Rapid Serial Processing Research Articles

Incidental learning during rapid information processing on the symbol-digit modalities test.

The Symbol--Digit Modalities Test (SDMT) is widely used to assess processing speed in MS patients. We developed a computerized version of the SDMT (c-SDMT) that scored participants' performance during subintervals over the course of the usual 90-s time period and also added an incidental learning test (c-ILT) to assess how well participants learned the symbol-digit associations while completing the c-SDMT. Patients with MS (n = 65) achieved lower scores than healthy controls (n = 38) on both the c-SDMT and c-ILT, and the scores on the two tests were correlated. However, no increase in the rate of item completion occurred for either group over the course of the c-SDMT, and the difference between groups was the same during each subinterval. Therefore, it seems implausible that controls completed more items on the c-SDMT because they were more adept at learning the symbol-digit associations as the test ensued. Instead, MS patients' poorer incidental learning performance appears to reflect the greater attentional burden that tasks requiring rapid serial processing of information impose upon them.

Rapid serial processing of natural scenes: Color modulates detection but neither recognition nor the attentional blink

The exact function of color vision for natural-scene perception has remained puzzling. In rapid serial visual presentation (RSVP) tasks, categorically defined targets (e.g., animals) are detected typically slightly better for color than for grayscale stimuli. Here we test the effect of color on animal detection, recognition, and the attentional blink. We present color and grayscale RSVP sequences with up to two target images (animals) embedded. In some conditions, we modify either the hue or the intensity of each pixel. We confirm a benefit of color over grayscale images for animal detection over a range of stimulus onset asynchronies (SOAs), with improved hit rates from 50 to 120 ms and overall improved performance from 90 to 120 ms. For stimuli in which the hue is inverted, performance is similar to grayscale for small SOAs and indistinguishable from original color only for large SOAs. For subordinate category discrimination, color provides no additional benefit. Color and grayscale sequences show an attentional blink, but differences between color and grayscale are fully explained by single-target differences, ruling out the possibility that the color benefit is purely attentional.

Procedural Variations in the Stroop and the Symbol Digit Modalities Test: Impact on Patients with Multiple Sclerosis

Decreased information processing speed is often cited as the primary cognitive deficit occurring in conjunction with multiple sclerosis (MS). Two common tools for assessing this deficit are the Stroop Test and the Symbol Digit Modalities Test (SDMT). However, there are procedural variations in these rapid serial processing (RSP) tests pertaining to the response format (e.g., verbal or manual) and the administration format (e.g., paper-based or computerized). The present study was designed to assess whether such variations impact MS patients' and healthy individuals' performance on these tests. In Experiment 1, we showed that response formats in which either the experimenter or the participant was responsible for advancing the items on computerized versions of the Stroop Test and the SDMT were basically equivalent in terms of distinguishing between patients and controls. In Experiment 2, we found differences between administration formats that appear to interact with some of the disease-related features of MS. Understanding how procedural variations differentially impact patients and controls can be useful for interpreting what RSP tests reveal about the cognitive impact of MS.

Reaction Time and Rapid Serial Processing Measures of Information Processing Speed in Multiple Sclerosis: Complexity, Compounding, and Augmentation

Information processing speed is frequently cited as the primary cognitive domain impacted by multiple sclerosis (MS) and is usually evaluated with reaction time (RT) or rapid serial processing (RSP) measures. The present study compared the efficacy of RT and RSP measures to distinguish between patients with MS (N = 42) and healthy controls (N = 40). The RT measure was patterned after the Computerized Tests of Information Processing and included measures of simple, choice, and semantic RT. The RSP measures consisted of the Symbol Digit Modalities Test (SDMT) and the Stroop Test. Substantial differences in information processing speed between patients and controls were found on all tests, with slightly larger effect sizes for RSP measures than RT measures and for the SDMT than the Stroop Test. Binary logistic regression analyses showed RSP measures performed better than RT measures at distinguishing patients from controls, and likewise, the SDMT score performed better than the scores derived from the Stroop Test. Results are discussed in the context of three effects associated with common measures of processing speed: complexity, compounding, and augmentation.

