Preferential Looking

Although domestic dogs can respond to many facial cues displayed by other dogs and humans, it remains unclear whether they can differentiate individual dogs or humans based on facial cues alone and, if so, whether they would demonstrate the face inversion effect, a behavioural hallmark commonly used in primates to differentiate face processing from object processing. In this study we first established the applicability of the Visual Paired Comparison (VPC or preferential looking) procedure for dogs using a simple object discrimination task with 2D pictures. The animals demonstrated a clear looking preference for novel objects when simultaneously presented with prior-exposed familiar objects. We then adopted this VPC procedure to assess their face discrimination and inversion responses. Dogs showed a deviation from random behaviour, indicating discrimination capability when inspecting upright dog faces, human faces and object images; but the pattern of viewing preference was dependent upon image category. They directed longer viewing time at novel (vs. familiar) human faces and objects, but not at dog faces, instead, a longer viewing time at familiar (vs. novel) dog faces was observed. No significant looking preference was detected for inverted images regardless of image category. Our results indicate that domestic dogs can use facial cues alone to differentiate individual dogs and humans, and that they exhibit a non-specific inversion response. In addition, the discrimination response by dogs of human and dog faces appears to differ with the type of face involved.

Birth to the age of 3-5 y.o. is the critical period of visual acuity development in children. Preferential looking is an early eye examination to detect visual impairment in children and has been known as an objective test for children below 5 y.o. The purpose of this study was to examine the children's accuracy in answering the computer-based preferential looking test. This research was conducted using a crosssectional method. The subjects used were children aged 3-5 y.o. who were taken by convenience sampling technique in four urban kindergartens in Yogyakarta, Indonesia, and had met the inclusion and exclusion criteria. The visual acuity measurement technique used was a preferential looking with hemispatial Gabor patch written in Python application. The eye tracker was used as a control. The analytical method used was the one-way ANOVA method to see the significance of differences in overall eye accuracy. Mean Lea's Chart visual acuity (LogMAR) of the eye tracked group: 0.21 ± 0.14 and the no eye tracked group: 0.28 ± 0.13. The accuracy of the eye tracked group (n=38 eyes) for the 3, 4, and 5 y.o. groups were: 81.14 ± 14.75, 75.98 ± 13.13, 81.00 ± 10.71, respectively (p= 0.459). Comparison between the eye tracked group and the no eye tracked group, the accuracy (n=38 eyes) of eye tracked group: 78.90 ± 12.11 and no eye tracked group (n=38 eyes): 86.21 ± 3,83 (p= 0.001). The children's accuracy when performing the preferential looking test was remarkable considering their early age. Therefore, this method is applicable to a basic examination to get objective visual acuity in preschool children.

In this study, we conducted a series of experiments using stimuli characterized by various attributes in order to understand the cat egorization process in an infant's pre-linguistic development. The iii are able to assign the same label to members within the same category focusing attention on specific features or functions common to the m bers. The ability to categorize is likely to play an essential role in an fant's overall cognitive development. Specifically, we investigated how t infants use different strategies in the process of linguistic categorizat In one strategy, members of a single category are derived from perceptu similarities within the most representative members, i.e., the prototypi members. Alternatively, each membership is established by referring the linguistic labels for each category provided by the caretaker, in a s bol grounding process. We found that the infant is able to employ the strategies in a flexible manner in its development. We discuss the inte between different cognitive strategies, including the prototype effects in infant's cognitive development and the implications for cortical mechani involved.

