respect for the validity of the infant's individuality promotes better social and emotional development in early childhood.
Past research has focused on infants’ visual preference for the mother’s face, however it is stil... more Past research has focused on infants’ visual preference for the mother’s face, however it is still unknown how these responses change over time and what factors associate with such changes. A longitudinal study (N ~ 60) was conducted to investigate the trajectories of infant visual preference for the mother’s face and how these are related to the development of emotion regulation in the first year of life. Identical face stimuli (i.e., the infant’s mother and a consistent stranger face) were used in a visual preference task at 2 weeks, 4, 6, and 9 months of age. At each time point, mothers were asked to complete a measure of infant temperament (the IBQ-R VSF, Putnam et al., 2014, and two subscales from the IBQ-R, Gartstein & Rothbart, 2003). Our results show that while at 2 weeks, 4 months and 9 months of age infants looked equally at both faces, infants at 6 months looked significantly longer at their mother’s face. We also observed prospective associations with emotion regulation ...
Unlike for faces, it is still unclear in the literature when and how images of bodies evoke speci... more Unlike for faces, it is still unclear in the literature when and how images of bodies evoke specialised neural activations in the infant brain. • Infant P400 reflects adult-like patterns of face inversion more than N290 suggesting that P400 may be a relatively stronger precursor of the adult N170. • Face and body perception may follow different developmental trajectories, as we show little evidence for body specialisation within the first 14 months. • Body representations are established by domain-general learning mechanisms that follow emerging infant motor development and visual exposure to entire bodies.
While current methodological approaches to data-acquisition and -analysis used in ERP-studies hav... more While current methodological approaches to data-acquisition and -analysis used in ERP-studies have shown to be appropriate for adult populations, their applicability with infant populations is debatable. Many researchers agree that they are, in fact, unsuitable for infants. However, due to a lack of alternatives, traditional ways of data-collection and -analysis originally designed for adults are still used with developmental and clinical populations. The four studies reported in the current thesis propose novel approaches to methodological issues involved in infant ERP-studies. Limiting the number of artefact-free trials included in the average, Study 1 shows that fewer trials from earlier stages of a test-session can convey meaningful information and provide new insights into infant cognition. Additionally, it is shown that large amounts of usable data are often discarded in a traditional data-analysis. Study 2 aimed to provide a general overview on attrition in infant ERP-studies -which often seems to be accepted as a given among developmental psychologists -and to find underlying causes for attrition which may be based on study-design features that are common to all studies. The majority of investigated features did not impact attrition. Therefore, further factors outside the scope of the current consideration are responsible for an increase in attrition. Studies 3 and 4 built on the findings of the first two. Presenting infants with eight experimental conditions, Study 3 illustrates a novel approach to study-design which both yielded more data from individual participants and decreased attrition. Finally, using the data-analysis outlined in Study 1 on the data collected for Study 3, Study 4 both substantiates the claims made in Study 1 and provides further, previously unanticipated insights into infant cognition. These findings illustrate that more infant-suitable strategies for study-design and data-analysis are possible and that they can enhance our knowledge about infant cognitive processes. Table of Contents Chapter 1 General Introduction ………………………………………………………… Chapter 2 -Study 1 Infant ERP Amplitudes Change Over the Course of an Experimental Session: Implications for Cognitive Processes and Methodology ………….
In order to elucidate the development of how infants use eye gaze as a referential cue, we invest... more In order to elucidate the development of how infants use eye gaze as a referential cue, we investigated theta and alpha oscillations in response to object-directed and object-averted eye gaze in infants aged 2, 4, 5, and 9months. At 2months of age, no difference between conditions was found. In 4- and 9-month-olds, alpha-band activity desynchronized more in response to faces looking at objects compared to faces looking away from objects. Theta activity in 5-month-old infants differed between conditions with more theta synchronization for object-averted eye gaze. Whereas alpha desynchronization might reflect mechanisms of early social object learning, theta is proposed to imply activity in the executive attention network. The interplay between alpha and theta activity represents developmental changes in both kinds of processes during early infancy.
