Central bottleneck influences on the processing stages of word production.

Does producing a word slow performance of a concurrent, unrelated task? In 2 experiments, 108 participants named pictures and discriminated tones. In Experiment 1, pictures were named after cloze sentences; the durations of the word-production stages of lemma and phonological word-form selection were manipulated with high- and low-constraint cloze sentences and high- and low-frequency-name pictures, respectively. In Experiment 2, pictures were presented with simultaneous distractor words; the durations of lemma and phoneme selection were manipulated with conceptually and phonologically related distractors. All manipulations, except the phoneme-selection manipulation, delayed tone-discrimination responses as much as picture-naming responses. These results suggest that early word-production stages-lemma and phonological word-form selection-are subject to a central processing bottleneck, whereas the later stage-phoneme selection-is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Making two responses to a single object: Implications for the central attentional bottleneck.

Experiments with 2 stimuli and 2 responses have revealed a central attentional bottleneck and pointed to response selection as its primary locus; however, little has been said about the underlying reasons for this bottleneck. These reasons are explored. In the 1st 3 experiments, Ss made 2 separate responses to different aspects of the same object. Interference between selection of the responses persisted, ruling out the possibility that the dual-task bottleneck is caused by the input to the response-selection mechanisms being limited to one object at a time. The next 4 experiments examined what happens when 2 responses are made to the same attribute of a single object. These experiments show that only one response selection occurred. Hence, the central mechanism is not limited to picking one motor action at a time. Several possible theories about the nature of the bottleneck are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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)     

Enhanced Memory for Negatively Emotionally Charged Pictures Without Selective Rumination.

Emotionally charged materials have been found to elicit higher levels of recall in many studies. However, the use of slow presentations and/or uncontrolled retention intervals may have allowed subjects to rehearse emotional materials preferentially. The authors presented a series of 5 pictures (1 emotionally charged) at a rate of 4 pictures per second, precluding selective rehearsal. In Experiment 1, subjects recalled the pictures immediately or after performing an arithmetic task for 20 s. In Experiment 2, the pictures were described as to-be-ignored distractors, and the memory test was unexpected. Stimulus emotionality greatly enhanced recall in all conditions. The speed of the presentations and the fact that enhancement did not spread to temporally adjacent items argues against some widely discussed mechanisms for emotional enhancement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Making two responses to a single object: Implications for the central attentional bottleneck": Correction.

Reports an error in the original article by C. Fagot and H. Pashler (Journal of Experimental Psychology: Human Perception and Performance, 1992[Nov], Vol 18[4], 1058–2079). Figures 3 and 7 are in error. The corrected figures are presented. (The following abstract of this article originally appeared in record 1993-12299-001.) Experiments with 2 stimuli and 2 responses have revealed a central attentional bottleneck and pointed to response selection as its primary locus; however, little has been said about the underlying reasons for this bottleneck. These reasons are explored. In the 1st 3 experiments, Ss made 2 separate responses to different aspects of the same object. Interference between selection of the responses persisted, ruling out the possibility that the dual-task bottleneck is caused by the input to the response-selection mechanisms being limited to one object at a time. The next 4 experiments examined what happens when 2 responses are made to the same attribute of a single object. These experiments show that only one response selection occurred. Hence, the central mechanism is not limited to picking one motor action at a time. Several possible theories about the nature of the bottleneck are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do response modality effects support multiprocessor models of divided attention?

Some studies have suggested that dual-task interference is greatly reduced when tasks requiring very different types of responses (e.g., manual and vocal) are combined. However, in those studies, the order of stimuli varied unpredictably. In Exps 1 and 2, with 33 undergraduates, variable stimulus order greatly inflated interference between 2 manual tasks, whereas interference between a manual and a vocal task was only slightly exacerbated. However, central interference (the psychological refractory period) persisted even with the manual/vocal combination. Selection of 2 manual responses with unknown stimulus order may require a special strategy to prelude intertask intrusion errors. Exp 3, with 12 undergraduates, demonstrated that such errors could be provoked with speed stress. Together, these results reconcile response modality effects with the response selection bottleneck model for dual-task interference (once it is suitably amended). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention and stimulus identification.

