Biomedical subjects

Jonathan Smallwood

Publications and source records attributed to Jonathan Smallwood.

8 recordsLinked to original sources

PubMed2006

The restless mind.

This article reviews the hypothesis that mind wandering can be integrated into executive models of attention. Evidence suggests that mind wandering shares many similarities with traditional notions of executive control. When mind wandering occurs, the executive components of attention appear to shift away from the primary task, leading to failures in task performance and superficial representations of the external environment. One challenge for incorporating mind wandering into standard executive models is that it often occurs in the absence of explicit intention--a hallmark of controlled processing. However, mind wandering, like other goal-related processes, can be engaged without explicit awareness; thus, mind wandering can be seen as a goal-driven process, albeit one that is not directed toward the primary task.

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PubMed2006

The facilitative effects of glucose ingestion on memory retrieval in younger and older adults: is task difficulty or task domain critical?

The ingestion of a glucose-containing drink has been shown to improve cognitive performance, particularly memory functioning. However, it remains unclear as to the extent to which task domain and task difficulty moderate the glucose enhancement effect. The aim of this research was to determine whether boosts in performance are restricted to particular classes of memory (episodic v. semantic) or to tasks of considerable cognitive load. A repeated measures (25 g glucose v. saccharin), counterbalanced, double-blind design was used with younger and older adults. Participants performed a battery of episodic (e.g. paired associate learning) and semantic memory (e.g. category verification) tasks under low and high cognitive load. Electrophysiological measures (heart rate and galvanic skin response) of arousal and mental effort were also gathered. The results indicated that whilst glucose appeared to aid episodic remembering, cognitive load did not exaggerate the facilitative effect. For semantic memory, there was little evidence to suggest that glucose can boost semantic memory retrieval even when the load was manipulated. One exception was that glucose facilitated performance during the difficult category fluency task. Regardless, the present findings are consistent with the domain-specific account in which glucose acts primarily on the hippocampal region, which is known to support episodic memory. The possible contribution of the hippocampus in semantic memory processing is also discussed.

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PubMed2005

Encoding during the attentional lapse: accuracy of encoding during the semantic sustained attention to response task.

An experiment investigated the relationship between the ability to encode verbal stimuli during an attentional lapse. The task employed a variation on the sustained attention to response task (SART, Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) which involved the detection of an infrequent target against a background of words. As a manipulation, participants were either instructed to encode the stimuli or were merely exposed to the stimuli. Retrieval was measured using process dissociation. Irrespective of the instructions given to the participants during the task, participants were more likely to retrieve information on the basis of recollection after an error was made than before, whilst the likelihood of retrieving information on the basis of familiarity remained invariant over the same period. The implications of this result for methods of investigating subjective experience are discussed.

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PubMed2005

The effects of self-administered alcohol-induced 'hangover' in a naturalistic setting on psychomotor and cognitive performance and subjective state.

AIMS: To examine in as naturalistic a setting as possible whether having an alcohol-induced 'hangover' impairs psychomotor and cognitive performance. PARTICIPANTS AND DESIGN: The sample consisted of 71 male and female social drinkers who were tested twice, once at baseline and once after exposure to the study condition. They were randomized into a control group who returned for testing on a prearranged date (n = 33), and a group who were instructed to make arrangements to return the day after a self-determined heavy drinking session (n = 38). Of the 'hangover' group, 13 participants still had a blood alcohol concentration of >1 mg/100 ml at the time of testing and these were analysed separately. All participants were students. MEASUREMENTS: Psychomotor performance was assessed by means of a battery of psychomotor tasks, rate of information processing was tested by the Speed and Capacity of Language Processing Test (SCOLP) and subjective state was assessed by questionnaire measures. FINDINGS: All participants in the 'hangover' group reported subjective and physical symptoms of hangover on the second testing session. Performance was significantly impaired on the hits-key components of the vigilance task, was less accurate on the primary and secondary reaction time tasks and showed greater dispersion in range of ability for participants in the 'acute and hangover' compared to 'control'. Probe memory revealed no significant group effect. Ratings of subjective state revealed significant group differences for the variables 'ability to drive', 'concentrate' and 'react quickly' as well as 'tiredness'. There were no group differences for performance on the SCOLP. CONCLUSION: Hangover had negative effects on self-reported subjective and physical state and subtle effects on performance.

