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Biomedical subjects

S Danziger

Publications and source records attributed to S Danziger.

17 recordsLinked to original sources
PubMed2001

Environmentally defined frames of reference: their time course and sensitivity to spatial cues and attention.

In a Simon task the effects of spatial cues and attention on spatial stimulus coding were explored. Participants made speeded responses corresponding to the direction of target arrows that were preceded by peripherally presented cues. Cue validity varied across experiments as did the percentage of trials on which the target appeared peripherally or centrally. The data indicate (a) that targets are coded relative to multiple reference frames, (b) that spatial coding of a target is not affected when attention is shifted to the target, and (c) that an object serves as a referent for spatial coding of other objects even after its spatial code no longer activates responses.

Adult↗
PubMed2000

Asymmetries in a unilateral flanker task depend on the direction of the response: the role of attentional shift and perceptual grouping.

Four experiments were conducted using a flanker task with 1 distractor appearing either on the left or right side of a central target. Responses were made on a keyboard aligned parallel to the displays. A larger flanker effect was obtained when the distractor was on the same side as the response. Two factors account for this asymmetry. First, when the flanker and target are identical, the 2 form a group that is assigned a spatial tag, creating a form of the Simon effect on the basis of the compatibility between the response keys and the group. Second, preparation of a lateralized response appears to entail a shift of visual attention in the corresponding direction, thus enhancing processing of the flanker on the response side. Consistent with the 2nd hypothesis, participants were more likely to correctly recognize letters that were briefly presented at the distractor position on the same side as the response.

Adult↗
PubMed2000

Social and environmental predictors of maternal depression in current and recent welfare recipients.

Depression is highly prevalent in welfare recipients, and is associated with failure to move from welfare to work. This paper examines the relationship between social and environmental factors in a large, community-based sample of mothers who currently or recently received welfare benefits. Specific and modifiable risk factors related to poverty, gender, and race were found to predict major depression beyond traditional risk factors. Research and practice implications are discussed.

Adult↗
PubMed2000

Welfare reform, substance use, and mental health.

Reform has transformed traditional entitlement to cash welfare under Aid to Families with Dependent Children (AFDC) into a transitional program known as Temporary Assistance to Needy Families (TANF). Because of the new work requirements and the time-limited nature of assistance, policy makers are increasingly confronted with what to do when welfare recipients do not effectively make the transition from welfare to work. Increasingly, the language of public health is being used to determine who is "employable" and who is not. Thus renewed attention is being focused on the individual characteristics of participants themselves, particularly specific diagnoses that might reduce employability. This article focuses on substance abuse and mental health problems among single mothers and examines their relationship to welfare receipt. We analyze data from the 1994 and 1995 National Household Survey of Drug Abuse (NHSDA) and find that 19 percent of welfare recipients meet the criteria for a DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders, third edition revised) psychiatric diagnosis. About the same percentage have used illicit drugs during the previous year. Logistic regression results indicate that mental and behavioral health problems that are significant barriers to self-sufficiency are increasingly important in this era of time-limited benefits.

Adult↗
PubMed2000

Stroop interference and negative priming: problems with inferences from null results.

The Stroop color-naming effect has often been taken as evidence for the automaticity of word processing (MacLeod, 1991). Recently, Besner, Stolz, and Boutilier (1997) reported that coloring a single letter instead of the whole word eliminated the Stroop effect. From this finding, they concluded that word processing could not be purely automatic, since it can be prevented. We asked whether the elimination of the Stroop effect is sufficient evidence for concluding that the word is not processed. Combining Besner et al.'s manipulation with a negative-priming procedure, we found intact negative priming from the prime color word in the absence of a Stroop effect. This result clearly indicates that the meaning of the prime word was processed. The findings highlight the importance of using converging methods to evaluate lack of processing.

Adult↗
PubMed1999

The oculomotor gap effect without a foveal fixation point.

Turning off a fixation point prior to or coincident with the appearance of a visual target reduces the latency of saccades to that target. We investigated this 'gap effect' when subjects fixated a central point or the center of a square formed by four points that were 4, 2 or 1 degree eccentric from the square's center. The fixation anchor vanished 200 ms prior to the appearance of a saccadic target in a Gap condition, coincident with the target's appearance in a 0-Gap condition, or remained on in an Overlap condition. Saccadic reaction time was reduced in the Gap relative to 0-Gap condition irrespective of the type of fixation anchor. However, saccadic reaction time was not reduced in the 0-Gap relative to Overlap condition when the points forming the square had eccentricities of 2 or 4 degrees. Results are interpreted in terms of a partial mediation of the gap effect by fixation cells in the rostral pole of the superior colliculus.

Analysis of Variance↗
PubMed1999

Unmasking the inhibition of return phenomenon.

