Saccadic reaction times in infants and adults: spatiotemporal factors, gender, and inter-laboratory variation

Saccade latency is widely used across infant psychology to investigate infants’understanding of events. Interpreting particular latency values requires knowledge of standard saccadic reaction times, but there is no consensus as to typical values. This study provides standard estimates of infants’ (n=194, ages 9 to 15 months) saccadic reaction times under a range of different spatiotemporal conditions. To investigate the reliability of such standard estimates, data is collected at four laboratories in three countries. Results indicate that reactions to the appearance of a new object are much faster than reactions to the deflection of a currently fixated moving object; upward saccades are slower than downward or horizontal saccades; reactions to more peripheral stimuli are much slower; and this slowdown is greater for boys than girls. There was little decrease in saccadic reaction times between 9 and 15 month, indicating that the period of slow development which is protracted into adolescence begins in late infancy. Except for appearance and deflection differences, infant effects were weak or absent in adults (n=40). Latency estimates and spatiotemporal effects on latency were generally consistent across laboratories, but a number of lab differences in factors such as individual variation were found. Some but not all differences were attributed to minor procedural differences, highlighting the importance of replication. Confidence intervals (95%) for infants’ median reaction latencies for appearance stimuli were 242 – 250 ms and for deflection stimuli 350 – 367 ms

Predictive action tracking without motor experience in 8-month-old infants

A popular idea in cognitive neuroscience is that to predict others’ actions, observers need to map those actions onto their own motor repertoire. If this is true, infants with a relatively limited motor repertoire should be unable to predict actions with which they have no previous motor experience. We investigated this idea by presenting pre-walking infants with videos of upright and inverted stepping actions that were briefly occluded from view, followed by either a correct (time-coherent) or an incorrect (time- incoherent) continuation of the action (Experiment 1). Pre-walking infants looked significantly longer to the still frame after the incorrect compared to the correct continuations of the upright, but not the inverted stepping actions. This demonstrates that motor experience is not necessary for predictive track- ing of action kinematics. In a follow-up study (Experiment 2), we investigated sensorimotor cortex acti- vation as a neural indication of predictive action tracking in another group of pre-walking infants. Infants showed significantly more sensorimotor cortex activation during the occlusion of the upright stepping actions that the infants in Experiment 1 could predictively track, than during the occlusion of the inverted stepping actions that the infants in Experiment 1 could not predictively track. Taken together, these find- ings are inconsistent with the idea that motor experience is necessary for the predictive tracking of action kinematics, and suggest that infants may be able to use their extensive experience with observing others’ actions to generate real-time action predictions

Sex Differences in Social Attention in Infants at Risk for Autism

We studied visual attention to emotional faces in 10-month-old infant siblings of children with ASD (ASD-sibs; N = 70) and a siblings of typically developing children (N = 29) using static stimuli. Contrary to our predictions, we found no evidence for atypical gaze behavior in ASD-sibs when boys and girls were analyzed together. However, a sex difference was found in ASD-sibs' visual attention to the mouth. Male ASD-sibs looked more at the mouth across emotions compared to male controls and female ASD-sibs. In contrast, female ASD-sibs looked less at the mouth compared to female controls. These findings suggest that some aspects of early emerging atypical social attention in ASD-sibs may be sex specific

Pupillary Stroop effects

We recorded the pupil diameters of participants performing the words’ color-naming Stroop task (i.e., naming the color of a word that names a color). Non-color words were used as baseline to firmly establish the effects of semantic relatedness induced by color word distractors. We replicated the classic Stroop effects of color congruency and color incongruency with pupillary diameter recordings: relative to non-color words, pupil diameters increased for color distractors that differed from color responses, while they reduced for color distractors that were identical to color responses. Analyses of the time courses of pupil responses revealed further differences between color-congruent and color-incongruent distractors, with the latter inducing a steep increase of pupil size and the former a relatively lower increase. Consistent with previous findings that have demonstrated that pupil size increases as task demands rise, the present results indicate that pupillometry is a robust measure of Stroop interference, and it represents a valuable addition to the cognitive scientist’s toolbox

Cues for Early Social Skills: Direct Gaze Modulates Newborns' Recognition of Talking Faces

