Grounding spatial language in the motor system: Reciprocal interactions between spatial semantics and orienting

Shifts of attention that are directed by spatial words are thought to be mediated by a spatial frame of reference. Previous studies have documented a selection cost when visual attention is directed along the left/right axis relative to the above/below axis due to the greater ambiguity of the horizontal endpoints. The present study investigated whether the horizontal endpoints may be more fully disambiguated when “left/right” cues are first enacted by nondivisible, more discrete, modes of orienting such as directional motor responses. This issue was investigated using a repetition priming paradigm in which the effects of prior enactments were measured on the subsequent conceptual control of visual attention. The results of four experiments showed that grounding spatial language in the motor system can enhance the focus of visual attention by disambiguating the endpoints of the horizontal axis. In so doing, the present study extends previous research demonstrating that spatial concepts can influence the spatial distribution of attention by demonstrating that different modes of orienting can also influence the semantics of space. Implications for the premotor theory of attention and grounded theories of cognition are also discussed.     

Attentional capture by onsets and offsets

Three experiments were conducted to examine whether human infants would form a categorical representation for the spatial relation between. Experiment 1 showed that 6- and 7-month-olds familiarized with stimuli depicting a diamond in different locations between two reference bars subsequently preferred a stimulus displaying the diamond located outside the bars over a stimulus displaying the diamond located in a novel position between the bars. Experiments 2 and 3 revealed that this preference could not be attributed to a failure to discriminate the location changes of the diamond between the bars or an a priori preference. The overall pattern of results indicates that 6- and 7-month-olds had formed a categorical representation for between. The findings are discussed in terms of factors affecting development of categorical representations for spatial relation information.     

Strategic and automatic effects of visual working memory on attention in visual search

Previous research indicates that visual attention can be automatically captured by sensory inputs that match the contents of visual working memory. However, Woodman and Luck (2007) showed that information in working memory can be used flexibly as a template for either selection or rejection according to task demands. We report two experiments that extend their work. Participants performed a visual search task while maintaining items in visual working memory. Memory items were presented for either a short or long exposure duration immediately prior to the search task. Memory was tested by a change-detection task immediately afterwards. On a random half of trials items in memory matched either one distractor in the search task (Experiment 1) or three (Experiment 2). The main result was that matching distractors speeded or slowed target detection depending on whether memory items were presented for a long or short duration. These effects were more in evidence with three matching distractors than one. We conclude that the influence of visual working memory on visual search is indeed flexible but is not solely a function of task demands. Our results suggest that attentional capture by perceptual inputs matching information in visual working memory involves a fast automatic process that can be overridden by a slower top-down process of attentional avoidance.     

Rewards shape attentional search modes

Visual attention can be configured for specific stimulus features (feature search mode) or it can be non-specifically set for salient pop-outs (singleton detection mode). Additionally, monetary rewards have been shown to bias attention toward specific features, but it is unknown whether secondary reinforcers (images of US$) can shape global attention via search modes. In a between-group study, we trained participants to value one search mode over the other. In a testing phase, a salient distractor captured the attention of the value-singleton group; however, the value feature group was completely unaffected. This suggests that rewards automatically bias global attention mechanisms and potentially mediate the handoff between stimulus-driven and goal-directed attentional control.     

You can't stop new motion: Attentional capture despite a control set for colour

When a stationary object begins to move, visual spatial attention is reflexively deployed to the location of that object. We tested whether this capture of attention by new motion is entirely stimulus driven, or whether it is contingent on an observer's goals. Participants monitored a visual display for a colour change, inducing an attentional control set (ACS) for colour. Across the three performed experiments, irrelevant new-motion cues always captured visual spatial attention, despite the ACS for colour. This persistence of the attentional cueing effect demonstrates that ACSs, in particular an ACS for colour, cannot prevent new motion from capturing attention. Unlike other stimulus types, such as luminance changes, colour singletons, and new objects, new motion may always capture attention regardless of an observer's goals. This conclusion entails that new motion is an important determinant of when, and to where, visual spatial attention is deployed.     

