Anxiety and attention to threat: cognitive mechanisms and treatment with attention bias modification

Anxiety disorders are common and difficult to treat. Some cognitive models of anxiety propose that attention bias to threat causes and maintains anxiety. This view led to the development of a computer-delivered treatment: attention bias modification (ABM) which predominantly trains attention avoidance of threat. However, meta-analyses indicate disappointing effectiveness of ABM-threat-avoidance training in reducing anxiety. This article considers how ABM may be improved, based on a review of key ideas from models of anxiety, attention and cognitive control. These are combined into an integrative framework of cognitive functions which support automatic threat evaluation/detection and goal-directed thought and action, which reciprocally influence each other. It considers roles of bottom-up and top-down processes involved in threat-evaluation, orienting and inhibitory control in different manifestations of attention bias (initial orienting, attention maintenance, threat avoidance, threat-distractor interference) and different ABM methods (e.g., ABM-threat-avoidance, ABM-positive-search). The framework has implications for computer-delivered treatments for anxiety. ABM methods which encourage active goal-focused attention-search for positive/nonthreat information and flexible cognitive control across multiple processes (particularly inhibitory control, which supports a positive goal-engagement mode over processing of minor threat cues) may prove more effective in reducing anxiety than ABM-threat-avoidance training which targets a specific bias in spatial orienting to threat

Dissociable roles of different types of working memory load in visual detection

We contrasted the effects of different types of working memory (WM) load on detection. Considering the sensory-recruitment hypothesis of visual short-term memory (VSTM) within load theory (e.g., Lavie, 2010) led us to predict that VSTM load would reduce visual-representation capacity, thus leading to reduced detection sensitivity during maintenance, whereas load on WM cognitive control processes would reduce priority-based control, thus leading to enhanced detection sensitivity for a low-priority stimulus. During the retention interval of a WM task, participants performed a visual-search task while also asked to detect a masked stimulus in the periphery. Loading WM cognitive control processes (with the demand to maintain a random digit order [vs. fixed in conditions of low load]) led to enhanced detection sensitivity. In contrast, loading VSTM (with the demand to maintain the color and positions of six squares [vs. one in conditions of low load]) reduced detection sensitivity, an effect comparable with that found for manipulating perceptual load in the search task. The results confirmed our predictions and established a new functional dissociation between the roles of different types of WM load in the fundamental visual perception process of detection

Effects of Long-Term Memory on Visual Attention and Access to Visual Consciousness