Previous studies showed that, from birth, speech and eye gaze are two important cues in guiding early face processing and social cognition. These studies tested the role of each cue independently; however, infants normally perceive speech and eye gaze together. Using a familiarization-test procedure, we first familiarized newborn infants (n = 24) with videos of unfamiliar talking faces with either direct gaze or averted gaze. Newborns were then tested with photographs of the previously seen face and of a new one. The newborns looked longer at the face that previously talked to them, but only in the direct gaze condition. These results highlight the importance of both speech and eye gaze as socio-communicative cues by which infants identify others. They suggest that gaze and infant-directed speech, experienced together, are powerful cues for the development of early social skills

The development of spontaneous facial responses to others’ emotions in infancy. An EMG study

Viewing facial expressions often evokes facial responses in the observer. These spontaneous facial reactions (SFRs) are believed to play an important role for social interactions. However, their developmental trajectory and the underlying neurocognitive mechanisms are still little understood. In the current study, 4- and 7-month old infants were presented with facial expressions of happiness, anger, and fear. Electromyography (EMG) was used to measure activation in muscles relevant for forming these expressions: zygomaticus major (smiling), corrugator supercilii (frowning), and frontalis (forehead raising). The results indicated no selective activation of the facial muscles for the expressions in 4-month-old infants. For 7-month-old infants, evidence for selective facial reactions was found especially for happy faces (leading to increased zygomaticus major activation) and fearful faces (leading to increased frontalis activation), while angry faces did not show a clear differential response. This suggests that emotional SFRs may be the result of complex neurocognitive mechanisms which lead to partial mimicry but are also likely to be influenced by evaluative processes. Such mechanisms seem to undergo important developments at least until the second half of the first year of life

Registro de movimientos oculares con el eye tracker Mobile eye XG

93 p.Debido a su importancia en la investigación sobre lo que sucede en el cerebro, el estudio sobre el sistema visual humano se ha especializado cada vez más para indagar sobre la influencia de los movimientos oculares en la percepción durante la observación. Con el fin de acceder a este tipo de procesos se ha diseñado un conjunto de herramientas que permiten hacer un seguimiento a los movimientos oculares, conocidos como eye trackers. Este libro tiene como objetivo aportar elementos para la planeación, el diseño y la ejecución de investigaciones que incluya el uso de eye trackers, en particular del eye tracker Mobile eye XG. Esta es una de las primeras revisiones en español que recopila información sobre los movimientos oculares. Contiene una descripción sobre el eye tracker Mobile eye XG y otros dispositivos; una revisión sobre la visión humana y los movimientos oculares; una reseña acerca de los determinantes cognoscitivos de los movimientos oculares; una aproximación a las condiciones para el diseño, la ejecución y el análisis de datos de las investigaciones con esta herramienta y una revisión sobre sus campos de aplicación.Technological advances in recent decades have made eye trackers, especially glasses, an important tool in the field of cognitive, emotional, and social neurosciences, due to the relationship that exists between visual behavior and neuronal processes. This has facilitated the study of a significant number of psychological processes, including perception, emotions, social cognition, decision making, attention, and literacy, among others. Eye trackers have been applied to research a wide range of human activities, including web page and application design and market studies, the visual behavior of drivers and athletes, human-computer interactions, simulations for military training, and as a support for the clinical diagnosis of personality disorders and neurological conditions. This book aims to provide elements for the planning, design, and execution of research that includes the use of eye trackers, in particular the Mobile Eye-XG eye tracker. This is one of the first reviews in Spanish that collects information on eye movements. The study contains a description of the Mobile Eye-XG eye tracker and other devices; a review of human vision and eye movements; a review of the cognitive determinants of eye movements; an exploration of the conditions that determine the design, execution, and data analysis of research that uses this tool, as well as a review of its fields of application.Introducción Parte 1. Descripción del eye tracker Mobile eye XG Parte 2. Visión humana y movimientos oculares Parte 3. Neurobiología de los movimientos oculares Parte 4. Determinantes cognoscitivos de las fijaciones y de los movimientos oculares Parte 5. Condiciones para el diseño y el registro de estudios con el eye tracker Mobile eye XG Parte 6. Análisis y representación gráfica de los datos Parte 7. Condiciones para el reporte de investigación Parte 8. Aplicaciones del eye tracking Referencias Anexo