Infant ERP studies often feature high attrition rates with large numbers of trials excluded from ... more Infant ERP studies often feature high attrition rates with large numbers of trials excluded from statistical analyses. The number of experimental conditions is conventionally limited to reduce the test-sessions' durations and to ensure that reasonable trial-numbers will be obtained for each condition. Here, we designed an ERP study involving eight conditions originating from three previously published studies and presented them to 18 1-year-olds. We expected to replicate original results at least partly. Additionally, we were interested in the effect this novel method of stimulus presentation would have on infant attention. Due to the requirement for sustained attention, interest may decrease. Alternatively, the stimulus-variability may extend attention, allowing the acquisition of more valid trials. Our main finding was that the variability of the stimulus presentation sustained the infants' attention beyond normal parameters.This is apparent from the markedly increased number of artifact-free trials obtained and from the substantially decreased attrition rates. Results from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.
This study investigated the role of joint attention in infants&am... more This study investigated the role of joint attention in infants' word learning. Infants aged 18-21 months were taught new words in two social contexts, joint attention (eye contact, positive tone of voice) or non-joint attention (no eye contact, neutral tone of voice). Event-related potentials were measured as the infants saw objects either congruent or incongruent with the taught words. For both social contexts, an early negativity was observed for the congruent condition, reflecting a phonological-lexical priming effect between objects and the taught words. In addition, for the joint attention, the incongruent condition elicited a late, widely distributed negativity, attributed to semantic integration difficulties. Thus, social cues have an impact on how words are learned and represented in a child's mental lexicon.
Postnatal maternal depression is associated with negative developmental outcomes in infancy and c... more Postnatal maternal depression is associated with negative developmental outcomes in infancy and childhood. In a longitudinal study, mothers (N=63) completed questionnaires about their own depressive symptoms and their child’s behaviour at four time-points during the first year postpartum and again at 3 years postpartum. Maternal depressive symptoms and infant temperament measured in the first year of life by the Beck Depression Inventory-II (Beck et al., 1996) and the Infant Behavior Questionnaire – Revised, Very Short Form (Putnam et al., 2014), respectively, were related to child behaviour at 3 years of age as measured by the Strengths and Difficulties Questionnaire (Goodman, 1997). Maternal depressive scores during infancy was associated with later child conduct problems, suggesting a long-term association between maternal mental health and the development of child behaviour. Temperament across the first year of life was also associated with behavioural outcomes at 3 years of age...
Journal of Contemporary Physics (Armenian Academy of Sciences)
The method of standard sets is considered without use of a reference sample. In this method a set... more The method of standard sets is considered without use of a reference sample. In this method a set of ordered sequences of the activities of 232Th, 235U and 238U series radionuclides is used. The ordering of nuclide activities is determined by solving a system of Bateman–Rubinson differential equations. The calculated activities of nuclides are arranged in the form of a table of standards. The table of standards serves as an internal mathematical reference (the reference sample).
We aimed to progress understanding of prosodic emotion expression by establishing brain regions a... more We aimed to progress understanding of prosodic emotion expression by establishing brain regions active when expressing specific emotions, those activated irrespective of the target emotion, and those whose activation intensity varied depending on individual performance. BOLD contrast data were acquired whilst participants spoke non-sense words in happy, angry or neutral tones, or performed jaw-movements. Emotion-specific analyses demonstrated that when expressing angry prosody, activated brain regions included the inferior frontal and superior temporal gyri, the insula, and the basal ganglia. When expressing happy prosody, the activated brain regions also included the superior temporal gyrus, insula, and basal ganglia, with additional activation in the anterior cingulate. Conjunction analysis confirmed that the superior temporal gyrus and basal ganglia were activated regardless of the specific emotion concerned. Nevertheless, disjunctive comparisons between the expression of angry a...
