Perceptual narrowing in speech and face recognition : evidence for intra-individual cross-domain relations

During the first year of life, infants undergo perceptual narrowing in the domains of speech and face perception. This is typically characterized by improvements in infants' abilities in discriminating among stimuli of familiar types, such as native speech tones and same-race faces. Simultaneously, infants begin to decline in their ability to discriminate among stimuli of types with which they have little experience, such as non-native tones and other-race faces. The similarity in time-frames during which perceptual narrowing seems to occur in the domains of speech and face perception has led some researchers to hypothesize that the perceptual narrowing in these domains could be driven by shared domain-general processes. To explore this hypothesis, we tested 53 Caucasian 9-month-old infants from monolingual German households on their ability to discriminate among non-native Cantonese speech tones, as well among same-race German faces and other-race Chinese faces. We tested the infants using an infant-controlled habituation-dishabituation paradigm, with infants' preferences for looking at novel stimuli versus the habituated stimuli (dishabituation scores) acting as indicators of discrimination ability. As expected for their age, infants were able to discriminate between same-race faces, but not between other-race faces or non-native speech tones. Most interestingly, we found that infants' dishabituation scores for the non-native speech tones and other-race faces showed significant positive correlations, while the dishabituation scores for non-native speech tones and same-race faces did not. These results therefore support the hypothesis that shared domain-general mechanisms may drive perceptual narrowing in the domains of speech and face perception

Perceptual narrowing in speech and face recognition : evidence for intra-individual cross-domain relations

During the first year of life, infants undergo perceptual narrowing in the domains of speech and face perception. This is typically characterized by improvements in infants' abilities in discriminating among stimuli of familiar types, such as native speech tones and same-race faces. Simultaneously, infants begin to decline in their ability to discriminate among stimuli of types with which they have little experience, such as non-native tones and other-race faces. The similarity in time-frames during which perceptual narrowing seems to occur in the domains of speech and face perception has led some researchers to hypothesize that the perceptual narrowing in these domains could be driven by shared domain-general processes. To explore this hypothesis, we tested 53 Caucasian 9-month-old infants from monolingual German households on their ability to discriminate among non-native Cantonese speech tones, as well among same-race German faces and other-race Chinese faces. We tested the infants using an infant-controlled habituation-dishabituation paradigm, with infants' preferences for looking at novel stimuli versus the habituated stimuli (dishabituation scores) acting as indicators of discrimination ability. As expected for their age, infants were able to discriminate between same-race faces, but not between other-race faces or non-native speech tones. Most interestingly, we found that infants' dishabituation scores for the non-native speech tones and other-race faces showed significant positive correlations, while the dishabituation scores for non-native speech tones and same-race faces did not. These results therefore support the hypothesis that shared domain-general mechanisms may drive perceptual narrowing in the domains of speech and face perception

Perceptual reorganization of lexical tones : effects of age and experimental procedure

Findings on the perceptual reorganization of lexical tones are mixed. Some studies report good tone discrimination abilities for all tested age groups, others report decreased or enhanced discrimination with increasing age, and still others report U-shaped developmental curves. Since prior studies have used a wide range of contrasts and experimental procedures, it is unclear how specific task requirements interact with discrimination abilities at different ages. In the present work, we tested German and Cantonese adults on their discrimination of Cantonese lexical tones, as well as German-learning infants between 6 and 18 months of age on their discrimination of two specific Cantonese tones using two different types of experimental procedures. The adult experiment showed that German native speakers can discriminate between lexical tones, but native Cantonese speakers show significantly better performance. The results from German-learning infants suggest that 6-and 18-month-olds discriminate tones, while 9-month-olds do not, supporting a U-shaped developmental curve. Furthermore, our results revealed an effect of methodology, with good discrimination performance at 6 months after habituation but not after familiarization. These results support three main conclusions. First, habituation can be a more sensitive procedure for measuring infants' discrimination than familiarization. Second, the previous finding of a U-shaped curve in the discrimination of lexical tones is further supported. Third, discrimination abilities at 18 months appear to reflect mature perceptual sensitivity to lexical tones, since German adults also discriminated the lexical tones with high accuracy

Unique titanium Deposits of Timan: genesis and age issues

The article critically analysesthe hypotheses about the formation, age, and sources of material of large Timan titanium deposits, which were previously considered ancient buried placers formed along the weathering crusts of the Riphean shales. We discuss an alternative hydrothermal-metamorphic hypothesis about the formation of these deposits and the source of ore material. It is established that the incoming zircon of different ages (570-3200 Ma), as well as two other geochronometers, rutile and monazite, underwent a thermal effect common for all varieties as a result of a hydrothermal process about 600 Ma ago. According to modern concepts, the closing temperature of the U-Pb system in rutile exceeds 500 °С, which suggests high-temperature conditions for the hydrothermal processing of rutile during the formation of the considered deposits in the Riphean

Infants’ Gaze Patterns for Same-Race and Other-Race Faces, and the Other-Race Effect

The other-race effect (ORE) can be described as difficulties in discriminating between faces of ethnicities other than one’s own, and can already be observed at approximately 9 months of age. Recent studies also showed that infants visually explore same-and other-race faces differently. However, it is still unclear whether infants’ looking behavior for same- and other-race faces is related to their face discrimination abilities. To investigate this question we conducted a habituation–dishabituation experiment to examine Caucasian 9-month-old infants’ gaze behavior, and their discrimination of same- and other-race faces, using eye-tracking measurements. We found that infants looked longer at the eyes of same-race faces over the course of habituation, as compared to other-race faces. After habituation, infants demonstrated a clear other-race effect by successfully discriminating between same-race faces, but not other-race faces. Importantly, the infants’ ability to discriminate between same-race faces significantly correlated with their fixation time towards the eyes of same-race faces during habituation. Thus, our findings suggest that for infants old enough to begin exhibiting the ORE, gaze behavior during habituation is related to their ability to differentiate among same-race faces, compared to other-race faces