Visual problems that occur early in life can have major impact on a child's development. Without verbal communication and only based on observational methods, it is difficult to make a quantitative assessment of a child's visual problems. This limits accurate diagnostics in children under the age of 4 years and in children with intellectual disabilities. Here we describe a quantitative method that overcomes these problems. The method uses a remote eye tracker and a four choice preferential looking paradigm to measure eye movement responses to different visual stimuli. The child sits without head support in front of a monitor with integrated infrared cameras. In one of four monitor quadrants a visual stimulus is presented. Each stimulus has a specific visual modality with respect to the background, e.g., form, motion, contrast or color. From the reflexive eye movement responses to these specific visual modalities, output parameters such as reaction times, fixation accuracy and fixation duration are calculated to quantify a child's viewing behavior. With this approach, the quality of visual information processing can be assessed without the use of communication. By comparing results with reference values obtained in typically developing children from 0-12 years, the method provides a characterization of visual information processing in visually impaired children. The quantitative information provided by this method can be advantageous for the field of clinical visual assessment and rehabilitation in multiple ways. The parameter values provide a good basis to: (i) characterize early visual capacities and consequently to enable early interventions; (ii) compare risk groups and follow visual development over time; and (iii), construct an individual visual profile for each child.

Development of visuospatial attention can be quantified from infancy onward using visually-guided eye movement responses. We investigated the interaction between eye movement response times and salience in target areas of visual stimuli over age in a cohort of typically developing children. A preferential looking (PL) paradigm consisting of stimuli with six different visual modalities (cartoons, contrast, form, local motion, color, global motion) was combined with the automated measurement of reflexive eye movements. Effective salience was defined as visual salience of each target area relative to its background. Three classes of PL stimuli were used: with high-(cartoon, contrast), intermediate-(local motion, form), and low-effective salience (global motion, color). Eye movement response times to the target areas of the six PL stimuli were nonverbally assessed in 220 children aged 1-12 years. The development of response times with age was influenced by effective salience: Response times to targets with high salience reached stable values earlier in development (around 4 years of age) than to targets with low salience (around 9 years of age). Intra-individual response time variability was highest for low-salient stimuli, and stabilized later (around 4 years) than for highly salient stimuli (2 years). The improvement of eye movement response times to visual modalities in PL stimuli occurred earlier in development for highly salient than for low-salient targets. The present age-dependent and saliencerelated results provide a quantitative and theoretical framework to assess the development of visuospatial attention, and of related visual processing capacities, in children from 1 year of age.

Observations of eye movements of young children in a modified preferential looking task suggest a change in the visual looking pattern taking place during a very brief time between 32 and 33 months of age. In the younger children, a grating stimulus elicited eye movements towards the target followed by a few seconds of focused attention; in the older children a visual avoidance behavior was observed where subjects looked consistently in the opposite direction of the target. An analysis of video recordings suggests that this avoidance pattern was a composite of a very brief initial targetdirected eyemovement which was quickly arrested, and followed by eye movements in the opposite direction, initiating a search of the visual scene.

Much of our basic understanding of cognitive and social processes in infancy relies on measures of looking time, and specifically on infants’ visual preference for a novel or familiar stimulus. However, despite being the foundation of many behavioral tasks in infant research, the determinants of infants’ visual preferences are poorly understood, and differences in the expression of preferences can be difficult to interpret. In this large-scale study, we test predictions from the Hunter and Ames model of infants' visual preferences. We investigate the effects of three factors predicted by this model to determine infants’ preference for novel versus familiar stimuli: age, stimulus familiarity, and stimulus complexity. Drawing from a large and diverse sample of infant participants (N = XX), this study will provide crucial empirical evidence for a robust and generalizable model of infant visual preferences, leading to a more solid theoretical foundation for understanding the mechani...

In this study, we conducted a series of experiments using stimuli characterized by various attributes in order to understand the cat egorization process in an infant's pre-linguistic development. The iii are able to assign the same label to members within the same category focusing attention on specific features or functions common to the m bers. The ability to categorize is likely to play an essential role in an fant's overall cognitive development. Specifically, we investigated how t infants use different strategies in the process of linguistic categorizat In one strategy, members of a single category are derived from perceptu similarities within the most representative members, i.e., the prototypi members. Alternatively, each membership is established by referring the linguistic labels for each category provided by the caretaker, in a s bol grounding process. We found that the infant is able to employ the strategies in a flexible manner in its development. We discuss the inte between different cognitive strategies, including the prototype effects in infant's cognitive development and the implications for cortical mechani involved.

