Attentional limits in memory retrieval.

The hypothesis that episodic memory retrieval can occur in parallel with other cognitive processes was tested in 2 experiments. Participants memorized words and then performed speeded cued recall (Experiment 1) or speeded yes-no recognition (Experiment 2) in a dual-task situation. The psychological refractory period design was used: The participant was presented with a single test item at various stimulus onset asynchronies (SOAs; 50-1,000 ms) after a tone was presented in an auditory-manual 2-alternative choice reaction task. Reducing the SOA increased the memory task reaction times. This slowing was additive with the effect of variables slowing retrieval in the memory task. The results indicate that memory retrieval is delayed by central processes in the choice task, arguing that the central bottleneck responsible for dual-task interference encompasses memory retrieval as well as response selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial modules in parallel: The psychological refractory period and perfect time-sharing.

The authors describe ACT-R/perceptual-motor (ACT-R/PM), an integrated theory of cognition, perception, and action that consists of the ACT-R production system and a set of perceptual-motor modules. Each module (including cognition) is essentially serial, but modules run in parallel with one another. ACT-R/PM can model simple dual tasks such as the psychological refractory period (PRP), including subtle results previously explained with executive process interactive control (EPIC, D. E. Meyer & D. E. Kieras, 1997a). The central difference between the theories is that EPIC's productions can fire in parallel, whereas in ACT-R/PM, they are serial. Results from three PRP-like experiments with more demanding cognitive requirements indicate that cognitive processing for the 2 tasks need not overlap. ACT-R's activation-based retrieval processes are critical in accounting for the timing of these tasks and for explaining the dual-task performance decrement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On Doing Two Things at Once: IV. Necessary and Sufficient Conditions: Rejoinder to Lien, Proctor, and Ruthruff (2003).

Responds to the reply by Lien et al (see case 2003-09958-012) to the author's comments (see record 2003-08747-004) on Lien et al's (see record 2002-02027-010) article about the psychological refractory period. Four publications have demonstrated perfect timesharing of 1 simultaneous decisions. In all of these, (a) subjects were motivated to respond as quickly as possible, and with 1 exception that involved unusually extensive practice (E. Hazeltine, D. Teague, & R. B. Ivry, 2002, Experiment 4), (b) at least 1 of the 2 tasks was characterized by ideomotor (IM) compatibility, meaning that each task stimulus incorporated a component of the sensory feedback from its required response. Conclusions justified by these reports are that (a) the use of speed-stress instructions is necessary for perfect timesharing of 2 simultaneous decision tasks: (b) when both tasks are IM compatible, perfect timesharing requires little or no practice: (c) extensive practice is needed to achieve perfect timesharing when only 1 of the 2 tasks is IM compatible: and (d) very large amounts of practice can yield perfect timesharing of 2 decision tasks when neither is IM compatible. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The problem state: A cognitive bottleneck in multitasking.

The main challenge for theories of multitasking is to predict when and how tasks interfere. Here, we focus on interference related to the problem state, a directly accessible intermediate representation of the current state of a task. On the basis of Salvucci and Taatgen’s (2008) threaded cognition theory, we predict interference if 2 or more tasks require a problem state but not when only one task requires one. This prediction was tested in a series of 3 experiments. In Experiment 1, a subtraction task and a text entry task had to be carried out concurrently. Both tasks were presented in 2 versions: one that required maintaining a problem state and one that did not. A significant overadditive interaction effect was observed, showing that the interference between tasks was maximal when both tasks required a problem state. The other 2 experiments tested whether the interference was indeed due to a problem state bottleneck, instead of cognitive load (Experiment 2: an alternative subtraction and text entry experiment) or a phonological loop bottleneck (Experiment 3: a triple-task experiment that added phonological processing). Both experiments supported the problem state hypothesis. To account for the observed behavior, computational cognitive models were developed using threaded cognition within the context of the cognitive architecture ACT-R (Anderson, 2007). The models confirm that a problem state bottleneck can explain the observed interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List-context effects in evaluative priming.

Evaluative priming effects are often found in the evaluative decision task, in which persons judge the affective connotation (positive vs. negative) of a target word. The present experiments examined list-context effects to test whether evaluative and semantic priming follow the same laws. In Experiment 1, evaluative priming was found at prime-target stimulus onset asynchronies (SOAs) of 0 ms and 100 ms, but not at SOAs of -100, 200, 600, and 1,200 ms. Experiment 2 manipulated SOA (0, 200, and 1,200 ms) and the proportion (25%, 50%, and 75%) of the prime-target pairs that were evaluatively related. Contrary to the typical finding that increases in the proportion of related prime-target pairs lead to increased priming at long but not short SOAs, an effect of consistency proportion was found at SOAs of 0 ms (for reaction times) and 200 ms (in the accuracy data), but not at the 1,200-ms SOA. The pattern of results is discussed in relation to possible explanatory mechanisms of evaluative priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in mental multiplication: evidence for peripheral but not central decrements

