Dual-task interference in simple tasks: Data and theory.

People often have trouble performing 2 relatively simple tasks concurrently. The causes of this interference and its implications for the nature of attentional limitations have been controversial for 40 years, but recent experimental findings are beginning to provide some answers. Studies of the psychological refractory period effect indicate a stubborn bottleneck encompassing the process of choosing actions and probably memory retrieval generally, together with certain other cognitive operations. Other limitations associated with task preparation, sensory-perceptual processes, and timing can generate additional and distinct forms of interference. These conclusions challenge widely accepted ideas about attentional resources and probe reaction time (RT) methodologies. They also suggest new ways of thinking about continuous dual-task performance, effects of extraneous stimulation (e.g., stop signals), and automaticity. Implications for higher mental processes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-task interference and visual encoding.

A visual target (T?) containing either 1 or 2 letters, or a random 10-sided polygon, was presented after an auditory target (T?) at a stimulus onset asynchrony (SOA) of either 50, 150, 250, or 600 ms. Task? was a speeded pitch discrimination to the tone, and across experiments, T? was either 1 of 2 tones (2-alternative discrimination [2AD]) or 1 of 4 tones (4-alternative discrimination [4AD]). Memory for the visual information decreased as SOA was reduced when a mask was used, but not when there was no mask. The effects of SOA were larger for the 4AD Task? than the 2AD Task?. The results demonstrate cross-modal, dual-task interference on visual encoding and suggest central interference with the short-term consolidation of visual information in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movement as an indicator of sensory components in thought.

This study investigated a claim of the Neuro-Linguistic Programming (NLP) eye movement model, which states that specific eye movements are indicative of specific sensory components in thought. Forty-eight graduates and undergraduates were asked to concentrate on a single thought while their eye movements were videotaped. They were subsequently asked to report if their thoughts contained visual, auditory, or kinesthetic components. Two NLP-trained observers independently viewed silent videotapes of participants concentrating and recorded the presence or absence of eye movements posited by NLP theorists to indicate visual, auditory, or kinesthetic components in thought. Coefficients of agreement (Cohen's K) between participants' self-reports and trained observers' records indicate support for the visual (K?=?.81, p?p?p?     

Dual-task interference and the cerebral hemispheres.

It has been argued that dual-task interference is reduced when the 2 cerebral hemispheres can carry out the 2 tasks independently. Evidence for this idea has arisen from studies involving manipulations such as lateralized stimulation or response, or requiring mental operations believed to depend primarily on a particular hemisphere. However, these studies have typically involved a very limited degree of response uncertainty, which appears critical in producing the most extreme dual-task interference (the psychological refractory effect). Pairs of tasks with independent response uncertainty were examined, and various manipulations were used to promote hemispheric task separation. Dual-task interference was not modulated by these manipulations. It seems likely that response selection represents a central bottleneck, in the sense that this process cannot operate simultaneously and independently in the 2 hemispheres. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning of movement sequences.

Argues that the instrumental learning of the behavioral act, defined as a response class whose members are in temporal contiguity with reinforcement, has slowed understanding of how movement sequences are learned since the act does not require consideration of the movement patterns of the responses that produce the reinforcement. Throughout learning's experimental history, psychologists have asked where movement segments come from and how they are organized into more complex movement sequences. From the beginning, animal psychologists have asked the extent to which movement segments and their organization into sequences is instinctive. For decades the response-chaining hypothesis has been the explanation of how segments are organized by learning; however, modern research does not support it and has tilted the explanation toward a cognitive interpretation. A parallel account of how humans learn movement sequences is presented. The positions of Piaget (1952) and J. S. Bruner (1973) from developmental psychology, as well as those of K. S. Lashley (1951) and more recent analysts of movement regulation, are reviewed. Here, too, cognitive interpretations prevail. It is suggested that animal and human motor behavior settle on error as the focus of measurement. (152 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Skin potential as an indicator of emotion.

Monitored the skin-potential responses of 6 college students while each was seen for 10 counseling sessions. Results indicate that the nature of a S's skin-potential wave was generally a reliable indicator of the way the S was managing or experiencing his feelings, as reported on the Mood Adjective Check List during the sessions. Negative skin-potential responses were accompanied by feelings described as pleasant and released; positive responses were associated with unpleasant and inhibited feelings, and neutral responses were often associated with unpleasant and inhibited feelings but also tended to coincide with thoughtful moods. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alumni ratings as an indicator of departmental quality.

University alumni and enrolled students from 22 departments responded to 11 satisfaction items concerning instructional, curricular, advising, and operational aspects of their major departments. Factor structures for the 2 groups were nearly identical and included 2 factors: General Satisfaction With Major and Satisfaction With Mentorship. Comparisons of department means showed differences between alumni and enrolled students on many items, particularly vocational guidance. Alumni ratings were relatively uninfluenced by job-related variables. It is concluded that they are an important source of information in assessing departmental quality. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference intrasitivity as an indicator of cognitive slippage in schizophrenia.