The ability to discriminate the trajectories of moving objects is highly adaptive and fundamental for physical and social interactions. Therefore, we could reasonably expect sensitivity to different trajectories already at birth, as a precursor of later communicative and defensive abilities. To investigate this possibility, we measured newborns' looking behavior to evaluate their ability to discriminate between visual stimuli depicting motion along different trajectories happening within the space surrounding their body. Differently from previous studies, we did not take into account defensive reactions, which may not be elicited by impending collision as newborns might not categorize approaching stimuli as possible dangers. In two experiments, we showed that newborns display a spontaneous visual preference for trajectories directed toward their body. We found this visual preference when visual stimuli depicted motion in opposite directions (approaching vs. receding) as well as ...

The aim in this study was to investigate the association between infants' developing interest in their self-image and the onset of mirror self-recognition (MSR). A longitudinal study was conducted with 98 infants who were seen at intervals of 3 months from 9-24 months of age. At each session, the infants were administered a preferential-looking test whereby they were presented with a video image of themselves alongside a video image of a same-aged peer in two conditions, unmarked and marked. From the 12-month session onwards, the infants were also administered a version of the standard "mark test" of MSR. The infants showed a significant preference for looking at images of themselves in both conditions coincident with the onset of MSR. This result indicates that developing an interest in the self-image is an important component in the development of MSR.

Children acquiring fixed word order languages almost always obey the word order restrictions of their language (Brown, 1973). A critical question is whether children who are learning free word order languages also exhibit word order preferences. The goal of this study is to determine whether children, who speak Turkish (a free word order language), prefer certain word orders over others. In our study, Turkish-speaking children imitated and judged SOV, OVS, SVO and OSV sentences which were not overtly marked with accusative case. The results of our study indicate that, although both SOV and OVS are grammatical when objects are not case-marked, children treat SOV as being the word order for Turkish. We argue that this preference reflects the fact that SOV is the underlying word order in Turkish and all other word orders result from scrambling. The finding that Turkish children prefer SOV and OVS word orders to the ungrammatical word orders may reflect the fact that they have innate knowledge of the structural conditions under which verbs can assign structural case. Weist, Richard. 1986. Cross-linguistic Perspective in Cogntive Development. In T. Schlecter and M. P. Toglia (eds.

There is a growing need to understand the global impact of poverty on early brain and behavioural development, particularly with regard to key cognitive processes that emerge in early development. Although the impact of adversity on brain development can trap children in an intergenerational cycle of poverty, the massive potential for brain plasticity is also a source of hope: reliable, accessible, culturally agnostic methods to assess early brain development in low resource settings might be used to measure the impact of early adversity, identify infants for timely intervention and guide the development and monitor the effectiveness of early interventions. Visual working memory (VWM) is an early marker of cognitive capacity that has been assessed reliably in early infancy and is predictive of later academic achievement in Western countries. Here, we localized the functional brain networks that underlie VWM in early development in rural India using a portable neuroimaging system, an...

We compare the processing of transitive sentences in young learners of a strict word order language (English) and two languages that allow noun omissions and many variant word orders: Turkish, a case-marked language, and Mandarin Chinese, a non case-marked language. Children aged 1-3 years listened to simple transitive sentences in the typical word order of their language, paired with two visual scenes, only one of which matched the sentence. Multiple measures of comprehension (percent of looking to match, latency to look to match, number of switches of attention) revealed a general pattern of early sensitivity to word order, coupled with language and age effects in children's processing efficiency. In particular, English learners showed temporally speedier processing of transitive sentences than Turkish learners, who also displayed more uncertainty about the matching scene. Mandarin learners behaved like Turkish learners in showing slower processing of sentences, and all language groups displayed faster processing by older than younger children. These results demonstrate that sentence processing is sensitive to crosslinguistic features beginning early in language development.