ABSTRACT Do 5-month-old infants show differences in processing objects as a function of a prior i... more ABSTRACT Do 5-month-old infants show differences in processing objects as a function of a prior interaction with an adult? Using a live ERP paradigm we assessed this question utilizing a within subjects design. Infants saw objects during two pre-test phases with an adult experimenter. We recorded event-related potentials to the presentation of objects following the interactive pre-test phases. Experimental conditions differed only in the nature of eye contact between the infant and the experimenter during the pre-tests. In one condition the experimenter engaged the infant with direct eye contact. In a second condition, the experimenter looked only at the infant’s chest. We found that the Negative component, related to attentional processes, showed differences between experimental conditions in left fronto-central locations. These data show that 5-month-old infants allocate more attention towards objects that have been previously seen during direct eye contact interaction. In addition, these results clarify the functional nature of the Negative component.
Objective: Maternal depression is associated with a range of effects on child development, includ... more Objective: Maternal depression is associated with a range of effects on child development, including difficult temperament. This study investigated the impact of depressive symptoms (DS) that mothers experience after childbirth on infant negative affect (NA) across the first year of life.Method: In this longitudinal study (N = 65), identical questionnaires (the Beck Depression Inventory II, and the Infant Behavior Questionnaire – Revised, Very Short Form) were administered at four time points: 2 weeks, 4, 6, and 9 months after birth. Using structural equation modelling, we tested which of four different models of the relationship between maternal DS and infant NA during the postpartum months fit the data best. Results: The best-fitting model showed that maternal DS at 2 weeks were significantly associated with infant NA at 2 weeks and 4 months. Furthermore, a new independent effect emerged later during the first year, indicating that maternal DS at 4 months reliably predicted infant...
We aimed to progress understanding of prosodic emotion expression by establishing brain regions a... more We aimed to progress understanding of prosodic emotion expression by establishing brain regions active when expressing specific emotions, those activated irrespective of the target emotion, and those whose activation intensity varied depending on individual performance. BOLD contrast data were acquired whilst participants spoke non-sense words in happy, angry or neutral tones, or performed jaw-movements. Emotion-specific analyses demonstrated that when expressing angry prosody, activated brain regions included the inferior frontal and superior temporal gyri, the insula, and the basal ganglia. When expressing happy prosody, the activated brain regions also included the superior temporal gyrus, insula, and basal ganglia, with additional activation in the anterior cingulate. Conjunction analysis confirmed that the superior temporal gyrus and basal ganglia were activated regardless of the specific emotion concerned. Nevertheless, disjunctive comparisons between the expression of angry and happy prosody established that anterior cingulate activity was significantly higher for angry prosody than for happy prosody production. Degree of inferior frontal gyrus activity correlated with the ability to express the target emotion through prosody. We conclude that expressing prosodic emotions (vs. neutral intonation) requires generic brain regions involved in comprehending numerous aspects of language, emotion-related processes such as experiencing emotions, and in the time-critical integration of speech information.
In order to elucidate the development of how infants use eye gaze as a referential cue, we invest... more In order to elucidate the development of how infants use eye gaze as a referential cue, we investigated theta and alpha oscillations in response to object-directed and object-averted eye gaze in infants aged 2, 4, 5, and 9 months. At 2 months of age, no difference between conditions was found. In 4- and 9-month-olds, alpha-band activity desynchronized more in response to faces looking at objects compared to faces looking away from objects. Theta activity in 5-month-old infants differed between conditions with more theta synchronization for object-averted eye gaze. Whereas alpha desynchronization might reflect mechanisms of early social object learning, theta is proposed to imply activity in the executive attention network. The interplay between alpha and theta activity represents developmental changes in both kinds of processes during early infancy.
Infant ERP studies often feature high attrition rates with large numbers of trials excluded from ... more Infant ERP studies often feature high attrition rates with large numbers of trials excluded from statistical analyses. The number of experimental conditions is conventionally limited to reduce the test-sessions’ durations and to ensure that reasonable trial-numbers will be obtained for each condition. Here, we designed an ERP study involving eight conditions originating from three previously published studies and presented them to 18 1-year-olds. We expected to replicate original results at least partly. Additionally, we were interested in the effect this novel method of stimulus presentation would have on infant attention. Due to the requirement for sustained attention, interest may decrease. Alternatively, the stimulus-variability may extend attention, allowing the acquisition of more valid trials. Our main finding was that the variability of the stimulus presentation sustained the infants’ attention beyond normal parameters.This is apparent from the markedly increased number of artifact-free trials obtained and from the substantially decreased attrition rates. Results
from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.
