Applicability and attachment findings of the Strange Situation Paradigm in infants with visual impairment.

Attachment studies with diverse populations enrich the understanding of infants' socioemotional development by documenting both universal and idiosyncratic aspects of attachment. Given the effects of attachment in children's socioemotional outcomes, such studies are necessary to investigate the impact of children's sensory impairments on attachment development. Yet, very little attachment research has focused on infants with visual impairment (VI infants), a population in which infant-caregiver emotional exchanges through visual means are reduced/absent. We investigated the applicability of the Strange Situation Paradigm (SSP), with added instructions to compensate for degraded visual input, in 20 VI infants (with no additional disabilities and who were receiving developmental counseling). In all but 1 of the SSPs coded, VI infants displayed observable attachment behavior that was classifiable. Nineteen VI infants showed attachment by 12 months of age. Across the ages tested (fractional age range = 0.9-2.33 months), most VI infants' attachment patterns were classified as secure and organized.

Los estudios sobre la afectividad con grupos diversos enriquecen la comprensión acerca del desarrollo socio-emocional de los infantes ya que documentan tanto los aspectos universales como idiosincráticos de la afectividad. Dados los efectos de la afectividad en los resultados socio-emocionales de los niños, tales estudios son necesarios para investigar el impacto que los impedimentos sensoriales de los niños tienen en el desarrollo de la afectividad. Aun así, poca investigación sobre la afectividad se ha enfocado en infantes con impedimentos visuales (infantes VI), un grupo en el cual los intercambios emocionales por medios visuales entre el infante y quien le cuida son reducidos o no existen. Nosotros investigamos la aplicabilidad del Paradigma de la Situación Extraña (SSP), con instrucciones adicionales para compensar por la debilitada interacción visual, en 20 infantes VI (que no presentaban ninguna discapacidad adicional y quienes recibían consejería sobre el desarrollo). En todos los casos codificados como SSP, excepto en uno, los infantes VI mostraron una conducta de afectividad observable la cual era clasificable. Diecinueve infantes VI mostraron afectividad para los 12 meses de edad. A lo largo de la gama de edades examinadas (promedio de edad fraccional = 0.9-2.33), la mayoría de los patrones de afectividad de los infantes VI fueron clasificados como seguros y organizados.

Les études sur l'attachement avec des populations diverses enrichissent la compréhension du développement socio-émotionnel des nourrissons en documentant à la fois les aspects universels et les aspects idiosyncratiques de l'attachement. Au vu des effets de l'attachement dans les résultats socio-émotionnels des enfants, de telles études sont nécessaires afin d'enquêter sur l'impact des déficiences sensorielles des enfants sur le développement de l'attachement. Cependant très peu de recherches sur l'attachement ont porté sur le handicap visuel des nourrissons (nourrissons VI), une population chez qui l'échange émotionnel nourrisson-personne s'occupant du nourrisson au travers de moyens visuels est réduit/absent. Nos recherches ont porté sur l'applicabilité du Paradigme de Situation Etrange (SSP), avec des directives ajoutées pour compenser la saisie visuelle dégradée, chez 20 nourrissons (sans aucun autre handicap et qui étaient en consultation pour leur développement). Dans tous sauf 1 des points SSP codés, les nourrissons VI ont fait état d'un comportement d'attachement observable qui était classifiable. Dix-neuf des nourrissons CI ont fait preuve d'attachement à l'âge de 12 mois. Au travers des âges testés (étendue fractionnelle d'âge = 0,9-2,33), la plupart des patterns d'attachement des nourrissons ont été classifiés comme étant sécures et organisés.

Determining the bias and variance of a deterministic finger-tracking algorithm.