Deficits in Processing Speed in Patients with Multiple Sclerosis: Evidence from Explicit and Covert Measures

Cognitive slowing in individuals with multiple sclerosis (MS) has been documented by numerous studies employing explicitly timed measures in which speed of responding is an obvious focus of task performance. The present study examined information processing speed in MS patients and controls with a computerized battery of covertly timed as well as explicitly timed measures. The explicit measures were derived from two tests requiring rapid serial processing of visual stimuli, the Stroop Test and a Picture Naming Test. Covert measures were derived from the Rotated Figures Test, Remote Associates Test, and Tower of London, all tasks in which participants' attention was drawn toward arriving at an accurate solution, and the latency with which they arrived at these solutions was timed by the computer "behind the scenes." Significant differences in processing speed for patients and controls occurred on both types of measures, although the effect sizes were notably larger on the explicit measures.

Competition for Cognitive Resources During Rapid Serial Processing: Changes Across Childhood

The ability to direct cognitive resources to target objects despite distraction by competing information plays an important role for the development of mental aptitudes and skills. We examined developmental changes of this ability in a cross-sectional design, using the “attentional blink” (AB) paradigm. The AB is a pronounced impairment of T2 report, which occurs when a first (T1) and second target (T2) embedded in a rapid stimulus sequence are separated by at least one distractor and occur within 500 ms of each other. Two groups of children (6- to 7-year-olds and 10- to 11-year-olds; ns = 21 and 24, respectively) were asked to identify green targets in two AB tasks: one using non-linguistic symbols and the other letters or words. The temporal distance or stimulus-onset asynchrony (SOA) between T1 and T2 varied between no intervening distractor (Lag 1, 116-ms SOA) and up to 7 intervening distractors (Lag 8, 928-ms SOA). In the symbol task, younger children linearly increased T2 identification with increasing lag. Older children, however, displayed a hook-shaped pattern as typically seen in adults, with lowest identification reports in T2 symbols at the critical blink interval (Lag 2, 232-ms SOA), and a slight performance gain for the Lag 1 condition. In the verbal task, the older group again exhibited a prominent drop in T2 identification at Lag 2, whereas the younger group showed a more alleviated and temporally diffuse AB impairment. Taken together, this pattern of results suggests that the control of attention allocation and/or working memory consolidation of targets among distractors represents a cognitive skill that emerges during primary school age.

Evaluating Processing Speed in Multiple Sclerosis: A Comparison of Two Rapid Serial Processing Measures

Processing speed deficits in patients with multiple sclerosis (MS) are usually assessed with tests requiring rapid serial processing. Two such tests were compared here, the Paced Auditory Serial Addition Test (PASAT) and a computerized version of the Stroop test. The purpose of this study was to examine the concurrent validity of processing speed measures derived from the Stroop test and to relate these measures to disability ratings in a sample of 75 patients with relapsing-remitting MS. Patients evidenced slower processing speed than controls on both tests. Processing speed scores on the Stroop test were more closely related to patients’ disability status. These results demonstrate the usefulness of rapid serial processing tests in assessing what is increasingly recognized as the primary cognitive deficit in MS. A less-distressing approach than the item-paced performance required by the PASAT appears to be fully adequate for evaluating this deficit.

Instinctive modulation of cognitive behavior: A human evoked potential study

Successful adaptive behavior requires fast information processing. Behavioral switches may be necessary in response to threatening stimuli or when anticipated outcomes fail to occur. In this study, we explored the cortical processing of these two components using high-resolution evoked potentials. Subjects made a reversal learning task where they had to predict which one of two faces had a target stimulus on the nose. We found early electrocortical differences at 100-200 ms depending on whether the target stimulus was a spider or a disk. Source estimation indicated that this distinction was mediated by an anterior medial temporal region including the amygdala and adjacent cortex. When a switch to the alternate face was required, there was a discrete early electrocortical correlate after 200 ms, mediated by ventromedial prefrontal areas. Continued validity of stimulus-target associations was signaled at 400-520 ms, mediated by the parahippocampal region. The study indicates rapid serial processing of innate emotional quality, then cognitive-behavioral relevance of stimuli, mediated by limbic and paralimbic structures.

Rapid serial processing in patients with multiple sclerosis: The role of peripheral deficits

This study compared speed of information processing in patients with relapsing-remitting or secondary progressive multiple sclerosis (MS) and healthy controls using the Stroop Test and a Picture Naming Test (PNT). While both tests evaluated processing speed within a format calling for rapid serial processing of stimulus information, the PNT included trials designed to impose greater verbal-motor and ocular-motor challenges by using novel rather than repeated pictures and by presenting the pictures in distributed locations rather than always centered on the screen. The results confirmed that a decrease in the speed of information processing is a key feature of the cognitive impairment occurring in conjunction with MS. When this feature is evaluated with tests requiring rapid serial processing of stimulus information, the contribution of peripheral motor deficits appears to be modest.