A longitudinal study of the development of shifts of gaze to a peripheral stimulus in preterm infants with transient periventricular echogenicity

Shifts of gaze to peripheral targets were studied longitudinally, between 6 and 26 weeks corrected age, in full-term and very preterm infants with transient periventricular echogenicity (PVE). Before 10 weeks, simple shifts of gaze were faster and more frequent in preterms with PVE<14 days than in full-terms, suggesting these preterms profited from additional early visual experience. After 16 weeks, there were subtle differences between full- and preterm infants in the development of shifts of gaze requiring disengagement. The differences suggest that, after disengagement had become established, its fine-tuning occurred more slowly in the preterms. Slower fine-tuning of disengagement was not associated with duration of PVE, since it was more marked in preterms with PVE<14 days than in preterms with PVE> or =14 days. The differences in performance between full- and preterm infants were small. However, even small differences may affect the efficiency of visually guided behaviors.     

Development of selective attention in young infants: Enhancement and attenuation of startle reflex by attention

This study examined the effect of level of attention engagement on the modification of the blink reflex in young infants. Infants at 8, 14, 20, or 26 weeks of age were presented with interesting visual or auditory stimuli. At delays defined by changes in heart rate known to be associated with sustained attention or attention disengagement, blink reflexes were elicited by visual or auditory blink reflex stimuli. Blink amplitude varied according to the level of attention, and the match between the foreground and blink reflex stimulus. If the infant was attending to the foreground stimulus, a blink reflex stimulus in the same modality resulted in enhanced blink reflex magnitude. A blink reflex stimulus in the other modality resulted in an attenuated blink reflex magnitude. If attention was not engaged with the foreground stimulus, this modulation of the blink reflex did not occur. This ‘selective modality effect’ showed an increasing tendency to occur between 8 and 26 weeks of age. These results show that selective attention to modalities increases over this age range.     

Social monitoring in a primate group: the relationship between visual attention and hierarchical ranks

Social monitoring has been hypothesized to be an important component of primate social behavior. If the gaze direction of one animal can redirect the gaze of another, visual scanning of conspecifics can provide a more efficient means of locating food or predators than directly scanning the entire nonsocial environment. Social monitoring also allows distance regulation between members of a group, reducing the likelihood of agonistic encounters. Although assessment of gaze direction in freely moving primates is problematic, we were successful in assessing amounts of visual scanning among adult females of a captive, socially housed group of patas monkeys (Erythrocebus patas) using a focal sampling technique with on-the-dot recording (5-s sampling intervals). In study 1, relative amounts of scanning were assessed as subjects gazed at any other member of the group. Percentages of agreement between observers ranged from 80% to 92%, with corresponding κ values ranging from 0.74 to 0.92. In study 2, relative amounts of visual scanning were assessed so that specific targets of gaze were identified. The resultant data supported a long-standing prediction about the role of social monitoring in primate group dynamics. Lower-ranking animals gazed toward higher-ranking animals more often than vice versa. Although the specific cues eliciting social monitoring remain to be determined, visual attention in this social primate group appeared to be systematically related to hierarchical ranks, assessed by displacements. Minimally, these results suggest that patas monkeys structure their visual attention based on previous encounters with other members of their social group. While simple discrimination learning could account for these results, the demonstration of a systematic relationship between visual attention and primate social dynamics is relevant to current discussions of a primate’s understanding of conspecific gaze direction. Received: 26 January 1998 / Accepted after revision: 29 March 1998     

Visual disengagement in young infants in relation to age,sex, SES,developmental level and adaptive functioning

Visual attention plays a key role in infants’ interaction with the environment, and shapes their behavioral and brain development. As such, early problems with flexibly switching gaze from one stimulus to another (visual disengagement) have been hypothesized to lead to developmental difficulties (e.g. joint attention and social skills) over time. This study aimed to identify cross-sectional associations between performance in the Gap task (gaze shift latencies and visual attention disengagement) and measures of development and adaptive behavior in conjunction to any sex or socioeconomic status effects in infancy. We measured visual attention disengagement in 436 5-month-old infants and calculated its association with cognitive developmental level, adaptive behaviours, socioeconomic status (SES) and biological sex. In the Gap task, participants must redirect their gaze from a central stimulus to an appearing peripheral stimulus. The three experimental conditions of the task (Gap, Baseline and Overlap) differ on the timepoint when the central stimuli disappears in relation to the appearance of the peripheral stimulus: 200 ms before the peripheral stimulus appears (Gap), simultaneously to its appearance (Baseline), or with peripheral stimulus offset (Overlap). The data from the experimental conditions showed the expected pattern, with average latencies being the shortest in the Gap and longest in the Overlap condition. Females were faster (p = .004) than males in the Gap condition, which could indicate that arousal-related effects differ as a function of biological sex. Infants from higher SES were slower (p = .031) in the Overlap condition compared to lower SES infants. This suggests that basic visual attention may differ by socio-cultural background, and should be considered when studying visual attention and its developmental correlates. We observed no significant association to concurrent developmental level or adaptive function. Given its large sample size, this study provides a useful reference for future studies of visual disengagement in early infancy.     