Finger tracking has the potential to expand haptic research and applications, as eye tracking has done in vision research. In research applications, it is desirable to know the bias and variance associated with a finger-tracking method. However, assessing the bias and variance of a deterministic method is not straightforward. Multiple measurements of the same finger position data will not produce different results, implying zero variance. Here, we present a method of assessing deterministic finger-tracking variance and bias through comparison to a non-deterministic measure. A proof-of-concept is presented using a video-based finger-tracking algorithm developed for the specific purpose of tracking participant fingers during a psychological research study. The algorithm uses ridge detection on videos of the participant's hand, and estimates the location of the right index fingertip. The algorithm was evaluated using data from four participants, who explored tactile maps using only their right index finger and all right-hand fingers. The algorithm identified the index fingertip in 99.78 % of one-finger video frames and 97.55 % of five-finger video frames. Although the algorithm produced slightly biased and more dispersed estimates relative to a human coder, these differences (x=0.08 cm, y=0.04 cm) and standard deviations (σ x =0.16 cm, σ y =0.21 cm) were small compared to the size of a fingertip (1.5-2.0 cm). Some example finger-tracking results are provided where corrections are made using the bias and variance estimates.

Effect of modulating braille dot height on reading regressions.

It is well known that people who read print or braille sometimes make eye or finger movements against the reading direction. The way these regressions are elicited has been studied in detail by manipulating linguistic aspects of the reading material. Actually, it has been shown that reducing the physical intensity or clarity of the visual input signal can also lead to increased regressions during reading. We asked whether the same might be true in the haptic realm while reading braille. We set the height of braille dots at three different levels (high, medium, and low) and asked adult blind, practiced braille readers to read standardized texts without any repetition of content. The results show that setting the braille dot height near the tactile threshold significantly increased the frequency of regressive finger movements. Additionally, at the lowest braille dot height, braille reading speed significantly diminished. These effects did not occur at braille dot heights that were closer to the height of standard braille (medium and high). We tentatively conclude that this effect may be due to a heightened sense of uncertainty elicited by perception near the threshold that seems to be common to the reading process, independent of the sensory input modality. Furthermore, the described effect may be a feature of a brain area that contributes to the reading process mediated by vision as well as touch.

Joint engagement in infants and its relationship to their visual impairment measurements.

Coordination of attention between a social partner and an external focus of shared interest, called joint engagement, is associated with positive developmental outcomes such as better language, socio-emotional, and theory of mind skills in sighted infants. Current measures of joint engagement rely on an infant's visual behaviors, making it difficult to study joint engagement in infants with low or no vision. In a naturalistic observational study, 20 infants with various levels of visual impairments - mean ages: 1.08 years (N=9) and 1.62 years (N=18), were videotaped during 30-min free play sessions with their caregivers. Seven infants were tested at both ages. Videos were coded to determine the percentage of time the dyads participated in joint engagement. Results showed that all visually impaired infants participated in joint engagement, with a significant increase between earlier and later ages. Infants' visual impairment levels were described in terms of visual acuity and contrast sensitivity as measured using both visual evoked potential and preferential looking techniques. Of the visual measurements, infants' reduction in contrast sensitivity measured with preferential looking, alone, predicted the infants' percentage of time in joint engagement across ages. Contrary to prior research that exclusively focused on visual acuity, this finding supports the need to include contrast sensitivity measurements in studies with visually impaired infants.

Evaluating Approaches to Rendering Braille Text on a High-Density Pin Display.

Refreshable displays for tactile graphics are typically composed of pins that have smaller diameters and spacing than standard braille dots. We investigated configurations of high-density pins to form braille text on such displays using non-refreshable stimuli produced with a 3D printer. Normal dot braille (diameter 1.5 mm) was compared to high-density dot braille (diameter 0.75 mm) wherein each normal dot was rendered by high-density simulated pins alone or in a cluster of pins configured in a diamond, X, or square; and to "blobs" that could result from covering normal braille and high-density multi-pin configurations with a thin membrane. Twelve blind participants read MNREAD sentences displayed in these conditions. For high-density simulated pins, single pins were as quickly and easily read as normal braille, but diamond, X, and square multi-pin configurations were slower and/or harder to read than normal braille. We therefore conclude that as long as center-to-center dot spacing and dot placement is maintained, the dot diameter may be open to variability for rendering braille on a high density tactile display.

