Biomedical subjects

Karen M Arnell

Publications and source records attributed to Karen M Arnell.

7 recordsLinked to original sources

PubMed2006

The ABCs of computerized naming: equivalency, reliability, and predictive validity of a computerized rapid automatized naming (RAN) task.

Population-based studies indicate dual routes to disabled reading in adolescence and adulthood: slowed acquisition of single word reading and ADHD (particularly inattention) in early childhood. Impairments in rapid serial naming may be a factor common to both problems. The gold-standard measure of this ability, the Rapid Automatized Naming Task (RAN; [Denckla MB, Rudel R. Rapid automatized naming of pictured objects, colors, letters and numbers by normal children. Cortex 1974;10:186-202]), has traditionally been administered in a paper-pencil format. Recently however, researchers [Neuhaus GF, Carlson CD, Jeng WM, Post Y, Swank PR. The reliability and validity of rapid automatized scoring software ratings for the determination of pause and articulation component durations. Educ Psychol Meas 2001;61:490-504] have begun to use computerized versions of the RAN. Here a slightly modified computerized version of the RAN was created and the equivalency between the computerized RAN and the conventional version was investigated using a university student sample. Naming times on the conventional and computerized RAN were highly correlated, overall, and for each of the four RAN stimulus types (letters, digit, colors, objects). Conventional and computerized RAN times predicted reading rate and reading comprehension scores equally well and both showed very high test-retest reliability. With our university student sample, findings indicate equivalency between the two testing mediums in all areas examined.

Adult↗

PubMed2006

Visual, auditory, and cross-modality dual-task costs: electrophysiological evidence for an amodal bottleneck on working memory consolidation.

When two masked, attended targets (T1 and T2) are presented within approximately half a second of each other, report of T2 is poor, compared with when the targets are presented farther apart in time--a phenomenon known as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992). Some researchers have suggested that an amodal bottleneck on working memory consolidation underlies the AB (see, e.g., Arnell & Jolicoeur, 1999). In the present work, T1 was masked, whereas T2 was unmasked. The modality of T1 (visual or auditory) and the modality of T2 (visual or auditory) were factorially manipulated across four experiments. For all modality combinations, T2's P3 event-related brain potential component was found to be delayed when T2 was presented soon after T1 (lag 3), compared with when T1 and T2 were presented farther apart (lag 8). Results suggest that the working memory consolidation bottleneck is amodal in nature, and provide evidence that visual, auditory, and cross-modality ABs all result from a bottleneck on consolidation operations.

Adolescent↗

PubMed2004

Revisiting within-modality and cross-modality attentional blinks: effects of target-distractor similarity.

When two masked targets (T1 and T2) require attention and are presented within half a second of each other, the report accuracy for T2 is reduced, relative to when the two targets are presented farther apart in time. This effect is known as the attentional blink (AB). Potter, Chun, Banks, and Muckenhoupt (1998) argued that all AB-like effects observed when at least one of the targets was presented outside of the visual modality did not represent true instances of the AB, but instead were artifacts of task-set switching. However, in the Potter et al. experiments the presence or absence of task-set switching opportunities was confounded with the T2 task, as well as the alphanumeric class of T2 with respect to the distractors. In the present experiment, we examine the influence of T1 alphanumeric class, T2 alphanumeric class, and switching operations in a fully crossed design that unconfounds these factors. In contrast to the conclusions of Potter et al., the present results suggest that the T2 alphanumeric class can account for the pattern of ABs observed across conditions, without necessarily implicating a separate switch cost. The implications for theoretical models of the AB and the debate over the validity of cross-modal ABs are discussed.

Adolescent↗

PubMed2004

Dissociating sources of dual-task interference using human electrophysiology.