In this meta-analysis, we examined interrelationships between characteristics of infant event-rel... more In this meta-analysis, we examined interrelationships between characteristics of infant event-related potential (ERP) studies and their attrition rates. One-hundred and forty-nine published studies provided information on 314 experimental groups of which 181 provided data on attrition. A random effects meta-analysis revealed a high average attrition rate of 49.2%. Additionally, we used meta-regression for 178 groups with attrition data to analyze which variables best explained attrition variance. Our main findings were that the nature of the stimuli—visual, auditory, or combined as well as if stimuli were animated—influenced exclusion rates from the final analysis and that infant age did not alter attrition rates.
Attentional control is key to the development of executive functions. Previous studies have indic... more Attentional control is key to the development of executive functions. Previous studies have indicated that individual differences in attentional control behaviour may be stable from 6 months. Here, we analyse electroencephalogram data collected from 59 6-month-olds to gain insights into the neural processes underlying attentional control in infancy. Firstly, we examine the neural activity preceding distinct looking behaviours in a task designed to elicit attentional control. Secondly, we test whether those neural markers show predictive associations to behavioural measures of attentional control (Freeze-Frame task) and executive function (A-not-B task) in the same infants at 9 months. Whilst our data do not show evidence that 6-9Hz power is implicated in attentional control at 6 months, or that the P1 ERP component plays a role in our attentional control task, we do find evidence that corroborates and extends research linking 3-6Hz power to attentional control. At the group level, f...
Past research has focused on infants’ visual preference for the mother’s face, however it is stil... more Past research has focused on infants’ visual preference for the mother’s face, however it is still unknown how these responses change over time and what factors associate with such changes. A longitudinal study (N ~ 60) was conducted to investigate the trajectories of infant visual preference for the mother’s face and how these are related to the development of emotional reactivity in the first year of life. Two face stimuli (i.e., the infant’s mother and a consistent stranger face) were used in a visual preference task at 2 weeks, 4, 6, and 9 months of age. At each time point, mothers were asked to complete a measure of infant temperament via standardised questionnaires. Our results show that while at 2 weeks, 4 months and 9 months of age infants looked equally at both faces, infants at 6 months looked significantly longer at their mother’s face. We also observed prospective associations with emotional reactivity variables so that infants who looked longer at the mother’s face at 6...
This longitudinal study investigated the associations between mother-infant interaction character... more This longitudinal study investigated the associations between mother-infant interaction characteristics at 9 months of age with maternal mental health and infant temperament in the first year postpartum, and with child behaviour at 3 years of age. The infants (N = 54, 22 females) mainly had White British ethnic backgrounds (85.7%). Results showed that 1) mother-infant dyadic affective mutuality correlated positively with infant falling reactivity, suggesting that better infant regulatory skills are associated with the dyad’s ability to share and understand each other’s emotions; and 2) maternal respect for infant autonomy predicted fewer child peer problems at 3 years of age, suggesting that maternal respect for the validity of the infant's individuality promotes better social and emotional development in early childhood.
Past research has focused on infants’ visual preference for the mother’s face, however it is stil... more Past research has focused on infants’ visual preference for the mother’s face, however it is still unknown how these responses change over time and what factors associate with such changes. A longitudinal study (N ~ 60) was conducted to investigate the trajectories of infant visual preference for the mother’s face and how these are related to the development of emotion regulation in the first year of life. Identical face stimuli (i.e., the infant’s mother and a consistent stranger face) were used in a visual preference task at 2 weeks, 4, 6, and 9 months of age. At each time point, mothers were asked to complete a measure of infant temperament (the IBQ-R VSF, Putnam et al., 2014, and two subscales from the IBQ-R, Gartstein & Rothbart, 2003). Our results show that while at 2 weeks, 4 months and 9 months of age infants looked equally at both faces, infants at 6 months looked significantly longer at their mother’s face. We also observed prospective associations with emotion regulation ...