Direct gaze captures visuospatial attention

This study investigated whether the direct gaze of others influences attentional disengagement from faces in an experimental situation. Participants were required to fixate on a centrally presented face with varying gaze directions and to detect the appearance of a peripheral target as quickly as possible. Results revealed that target detection was delayed when the preceding face was directly gazing at the subject (direct gaze), as compared with an averted gaze (averted gaze) or with closed eyes (closed eyes). This effect disappeared when a temporal gap was inserted between the offset of the centrally presented face and the onset of a peripheral target, suggesting that attentional disengagement contributed to the delayed response in the direct gaze condition. The response delay to direct gaze was not found when the contrast polarity of eyes in the facial stimuli was reversed, reinforcing the importance of gaze perception in delayed disengagement from direct gaze.     

Attentional gating in primary visual cortex: a physiological basis for dyslexia

The visual magnocellular pathway is known to play a central part in visuospatial attention and in directing attention to specific parts of the visual world in serial search. It is proposed that, in the case of reading, this mechanism is trained to perform a sequential gating of visual information coming into the primary visual cortex to enable further orderly processing by the ventral stream. This scheme, taken together with the potential for plasticity between the different afferent channels in the case of a relative impairment of the magnocellular system, can provide some limited rationale for the beneficial effects that have been claimed for the use of coloured overlays and glasses.     

Reduced Alternating Gaze During Social Interaction in Infancy is Associated with Elevated Symptoms of Autism in Toddlerhood

In typical development, infants often alternate their gaze between their interaction partners and interesting stimuli, increasing the probability of joint attention toward surrounding objects and creating opportunities for communication and learning. Children with Autism Spectrum Disorder (ASD) have been found to engage less in behaviors that can initiate joint attention compared to typically developing children, but the role of such atypicalities in the development of ASD during infancy is not fully understood. Here, using eye tracking technology in a live setting, we show that 10-month-olds at high familial risk for ASD engage less in alternating gaze during interaction with an adult compared to low risk infants. These differences could not be explained by low general social preference or slow visual disengagement, as the groups performed similarly in these respects. We also found that less alternating gaze at 10 months was associated with more social ASD symptoms and less showing and pointing at 18 months. These relations were similar in both the high risk and the low risk groups, and remained when controlling for general social preference and disengagement latencies. This study shows that atypicalities in alternating gaze in infants at high risk for ASD emerge already during the first 10 months of life - a finding with theoretical as well as potential practical implications.     

Modulation of the Directional Attention Deficit in Visual Neglect by Hemispatial Factors

Using a visuo-spatial cuing paradigm, Posner and collaborators (Posner, Cohen, & Rafal, 1982; Posner, Walker, Friedrich, & Rafal, 1984) reported that subjects with a parietal lobe lesion have difficulty in disengaging their visual attention from an invalidly precued location in the ipsilesional hemifield when the target they have to respond to is presented in the contralesional field. Later, these authors (Posner, Walker, Friedrich, & Rafal, 1987) proposed that this disengagement deficit is one involving spatial shifts of attention in a contralesional direction, irrespective of the visual hemifield in which the target is presented. This proposal of a directional disengagement deficit along the horizontal axis, present in either hemifield, contrasts with a report by Baynes, Holtzman, & Volpe (1986) showing, in right parietal subjects, a disengagement deficit for shifts of attention along the vertical axis that is only manifest in the contralesional hemifield. In the present report, we assessed the disengagement deficit of a neglect subject along the horizontal and vertical axes. Results show a disengagement deficit restricted to shifts of attention in the contralesional direction (horizontal axis), which is significant only in the contralesional visual hemifield. However, there is a clear trend for a directional disengagement deficit in the ipsilateral field. These observations indicate that the attention deficit present in neglect is directional and is modulated either by hemispatial factors or by the lateral target location in the visual field. On the basis of the present results, it is proposed that the deficit of parietal subjects may best be conceptualized as one of attentional capture for stimuli located on the contralesional side of the current focus of attention rather than one of disengagement.     

