Good continuation affects discrimination of visual pattern information in young infants

A familiarization-novelty preference procedure was used to determine whether 3- to 4-month-old and 6- to 7-month-old infants utilize the Gestalt principle of good continuation to organize visual patterns. The study involved presentation of a target item (i.e., a square or diamond) either in-line or off-line with a set of distractor items (i.e., circles). Infants in both age groups responded to a change in the target element in the off-line, but not in the in-line, condition. The results suggest that infants organize visual pattern information in accord with the principle of good continuation. Implications of this finding for models of the ontogenesis and microgenesis of object perception in infants and adults are discussed.     

The interplay between perceptual organization and categorization in the representation of complex visual patterns by young infants

The relation between perceptual organization and categorization processes in 3- and 4-month-olds was explored. The question was whether an invariant part abstracted during category learning could interfere with Gestalt organizational processes. A 2003 study by Quinn and Schyns had reported that an initial category familiarization experience in which infants were presented with visual patterns consisting of a pacman shape and a complex polygon could interfere with infants' subsequent good continuation-based parsing of a circle from visual patterns consisting of a circle and a complex polygon. However, an alternative noninterference explanation for the results was possible because the pacman had been presented with greater frequency and duration than had the circle. The current study repeated Quinn and Schyns's procedure but provided an equivalent number of familiarization trials and duration of study time for the infants to process the pacman during initial familiarization and the circle during subsequent familiarization. The results replicated the previous findings of Quinn and Schyns. The data are consistent with the interference account and suggest that a cognitive system of adaptable feature creation can take precedence over organizational principles with which a perceptual system comes pre-equipped.     

Young infants readily use proximity to organize visual pattern information

Four experiments relying on novelty and spontaneous preference procedures were performed to determine whether 3-4-month-old infants utilize the Gestalt principle of proximity to organize visual pattern information. In Experiment 1, infants familiarized with arrays of elements that could be organized into either columns or rows were tested for their preference between vertical and horizontal bars. The infants preferred the novel organization of bars. Experiments 2 and 3 showed that the novelty preference could not be attributed to an a priori preference or an inability to discriminate between the elements comprising the patterns. Experiment 4 replicated the results of Experiment 1 in a bars --> elements version of the task, indicating that extended exposure is not necessary for infants to organize based on proximity. The results suggest that infants readily organize visual pattern information in accord with proximity. Implications of this finding for models of the ontogenesis and microgenesis of object perception in infants and adults are discussed.     

Auditory processing of relational information by young infants

The ability of 5-month-old infants to process relational information was assessed by means of a habituation-dishabituation paradigm with cardiac deceleration as the response measure. Infants were first habituated to a six-tone pattern and then shifted either to a transposition of the standard pattern or to a control pattern which comprised the elements of the transposed pattern in scrambled order. Dishabituation was not evident in the case of the transposed group but was clearly evident for the control group. These results indicate that infants can process relational information from tonal patterns.     

The representation of visual scenes

The visual world exists all around us, yet this information must be gleaned through a succession of eye fixations in which high visual acuity is limited to the small foveal region of each retina. In spite of these physiological constraints, we experience a richly detailed and continuous visual world. Research on transsaccadic memory, perception, picture memory and imagination of scenes will be reviewed. Converging evidence suggests that the representation of visual scenes is much more schematic and abstract than our immediate experience would indicate. The visual system may have evolved to maximize comprehension of discrete views at the expense of representing unnecessary detail, but through the action of attention it allows the viewer to access detail when the need arises. This capability helps to maintain the 'illusion' of seeing a rich and detailed visual world at every glance.     

The representation of nonstructural information in visual memory: Evidence from image combination

Two experiments investigated the differential representation of the figure and ground of a picture in visual short-term and long-term memory. It is known (Hitch, Brandimonte, & Walker, 1995) that subjects find it more difficult to combine mental images of two separately presented pictures in order to identify a novel form when the two pictures are incongruent in color (i.e., when a black-on-white line drawing has to be combined with a white-on-black drawing). In the present experiments, thefigures were depicted in solid form to allow color congruity to be varied independently for figure and ground. Results showed a clear impairment in image combination when the to-be-combined figures were incongruent in color (black-on-gray and white-on-gray) but not when theirgrounds were incongruently colored (gray-on-black and gray-on-white). In this way, image combination was seen to be supported by a representation of the object depicted in the picture rather than by a literal representation of the picture itself (i.e., a pictorial code). In line with previous findings, the same representation was seen to support image combination based on short-term memory (Experiment 1) and long-term memory (Experiment 2), provided that in the latter case verbal recoding was precluded. When verbal recoding was allowed, image combination based on long-term memory was insensitive to color congruity, implying the involvement of a more abstract structural representation.     