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PubMed2005

Variability in lay perceptions of depression: a vignette study.

This paper describes a study investigating lay perceptions of depression in terms of perceived severity. Students (N = 128) were presented with vignettes describing individuals with symptoms of depression based on DSM-IV. The descriptions were varied in terms of gender, social status, and a self-referent manner of communicating depressive symptomatology. Participants were asked to rate the degree to which vignette characters were thought to be depressed on a Likert-type scale. Results indicate that a non-self-referent style of communicating depressive symptoms by female vignette characters was seen as an indication of elevated levels of depression, and these findings are discussed with reference to the literature.

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PubMed2004

Subjective experience and the attentional lapse: task engagement and disengagement during sustained attention.

Three experiments investigated the relationship between subjective experience and attentional lapses during sustained attention. These experiments employed two measures of subjective experience (thought probes and questionnaires) to examine how differences in awareness correspond to variations in both task performance (reaction time and errors) and psycho-physiological measures (heart rate and galvanic skin response). This series of experiments examine these phenomena during the Sustained Attention to Response Task (SART, Robertson, Manly, Adrade, Baddeley, & Yiend, 1997). The results suggest we can dissociate between two components of subjective experience during sustained attention: (A) task unrelated thought which corresponds to an absent minded disengagement from the task and (B) a pre-occupation with one's task performance that seems to be best conceptualised as a strategic attempt to deploy attentional resources in response to a perception of environmental demands which exceed ones ability to perform the task. The implications of these findings for our understanding of how awareness is maintained on task relevant material during periods of sustained attention are discussed.

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PubMed2004

The consequences of encoding information on the maintenance of internally generated images and thoughts: the role of meaning complexes.

Three experiments investigated the hypothesis that internally generated images and thoughts were driven by meaning complexes, a construct which reflects a synthesis of semantic meaning and personal salience (Klinger, 1999). Experiments 1 and 2 contrasted the mutual inhibition between encoding words and non-words on: (i) the frequency that thoughts and images unrelated to the task (task unrelated thought, TUT) were experienced (Experiment 1) and (ii) on the intensity of images generated from long-term memory and maintained under dual task conditions, which whilst familiar were not of particular personal salience (Experiment 2). Experiment 3 examined the physiological arousal associated with the experience of TUT in a semantic encoding task. Evidence suggested that, in general, internally generated images and thoughts, irrespective of the personal salience, were suppressed by the co-ordination of information in working memory. In addition, only the experience of spontaneous images and thoughts of personal salience (TUT, Experiments 1 and 3) interfered reliably with the encoding/retrieval of semantic information from memory. Finally, in Experiment 3, physiological arousal, as indexed by mean heart rate, was associated with a high frequency of TUT. The results of all three experiments support the notion that the maintenance of spontaneously occurring images and thoughts is simultaneously influenced by both the semantic content and the personal salience of the information held in working memory.

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PubMed2003

Task unrelated thought: the role of distributed processing.

Task unrelated thought (TUT) refers to thought directed away from the current situation; for example, a day dream. Encapsulated models of cognition propose that qualitative changes in consciousness, i.e., the production of TUT, can be explained in terms of changes in the quantity of resources deployed for task completion. In contrast, distributed models of cognition emphasize the importance of holistic processes in the generation and maintenance of task focus and are consistent with the effects of higher order variables such as schemata. Three experiments were conducted on healthy participants using a categorical stimulus organization to contrast distributed and encapsulated views of cognition. Experiments 1 and 2 showed that despite the increased difficulty of the alphabetical verbal fluency task fewer TUTs were produced during category fluency condition. Experiment 3 replicated the categorical suppression of TUT while encoding and recalling information in a memory task. The results of these three experiments support the predictions derived from models of cognition emphasizing the importance of stimulus organization in the generation and maintenance of task focus and have potential importance for the scientific evaluation of cognition.

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