Biomedical subjects

Cathleen M Moore

Publications and source records attributed to Cathleen M Moore.

9 recordsLinked to original sources

PubMed2006

What you see is what you get: functional equivalence of a perceptually filled-in surface and a physically presented stimulus.

A perceptually filled-in surface, such as occurs during sustained attention to a peripheral stimulus (Troxler fading), can be functionally equivalent to a physically presented stimulus. Observers failed to detect probes that were presented in the location of a filled-in surface that had the same surface attributes as the probes; this was true even though, physically, the probes contrasted with the background. Probe stimuli with surface characteristics different from those of the filled-in surface were detected more often, though not quite as often as when there was no filled-in surface. Together, these findings support the idea that there are two components in perceptual filling: a neural filling-in component and a sustained-attention component, which actively suppresses perceptual processing at the filled-in location. More broadly, they illustrate the interplay of basic visual mechanisms in the creation and representation of visual surfaces and in the coding and detection of changes to these surfaces.

Attention↗

PubMed2005

On the role of object representations in substitution masking.

Three experiments were conducted to investigate the role of object representations in object substitution masking (OSM). OSM occurs when a very sparse mask is presented simultaneously with a target stimulus and the target offsets first, leaving the mask to linger in the display for some time. Results confirm earlier claims that there is an isolatable object-level component to OSM and indicate that a target can be protected from OSM if, prior to offsetting, it can be represented as a distinct object from the mask. When the mask was presented as sliding past the target (Experiment 1), as jiggling independently of the target (Experiment 2), or in a different color from the target (Experiment 3), OSM was reduced or eliminated. This suggests that OSM reflects basic updating processes that allow the perception of continuity of object identity over change.

Humans↗

PubMed2005

The spread of attention to hidden portions of occluded surfaces.

We report two experiments in which the two-rectangles method of Egly, Driver, and Rafal (1994) was used to test whether object-specific attentional cuing advantages can spread to hidden portions of occluded objects. Displays began with portions of two rectangles hidden by a third, occluding object. One end of one of the two rectangles was cued, after which the occluder rotated around its center point and target stimuli were presented. In one condition, the occluder was removed from in front of the other objects, either by rotating away from them (Experiment 1B) or by rotating and then slipping behind them (Experiment 1B). In another condition, the occluder first rotated away but then returned to its original position. In both experiments, an object-specific cuing advantage occurred in the occluder-removed condition for targets that appeared in what had been hidden locations of the cued object. No analogous advantage occurred in the occluder-returned condition.

Adolescent↗

PubMed2004

Object updating and the flash-lag effect.

Flash lag is a misperception of spatial relations between a moving object and a briefly flashed stationary one. This study began with the observation that the illusion occurs when the moving object continues following the flash, but is eliminated if the object's motion path ends with the flash. The data show that disrupting the continuity of the moving object, via a transient change in size or color, also eliminates the illusion. We propose that this is because a large feature change leads to the formation of a second object representation. Direct evidence for this proposal is provided by the results for a corollary perceptual feature of the disruption in object continuity: the perception of two objects, rather than only one, on the motion path.

Analysis of Variance↗

PubMed2004

Looking for the source of the simon effect: evidence of multiple codes.

The Simon effect (SE) usually is described as the performance advantage that results when a target and its associated response share the same spatial code, as opposed to when they do not, even when the target's spatial code is task-irrelevant. To some, this task-irrelevant code represents the location of the target with respect to the participant (Simon & Craft, 1970), whereas to others (Umiltà & Nicoletti, 1992) it represents the location of the target with respect to the locus of attention. By using a spatial cuing procedure, we simultaneously tested both of these hypotheses and found evidence that both types of codes produce independent SEs, therefore providing evidence that multiple spatial codes can simultaneously influence performance in a Simon task.

Attention↗

PubMed2003

Temporal organization of covert motor processes during response selection and preparation.

Onset of a movement-related brain potential (lateralized readiness potential, LRP) was used to divide reaction time (RT) into two intervals: (1) stimulus onset to LRP onset, and (2) LRP onset to onset of the overt response. Effects on these intervals of advance information about the to-be-signaled response and of the mapping between fingers and response buttons were examined. These effects were used to reach conclusions about the organization of response preparation and about the identity of the processes influenced by advance information. In the absence of advance information, response preparation involved two steps. First, two of the four possible response alternatives were prepared, then one of these two was prepared further. Which pair of responses was prepared during the first step depended on the spatial arrangement of the fingers on the buttons, rather than on any common anatomical feature. Advance information about the upcoming response allowed the first step to be performed prior to the response signal, thus removing its contribution to RT. The second step, however, remained unaffected.

Arousal↗

PubMed2003

Object-based selection in the two-rectangles method is not an artifact of the three-sided directional cue.

A common means of investigating object-specific selection is the two-rectangles method, in which a target appears at one end of two rectangles (Egly, Driver, & Rafal, 1994). Prior to target presentation, one end of two parallel rectangles is cued by brightening the three line segments along one of its ends. When the target appears in the opposite end of the cued rectangle, responses tend to be faster and more accurate than when it appears in the end of the other rectangle, which is equally distant from the cue. This effect has been taken as evidence of object-specific selection of information. The present study rules out the concern that the object-specific effect that is found with this method is caused by the directional nature of the cue. That is, the three-sided cue, which essentially points to the "same-object" location, does not itself give rise to the object-specific advantage. These results are discussed in terms of the combined roles of explicit object structure in the scene, past experience, and task set as contributing to the way in which information is organized and selected from a scene.

Adult↗

PubMed2003

When the target becomes the mask: using apparent motion to isolate the object-level component of object substitution masking.

J. T. Enns and V. Di Lollo (1997) discovered a new form of visual masking that they labeled object substitution masking (OSM). OSM occurs when 4 dots, presented around a target, trail in the display after target offset. The present study showed that the physical presence of the masking dots after target offset is not necessary for OSM. Instead, the continued presence of a changing high-level representation associated with the target suffices to yield OSM. Apparent motion was used to define such representation. In these experiments, the initial display offset and was followed by a 2nd display where masks appeared at new locations. Only when the spatiotemporal properties of the stimuli on the 2nd display supported the perception of the target moving and turning into the mask was OSM observed.

Analysis of Variance↗

PubMed2002

Feature-specific perceptual processing dissociates action from recognition.

Does visual processing differ for action and recognition? To address this question, the authors capitalized on research showing that color is preferred over binocular disparity in the ventral (recognition) stream, whereas disparity is preferred over color in the dorsal (action) stream. Participants searched for oblique targets among vertical distractors in displays defined only by color or disparity. Action-task participants stamped the target with a handheld block, whereas recognition-task participants lifted the block through a target-compatible gap. Analyses of reaction time and time-varying hand orientation showed that disparity and color displays were processed equally efficiently during action, but disparity was processed less efficiently than color during recognition. The results suggest that visual processing differs for action and recognition.

Adolescent↗