We investigate when infants exhibit knowledge of the familiar size of well-known objects and whether this knowledge is affected by stimulus format, that is, whether the stimuli are presented as real objects or matched pictures. Highlights • We investigated under which conditions 7-and 12-month-olds exhibit knowledge of the familiar size of objects. • By presenting real objects and matched pictures within reach, we found that infants of both age groups show familiar size knowledge, but only for the real objects.

We compare the processing of transitive sentences in young learners of a strict word order language (English) and two languages that allow noun omissions and many variant word orders: Turkish, a case-marked language, and Mandarin Chinese, a non case-marked language. Children aged 1-3 years listened to simple transitive sentences in the typical word order of their language, paired with two visual scenes, only one of which matched the sentence. Multiple measures of comprehension (percent of looking to match, latency to look to match, number of switches of attention) revealed a general pattern of early sensitivity to word order, coupled with language and age effects in children's processing efficiency. In particular, English learners showed temporally speedier processing of transitive sentences than Turkish learners, who also displayed more uncertainty about the matching scene. Mandarin learners behaved like Turkish learners in showing slower processing of sentences, and all language groups displayed faster processing by older than younger children. These results demonstrate that sentence processing is sensitive to crosslinguistic features beginning early in language development.

Although domestic dogs can respond to many facial cues displayed by other dogs and humans, it remains unclear whether they can differentiate individual dogs or humans based on facial cues alone and, if so, whether they would demonstrate the face inversion effect, a behavioural hallmark commonly used in primates to differentiate face processing from object processing. In this study we first established the applicability of the Visual Paired Comparison (VPC or preferential looking) procedure for dogs using a simple object discrimination task with 2D pictures. The animals demonstrated a clear looking preference for novel objects when simultaneously presented with prior-exposed familiar objects. We then adopted this VPC procedure to assess their face discrimination and inversion responses. Dogs showed a deviation from random behaviour, indicating discrimination capability when inspecting upright dog faces, human faces and object images; but the pattern of viewing preference was dependent upon image category. They directed longer viewing time at novel (vs. familiar) human faces and objects, but not at dog faces, instead, a longer viewing time at familiar (vs. novel) dog faces was observed. No significant looking preference was detected for inverted images regardless of image category. Our results indicate that domestic dogs can use facial cues alone to differentiate individual dogs and humans, and that they exhibit a non-specific inversion response. In addition, the discrimination response by dogs of human and dog faces appears to differ with the type of face involved.

In this study, we conducted a series of experiments using stimuli characterized by various attributes in order to understand the cat egorization process in an infant's pre-linguistic development. The iii are able to assign the same label to members within the same category focusing attention on specific features or functions common to the m bers. The ability to categorize is likely to play an essential role in an fant's overall cognitive development. Specifically, we investigated how t infants use different strategies in the process of linguistic categorizat In one strategy, members of a single category are derived from perceptu similarities within the most representative members, i.e., the prototypi members. Alternatively, each membership is established by referring the linguistic labels for each category provided by the caretaker, in a s bol grounding process. We found that the infant is able to employ the strategies in a flexible manner in its development. We discuss the inte between different cognitive strategies, including the prototype effects in infant's cognitive development and the implications for cortical mechani involved.

Children use causative verbs in language to express causality. The learning of causatives relies on cues in children's interaction with caregivers. Argument structure has been widely posited as a facilitative cue for learning causatives. However, it may lack reliability due to ellipsis allowed in many languages, thus affecting children's acquisition of causatives. In this study, we investigate the role of object ellipsis in the learning of two prevalent types of causatives, namely lexical and morphological causatives. We take Turkish as a test case, which employs both types of causatives. The results show that the ellipsis in child-directed speech is pervasive in both causatives, with morphological causatives exhibiting a substantially lower proportion of ellipsis. However, by examining children's developmental trajectory, we show that lexical causatives develop with a pattern strikingly similar to the general development of verbs, whereas morphological causatives develo...