This study reports two mental multiplication experiments that were designed to measure age differences in central and peripheral processes. Experiment 1 varied task type (verification vs production), and Experiment 2 varied exposure duration (presentation until response, 600 ms, and 300 ms) on a production task. Neither experiment showed evidence of age differences in central processes (e.g., retrieval speed); however, there was some evidence of a peripheral-process (e.g., encoding) decrement for older adults. Specifically, there were no Age X Problem Size interactions for either experiment. Experiment 2 revealed decreasing age differences as problem difficulty increased. Indeed, for the 300-ms exposure duration, there were no age differences in RT or error rate. These results suggest that the magnitude of age differences in central processing speed are significantly less extreme than are age differences for peripheral processing speed for this type of mental arithmetic task. Also, older adults, in general, may have a higher skill level for basic fact retrieval in mental arithmetic than do young adults.     

Ideomotor compatibility in the psychological refractory period effect: 29 years of oversimplification.

Four experiments examined whether the psychological refractory period (PRP) effect can be eliminated with ideomotor compatible (IM) but not stimulus-response compatible (SR) tasks, as reported by A. G. Greenwald and H. G. Shulman (1973). Their tasks were used: a left or right movement to a left- or right-pointing arrow (IM) or to the word left or right (SR) for Task 1; saying "A" or "B" (IM) or "1" or "2" (SR) to an auditory A or B for Task 2. The stimulus onset asynchronies were 0, 100, 200, 300, 500, and 1,000 ms in Experiment 1, and only 0, 100, 200, and 1,000 ms in Experiments 2-4. The arrow was in the center of the screen in Experiments 1-3 and to the left or right in Experiment 4. As in Greenwald and Shulman's Experiment 2, the instructions stated that most often the 2 stimuli would be presented simultaneously. A PRP effect was obtained in all conditions, most likely because response-selection decisions are required even for IM tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic and spatial components of selective attention.

Semantic and spatial effects on selective processing were examined. A prime presented 250 ms or 1,000 ms before a pair of masked words was related to 1 of the words on 1/3 of the trials. Although Experiments 1 and 2 required report of both words, processing was selective; typically, just 1 word could be reported. In Experiment 1, reported words were more often top words, showing spatial selectivity, and more often words related to the prime, showing semantic selectivity. Experiment 2 included to-be-ignored peripheral cues 50 ms before the pair. Related words were reported more often at both delays, and cuing produced an additive benefit at 1,000 ms. Experiment 3 required report of just the cued word and included 100-ms cues. Cued words were reported more often, especially at 1,000 ms and with 100-ms cues, but semantic selectivity also occurred. Selectivity via semantic priming and via location reflect separate attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Viewer perspective affects central bottleneck requirements in spatial translation tasks.

A psychological refractory period (PRP) approach and the locus of slack logic were applied to examine the novel question of whether spatial translation processes can begin before the central bottleneck when effector or noneffector stimuli are processed from an egocentric (viewer-centered) perspective. In single tasks, trials requiring spatial translations were considerably slower than trials without translations (Experiment 1). Dual tasks consisted of tone discriminations (Task 1) and spatial translations (Task 2) using PRP methods with different manipulations on perceptual and response demands. When a viewer-centered perspective was used, the effect of spatial translation was reduced at short compared with long stimulus onset asynchronies (SOAs) when the potential for code overlap between tasks was removed (Experiments 2, 3, and 4); this finding supports the view that translation processes can begin before the central bottleneck. When an allocentric (non-viewer-centered) perspective was used (Experiment 5), the slowing associated with spatial translation was additive with SOA, suggesting that the processes of spatial translation cannot begin before the bottleneck. These findings highlight the importance of viewer perspective on central bottleneck requirements. Findings are further discussed in relation to the dorsal-ventral model of action and perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simon-Type Effects: Chronometric Evidence for Keypress Schemata in Typewriting.

In 4 experiments, chronometric evidence for keypress schemata in typing was sought by presenting stimuli to be typed in positions that were displaced from a central fixation point. Reaction times were shorter when stimulus positions corresponded to keyboard locations of the letters to be typed, suggesting that position was an important part of the internal representation of the response. Experiment 1 presented single letters left and right of fixation. Experiment 2 presented single letters above and below fixation. Experiment 3 presented words left and right of fixation and found evidence of parallel activation of keypress schemata. Experiment 4 found no effect of the eccentricity of the keyboard locations and responding fingers, suggesting that response-location codes are categorical, not metric. The results are consistent with D. E. Rumelhart and D. A. Norman's (1982) theory of typewriting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-related potentials indicate different processes to mediate categorical and associative priming in person recognition.