Unlike for faces, it is still unclear in the literature when and how images of bodies evoke speci... more Unlike for faces, it is still unclear in the literature when and how images of bodies evoke specialised neural activations in the infant brain. • Infant P400 reflects adult-like patterns of face inversion more than N290 suggesting that P400 may be a relatively stronger precursor of the adult N170. • Face and body perception may follow different developmental trajectories, as we show little evidence for body specialisation within the first 14 months. • Body representations are established by domain-general learning mechanisms that follow emerging infant motor development and visual exposure to entire bodies.
While current methodological approaches to data-acquisition and -analysis used in ERP-studies hav... more While current methodological approaches to data-acquisition and -analysis used in ERP-studies have shown to be appropriate for adult populations, their applicability with infant populations is debatable. Many researchers agree that they are, in fact, unsuitable for infants. However, due to a lack of alternatives, traditional ways of data-collection and -analysis originally designed for adults are still used with developmental and clinical populations. The four studies reported in the current thesis propose novel approaches to methodological issues involved in infant ERP-studies. Limiting the number of artefact-free trials included in the average, Study 1 shows that fewer trials from earlier stages of a test-session can convey meaningful information and provide new insights into infant cognition. Additionally, it is shown that large amounts of usable data are often discarded in a traditional data-analysis. Study 2 aimed to provide a general overview on attrition in infant ERP-studies -which often seems to be accepted as a given among developmental psychologists -and to find underlying causes for attrition which may be based on study-design features that are common to all studies. The majority of investigated features did not impact attrition. Therefore, further factors outside the scope of the current consideration are responsible for an increase in attrition. Studies 3 and 4 built on the findings of the first two. Presenting infants with eight experimental conditions, Study 3 illustrates a novel approach to study-design which both yielded more data from individual participants and decreased attrition. Finally, using the data-analysis outlined in Study 1 on the data collected for Study 3, Study 4 both substantiates the claims made in Study 1 and provides further, previously unanticipated insights into infant cognition. These findings illustrate that more infant-suitable strategies for study-design and data-analysis are possible and that they can enhance our knowledge about infant cognitive processes. Table of Contents Chapter 1 General Introduction ………………………………………………………… Chapter 2 -Study 1 Infant ERP Amplitudes Change Over the Course of an Experimental Session: Implications for Cognitive Processes and Methodology ………….
In order to elucidate the development of how infants use eye gaze as a referential cue, we invest... more In order to elucidate the development of how infants use eye gaze as a referential cue, we investigated theta and alpha oscillations in response to object-directed and object-averted eye gaze in infants aged 2, 4, 5, and 9months. At 2months of age, no difference between conditions was found. In 4- and 9-month-olds, alpha-band activity desynchronized more in response to faces looking at objects compared to faces looking away from objects. Theta activity in 5-month-old infants differed between conditions with more theta synchronization for object-averted eye gaze. Whereas alpha desynchronization might reflect mechanisms of early social object learning, theta is proposed to imply activity in the executive attention network. The interplay between alpha and theta activity represents developmental changes in both kinds of processes during early infancy.
Infant ERP studies often feature high attrition rates with large numbers of trials excluded from ... more Infant ERP studies often feature high attrition rates with large numbers of trials excluded from statistical analyses. The number of experimental conditions is conventionally limited to reduce the test-sessions' durations and to ensure that reasonable trial-numbers will be obtained for each condition. Here, we designed an ERP study involving eight conditions originating from three previously published studies and presented them to 18 1-year-olds. We expected to replicate original results at least partly. Additionally, we were interested in the effect this novel method of stimulus presentation would have on infant attention. Due to the requirement for sustained attention, interest may decrease. Alternatively, the stimulus-variability may extend attention, allowing the acquisition of more valid trials. Our main finding was that the variability of the stimulus presentation sustained the infants' attention beyond normal parameters.This is apparent from the markedly increased number of artifact-free trials obtained and from the substantially decreased attrition rates. Results from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.
This study investigated the role of joint attention in infants&am... more This study investigated the role of joint attention in infants' word learning. Infants aged 18-21 months were taught new words in two social contexts, joint attention (eye contact, positive tone of voice) or non-joint attention (no eye contact, neutral tone of voice). Event-related potentials were measured as the infants saw objects either congruent or incongruent with the taught words. For both social contexts, an early negativity was observed for the congruent condition, reflecting a phonological-lexical priming effect between objects and the taught words. In addition, for the joint attention, the incongruent condition elicited a late, widely distributed negativity, attributed to semantic integration difficulties. Thus, social cues have an impact on how words are learned and represented in a child's mental lexicon.