Although domestic dogs can respond to many facial cues displayed by other dogs and humans, it remains unclear whether they can differentiate individual dogs or humans based on facial cues alone and, if so, whether they would demonstrate the face inversion effect, a behavioural hallmark commonly used in primates to differentiate face processing from object processing. In this study we first established the applicability of the Visual Paired Comparison (VPC or preferential looking) procedure for dogs using a simple object discrimination task with 2D pictures. The animals demonstrated a clear looking preference for novel objects when simultaneously presented with prior-exposed familiar objects. We then adopted this VPC procedure to assess their face discrimination and inversion responses. Dogs showed a deviation from random behaviour, indicating discrimination capability when inspecting upright dog faces, human faces and object images; but the pattern of viewing preference was dependent upon image category. They directed longer viewing time at novel (vs. familiar) human faces and objects, but not at dog faces, instead, a longer viewing time at familiar (vs. novel) dog faces was observed. No significant looking preference was detected for inverted images regardless of image category. Our results indicate that domestic dogs can use facial cues alone to differentiate individual dogs and humans, and that they exhibit a non-specific inversion response. In addition, the discrimination response by dogs of human and dog faces appears to differ with the type of face involved.

We used a preferential looking paradigm to evaluate infants' preferences for correct versus incorrect counting. Infants viewed a video depicting six fish. In the correct counting sequence, a hand pointed to each fish in turn, accompanied by verbal counting up to six. In the incorrect counting sequence, the hand moved between two of the six fish while there was still verbal counting to six, thereby violating the one-to-one correspondence principle of correct counting. Experiment 1 showed that Australian 18 month olds, but not 15 month olds, significantly preferred to watch the correct counting sequence. In experiment 2, Australian infants' preference for correct counting disappeared when the count words were replaced by beeps or by Japanese count words. In experiment 3, Japanese 18 month olds significantly preferred the correct counting video only when counting was in Japanese. These results show that infants start to acquire the abstract principles governing correct counting...

Grating acuity values obtained with preferential looking techniques do not correspond to test results obtained with letter charts. The aim of the study was to investigate the agreement between grating acuity and other acuity tests. Methodc Twenty-eight adult patients with strabismic amblyopia were assessed with the preferential looking-method and other linear and single letter and symbol tests. Results: Assessment with preferential looking regularly led to an overestimation of the acuity values, but between preferential looking and single optotypes there was a much better agreement. This is most likely due to 'crowding' in strabismic amblyopia. A crowding ratio was calculated in the amblyopic eye, and crowding was found to be more prominent for comparisons of preferential looking with optotypes in rows, than for preferential looking and single optotypes. Conclusions: Strabismic amblyopia cannot be reliably identified with grating acuity. Preferential looking-testing is therefore of limited use as a screening method for the detection of amblyopia, but preferential looking could still be useful in the assessment and treatment. Key words: strabismic amblyopiapreferential lookinggrating acuityresolution acuityrecognition acuitycrowdingbehavioural testingscreeningvisual acuity.

Purpose Acuity tests for infants and young children use preferential looking methods that require a perceptual match of brightness and color between grey background and target spatial average. As a first step in exploring this matching, this article measures photometric and colorimetric matches in these acuity tests. Methods The luminance, uniformity, contrast, and color spectra of Teller Acuity Cards, Keeler Acuity Cards for Infants, and Lea Paddles under ambient, warm, and cold lighting, and of grey-emulating patterns on four digital displays, were measured. Five normal adults’ acuities were tested at 10 m observationally. Results Luminance and spectral mismatches between target and background were found for the printed tests (Weber contrasts of 0.3% [Teller Acuity Cards], −1.7% [Keeler Acuity Cards for Infants], and −26% [Lea Paddles]). Lighting condition had little effect on contrast, and all printed tests and digital displays met established adult test luminance and uniformity ...