The role of space and time in object-based visual search

Recently we have provided evidence that observers more readily select a target from a visual search display if the motion trajectory of the display object suggests that the observer has dealt with it before. Here we test the prediction that this object-based memory effect on search breaks down if the spatiotemporal trajectory is disrupted. Observers searched a display for a target shape among multiple distractors. The entire search display then passed behind an occluder and reemerged in either the same or a different configuration. Experiment 1 shows that the same-object benefit for selection disappears whenever a spatial disruption is involved, but that it may survive a brief temporal disruption. Experiment 2 shows that with sufficiently long gaps, a temporal disruption also destroys the same-object benefit for selective attention. Experiment 3 demonstrates that the same-object effect is even stronger when there only is a very small probability that the target can be found at the same location as before. This also made the task sensitive to brief temporal disruptions. We conclude that a coherent spatiotemporal history of a display object supports the selection of its relevant subregions.     

An outline explanation of how therapy heals

Therapists are unable to provide a comprehensive account of therapy as an intelligible activity. This is at least partly due to the unresolved problem of explaining how phenomenology is even possible. An alternative to providing a comprehensive account of therapy is to take the fact of phenomenology for granted and provide just an outline account of how therapy heals. One way this can be achieved is to set therapy in the context of medical anthropology which will facilitate a view of therapy as just another healing ritual. Insight into how healing rituals heal is provided in this paper by a long and in-depth look at the so-called ‘paradox’ of the placebo effect. This will reveal the so-called ‘placebo effect’ as a misunderstood, modern example of healing ritual self-healing. In fact, the single term ‘placebo effect’ will be abandoned and replaced by the two concepts of ‘SMCH’ (‘specifically modified consultation and health care’) and ‘RMH’ (‘response to modified health care’). These two concepts provide an outline explanation of how all healing rituals heal and so provide an outline explanation of how the healing ritual of therapy heals, also. At least one problem arises out of explaining therapy as healing ritual self-healing, namely that this conception conflicts with the idea in therapy circles that, in therapy, it is the relationship that counts. Nonetheless, it will be maintained that the purpose of therapy is healing, that the healing that is achieved is self-healing and that its fulfilment is not dependent upon one-to-one relationships. Finally, it will be argued that the further development of therapy requires a better understanding of what aids and obstructs psycho-emotional self-healing.     

To freeze or not to freeze? Affective and cognitive perturbations have markedly different effects on postural control

Similar effects have been reported for diverting attention from postural control and increased anxiety on the characteristics of center-of-pressure (COP) time series (decreased excursions and elevated mean power frequency). These effects have also received similar interpretations in terms of increased postural stiffness, suggesting that cognitive and affective manipulations have similar influences on postural control. The present experiment tested this hypothesis by comparing postural conditions involving manipulations of attention (diverting attention from posture using cognitive and motor dual tasks) and anxiety (standing at a height), and by complementing posturography with electromyographic analyses to directly examine neuromuscular stiffness control. Affective and cognitive manipulations had markedly different effects. Unlike the height condition, diverting attention from balance induced smaller COP amplitudes and higher sway frequencies. In addition, more regular COP trajectories (lower sample entropy) were found in the height condition than the dual-task conditions, suggesting elevated attentional investment in posture under the affective manipulation. Finally, based on an analysis of the cross-correlation function between anterior-posterior COP time series and enveloped calf muscle activity, indications of tighter anticipatory neuromuscular control of posture were found for the height condition only. Our data suggest that affective and cognitive perturbations have qualitatively different effects on postural control, and thus are likely to be associated with different control processes, as evidenced by differences in neuromuscular regulation and attentional investment in posture.     

Attentional disengagement in adults with Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder characterized by a distinctive behavioral and cognitive profile, including widespread problems with attention. However, the specific nature of their attentional difficulties, such as inappropriate attentional allocation and/or poor attentional disengagement abilities, has yet to be elucidated. Furthermore, it is unknown if there is an underlying difficulty with the temporal dynamics of attention in WS or if their attentional difficulties are task-dependent, because previous studies have examined attention in established areas of deficit and atypicality (specifically, visuospatial and face processing). In this study, we examined attentional processing in 14 adults with WS (20–59 years) and 17 typically developing controls (19–39 years) using an attentional blink (AB) paradigm. The AB is the decreased ability to detect a second target when it is presented in close proximity to an initial target. Overall, adults with WS had an AB that was prolonged in duration, but no different in magnitude, compared with typically developing control participants. AB performance was not explained by IQ, working memory, or processing speed in either group. Thus, results suggest that the attention problems in WS are primarily due to general attentional disengagement difficulties rather than inappropriate attentional allocation.     

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.