Low reliability of sighted-normed verbal assessment scores when administered to children with visual impairments.

The most common and advocated assessment approach when a child cannot access visual materials is to use the verbal subscales of a test the psychologist already has and is familiar with. However, previous research indicates that children with visual impairments experience atypical verbal development. This raises the question of whether verbal subscale scores retain their reliability and interpretation validity when given to children with visual impairments. To answer this question, we administered a vocabulary subscale from a common intelligence test along with several nonverbal subscales to 15 early-blind adolescents (onset of ≤2 years). Reliability of only the vocabulary test scores was insufficient for high-stakes testing. This finding points to the broader issue of difficulties in assessing populations of exceptional children who experience atypical development trajectories, possibly making their assessment with common tests inappropriate. (PsycINFO Database Record

Systematic Movements in Haptic Search: Spirals, Zigzags, and Parallel Sweeps.

Movement strategies were investigated in a one-handed haptic search task in which blindfolded-sighted participants used either one or five fingers to find a landmark on an unstructured tactile map. Search theory predicts that systematic strategies, such as spirals, zigzags, and parallel sweeps, should be more prevalent when the searcher's detection radius is small (one finger) and less common when the detection radius is large (five fingers). As predicted, systematic strategies were more common in one-finger than five-finger search. Participants were able to exploit the larger detection radius during five-finger searches to detect targets with any of their fingers, and in one-finger search used more systematic strategies. For the most part, participants' fingers moved together during five-finger search, expanding and moving quickly when looking for search targets/distractors, and contracting and moving slowly when examining search targets/distractors. There was no evidence of fingers being used as spatial anchors or other independent finger movements in five-finger search. While targets could be found with any fingers, examination was primarily accomplished using the index and middle fingers. Overall, these results indicate that untrained sighted participants will use optimal systematic strategies during haptic search, and this behavior is appropriately modulated by detection radius.

Effects of using multiple hands and fingers on haptic performance in individuals who are blind.

In a previous paper we documented that sighted participants complete haptic tasks faster with two hands and multiple fingers, but that these benefits are task specific. The present study investigates whether these effects are the same for participants who are blind. We compared the performance of fourteen blind participants on seven tactile-map tasks using seven finger conditions. As with sighted participants, blind participants performed all tasks faster with multiple fingers. Line-tracing tasks were faster with fingers added to an already in-use hand, and sometimes when added to the second hand. Local and global search tasks were faster with multiple fingers and two hands. Distance comparison tasks were performed faster with multiple fingers, but not two hands. Lastly, moving in a straight line was faster with multiple fingers. These results reinforce our previous finding that the haptic system performs best when it can exploit the independence of multiple fingers. Furthermore, in every instance that an effect was different between sighted and blind participants, the blind participants benefitted more from two hands or multiple fingers than the sighted participants. This indicates that the blind participants have learned, through experience or training, how to best take advantage of multiple fingers during haptic tasks.

Effects of using multiple hands and fingers on haptic performance.

It remains controversial whether using two hands and multiple fingers provides any perceptual advantage over a single index finger. The present study examines this long-running question in the haptic-exploration literature by applying rigorous, psychophysical, and mathematical modeling techniques. We compared the performance of fourteen blindfolded sighted participants on seven tactile-map tasks using seven finger conditions. All tasks were benefited by multiple fingers, but it varied whether multiple fingers were beneficial on one hand, two hands, or both. Line-tracing tasks were performed faster when two hands were used, but not more than one finger per hand. Local and global search tasks were faster with multiple fingers, but not two hands. Distance comparison tasks were also performed faster with multiple fingers, and sometimes with two hands. Lastly, moving in a straight line was faster with multiple fingers, but was especially difficult with just two index fingers. These results provide empirical evidence that multiple hands and fingers benefit haptic perception, but the benefits are more complex than simply extending the tactile field of 'view'. This analogy between touch and vision fails to account for the autonomous movements and sensations of the fingers, which we show benefit the haptic perceptual system.