Grating acuity thresholds obtained by the looking preference procedure have been based on the assumption that infants always prefer to look at visible patterns over blank fields. Consequently. it has been assumed that the infant's preference for gratings. when compared to blank fields. would decline monotonically from 100 to 50:; as the gratings increased in spatial frequency from above-threshold gratings to below-threshold gratings. Contrary to that assumption, we now find that the preference function falls significantly below 5OY, only to rise again at higher spatial frequencies. If preference for the grating drops significantly below So",,. then the infant must be preferentially fixating the blank field which. in turn. implies discrimination of the grating. Consequently. grating acuity must exceed that based only on preferences for the grating greater than 50",.

Spatial congruity effects reveal metaphors, not markedness Permalink https://escholarship.org/uc/item/9556q7sv Journal Abstract Spatial congruity effects have often been interpreted as evidence for metaphorical thinking, but an alternative markedness-based account challenges this view. In two experiments, we directly compared metaphor and markedness explanations for spatial congruity effects, using musical pitch as a testbed. English speakers who talk about pitch in terms of spatial height were tested in speeded space-pitch compatibility tasks. To determine whether space-pitch congruency effects could be elicited by any marked spatial continuum, participants were asked to classify high-and low-frequency pitches as 'high' and 'low' or as 'front' and 'back' (both pairs of terms constitute cases of marked continuums). We found congruency effects in high/low conditions but not in front/back conditions, indicating that markedness is not sufficient to accou...

People often talk about musical pitch in terms of spatial metaphors. In English, for instance, pitches can be high or low, whereas in other languages pitches are described as thick or thin. According to psychophysical studies, metaphors in language can also shape people’s nonlinguistic space-pitch representations. But does language establish mappings between space and pitch in the first place or does it modify preexisting associations? Here we tested 4-month-old Dutch infants’ sensitivity to height-pitch and thickness-pitch mappings in two preferential looking tasks. Dutch infants looked significantly longer at cross-modally congruent stimuli in both experiments, indicating that infants are sensitive to space-pitch associations prior to language. This early presence of space-pitch mappings suggests that these associations do not originate from language. Rather, language may build upon pre-existing mappings and change them gradually via some form of competitive associative learning.

The grating acuity of 181 patients from 6 weeks to 18 years of age who had neurological abnormalities and documented developmental delay was assessed using preferential looking (PL) procedures. PL acuities were estimated by a staircase procedure in 79~o of all patients (143 of 181) on the first attempt. PL acuities were poorer than normal on the average in all patient groups, including those without ophthalmological disorders. However, PL acuities varied systematically with the severity of the eye disorder in each category, with two exceptions, high refractive error and nystagrnus. Interocular acuity differences were sensitive to such asymmetric eye disorders as strabismic amblyopia and unilateral ocular abnormalities and enabled monitoring of occlusion therapy for these conditions. Many patients who were 'visually inattentive' despite the absence of major ophthalmological abnormalities were testable but had very poor acuity. This study evaluates the clinical applicability of PL procedures for routine assessment of visual acuity in pediatric patients with developmental disabilities.

A forced-choice preferential looking paradigm, similar to that developed for human infants, was used to assess visual thresholds in kittens between 21 and 45 days of age. In agreement with the earlier work of Sireteanu [ 19,30], the technique was found to be successful for grating acuity measurement. Acuity for square wave gratings (vs. matched greys) increased from 0.12 cycles/° at 21 days to 1.6 cycles/° at 40 days of age. Comparable results were obtained at three viewing distances: 20, 40 and 60 cm, indicating that accommodation is not a limiting factor in spatial resolution over this range of distances. Kittens also showed preferences for texture arrays with strong oriented components and 'texture acuities' were found to be comparable to acuity for square wave gratings. A consistent orientation anisotropy favouring horizontal line elements was seen in very young kittens but disappeared by 5 weeks of age. Preferences for texture arrays composed of dots were much weaker and thresholds could not be determined in all cases. The results are discussed in the context of the Banks and Ginsberg [2] model of infant preferences.