Postnatal maternal depression is associated with negative developmental outcomes in infancy and c... more Postnatal maternal depression is associated with negative developmental outcomes in infancy and childhood. In a longitudinal study, mothers (N=63) completed questionnaires about their own depressive symptoms and their child’s behaviour at four time-points during the first year postpartum and again at 3 years postpartum. Maternal depressive symptoms and infant temperament measured in the first year of life by the Beck Depression Inventory-II (Beck et al., 1996) and the Infant Behavior Questionnaire – Revised, Very Short Form (Putnam et al., 2014), respectively, were related to child behaviour at 3 years of age as measured by the Strengths and Difficulties Questionnaire (Goodman, 1997). Maternal depressive scores during infancy was associated with later child conduct problems, suggesting a long-term association between maternal mental health and the development of child behaviour. Temperament across the first year of life was also associated with behavioural outcomes at 3 years of age...
Journal of Contemporary Physics (Armenian Academy of Sciences)
The method of standard sets is considered without use of a reference sample. In this method a set... more The method of standard sets is considered without use of a reference sample. In this method a set of ordered sequences of the activities of 232Th, 235U and 238U series radionuclides is used. The ordering of nuclide activities is determined by solving a system of Bateman–Rubinson differential equations. The calculated activities of nuclides are arranged in the form of a table of standards. The table of standards serves as an internal mathematical reference (the reference sample).
We aimed to progress understanding of prosodic emotion expression by establishing brain regions a... more We aimed to progress understanding of prosodic emotion expression by establishing brain regions active when expressing specific emotions, those activated irrespective of the target emotion, and those whose activation intensity varied depending on individual performance. BOLD contrast data were acquired whilst participants spoke non-sense words in happy, angry or neutral tones, or performed jaw-movements. Emotion-specific analyses demonstrated that when expressing angry prosody, activated brain regions included the inferior frontal and superior temporal gyri, the insula, and the basal ganglia. When expressing happy prosody, the activated brain regions also included the superior temporal gyrus, insula, and basal ganglia, with additional activation in the anterior cingulate. Conjunction analysis confirmed that the superior temporal gyrus and basal ganglia were activated regardless of the specific emotion concerned. Nevertheless, disjunctive comparisons between the expression of angry a...
ABSTRACT Do 5-month-old infants show differences in processing objects as a function of a prior i... more ABSTRACT Do 5-month-old infants show differences in processing objects as a function of a prior interaction with an adult? Using a live ERP paradigm we assessed this question utilizing a within subjects design. Infants saw objects during two pre-test phases with an adult experimenter. We recorded event-related potentials to the presentation of objects following the interactive pre-test phases. Experimental conditions differed only in the nature of eye contact between the infant and the experimenter during the pre-tests. In one condition the experimenter engaged the infant with direct eye contact. In a second condition, the experimenter looked only at the infant’s chest. We found that the Negative component, related to attentional processes, showed differences between experimental conditions in left fronto-central locations. These data show that 5-month-old infants allocate more attention towards objects that have been previously seen during direct eye contact interaction. In addition, these results clarify the functional nature of the Negative component.
Objective: Maternal depression is associated with a range of effects on child development, includ... more Objective: Maternal depression is associated with a range of effects on child development, including difficult temperament. This study investigated the impact of depressive symptoms (DS) that mothers experience after childbirth on infant negative affect (NA) across the first year of life.Method: In this longitudinal study (N = 65), identical questionnaires (the Beck Depression Inventory II, and the Infant Behavior Questionnaire – Revised, Very Short Form) were administered at four time points: 2 weeks, 4, 6, and 9 months after birth. Using structural equation modelling, we tested which of four different models of the relationship between maternal DS and infant NA during the postpartum months fit the data best. Results: The best-fitting model showed that maternal DS at 2 weeks were significantly associated with infant NA at 2 weeks and 4 months. Furthermore, a new independent effect emerged later during the first year, indicating that maternal DS at 4 months reliably predicted infant...