Perceptual narrowing in face- and speech-perception domains in infancy : a longitudinal approach

During the first year of life, infants undergo a process known as perceptual narrowing, which reduces their sensitivity to classes of stimuli which the infants do not encounter in their environment. It has been proposed that perceptual narrowing for faces and speech may be driven by shared domain-general processes. To investigate this theory, our study longitudinally tested 50 German Caucasian infants with respect to these domains first at 6 months of age followed by a second testing at 9 months of age. We used an infant-controlled habituation-dishabituation paradigm to test the infants’ ability to discriminate among other-race Asian faces and non-native Cantonese speech tones, as well as same-race Caucasian faces as a control. We found that while at 6 months of age infants could discriminate among all stimuli, by 9 months of age they could no longer discriminate among other-race faces or non-native tones. However, infants could discriminate among same-race stimuli both at 6 and at 9 months of age. These results demonstrate that the same infants undergo perceptual narrowing for both other-race faces and non-native speech tones between the ages of 6 and 9 months. This parallel development of perceptual narrowing occurring in both the face and speech perception modalities over the same period of time lends support to the domain-general theory of perceptual narrowing in face and speech perception

Bimodal familiarization re-sensitizes 12-month-old infants to other-race faces

Perceptual narrowing in the domain of face perception typically begins to reduce infants’ sensitivity to differences distinguishing other-race faces from approximately 6 months of age. The present study investigated whether it is possible to re-sensitize Caucasian 12-month-old infants to other-race Asian faces through statistical learning by familiarizing them with different statistical distributions of these faces. The familiarization faces were created by generating a morphed continuum from one Asian face identity to another. In the unimodal condition, infants were familiarized with a frequency distribution wherein they saw the midpoint face of the morphed continuum the most frequently. In the bimodal condition, infants were familiarized with a frequency distribution wherein they saw faces closer to the endpoints of the morphed continuum the most frequently. After familiarization, infants were tested on their discrimination of the two original Asian faces. The infants’ looking times during the test indicated that infants in the bimodal condition could discriminate between the two faces, while infants in the unimodal condition could not. These findings therefore suggest that 12-month-old Caucasian infants could be re-sensitized to Asian faces by familiarizing them with a bimodal frequency distribution of such faces

The first data on the U-Pb age (TIMS and LA-ICP-MS) of rutile from the Ichetju polymineral occurrence, The Middle Timan

A study on the U-Pb age of rutile from the Ichetju polymineral occurrence has been done for the first time by LA-ICP-MS and TIMS methods. It was established that rutile originates from various sources with different ages (presumably, ca. 1000, 1660, 1860 and 1980 Ma), but all the rutile types have undergone a common thermal event at ca. 580 Ma. Obtained results are consistent with U-Pb zircon data for the Ichetju occurrence and the Pizhemskoe deposit. According to modern concepts, the closure temperature for the U-Pb system in rutile is higher than 500 С, which suggests fairly high-temperature conditions of the rutile hydrothermal transformation during the formation of the deposits in Riphean. Obviously, a placer hypothesis of formation of titanium deposits of the Middle Timan which is supported by a number of researchers does not explain such temperature of rutile alteration

Perceptual Reorganization of Lexical Tones: Effects of Age and Experimental Procedure

Findings on the perceptual reorganization of lexical tones are mixed. Some studies report good tone discrimination abilities for all tested age groups, others report decreased or enhanced discrimination with increasing age, and still others report U-shaped developmental curves. Since prior studies have used a wide range of contrasts and experimental procedures, it is unclear how specific task requirements interact with discrimination abilities at different ages. In the present work, we tested German and Cantonese adults on their discrimination of Cantonese lexical tones, as well as German-learning infants between 6 and 18 months of age on their discrimination of two specific Cantonese tones using two different types of experimental procedures. The adult experiment showed that German native speakers can discriminate between lexical tones, but native Cantonese speakers show significantly better performance. The results from German-learning infants suggest that 6- and 18-month-olds discriminate tones, while 9-month-olds do not, supporting a U-shaped developmental curve. Furthermore, our results revealed an effect of methodology, with good discrimination performance at 6 months after habituation but not after familiarization. These results support three main conclusions. First, habituation can be a more sensitive procedure for measuring infants' discrimination than familiarization. Second, the previous finding of a U-shaped curve in the discrimination of lexical tones is further supported. Third, discrimination abilities at 18 months appear to reflect mature perceptual sensitivity to lexical tones, since German adults also discriminated the lexical tones with high accuracy

Older infants' social learning behavior under uncertainty is modulated by the interaction of face and speech processing

International audienceAbstract The origin of face or language influences infants' perceptual processing and social learning behavior. However, it remains unclear how infants' social learning behavior is affected when both information are provided simultaneously. Hence, the current study investigated whether and how infants' social learning in terms of gaze following is influenced by face race and language origin of an interaction partner in an uncertain situation. Our sample consisted of 91 Caucasian infants from German speaking families. They were divided into 2 age groups: Younger infants were 5‐ to 8‐month‐old ( n = 46) and the older infants 11‐ to 20‐month‐old ( n = 45). We used a modified online version of the gaze following paradigm by Xiao and colleagues by varying face race (Caucasian, and Asian faces) and language (German and French) of a female actor. We recorded infants looking behavior via webcam and coded it offline. Our results revealed that older but not younger infants were biased to follow the gaze of own‐race adults speaking their native language. Our findings show that older infants are clearly influenced by adults' ethnicity and language in social learning situations of uncertainty