Observations of eye movements of young children in a modified preferential looking task suggest a change in the visual looking pattern taking place during a very brief time between 32 and 33 months of age. In the younger children, a grating stimulus elicited eye movements towards the target followed by a few seconds of focused attention; in the older children a visual avoidance behavior was observed where subjects looked consistently in the opposite direction of the target. An analysis of video recordings suggests that this avoidance pattern was a composite of a very brief initial targetdirected eyemovement which was quickly arrested, and followed by eye movements in the opposite direction, initiating a search of the visual scene.

We investigated the impact of perceptual and categorical relatedness between a target and a distracter object on early referent identification in infants and adults. In an intermodal preferential looking (IPL) task, participants looked at a target object paired with a distracter object that could be perceptually similar or dissimilar and drawn from the same or different global category. The proportion of target looking measures revealed that infants and adults were sensitive to the interplay between category membership and perceptual similarity. Online latency measures demonstrated an advantage for perceptually dissimilar items regardless of their categorical status, indicating that different IPL measures index different processes during target identification. Results suggest that perceptual similarity and category membership of the objects lead to competition effects in word recognition and referent identification in both adults and infants and that lexical categorization and nonlinguistic categorization processes are closely related during infancy.

For group-living animals, it is crucial to distinguish one's own group members from those of other groups. Studies applying operant conditioning revealed that monkeys living in relatively small groups are able to recognize their own group members when tested with photographs of group members and other conspecifics. Employing a simple looking time paradigm, we here show that Barbary macaques living in two social groups comprising 46 and 57 individuals, respectively, at the enclosure 'La Forêt des Singes' at Rocamadour are able to spontaneously distinguish photographs of members of their own group from those depicting animals that belong to another group. This ability appears to develop with age, as juveniles did not discriminate between members of their own group and another group, although they showed generally more interest in the pictures than did adults. Juveniles frequently displayed picture directed behaviours such as lip-smacking, touching and sniffing in both conditions, indicating that the stimuli were highly salient to them. In conclusion, it appears that at least adult monkeys are able to memorize the faces of a large number of individuals. Whether the difference in behaviour is based on individual recognition of one's own group members or simply the discrimination based on familiarity remains unresolved. However, both mechanisms would be sufficient for group membership identification.

We compare the processing of transitive sentences in young learners of a strict word order language (English) and two languages that allow noun omissions and many variant word orders: Turkish, a case-marked language, and Mandarin Chinese, a non case-marked language. Children aged 1-3 years listened to simple transitive sentences in the typical word order of their language, paired with two visual scenes, only one of which matched the sentence. Multiple measures of comprehension (percent of looking to match, latency to look to match, number of switches of attention) revealed a general pattern of early sensitivity to word order, coupled with language and age effects in children's processing efficiency. In particular, English learners showed temporally speedier processing of transitive sentences than Turkish learners, who also displayed more uncertainty about the matching scene. Mandarin learners behaved like Turkish learners in showing slower processing of sentences, and all language groups displayed faster processing by older than younger children. These results demonstrate that sentence processing is sensitive to crosslinguistic features beginning early in language development.

The aim in this study was to investigate the association between infants' developing interest in their self-image and the onset of mirror self-recognition (MSR). A longitudinal study was conducted with 98 infants who were seen at intervals of 3 months from 9-24 months of age. At each session, the infants were administered a preferential-looking test whereby they were presented with a video image of themselves alongside a video image of a same-aged peer in two conditions, unmarked and marked. From the 12-month session onwards, the infants were also administered a version of the standard "mark test" of MSR. The infants showed a significant preference for looking at images of themselves in both conditions coincident with the onset of MSR. This result indicates that developing an interest in the self-image is an important component in the development of MSR.