The role of the magnocellular visual pathway in the attentional blink

Visual attention has temporal limitations. In the attentional blink (AB) a stream of stimuli such as letters or digits are presented to a participant on a computer monitor at a rapid rate. Embedded in the stream are two targets that the participant must try to identify. Identification of the second target is severely impaired if it is presented within approximately 500ms of the first target. This is the 'blink' in visual attention. In this study we examined the role of the magnocellular visual pathway in the AB. This fast conducting pathway has high temporal resolution and contrast sensitivity. It is also insensitive to the direction of chromatic contrast, and this attribute was exploited in order to isolate its contributions to temporal attention. Colour defined, luminance noise masked AB streams were compared to AB streams of varying achromatic contrast. The four observers, (2F and 2M) aged between 21 and 35years, had normal visual acuity and colour vision. The colour stimuli produced a similar blink to the moderate contrast achromatic stimuli. This indicates that the magnocellular pathway does not have a privileged role in the attentional blink. We provide an explanation of previous apparently contradictory findings in terms of the role of different types of visual masking in the attentional blink.     

Linking patterns of infant eye movements to a neural network model of the ventral stream using representational similarity analysis

Little is known about the development of higher-level areas of visual cortex during infancy, and even less is known about how the development of visually guided behavior is related to the different levels of the cortical processing hierarchy. As a first step toward filling these gaps, we used representational similarity analysis (RSA) to assess links between gaze patterns and a neural network model that captures key properties of the ventral visual processing stream. We recorded the eye movements of 4- to 12-month-old infants (N = 54) as they viewed photographs of scenes. For each infant, we calculated the similarity of the gaze patterns for each pair of photographs. We also analyzed the images using a convolutional neural network model in which the successive layers correspond approximately to the sequence of areas along the ventral stream. For each layer of the network, we calculated the similarity of the activation patterns for each pair of photographs, which was then compared with the infant gaze data. We found that the network layers corresponding to lower-level areas of visual cortex accounted for gaze patterns better in younger infants than in older infants, whereas the network layers corresponding to higher-level areas of visual cortex accounted for gaze patterns better in older infants than in younger infants. Thus, between 4 and 12 months, gaze becomes increasingly controlled by more abstract, higher-level representations. These results also demonstrate the feasibility of using RSA to link infant gaze behavior to neural network models. A video abstract of this article can be viewed at https://youtu.be/K5mF2Rw98Is     

A Markovian model of adult gaze behavior

This study was designed to test a proposed Markov chain model of adult gaze behaviors. Hypotheses for an individual's gaze behavior, dyadic visual interaction, and dyadic gaze states within an independent decision model were examined. Subjects were assigned to a same-or mixed-sex dyad and instructed to converse for approximately 5 min about life at the university. Video tapes of the conversations were unobtrusively obtained and scored by an observer of gaze behaviors for 4^1/2 min in 24 pairs of subjects: eight male, eight female, and eight mixed-sex dyads. The results indicate that the occurrence of a gaze behavior is dependent on a 0.6-sec history, but infrequently prolonged Looking behaviors were found to occur slightly more often than Markovian formulations predicted. The mathematical properties of gaze behavior demonstrated in this experiment are congruent with those of dialogic time patterns, suggesting a regularity in the gross temporal organization of nonverbal communications.     

The development of fine-grained sensitivity to eye contact after 6 years of age

Adults use eye contact as a cue to the mental and emotional states of others. Here, we examined developmental changes in the ability to discriminate between eye contact and averted gaze. Children (6-, 8-, 10-, and 14-year-olds) and adults (n=18/age) viewed photographs of a model fixating the center of a camera lens and a series of positions to the left/right or upward/downward and judged whether the model's gaze was direct or averted to the left/right or upward/downward. The horizontal range of fixation positions leading to the perception of direct gaze (the cone of gaze) was more than 50% larger in 6-year-olds than in adults, but it was adult-like and smaller than the vertical cone of gaze by 8 years of age. The vertical cone of gaze was large and statistically adult-like by age 6, with only a small linear reduction thereafter. In all age groups, the horizontal cone of gaze was centered on the bridge of the participant's nose and the vertical cone was centered slightly below the participant's eye height. These findings indicate that until after age 6, relatively poor sensitivity to direct versus averted gaze limits children's ability to use gaze cues to make social judgments.     