Describes the development and application of a scale to detect thought disorder by means of preference intransitivity. The scale, containing a total of 120 item pairs to be judged for preference, was administered to 90 Ss (30 schizophrenics, 30 psychiatric controls, and 30 nonpsychiatric controls). Results indicate that schizophrenics produce more intransitive judgments than nonschizophrenics and that the intransitivity score is independent of age and intelligence. Although the scale may not be powerful enough for diagnostic use, the method warrants further development. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acceptance of uncertainty as an indicator of effective leadership.

Research and experience continue to reveal evolving modes of leadership behavior that challenge the practice of consulting psychology. Leadership development that has taken us beyond the notion of born leaders and stable environments has suggested that flexibility is vital. This may be partly because of the constant evolution of the organization and its leadership challenges, from command-and-control to paradigms that are participatory and recognize the importance of interpersonal skills, to an emerging paradigm concerned with organizational learning. Consulting psychologists have identified a wide variety of leadership modes or ideals to fit these newer paradigms. Common to many of these is the need to be comfortable navigating ambiguous situations. One of the metrics that is indicative of this skill is the capacity to effectively process the uncertainty that often accompanies ambiguity. We present preliminary data for a potential tool for assessing this skill. We suggest that measuring an individual's “aptitude for ambiguity” should be considered when identifying high performers for leadership roles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Position-linked interference in forming simple visual groups.

Experiments with 2-element visual groups reveal a form of interference that has several interesting properties. Observers judged the orientation of an imaginary line formed by 2 pixels (the target) while attempting to ignore a 3rd pixel (the noise). Noise interfered with performance, even when it was made distinct from the target in various ways. This interference was strongly position linked; a single equation described the interference pattern for many different target-noise configurations. Maximum interference was observed not when the noise was closest to the target but when it was at a distance of half the separation between target pixels. Some initial findings were consistent with the idea that visual grouping reflects the operation of visual channels with Gabor-like receptive-field profiles, but subsequent results implicated processes that automatically construct visual boundaries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response preparation and control of movement sequences.

Two experiments investigated the response complexity effect using elbow extension/flexion movements. In Exp 1 with 30 undergraduates, reaction time (RT) for an extension movement was significantly less than RT for an extension/flexion movement. However, this difference in RT was not evident when participants were asked to pause at the reversal of the extension/flexion for approximately 260 msec. Exp 2 with 10 undergraduates manipulated the duration of the pause between these movements and also measured the electromyographical activity of the triceps and biceps muscles. When the pause was reduced to 75 msec, Ss were not able to program the flexion portion of the movement at the reversal, forcing them to preprogram this movement: hence, increasing their premotor RT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of salivary thiocyanate as an indicator of smoking behavior.

Salivary samples from 3 placement sites under stimulated and unstimulated flow-rate conditions were collected from 18 smokers and 18 nonsmokers on each of 3 days. Salivary thiocyanate levels were significantly higher in smokers than in nonsmokers, in parotid site collections than either sublingual or mixed collections, and in unstimulated collections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-task performance as a function of adult age and task complexity.

A dual-task procedure was used to examine capacity demands of letter-matching in younger and older adults. Older subjects generally were slower on both tasks than were younger adults, but this difference was especially pronounced for the late stages of category matching, suggesting that retrieval and comparison of category information are particularly demanding for older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memorability functions as an indicator of qualitative age differences in text recall.

An analysis in which the probability of text unit recall for older adults [p(Re|O)] is plotted as a function of this probability for the young [p(Re|Y)] is considered as one way to assess whether there are qualitative differences in text recall for young and old. The application of this relative memorability analysis to previously reported data dealing with the immediate recall of spoken sentences (Stine, Wingfield, & Poon, 1986) revealed that although older adults show qualitative recall similar to younger adults when informational density is low, they show less discrimination among text elements when informational density is increased. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heritability as an indicator of genetical variation in fecundity

Heritability is well known to be a poor indicator of genetical variation in fitness. We show here that it is also an inadequate measure of genetical variation in fecundity.     

The coding and effector transfer of movement sequences.

Three experiments utilizing a 14-element arm movement sequence were designed to determine if reinstating the visual–spatial coordinates, which require movements to the same spatial locations utilized during acquisition, results in better effector transfer than reinstating the motor coordinates, which require the same pattern of homologous muscle activation. Results demonstrated better transfer when visual–spatial coordinates were reinstated than when motor coordinates where reinstated regardless of the amount of practice (1, 4, or 12 days; Experiments 1–3, respectively). Transfer (left to right and right to left) was symmetric when visual–spatial coordinates were reinstated but not when motor coordinates were reinstated. When motor coordinates were reinstated after 12 days of practice and vision occluded, transfer was better from right limb to left than vice versa. The data are also consistent with the notion that multiple codes (visual, spatial, and motor) are developed over practice, with each contributing to transfer performance when the respective coordinates are reinstated. Further, the results indicate a disruption of the linkage (concatenation) between subsequences when one or more coordinates are changed on the transfer test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)