In the psychological refractory period (PRP) paradigm, two unmasked targets are presented, each of which requires a speeded response. Response times to the second target (T2) are slowed when T2 is presented shortly after the first target (T1). Electrophysiological studies have previously shown that the P3 event-related potential component is not delayed during T2 response slowing in the PRP paradigm, but that the lateralized readiness potential is delayed, which suggests a bottleneck on response selection operations but not on stimulus identification. Recently, researchers (Arnell & Duncan, 2002; Jolicoeur & Dell'Acqua, 1999) observed T2 response slowing in an encoding-speeded response (ESR) paradigm where T2 followed a masked T1 that required identification but not a speeded response. T2 response slowing in the ESR paradigm is often indistinguishable from that in the PRP paradigm, prompting some researchers to postulate a common processing bottleneck for the two paradigms. With the use of the ESR paradigm, we observed T2 response slowing and, in contrast to the PRP paradigm, we also observed corresponding P3 delays. The results suggest that dissociable bottlenecks underlie the dual-task costs from the two paradigms.

Adult↗

PubMed2002

Separate and shared sources of dual-task cost in stimulus identification and response selection.

There is often strong interference if a second target stimulus (T2) is presented before processing of a prior target stimulus (T1) is complete. In the "Psychological Refractory Period" (PRP) paradigm, responses are speeded and interference manifests as increased response time for T2. In the "Attentional Blink" (AB) paradigm, stimuli are masked and responses unspeeded; interference manifests as reduced T2 accuracy. While different causes have usually been considered for PRP and AB phenomena, recent evidence has supported a unified account based on a single, shared restriction on concurrent processing. Here we show that a full assessment of separate and shared resource limitations requires direct comparison of hybrid PRP/AB trials with corresponding pure PRP and AB cases. Randomizing trial types in such a comparison also brings substantial benefit in addressing possible changes in task preparation or readiness. The data from two such experiments--combining speeded auditory (SA) and unspeeded visual (UV) task events--provide clear evidence for both separate and shared resource limitations. Often interference is strongest for T1 and T2 events of the same type, reflecting predominantly different limitations in SA and UV processing. With modest increases in demand, however, interference between different event types can also be made arbitrarily large, reflecting arbitrarily important shared limitations. For even such simple tasks as these, T--T2 interference reflects a combination of relatively local and relatively global sources.

Adolescent↗

PubMed2002

Cross-modality attentional blinks without preparatory task-set switching.

When two masked targets (T1 and T2), both requiring attention, are presented within half a second of each other, report of the second target is poor, demonstrating an attentional blink (AB). Potter, Chun, Banks, and Muckenhoupt (1998) argued that all previous demonstrations of an AB occurring when one or more targets were presented outside the visual modality did not represent true AB but were, instead, artifactual, resulting from switching of task set. In the present experiments, T1 and T2 modalities were independent and varied randomly from trial to trial, allowing no useful preparatory task-set switching from T1 to T2. However, reliable ABs were observed when both targets were visual, when both targets were auditory, and cross-modally when T2s were visual. Furthermore, the ABs observed for cross-modality visual T2s showed the characteristic U-shaped pattern often found in AB experiments in which two visual targets are used--a pattern that should not be observed under task-set switching conditions. These results provide evidence that cross-modality AB can be found under conditions that do not allow useful preparatory task-set switching.

Acoustic Stimulation↗

PubMed2002

Dual-task attention deficits in dysphoric mood.

The attentional functioning of nondysphoric, mildly dysphoric, and moderately to severely dysphoric college students was tested using the attentional blink (AB) paradigm. These groups performed equally well at reporting a single target appearing in a rapidly presented stream of stimuli. All groups showed an AB, with report sensitivity for a 2nd target being reduced when the 2 targets were presented less than 0.5 s apart. Nondysphoric and mildly dysphoric participants showed the same size ABs, but the ABs for moderately to severely dysphoric participants were larger and longer. As predicted, the results showed that moderately to severely dysphoric individuals have attentional impairments. These impairments, however, were evident only in the more demanding dual-task condition.

Adolescent↗