Manipulating the disengage operation of covert visual spatial attention

Processes of covert visual spatial attention have been closely linked to the programming of saccadic eye movements. In particular, it has been hypothesized that the reduction in saccadic latency that occurs in the gap paradigm is due to the prior disengagement of covert visual spatial attention. This explanation has received considerable criticism. No study as yet has attempted to demonstrate a facilitation of the disengagement of attention from a covertly attended object. If such facilitation were possible, it would support the hypothesis that the predisengagement of covert attention is necessary for the generation of express saccades. In two experiments using covert orienting of visual attention tasks (COVAT), with a high probability that targets would appear contralateral to the cued location, we attempted to facilitate the disengagement of covert attention by extinguishing peripheral cues prior to the appearance of targets. We hypothesized that the gap between cue offset and target onset would facilitate disengagement of attention from a covertly attended object. For both experiments, responses to targets appearing after a gap were slower than were responses in the no-gap condition. These results suggest that the prior offset of a covertly attended object does not facilitate the disengagement of attention.     

The Integration of Body Movement and Attention in Young Infants

The normal development of adaptive behavior in humans depends on the integration of visual attention and body movement, yet little is known about the initial state of movement-attention coupling at the beginning of postnatal life. We studied 1- and 3-month-old infants during extended periods of visual exploration and found that spontaneous shifts of gaze are preceded by rapid changes in general body movement. The results reveal a tight link between motor activation and overt attention on a time scale of seconds or less. This link undergoes substantial developmental change in the first few weeks after birth. During that time, phasic motor activation may play a key role in visual exploration by helping to unlock gaze when the environment is unchanging.     

Gaze aversion during social interaction in preterm infants: a function of attention skills?

Preterm infants avert their gaze more often and for longer periods in early social interactions compared to full term infants. In previous studies this finding is interpreted as being a function of the higher degree of parental stimulation that is often found in parents of preterm children. The current study explores an additional hypothesis. Since the development of general visual attention abilities is found to be less optimal in preterm children, it is possible that less optimal maturation of attention abilities partially explains the elevated gaze aversion in a social context. Therefore, the current study investigated the association between gaze aversion in a social context and the ability to disengage and shift visual attention in a non-social context in 20 preterm and 42 full term infants aged 4 and 6 months. Results confirm that preterm infants are slower to shift their attention in a non-social context and that they avert their gaze more often in a social context compared to full term children. Furthermore, more frequent gaze aversion during social interaction at 6 months was related to longer disengagement and the shifting of attention at 4 and 6 months, but only within the preterm group. The results suggest that attention maturation is less optimal in preterm children; this can be observed in a non-social as well as a social context. Less attention maturation in preterm children can negatively influence the amount of time they can stay actively involved in social interaction.     

Look at them and they will notice you: Distractor-independent attentional capture by direct gaze in change blindness

Humans have shown a detection advantage of direct vs. averted gaze stimuli in visual search tasks. However, instead of attentional capture by direct gaze, the detection advantage in visual search may depend on attention-grabbing potential of the distractor stimuli to which the target needs to be compared. We investigated attentional capture by direct gaze using the change blindness paradigm, in which successful detection does not require comparison between the target and the distractor items. Participants detected a masked gaze direction change in one of four simultaneously presented schematic faces. The distractor gaze directions were systematically varied across three experiments. Changes resulting in direct gaze were detected more efficiently than those resulting in averted gaze, independently of distractor gaze directions. This finding suggests that the detection advantage is specifically due to attentional capture by direct gaze, not properties of distractor items.     