We aimed to progress understanding of prosodic emotion expression by establishing brain regions a... more We aimed to progress understanding of prosodic emotion expression by establishing brain regions active when expressing specific emotions, those activated irrespective of the target emotion, and those whose activation intensity varied depending on individual performance. BOLD contrast data were acquired whilst participants spoke non-sense words in happy, angry or neutral tones, or performed jaw-movements. Emotion-specific analyses demonstrated that when expressing angry prosody, activated brain regions included the inferior frontal and superior temporal gyri, the insula, and the basal ganglia. When expressing happy prosody, the activated brain regions also included the superior temporal gyrus, insula, and basal ganglia, with additional activation in the anterior cingulate. Conjunction analysis confirmed that the superior temporal gyrus and basal ganglia were activated regardless of the specific emotion concerned. Nevertheless, disjunctive comparisons between the expression of angry and happy prosody established that anterior cingulate activity was significantly higher for angry prosody than for happy prosody production. Degree of inferior frontal gyrus activity correlated with the ability to express the target emotion through prosody. We conclude that expressing prosodic emotions (vs. neutral intonation) requires generic brain regions involved in comprehending numerous aspects of language, emotion-related processes such as experiencing emotions, and in the time-critical integration of speech information.
In order to elucidate the development of how infants use eye gaze as a referential cue, we invest... more In order to elucidate the development of how infants use eye gaze as a referential cue, we investigated theta and alpha oscillations in response to object-directed and object-averted eye gaze in infants aged 2, 4, 5, and 9 months. At 2 months of age, no difference between conditions was found. In 4- and 9-month-olds, alpha-band activity desynchronized more in response to faces looking at objects compared to faces looking away from objects. Theta activity in 5-month-old infants differed between conditions with more theta synchronization for object-averted eye gaze. Whereas alpha desynchronization might reflect mechanisms of early social object learning, theta is proposed to imply activity in the executive attention network. The interplay between alpha and theta activity represents developmental changes in both kinds of processes during early infancy.
Infant ERP studies often feature high attrition rates with large numbers of trials excluded from ... more Infant ERP studies often feature high attrition rates with large numbers of trials excluded from statistical analyses. The number of experimental conditions is conventionally limited to reduce the test-sessions’ durations and to ensure that reasonable trial-numbers will be obtained for each condition. Here, we designed an ERP study involving eight conditions originating from three previously published studies and presented them to 18 1-year-olds. We expected to replicate original results at least partly. Additionally, we were interested in the effect this novel method of stimulus presentation would have on infant attention. Due to the requirement for sustained attention, interest may decrease. Alternatively, the stimulus-variability may extend attention, allowing the acquisition of more valid trials. Our main finding was that the variability of the stimulus presentation sustained the infants’ attention beyond normal parameters.This is apparent from the markedly increased number of artifact-free trials obtained and from the substantially decreased attrition rates. Results
from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.
In this meta-analysis, we examined interrelationships between characteristics of infant event-rel... more In this meta-analysis, we examined interrelationships between characteristics of infant event-related potential (ERP) studies and their attrition rates. One-hundred and forty-nine published studies provided information on 314 experimental groups of which 181 provided data on attrition. A random effects meta-analysis revealed a high average attrition rate of 49.2%. Additionally, we used meta-regression for 178 groups with attrition data to analyze which variables best explained attrition variance. Our main findings were that the nature of the stimuli—visual, auditory, or combined as well as if stimuli were animated—influenced exclusion rates from the final analysis and that infant age did not alter attrition rates.
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Papers by Manuela Stets
from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.
from a gap-/no gap-task were fully replicated whereas others, related to face-processing, were replicated in part. Additionally, effects that were not reported in the original studies were found. This is most probably due to interference in the information processing between these conditions. The results show that presenting infants with varied stimuli extends their attention, allowing the acquisition of at least four times more data than via current infant ERP methods. However, stimuli from separate sub-experiments must be cognitively and perceptually distinct, otherwise contamination between related factors will occur.