Whether representations of people are stored in associative networks based on co-occurrence or are stored in terms of more abstract semantic categories is a controversial question. In the present study, participants performed fame decisions to unfamiliar or famous target faces (Experiment 1) or names (Experiment 2), which were primed, either by highly associated celebrity names or by names from the same occupational category, or were unprimed. Reaction times and event-related potentials (ERPs) were recorded. Reaction times yielded significant priming effects for both associated and same category conditions. ERPs to targets in the associated condition were significantly more positive than were ERPs in all other conditions over central and parietal areas (300-600 ms; N400 priming effect). By contrast, a more posterior effect was found for categorical priming. These findings held for both cross-domain (Experiment 1) and within-domain conditions (Experiment 2). Results (a) demonstrate behavioral and ERP evidence for categorical priming in person recognition, consistent with the assumption that shared semantic information units can mediate semantic priming, and (b) suggest that associative and categorical priming are based on mechanisms that are at least partially different. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-Task Performance With Ideomotor-Compatible Tasks: Is the Central Processing Bottleneck Intact, Bypassed, or Shifted in Locus?

The present study examined whether the central bottleneck, assumed to be primarily responsible for the psychological refractory period (PRP) effect, is intact, bypassed, or shifted in locus with ideomotor (IM)-compatible tasks. In 4 experiments, factorial combinations of IM- and non-IM-compatible tasks were used for Task 1 and Task 2. All experiments showed substantial PRP effects, with a strong dependency between Task 1 and Task 2 response times. These findings, along with model-based simulations, indicate that the processing bottleneck was not bypassed, even with two IM-compatible tasks. Nevertheless, systematic changes in the PRP and correspondence effects across experiments suggest that IM compatibility shifted the locus of the bottleneck. The findings favor an engage-bottleneck-later hypothesis, whereby parallelism between tasks occurs deeper into the processing stream for IM- than for non-IM-compatible tasks, without the bottleneck being actually eliminated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validity and reliability of measurements taken by the Peak 5 motion analysis system

Many new measurement tools are becoming available for physiotherapists; however, there is often a lack of data to support their validity and reliability. This study attempts to address this issue with respect to the Peak 5 video analysis system. Five experiments were conducted. Experiment A investigated the validity of static angular measurements by filming a universal goniometer. A high level of agreement was recorded with a mean difference between the two instruments of 0.2 degree. Experiment B investigated the validity of angular joint velocity by filming a Biodex isokinetic dynamometer. A high level of agreement was recorded with a mean difference between the two instruments of 0.96 degree s-1. Experiment C investigated the reliability of reflective marker placements on the hip, knee and ankle on 17 healthy volunteers, in weight bearing on three separate days. Reliability was high with the 95% confidence interval (CI) for marker placement being 1.5 cm. Experiment D investigated the normal intrasubject variation of knee joint 'critical angle' and angular velocity measures over time, by filming 17 healthy volunteers performing an eccentric step test on three separate days. For 'critical angle' measures the standard deviation was 5.72 degrees and the 95% CI was +/- 11.44 degrees. For angular velocity measures the standard deviation was 8.51 degrees s-1 and the 95% CI was +/- 17.02 degrees s-1. Experiment E repeated analysis of the reflective marker placement (mean standard deviation 0.6 cm), the 'critical angle' (mean standard deviation 1.32 degrees) and the angular velocity (mean standard deviation 1.29 degrees s-1 showed high consistency, when analysing three pieces of film three times. Data generated in this study suggest that the Peak 5 provides valid angular and angular velocity data when compared to other measuring devices. Reliable data are produced when filming healthy volunteers performing an eccentric step test. These data will be used in the next stage of the project investigating Anterior Knee Pain Patients.     

Cognitive engagement and story comprehension in typically developing children and children with ADHD from preschool through elementary school.

The present study examined children's cognitive engagement with television as a function of the continuity of central or incidental content and whether this varied with age and clinical status. In Experiment 1, 9- to 11-year-old children's response times on a secondary task were slower the later a probe occurred in a sequence of central events, and response times predicted recall. Experiment 2 extended these results to 6- to 8-year-old children. Experiment 3 revealed that children with attention-deficit/hyperactivity disorder (ADHD) failed to show the pattern consistently observed for comparison children. The results support the hypothesis that typically developing children build a representation during viewing that reflects the causal structure of the televised story but that this skill is deficient in 4- to 9-year-old children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of phoneme representation in spoken word recognition.