The operant preferential looking (OPL) procedure allows a behavioral estimate of visual acuity to be obtained from children 6 mo to 3 yr of age. In clinical settings, there is often too little time available to obtain an acuity estimate with the standard OPL procedure. The goal of this study was to identify specific spatial frequencies, termed diagnostic grating frequencies, that could enable the OPL technique to be used as a screening procedure under conditions where completion of acuity estimation was not possible. One hundred eighty presumptively normal children, 6, 12, 18, 24, 30, and 36 mo of age, were each tested with up to 20 trials of a potential diagnostic grating frequency to determine the highest spatial frequency grating that could be resolved by 90% of children at each age. For all ages except 18 mo, there existed a spatial frequency that produced uniformly high OPL performance within the age group; this spatial frequency was separated by one-half to one octave from a higher spatial frequency that more than 30% of children at that age failed to detect. These results suggest that at all ages except 18 mo, it should be possible to use the OPL procedure as a vision screening tool by testing individual children with the diagnostic grating frequency appropriate for their age.

The visual acuity of twelve multi-handicapped, mentally retarded subjects, diagnosed as deafblind, was measured on two occasions with the Teller Acuity Cards (TAC). Eight subjects scored above the criterion for legally blind and the results of six of these indicated various degrees of poor to approaching-normal eyesight. To evaluate high-level vision four subjects were tested with the Fagan Test, assessing visual recognition memory for faces subsequent to familiarization with the preferential looking technique. The results for three subjects showed evidence for perceptual recognition. It is concluded that TAC combined with the Fagan Test may detect perceptual capacities unnoticed by clinical observation.

People often talk about musical pitch in terms of spatial metaphors. In English, for instance, pitches can be high or low, whereas in other languages pitches are described as thick or thin. According to psychophysical studies, metaphors in language can also shape people’s nonlinguistic space-pitch representations. But does language establish mappings between space and pitch in the first place or does it modify preexisting associations? Here we tested 4-month-old Dutch infants’ sensitivity to heightpitch and thickness-pitch mappings in two preferential looking tasks. Dutch infants looked significantly longer at cross-modally congruent stimuli in both experiments, indicating that infants are sensitive to space-pitch associations prior to language. This early presence of space-pitch mappings suggests that these associations do not originate from language. Rather, language may build upon pre-existing mappings and change them gradually via some form of competitive associative learning.

The aim in this study was to investigate the association between infants' developing interest in their self-image and the onset of mirror self-recognition (MSR). A longitudinal study was conducted with 98 infants who were seen at intervals of 3 months from 9-24 months of age. At each session, the infants were administered a preferential-looking test whereby they were presented with a video image of themselves alongside a video image of a same-aged peer in two conditions, unmarked and marked. From the 12-month session onwards, the infants were also administered a version of the standard "mark test" of MSR. The infants showed a significant preference for looking at images of themselves in both conditions coincident with the onset of MSR. This result indicates that developing an interest in the self-image is an important component in the development of MSR.

Detection of social signals, such as biological motion and social causality, is of basic importance in early infancy. There have also been some accounts that infants' visual preference or reaction to social signals change during development because of their changing understanding of such signals, and the detective abilities of primary social signals are related to later social development. In this study, we attempted to find different developmental patterns in individuals in terms of their visual preference for biological motion and socially causal movements at 4, 9, and 18 months and 4 and 9 months, respectively, using a cluster analysis. It was found that for both types of social signals, the infants who demonstrated an increased interest in social stimuli at 9 months scored higher on the developmental index than those who showed a decrease, suggesting a difference in the quality of understanding of social signals at 9 months.

The forced-choice preferential looking method (FPL) shows the development of acuity during the first year of life, and is applicable to clinical assessment. A tracking test using a narrow strip of grating yields a more sensitive measure for the later part of this age range, however. The development of acuity is dominated by neural rather than optical or accommodative factors. By age 3 years resolution acuity is very close to adult performance, but at 5 years 'crowding' effects may still impair performance on practical acuity tasks more than for the adult.