Alison F. Eardley

Shifts of attention in the early blind: An ERP study of attentional control processes in the absence of visual spatial information

To investigate the role of visual spatial information in the control of spatial attention, event-related brain potentials (ERPs) were recorded during a tactile attention task for a group of totally blind participants who were either congenitally blind or had lost vision during infancy, and for an age-matched, sighted control group who performed the task in the dark. Participants had to shift attention to the left or right hand (as indicated by an auditory cue presented at the start of each trial) in order to detect infrequent tactile targets delivered to this hand. Effects of tactile attention on the processing of tactile events, as reflected by attentional modulations of somatosensory ERPs to tactile stimuli, were very similar for early blind and sighted participants, suggesting that the capacity to selectively process tactile information from one hand versus the other does not differ systematically between the blind and the sighted. ERPs measured during the cue-target interval revealed an anterior directing attention negativity (ADAN) that was present for the early blind group as well as for the sighted control group. In contrast, the subsequent posterior late direction attention negativity (LDAP) was absent in both groups. These results suggest that these two components reflect functionally distinct attentional control mechanisms which differ in their dependence on the availability of visually coded representations of external space.

Altered tactile spatial attention in the early blind

To investigate whether superior tactile acuity in the blind is due to alterations of attentional selection mechanisms, event-related brain potentials (ERPs) were measured in a group of early blind and a group of sighted individuals who performed a difficult tactile spatial selection task. We found systematic differences in the attentional processing of tactile events between early blind and sighted individuals. The blind not only responded faster to tactile targets, but also showed attentional modulations of early somatosensory ERP components (P100 and N140). In contrast, ERP effects of spatial attention in the sighted only emerged at longer-latencies (about 200 ms post-stimulus). Our findings suggest that increased use of one sense due to sensory deprivation, such as touch in blind people, leads to alterations of attentional selection mechanism within modality-specific cortex.

Event‐related potential evidence for the use of external coordinates in the preparation of tactile attention by the early blind

Recent studies have suggested that visual experience in childhood is crucial for the automatic activation of an external spatial reference frame in tactile perception. These findings are largely based on behavioural work, with limited exploration using event‐related potentials (ERPs). The present study examined the role of external spatial frameworks on tactile perception by recording ERP correlates of both preparatory processes and somatosensory processing during a tactile attention task for a group of early blind participants and age‐matched sighted controls who carried out the task in darkness. Participants had to shift attention to one hand or the other as indicated by an auditory cue presented at the start of each trial, in order to detect infrequent tactile targets delivered to the attended hand. Spatial information about the external environment was acquired in advance during tactile exploration of the testing booth. ERPs measured during the cue–target interval indicated a conflict between anatomical and external spatial reference frames for both early blind and sighted participants, as marked by the delayed onset of the anterior directing attention negativity, although the delay was more pronounced in the sighted. A delay was also observed, irrespective of visual experience, on the onset of attentional modulations of somatosensory ERPs elicited by tactile stimuli. Although these results confirm that neither concurrent nor developmental vision is necessary for the default use of an external spatial framework in tactile attention, they suggest that the relative impact of an external vs. an anatomical spatial coordinate system may be affected by visual experience.

Remembering the past and imagining the future: A role for nonvisual imagery in the everyday cognition of blind and sighted people

Images can be generated in all sensory modalities. Nevertheless, research on the everyday use of mental imagery, for example in autobiographical memory tasks, has suggested that it is only visual images that facilitate memory retrieval (e.g., Williams, Healy, & Ellis, 1999). If this is the case, individuals born without sight may be forced to rely more on verbal encoding (Goddard & Pring, 2001). This paper explores the presence and everyday role of nonvisual sensory imagery in 16 individuals with and 16 without sight. Using a cue word paradigm, contrary to previous research, Experiment 1 suggested that for both blind and sighted people, nonvisual imageries have a significant role to play in the generation of autobiographical memories. These results were reinforced by similar findings in Experiment 2, which used the same cue word method to explore the role of visual and nonvisual (auditory) imagery when generating future events. The results refute the claim that “useful” imagery in everyday tasks is exclusively visual.

Individual differences and personality correlates of navigational performance in the virtual route learning task

Psychoticism is positively correlated with the length of path taken in virtual environments (VEs).Increased wayfinding anxiety negatively affects the efficiency of navigation in VEs.Stronger immersive tendencies allow less erratic wayfinding in VEs.Application of the survey strategy facilitates navigation in VEs even despite a lack of any explicit global cues.Computer experience is an important factor affecting performance in wayfinding virtual tasks. Research on the mechanisms and processes underlying navigation has traditionally been limited by the practical problems of setting up and controlling navigation in a real-world setting. Thanks to advances in technology, a growing number of researchers are making use of computer-based virtual environments to draw inferences about real-world navigation. However, little research has been done on factors affecting human-computer interactions in navigation tasks. In this study female students completed a virtual route learning task and filled out a battery of questionnaires, which determined levels of computer experience, wayfinding anxiety, neuroticism, extraversion, psychoticism and immersive tendencies as well as their preference for a route or survey strategy. Scores on personality traits and individual differences were then correlated with the time taken to complete the navigation task, the length of path travelled, the velocity of the virtual walk and the number of errors.Navigation performance was significantly influenced by wayfinding anxiety, psychoticism, involvement and overall immersive tendencies and was improved in those participants who adopted a survey strategy. In other words, navigation in virtual environments is effected not only by navigational strategy, but also an individuals personality, and other factors such as their level of experience with computers. An understanding of these differences is crucial before performance in virtual environments can be generalised to real-world navigational performance.