Four experiments used the psychological refractory period logic to examine whether integration of multiple sources of phonemic information has a decisional locus. All experiments made use of a dual-task paradigm in which participants made forced-choice color categorization (Task 1) and phoneme categorization (Task 2) decisions at varying stimulus onset asynchronies. In Experiment 1, Task 2 difficulty was manipulated using words containing matching or mismatching coarticulatory cues to the final consonant. The results showed that difficulty and onset asynchrony combined in an underadditive way, suggesting that the phonemic mismatch was resolved prior to a central decisional bottleneck. Similar results were found in Experiment 2 using nonwords. In Experiment 3, the manipulation of task difficulty involved lexical status, which once again revealed an underadditive pattern of response times. Finally, Experiment 4 compared this prebottleneck variable with a decisional variable: response key bias. The latter showed an additive pattern of responses. The experiments show that resolution of phonemic ambiguity can take advantage of cognitive slack time at short asynchronies, indicating that phonemic integration takes place at a relatively early stage of spoken word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, optimal testing times, and negative priming.

The effects of time-of-day preferences on selective attention were tested in 2 experiments after normative work with 975 younger adults and 143 older adults verified C. P. May, L. Hasher, and E. R. Stoltzfus's (1993) finding that most older adults prefer the morning, whereas younger adults prefer activities later in the day. In Experiment 1, the cognitive effects of testing at preferred or nonpreferred times of day were examined in negative priming and related paradigms because (a) older adults typically have not shown negative priming and (b) previous research has not taken preference and testing times into account. In contrast to those tested at nonpreferred times, both younger and older groups tested at their preferred times showed negative priming. Age or testing optimality also affected other priming tasks. The central results were replicated in Experiment 2, which tested younger and older adults at their preferred times of the middle of the day. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous dual-task performance reveals parallel response selection after practice.

E. H. Schumacher, T. L. Seymour, J. A Glass, D. E. Kieras, and D. E. Meyer (2001) reported that dual-task costs are minimal when participants are practiced and give the 2 tasks equal emphasis. The present research examined whether such findings are compatible with the operation of an efficient response selection bottleneck. Participants trained until they were able to perform both tasks simultaneously without interference. Novel stimulus pairs produced no reaction time costs, arguing against the development of compound stimulus-response associations (Experiment 1). Manipulating the relative onsets (Experiments 2 and 4) and durations (Experiments 3 and 4) of response selection processes did not lead to dual-task costs. The results indicate that the 2 tasks did not share a bottleneck after practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention, gaze shifting, and dual-task interference from phonological encoding in spoken word planning.

Controversy exists about whether dual-task interference from word planning reflects structural bottleneck or attentional control factors. Here, participants named pictures whose names could or could not be phonologically prepared, and they manually responded to arrows presented away from (Experiment 1), or superimposed onto, the pictures (Experiments 2 and 3); or they responded to tones (Experiment 4). Pictures and arrows/tones were presented at stimulus onset asynchronies of 0, 300, and 1,000 ms. Earlier research showed that vocal responding hampers auditory perception, which predicts earlier shifts of attention to the tones than to the arrows. Word planning yielded dual-task interference. Phonological preparation reduced the latencies of picture naming and gaze shifting. The preparation benefit was propagated into the latencies of the manual responses to the arrows but not to the tones. The malleability of the interference supports the attentional control account. This conclusion was corroborated by computer simulations showing that an extension of WEAVER++ (A. Roelofs, 2003) with assumptions about the attentional control of tasks quantitatively accounts for the latencies of vocal responding, gaze shifting, and manual responding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partial mediation of strange-male-induced pregnancy blocks by sexual activity in mice (Mus musculus).

Novel male house mice (Mus musculus) can disrupt early pregnancy in females. Previous research (e.g., A. E. Storey; see record 1986-16382-001) focused on pheromonal rather than behavioral mediation of this phenomenon. In Experiment 1, novel males were housed with females shortly after insemination. Litter production was negatively correlated with the males' sexual activity. Experiment 2 replicated this finding with a larger sample. In Experiment 3, females were exposed to castrated males. Testosterone-treated males completely blocked pregnancy, whereas untreated males did not. In Experiment 4, castrated testosterone-treated males were presented at intervals after insemination. Pregnancy was totally blocked at Days 3 and 4 and mostly blocked at Days 1 and 2 but was less affected at Days 5 and 6. In Experiment 5, females were exposed through a wire-mesh grid to castrated males. Pregnancies occurred in all conditions, even with testosterone-treated males. These data suggest a role for sexual activity in male-induced pregnancy blocks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process, not representation: Reply to Radavansky (1999).

The size of fan effects is determined by processes at retrieval, not by whether or not information is represented as situations. Evidence contradicts G. A. Radvansky's (see record 1999-05245-005) claim that time to retrieve information from a situation does not depend on the number of elements in the situation. Moreover, Radvansky's principles for ascribing situational models to experiments appear to be post hoc ways of redescribing the data. On the other hand, the evidence does support the Adaptive Control of Thought—Rational (ACT-R) assumption that participants can adjust their attentional weightings and so produce differential fan effects. Moreover, the ACT-R theory of the fan effect is consistent with many other findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)