Keep your head down: Maintaining gait stability in challenging conditions

BackgroundPeripheral vision often deteriorates with age, disrupting our ability to maintain normal locomotion. Laboratory based studies have shown that lower visual field loss, in particular, is associated with changes in gaze and gait behaviour whilst walking and this, in turn, increases the risk of falling in the elderly. Separately, gaze and gait behaviours change and fall risk increases when walking over complex surfaces. It seems probable, but has not yet been established, that these challenges to stability interact.Research questionHow does loss of the lower visual field affect gaze and gait behaviour whilst walking on a variety of complex surfaces outside of the laboratory? Specifically, is there a synergistic interaction between the effects on behaviour of blocking the lower visual field and increased surface complexity?MethodsWe compared how full vision versus simulated lower visual field loss affected a diverse range of behavioural measures (head pitch angle, eye angle, muscle coactivation, gait speed and walking smoothness as measured by harmonic ratios) in young participants. Participants walked over a range of surfaces of different complexity, including pavements, grass, steps and pebbles.ResultsIn both full vision and blocked lower visual field conditions, surface complexity influenced gaze and gait behaviour. For example, more complex surfaces were shown to be associated with lowered head pitch angles, increased leg muscle coactivation, reduced gait speed and decreased walking smoothness. Relative to full vision, blocking the lower visual field caused a lowering of head pitch, especially for more complex surfaces. However, crucially, muscle coactivation, gait speed and walking smoothness did not show a significant change between full vision and blocked lower visual field conditions. Finally, head pitch angle, muscle coactivation, gait speed and walking smoothness were all correlated highly with each other.SignificanceOur study showed that blocking the lower visual field did not significantly change muscle coactivation, gait speed or walking smoothness. This suggests that young people cope well when walking with a blocked lower visual field, making minimal behavioural changes. Surface complexity had a greater effect on gaze and gait behaviour than blocking the lower visual field. Finally, head pitch angle was the only measure that showed a significant synergistic interaction between surface complexity and blocking the lower visual field. Together our results indicate that, first, a range of changes occur across the body when people walk over more complex surfaces and, second, that a relatively simple behavioural change (to gaze) suffices to maintain normal gait when the lower visual field is blocked, even in more challenging environments. Future research should assess whether young people cope as effectively when several impairments are simulated, representative of the comorbidities found with age.     

Active Listening Delays Attentional Disengagement and Saccadic Eye Movements

Successful goal-directed visual behavior depends on efficient disengagement of attention. Attention must be withdrawn from its current focus before being redeployed to a new object or internal process. Previous research has demonstrated that occupying cognitive processes with a secondary cellular phone conversation impairs attentional functioning and driving behavior. For example, attentional processing is significantly impacted by concurrent cell phone use, resulting in decreased explicit memory for on-road information. Here, we examined the impact of a critical component of cell-phone use—active listening—on the effectiveness of attentional disengagement. In the gap task—a saccadic manipulation of attentional disengagement—we measured saccade latencies while participants performed a secondary active listening task. Saccadic latencies significantly increased under an active listening load only when attention needed to be disengaged, indicating that active listening delays a disengagement operation. Simple dual-task interference did not account for the observed results. Rather, active cognitive engagement is required for measurable disengagement slowing to be observed. These results have implications for investigations of attention, gaze behavior, and distracted driving. Secondary tasks such as active listening or cell-phone conversations can have wide-ranging impacts on cognitive functioning, potentially impairing relatively elementary operations of attentional function, including disengagement.     

The role of the magnocellular and parvocellular pathways in the attentional blink

The attentional blink refers to the transient impairment in perceiving the 2nd of two targets presented in close temporal proximity in a rapid serial visual presentation (RSVP) stream. The purpose of this study was to examine the effect on human attentional-blink performance of disrupting the function of the magnocellular pathway--a major visual-processing pathway specialized in temporal segregation. The study was motivated by recent theories that relate the attentional blink to the limited temporal resolution of attentional responses, and by a number of poorly understood empirical findings, including the effects on the attentional blink of luminance adaptation and distraction. The attentional blink was assessed for stimuli on a red background (Experiment 1), stimuli on an equiluminant background (Experiment 2), and following flicker or motion adaptation (Experiment 3), three psychophysical manipulations known to disrupt magnocellular function. Contrary to our expectations, the attentional blink was not affected by these manipulations, suggesting no specific relationship between the attentional blink and magnocellular and/or parvocellular processing.     

Cultural influences on face scanning are consistent across infancy and adulthood

The emergence of cultural differences in face scanning is thought to be shaped by social experience. However, previous studies mainly investigated eye movements of adults and little is known about early development. The current study recorded eye movements of British and Japanese infants (aged 10 and 16 months) and adults, who were presented with static and dynamic faces on screen. Cultural differences were observed across all age groups, with British participants exhibiting more mouth scanning, and Japanese individuals showing increased central face (nose) scanning for dynamic stimuli. Age-related influences independent of culture were also revealed, with a shift from eye to mouth scanning between 10 and 16 months, while adults distributed their gaze more flexibly. Against our prediction, no age-related increases in cultural differences were observed, suggesting the possibility that cultural differences are largely manifest by 10 months of age. Overall, the findings suggest that individuals adopt visual strategies in line with their cultural background from early in infancy, pointing to the development of a highly adaptive face processing system that is shaped by early sociocultural experience.