Biomedical subjects

Richard A Abrams

Publications and source records attributed to Richard A Abrams.

6 recordsLinked to original sources

PubMed2003

Motion onset captures attention.

Although visual motion may seem salient, motion per se does not automatically attract attention. We show here, however, that the onset of motion does indeed attract attention. In three experiments, subjects identified target letters in displays that contained targets and distractors. There was no advantage for moving letters among static ones, but there was an advantage for objects that had recently started to move despite the fact that the motion was uninformative. If some additional time was allowed to elapse after motion onset, inhibition of return slowed responding to the item that had started to move-a further sign that the motion onset had captured attention. Finally, detection of target letters was found to be independent of the number of distractors in the display if the target had undergone motion onset, also indicative of attentional capture. We discuss the adaptive significance of sensitivity to onsets in the presence of a relative insensitivity to ongoing motion.

Adult↗

PubMed2003

Inhibitory control following perinatal brain injury.

Evidence from developmental, lesion, and neuroimaging studies indicates that the prefrontal cortex plays a major role in executive abilities, including inhibitory control. Proficient executive performance, however, relies not only on the integrity of the prefrontal cortex but also on its interactions with other brain regions. In the current study, the authors focused on the effect that early damage to the white matter tracts interconnecting prefrontal and other brain regions has on inhibitory control. Data were collected from 13 children with bilateral spastic cerebral palsy and from a control group of 20 children with no history of neurologic compromise. Converging evidence from 3 separate paradigms is presented that strongly suggests these children experience impairments in inhibitory control. Findings are discussed within the context of current cognitive and neuroanatomical models of inhibition.

Adolescent↗

PubMed2003

A comparison of private and public dental students' perceptions of extramural programming.

This project was undertaken to compare the opinions of private and public dental school students' perceptions concerning extramural programming, which is defined as any aspect of the curriculum in which undergraduate dental students provide dental care outside the main dental facility. A survey instrument was used to collect data from undergraduate students at a private (N = 267; 88.4 percent response rate) and at a public (N = 213; 67.2 percent response rate) dental school. When asked to rate the value of various extramural sites in making them a better dentist, both groups rated private dental offices the most valuable and prisons the least valuable. When questioned about the amount of time students should spend each year in extramural programming, private students, overall, desired 34 percent more time than did public students. When asked what percentage of the total time spent in extramural programming students should spend providing various categories of dental care, public school students thought 26 percent more time should be spent rendering preventive services/health education than did the private students. The private students indicated a stronger desire (13 percent more) for rendering clinical services than did public students. Both private and public students were most likely to enter group private practice after graduation. The increasing interest in community-based programs makes the information gained from this study useful for future curriculum planning.

Community Dentistry↗

PubMed2002

Object-based selection within and beyond the focus of spatial attention.

In a series of experiments, we examined the effect of perceptual objects on visual attentional processing in the presence of spatially cued attentional selection. Subjects made speeded judgments about two visual elements that were either both on the same object or on two different objects. Judgments were faster when the elements were on the same object than when they were on different objects, revealing an object advantage. Importantly, the object advantage remained even when either exogenous or endogenous spatial cues were used to direct the subjects' attention to a part of the display, contrary to earlier findings of other researchers. The object advantage, however, did disappear when the stimulus duration was shortened substantially. The results show that object-based selection is pervasive and is not diminished by the act of selective attention. The results are discussed in terms of their implications for the mechanisms that underlie attentional selection.

Attention↗

PubMed2002

Inhibition of return in static and dynamic displays.

Inhibition of return (IOR) causes people to be slower to return their attention to a recently attended object (object-based IOR) or location (location-based IOR). In attempts to separately measure the two components, moving stimuli have been used that permit the dissociation of the attended object from its location when it was attended. The implicit assumption has been that both object- and location-based components of IOR will operate whenever the cued object and cued location are identical. We show here that although this assumption may be true in a static display, it appears to be unwarranted when moving stimuli are involved: Very little IOR is observed when a cued object moves away from, and then subsequently returns to, its initial location. Thus, the processes that underlie IOR operate very differently in static versus dynamic scenes.

Eye Movements↗

PubMed2001

Random visual noise impairs object-based attention.

Object-based visual attention is observed when the benefit of attending to one element in a display extends to other elements that are part of the same perceptual object. Apperceptive agnosia is an object identification deficit in which spatial attention is preserved but object-based attention is impaired. Some debate exists regarding the extent to which the object-based impairment can be attributed to perceptual mechanisms that are specifically involved in grouping and segmentation of a scene, as opposed to early sensory processes. In the present paper we show that random visual noise is sufficient to eliminate the object benefit, a result inconsistent with the view that grouping mechanisms are responsible for the effect. The results have implications for an understanding of apperceptive agnosia, and for an understanding of object-based attention more generally.

Adult↗