The development of visual search in infants and very young children.

In two experiments, 90 1- to 3-year-olds were trained in a new nonverbal task to touch a video screen that displayed a unique target resembling a popular television character. The target appeared among varying numbers of distractors that resembled another familiar television character and was either a uniquely colored shape (the feature search task) or a unique color-shape combination (the conjunction search task). Each correct response triggered a sound and produced four animated objects on the screen. Irrespective of age and experimental design (between-subjects or within-subjects), children's reaction time (RT) patterns resembled those obtained from adults in corresponding search tasks: The RT slope for feature search was flat and independent of distractor number, whereas the RT slope for conjunction search increased linearly with distractor number. These results extend visual search effects found with adults to infants and very young children and suggest that the basic perceptual processes underlying visual search are qualitatively invariant over ontogeny.     

Learning by selection: visual search and object perception in young infants

The authors examined how visual selection mechanisms may relate to developing cognitive functions in infancy. Twenty-two 3-month-old infants were tested in 2 tasks on the same day: perceptual completion and visual search. In the perceptual completion task, infants were habituated to a partly occluded moving rod and subsequently presented with unoccluded broken and complete rod test stimuli. In the visual search task, infants viewed displays in which single targets of varying levels of salience were cast among homogeneous static vertical distractors. Infants whose posthabituation preference indicated unity perception in the completion task provided evidence of a functional visual selective attention mechanism in the search task. The authors discuss the implications of the efficiency of attentional mechanisms for information processing and learning.     

Dynamic pointing triggers shifts of visual attention in young infants

Pointing, like eye gaze, is a deictic gesture that can be used to orient the attention of another person towards an object or an event. Previous research suggests that infants first begin to follow a pointing gesture between 10 and 13 months of age. We investigated whether sensitivity to pointing could be seen at younger ages employing a technique recently used to show early sensitivity to perceived eye gaze. Three experiments were conducted with 4.5- and 6.5-month-old infants. Our first goal was to examine whether these infants could show a systematic response to pointing by shifting their visual attention in the direction of a pointing gesture when we eliminated the difficulty of disengaging fixation from a pointing hand. The results from Experiments 1 and 2 suggest that a dynamic, but not a static, pointing gesture triggers shifts of visual attention in infants as young as 4.5 months of age. Our second goal was to clarify whether this response was based on sensitivity to the directional posture of the pointing hand, the motion of the pointing hand, or both. The results from Experiment 3 suggest that the direction of motion is necessary but not sufficient to orient infants' attention toward a distal target. Infants shifted their attention in the direction of the pointing finger, but only when the hand was moving in the same direction. These results suggest that infants are prepared to orient to the distal referent of a pointing gesture which likely contributes to their learning the communicative function of pointing.     

The scanning of compound figures by young infants

We studied infants' scanning of two compound stimuli, in each case by presenting features inside a frame, the frame alone, and the features alone. One stimulus was composed of squares and was like that studied by P. Salapatek (in L. Cohen & P. Salapatek (Eds.), New York: Academic Press, 1975); the other was a schematic face. Newborns and 1-month-olds looked at the small square when it was presented alone, but rarely looked at it when it was framed by the larger square. In contrast, 2-month-olds looked at the small square for long periods whether or not it was framed. However, when newborns and 1-month-olds were shown a schematic face, they looked at its internal features at least half the time. Thus, young infants show no external bias when scanning a schematic face.     

The role of categorical information in processing relational attributes

In two experiments, the effect of knowledge about relevant common taxonomic categories on judgments of relative magnitude was investigated. In Experiment 1, subjects judged the relative size of objects that belonged to the categoriesbuilding andanimal. The symbolic distance effect was smaller for between-category pairs (e.g.,horse-cabin) whose members could be classified more quickly into the two categories. This result strongly suggests that subjects used category membership to determine relative size on at least some portion of the trials. In Experiment 2, a similar attenuation of symbolic distance was obtained when subjects judged the relative height of furniture and vehicles. A simple explanation of the reduced symbolic distance effect for between-category pairs is that subjects occasionally fail to categorize the items into different categories and have to compute relative magnitude from the magnitudes of the two items. Fits to the data using the bootstrap technique suggest that more involved assumptions are required.     