Conventional wisdom holds that a nonpredictive peripheral cue produces a biphasic response time (RT) pattern: early facilitation at the cued location, followed by an RT delay at that location. The latter effect is called inhibition of return (IOR). In two experiments, we report that IOR occurs at a cued location far earlier than was previously thought, and that it is distinct from attentional orienting. In Experiment 1, IOR was observed early (i.e., within 50 msec) at the cued location, when the cue predicted that a detection target would occur at another location. In Experiment 2, this early IOR effect was demonstrated to occur for target detection, but not for target identification. We conclude that previous failures to observe early IOR at a cued location may have been due to attention being directed to the cued location and thus "masking" IOR.

Adolescent↗
PubMed1998

Inhibition of return to successively stimulated locations in a sequential visual search paradigm.

The inhibition of return (IOR) effect refers to a slowing in response time for a target that appears at a previously attended location. Many investigators have speculated that IOR's inherent ecological validity may be to ensure an efficient search of a complex environment by creating a bias against returning to locations that have already been investigated. Unfortunately, this intriguing idea has lacked compelling empirical support. The current study addressed this issue. It was shown that in a novel visual search task, the IOR could dwell at a minimum of 3 spatially noncontiguous locations. These data suggest that IOR may serve as an important mechanism for facilitating visual search in complex environments, by inhibiting attention from returning to previously inspected locations.

Adult↗
PubMed1997

Inhibitory Tagging of Locations in the Blind Field of Hemianopic Patients

This study evaluated the potential contribution of extrageniculate visual pathways to oculomotor orienting reflexes in hemianopic patients. It tested whether extrageniculate pathways mediate inhibition of return (IOR)-a phenomenon characterized by slowed target detections at recently stimulated locations (Posner & Cohen, 1984). Because hemianopic subjects cannot overtly respond to stimuli presented within their hemianopic field, we utilized a spatial cueing paradigm that capitalized on the fact that IOR operates in spatiotopic coordinates. Subjects moved their eyes so that a cue and a target presented at the same spatial location were imaged successively onto blind and seeing portions of their retinas. One hemianopic patient showed a similar IOR effect from cues presented within both the seeing and the hemianopic fields. With a second hemianopic patient, only presentations of the cue to the subject's seeing field produced IOR. The explanation for this discrepancy is not evident. These observations highlight both the potential value and the pitfalls inherent in using "blindsight" as a window into human consciousness.

Journal Article↗
PubMed1987

Interpreting changes in the economic status of the elderly, 1949-1979.

"This paper analyzes changes in the economic well-being of the elderly using data from the [U.S.] Decennial Censuses of 1950 through 1980. We find that the economic status of each elderly cohort is higher on average than that of the preceding cohort. Certain events associated with age--retirement for both men and women and widowhood for women--are associated with declining incomes. Controlling for sex, labor force participation, and marital status, however, the economic well-being of elderly cohorts generally increases with age."

Adult↗
PubMedDate not supplied

Inhibitory tagging of locations in the blind field of hemianopic patients.

This study evaluated the potential contribution of extrageniculate visual pathways to oculomotor orienting reflexes in hemianopic patients. It tested whether extrageniculate pathways mediate inhibition of return (IOR)-a phenomenon characterized by slowed target detections at recently stimulated locations (Posner & Cohen, 1984). Because hemianopic subjects cannot overtly respond to stimuli presented within their hemianopic field, we utilized a spatial cueing paradigm that capitalized on the fact that IOR operates in spatiotopic coordinates. Subjects moved their eyes so that a cue and a target presented at the same spatial location were imaged successively onto blind and seeing portions of their retinas. One hemianopic patient showed a similar IOR effect from cues presented within both the seeing and the hemianopic fields. With a second hemianopic patient, only presentations of the cue to the subject's seeing field produced IOR. The explanation for this discrepancy is not evident. These observations highlight both the potential value and the pitfalls inherent in using "blindsight" as a window into human consciousness.

Brain↗
PubMedDate not supplied

The effects of unilateral pulvinar damage in humans on reflexive orienting and filtering of irrelevant information.

The effects of damage to the pulvinar nucleus of the thalamus in humans on reflexive orienting and selective attention were investigated. In a spatial orienting task three patients with unilateral pulvinar damage determined the location of a visual target that followed a cue that was not informative as to the targets location. Contralesional targets were responded to more slowly than ipsilesional targets. Also, at long cue target intervals patients responses to contralesional targets that appeared at previously cued locations were slower than to non-cued locations indicating that pulvinar damage does not affect inhibition of return. In the selective attention task two of the patients identified a target that appeared at one level of a global-local hierarchical stimulus while ignoring a distractor present at the other level. The distractor indicated either the same response as the target or a different response. Response times to targets in both visual fields were similar as were interference effects from the ignored distractors. These data indicate that engaging attention contralesionally is not impaired in discrimination tasks and that filtering of irrelevant information was not impaired contralesionally.

Attention↗