Previous research has provided evidence for parallel stimulus processing in visual search tasks; however, it has frequently been noted that detecting prespecified targets might be accomplished without actually identifying targets and/or distractors. In the present 5 experiments, with 61 university students, a novel task was employed to require exhaustive identification. In this task, Ss named the highest digit in an array. RTs and display size effects in this task were strikingly similar to those obtained in conventional search tasks. Manipulation of display size and visual quality was used to test predictions of serial and parallel encoding models. Display size was additive with 2 different visual quality factors in the highest digit task, a finding that argues against serial execution of the corresponding stages. Interactions with decision-related factors suggest that visual quality may have affected the rate of character recognition, not just feature extraction. Thus, results strengthen the case for parallel (though perhaps capacity-limited) identification of multiple familiar stimuli. It is pointed out that parallel identification need not entail late selection, and some alternative possibilities are suggested. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coordinate frame for symmetry detection and object recognition.

Ss were required to determine whether dot patterns were symmetric. Cuing the Ss in advance about the orientation of the axis of symmetry produced a substantial speedup in performance (Exps 1 and 3) and an increase in accuracy with brief displays (Exp 2). The effects appeared roughly additive, with an overall advantage for vertical symmetry; thus, the vertical axis effect is not due to a tendency to prepare for the vertical axis. The cuing advantage was found to depend upon the S's knowing in advance the spatial location as well as orientation of the frame of reference (Exp 4). Exp 5 provided evidence that the frame of reference responsible for these effects is the same as the one that determines shape perception: Ss viewed displays containing a letter (at an unpredictable orientation) and a dot pattern, rapidly naming the letter and then determining whether the dots were symmetric about a prespecific axis. When the top–bottom axis of the letter was oriented the same way as the axis of symmetry for the dots, symmetry judgments were significantly more accurate. Results suggest a single frame of reference for both types of judgment. A theory of visual symmetry is proposed to account for the phenomena and characterize their relation to "mental rotation" effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How persuasive is a good fit? A comment on theory testing.

Quantitative theories with free parameters often gain credence when they closely fit data. This is a mistake. A good fit reveals nothing about the flexibility of the theory (how much it cannot fit), the variability of the data (how firmly the data rule out what the theory cannot fit), or the likelihood of other outcomes (perhaps the theory could have fit any plausible result), and a reader needs all 3 pieces of information to decide how much the fit should increase belief in the theory. The use of good fits as evidence is not supported by philosophers of science nor by the history of psychology; there seem to be no examples of a theory supported mainly by good fits that has led to demonstrable progress. A better way to test a theory with free parameters is to determine how the theory constrains possible outcomes (i.e., what it predicts), assess how firmly actual outcomes agree with those constraints, and determine if plausible alternative outcomes would have been inconsistent with the theory, allowing for the variability of the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Graded capacity-sharing in dual-task interference?

Research suggests that dual-task interference is caused by a central bottleneck (together with response grouping and impaired preparation). The emphasis placed on the 1st response in these experiments, however, may have discouraged the sharing of processing resources between tasks. In the present experiment, instructions placed equal emphasis on 2 choice reaction time (RT) tasks in which stimuli were presented simultaneously on 20% of the trials. In contrast to a graded trade-off of resources, a bottleneck predicts bimodality in the distribution of interresponse intervals for the 2 tasks, reflecting the 2 possible orders in which their respective central stages might be performed. Most Ss showed such a bimodality, along with other signs of a bottleneck; the remainder showed evidence of response grouping. Data suggest that the bottleneck is structural rather than strategic and make the graded sharing of resources less plausible. (PsycINFO Database Record (c) 2010 APA, all rights reserved)