The time course of abstract visual representation

Studies in change blindness re-enforce the suggestion that veridical, pictorial representations that survive multiple relocations of gaze are unlikely to be generated in the visual system. However, more abstract information may well be extracted and represented by the visual system. In this paper we study the types of information that are retained and the time courses over which these representations are constructed when participants view complex natural scenes. We find that such information is retained and that the resultant abstract representations encode a range of information. Different types of information are extracted and represented over different time courses. After several seconds of viewing natural scenes, our visual system is able to construct a complex information-rich representation.     

Characterizing the information content of a newly hatched chick's first visual object representation

How does object recognition emerge in the newborn brain? To address this question, I examined the information content of the first visual object representation built by newly hatched chicks (Gallus gallus). In their first week of life, chicks were raised in controlled‐rearing chambers that contained a single virtual object rotating around a single axis. In their second week of life, I tested whether subjects had encoded information about the identity and viewpoint of the virtual object. The results showed that chicks built object representations that contained both object identity information and view‐specific information. However, there was a trade‐off between these two types of information: subjects who were more sensitive to identity information were less sensitive to view‐specific information, and vice versa. This pattern of results is predicted by iterative, hierarchically organized visual processing machinery, the machinery that supports object recognition in adult primates. More generally, this study shows that invariant object recognition is a core cognitive ability that can be operational at the onset of visual object experience.     

Heart rate conditioning in young infants using a visual conditional stimulus

Trace heart rate conditioning was evaluated in 16 infants having a mean age of 4.5 months. The Experimental Group received a 3-sec blinking light pattern as the CS, followed by a 3-sec interstimulus interval (ISI), and 3-sec tone as the UCS. The Control Group received an equal number of presentations of the CS and UCS at randomized intervals and in a randomized order. The acquisition of a conditioned deceleration during the period which included the visual CS and the ISI was demonstrated only in the Experimental males. Response differences were also found in the absence of the auditory UCS, with only Experimental females exhibiting a deceleration.     

The contribution of visual and vestibular information to spatial orientation by 6- to 14-month-old infants and adults

Although there is much research on infants' ability to orient in space, little is known regarding the information they use to do so. This research uses a rotating room to evaluate the relative contribution of visual and vestibular information to location of a target following bodily rotation. Adults responded precisely on the basis of visual flow information. Seven-month-olds responded mostly on the basis of visual flow, whereas 9-month-olds responded mostly on the basis of vestibular information, and 12-month-olds responded mostly on the basis of visual information. Unlike adults, infants of all ages showed partial influence by both modalities. Additionally, 7-month-olds were capable of using vestibular information when there was no visual information for movement or stability, and 9-month-olds still relied on vestibular information when visual information was enhanced. These results are discussed in the context of neuroscientific evidence regarding visual-vestibular interaction, and in relation to possible changes in reliance on visual and vestibular information following acquisition of locomotion.     

The spatiotopic representation of visual objects across time

Each eye movement introduces changes in the retinal location of objects. How a stable spatiotopic representation emerges from such variable input is an important question for the study of vision. Researchers have classically probed human observers' performance in a task requiring a location judgment about an object presented at different locations across a saccade. Correct performance on this task requires realigning or remapping retinal locations to compensate for the saccade. A recent study showed that performance improved with longer presaccadic viewing time, suggesting that accurate spatiotopic representations take time to build up. The first goal of the study was to replicate that finding. Two experiments, one an exact replication and the second a modified version, failed to replicate improved performance with longer presaccadic viewing time. The second goal of this study was to examine the role of attention in constructing spatiotopic representations, as theoretical and neurophysiological accounts of remapping have proposed that only attended targets are remapped. A third experiment thus manipulated attention with a spatial cueing paradigm and compared transsaccadic location performance of attended versus unattended targets. No difference in spatiotopic performance was found between attended and unattended targets. Although only negative results are reported, they might nevertheless suggest that spatiotopic representations are relatively stable over time.     

The structure of visual pattern associates and pattern goodness

Two tasks were used with a total set of 126 dot patterns. In one task Ss rated the goodness of each pattern. In another task they produced a dot pattern as an associate to each of the patterns used as a stimulus. The distributions of the associates suggest that the total set of patterns is both partitioned and nested. Groups defined by rotation and reflection are partitioned, thus kept intact. These groups in turn form a series of nested subsets., Both partitioning and nesting produce subsets of different size. The size of these subsets is related to pattern goodness, with good patterns coming from small subsets.