Spatial processing, mental imagery, and creativity in individuals with and without sight

It has been argued that individuals born without sight are impaired on all “active” spatial imagery tasks (e.g., Vecchi, 1998). If this were the case, people without sight would be limited in their capacity to manipulate, amalgamate, or reorganise information within imagery. A consequence of this would be a difficulty in creating novel forms using imagery alone, which is the basis of the mental synthesis task (Finke & Slayton, 1988). This potential difficulty is investigated by exploring the performance of 12 early blind individuals and 15 blindfolded-sighted participants on both two- and three-dimensional versions of the mental synthesis task. Results indicated that, irrespective of visual status, spatial interference was detrimental to performance on the mental synthesis task. Furthermore, although those with sight performed better than those without sight in two dimensions, vision provided no performance advantage on the three-dimensional version of this task. In other words, individuals without sight are not impaired on all complex spatial tasks.

Exploring the impact of sucking sweets on flavour imagery

Self-report measures have suggested that individuals experience vivid images in all sensory modalities, including flavour (e.g., Betts, 1909; Johnson, 1980). The validity of subjective reports are supported indirectly by neuroscientific evidence suggesting a role for perception in visual imagery experiences (e.g., Kikuchi, Kubota, Nisijima, Washiya, & Kato, 2005). However, there have been limited behavioural studies directly exploring the objective validity of subjective measures for imagery vividness. In this experiment, 15 individuals who were early blind, and 15 sighted individuals rated the vividness of images of eating foods, both with and without an interference task—sucking a boiled sweet. This was followed, after a 45 minute delay, by a surprise free recall task. For all participants flavour images were less memorable when generated at the same time as sucking a sweet. The subjective ratings mirrored these results, suggesting that participants are sensitive to quantitative changes in the vividness of flavour imagery.

Relationship between post-awakening salivary cortisol and melatonin secretion in healthy participants

Abstract We report the relationship between patterns of post-awakening salivary melatonin and cortisol secretion in healthy participants (n = 51; mean age 21.6 ± 5.0 years). Saliva samples were collected within the domestic setting, at 0-, 15-, 30-, and 45-min post-awakening on 2 consecutive typical weekdays. Analyses were undertaken on data with electronically verified sample timing accuracy (<5-min delay between awakening and the start of saliva sampling). Melatonin secretion declined linearly by an average of 29% within the first 45-min post-awakening. In contrast, there was a marked 112% surge in cortisol, characteristic of the cortisol awakening response. No day differences in melatonin or cortisol secretion were observed but melatonin concentrations were lower with later awakening. Despite contrasting post-awakening changes in these hormones, there was a lack of relationship between overall levels or patterns of melatonin and cortisol during this period.

Allocentric Spatial Performance Higher in Early-Blind and Sighted Adults Than in Retinopathy-of-Prematurity Adults

The question as to whether people totally blind since infancy process allocentric or external spatial information like the sighted has caused considerable debate within the literature. Due to the extreme rarity of the population, researchers have often included individuals with retinopathy of prematurity (RoP—over oxygenation at birth) within the sample. However, RoP is inextricably confounded with prematurity per se. Prematurity, without visual disability, has been associated with spatial processing difficulties. In this experiment, blindfolded sighted participants and two groups of functionally totally blind participants heard text descriptions from a survey (allocentric) or route (egocentric) perspective. One blind group lost their sight due to RoP and a second group before 24 months of age. The accuracy of participants’ mental representations derived from the text descriptions was assessed via questions and maps. The RoP participants had lower scores than the sighted and early blind, who performed similarly. In other words, it was not visual impairment alone that resulted in impaired allocentric spatial performance in this task but visual impairment together with RoP. This finding may help explain the contradictions within the existing literature on the role of vision in allocentric spatial processing.

Enriched Audio Description: Working Towards an Inclusive Museum Experience

Within a museum context, audio description (AD) is generally thought to be a tool for enhancing access for people with a visual impairment, in other words, as a means of providing access, through verbal description, to visual details of an object or artwork. Taking evidence from researchers and practitioners, we argue that AD has a much broader potential scope and benefit. We consider AD in more established fields, such as film, and then explore the issues impacting on AD within museum environments. We also explore the literature on multisensory learning and memory, to create a rationale for the benefits of AD based on multisensory imagery, with or without perceptual experience. We conclude that, through the use of imagery, AD has the potential to guide people around a painting or object in a way which can enhance the ‘seeing’ ability of all people, whether or not they have sight. Further, multisensory experience, based on imagery or perceptual experience, combined with semantic or fact information, would enhance memorability. As such, taking AD from the niche audience of visual impairment, and projecting it into the mass market of the ‘sighted’, could have a revolutionary impact on the museum experience and our understanding of access and difference.