In dieser Dissertation zeige ich anhand einer Reihe von Beispielen, wie das Langzeitgedächtnis die perzeptuelle Verarbeitung beeinflussen kann. Anhand einer Aufgabe zur visuellen Aufmerksamkeit verdeutliche ich, inwiefern episodische Erinnerungen perzeptuelle Distrakoreffekte reduzieren können. In Experiment 1 sollten Versuchspersonen zuvor gelernte Worte entweder ins Gedächtnis zu rufen oder die Erinnerung an die Worte zu unterdrücken. Anschließend mussten sie unter Zeitdruck neue, bisher nicht präsentierte Worte semantisch einordnen, wobei die Zielworte von den zuvor abgerufenen oder unterdrückten Worten flankiert waren. Da die flankierenden Worte für die semantische Entscheidungsaufgabe irrelevant und die Versuchspersonen instruiert worden waren, diese zu ignorieren, kann von einem perzeptuellen Distraktoreffekt ausgegangen werden. Distraktoreffekte waren für zuvor unterdrückte Gedächtnisinhalte im Vergleich zur abgerufenen Gedächtnisinhalten deutlich reduziert, was nahelegt, dass episodische Gedächtnisinhalte die Wahrnehmung beeinflussen. Auf dieser Erkenntnis aufbauend zeige ich in Experiment 2, wie die suppressionsinduzierte Reduktion der Verarbeitung von Distraktorreizen durch individuelle Differenzen maskiert werden kann. Schließlich wurden den Versuchspersonen in Experiment 3 in einer „Attentional-Blink“-Aufgabe unbekannte Objekte als zweites von zwei aufeinander folgenden Zielobjekten dargeboten. Versuchspersonen konnten Objekte, die mit einer neu gelernten semantischen Information assoziiert waren, besser erkennen als Objekte, die mit minimaler Information assoziiert waren. Dieser Effekt ging mit einer Modulation der ereigniskorrelierten Potenziale 100ms nach Erscheinen des Reizes einher. Diese Ergebnisse zeigen, dass Inhalte aus dem Langzeitgedächtnis Wahrnehmungsprozesse beeinflussen können und leisten damit einen weiteren Beitrag zur Erkenntnis, dass die Wahrnehmung gegenüber höheren Kognitionen nicht unabhängig ist.Numerous studies are emerging which suggest that long-term memories can influence early perceptual processing. Notwithstanding, these finding have come under fire from critics who view perceptual processing as independent of cognition. In this dissertation I demonstrate novel instances of long-term memory effects on perceptual processing, both in the context of an attentional task where I look at the extent to which episodic memory can reduce perceptual distraction and in a conscious detection task where I assess the effect of semantic knowledge on peoples ability to consciously detect briefly presented objects. In experiment one, participants retrieved or suppressed previously memorised words. Following this task, participants made speeded semantic judgments on novel target words that were flanked by the words that had previously undergone suppression or retrieval. Because the flanking words were irrelevant to the semantic judgment and were supposed to be ignored, any influence of their presence on semantic judgment speed can be taken as a marker of perceptual distraction. Results showed that the tendency for flankers to distract from target processing was markedly reduced if those flankers had undergone suppression. In experiment two, I expanded upon this finding by showing how this suppression-induced reduction in distractor processing can be masked by individual differences. Finally, in experiment three, I presented pictures of novel objects to participants as the second of two targets in an attentional blink paradigm. Results showed that participants were able to perceive objects associated with newly acquired semantic knowledge better than objects associated with minimal knowledge, a finding that was associated with a modulation of event-related brain potentials 100 msec after stimulus onset. Taken together, these experiments contribute to the growing body of evidence showing that information from long-term memory can influence perceptual processing

Motivation and visual attention in adolescents and adults

This thesis explores how the motivation to process a visual stimulus influences attentional control. A core aim was to develop and test a motivation-based as opposed to a perception-based explanation for reward association effects on visual selective attention. To do so, in a series of 12 experiments, stimuli were first imbued with a value, reinforced with monetary wins and losses. Then, these same value-associated stimuli were used as distractors in spatial attention paradigms, including flanker and visual search tasks, incentive cues in a simple detection task, or targets in an ensemble perceptual judgment task. Of primary interest were measures of attentional capture by value-laden opposed to neutral stimuli. Taking a developmental approach, in a subset of the experiments value-driven biases in late adolescents compared to adults were also examined while simultaneous electroencephalography was recorded. Collectively, the results from these experiments suggest that the effects of motivational salience are inconsistent with perception-based accounts but can be encompassed in a motivation-based framework that suggests value-associated stimuli compete to alter current goals. This motivation-based model is grounded in the cognitive control literature and posits a competition among potential goals driven by the costs versus benefits of cognitive engagement with stimuli

Twenty years of load theory—Where are we now, and where should we go next?

Selective attention allows us to ignore what is task-irrelevant and focus on what is task-relevant. The cognitive and neural mechanisms that underlie this process are key topics of investigation in cognitive psychology. One of the more prominent theories of attention is perceptual load theory, which suggests that the efficiency of selective attention is dependent on both perceptual and cognitive load. It is now more than 20 years since the proposal of load theory, and it is a good time to evaluate the evidence in support of this influential model. The present article supplements and extends previous reviews (Lavie, Trends in Cognitive Sciences, 9, 75–82. doi:10.​1016/​j.​tics.​2004.​12.​004, 2005, Current Directions in Psychological Science, 19, 143–148. doi:10.​1177/​0963721410370295​, 2010) by examining more recent research in what appears to be a rapidly expanding area. The article comprises five parts, examining (1) evidence for the effects of perceptual load on attention, (2) cognitive load, (3) individual differences under load, (4) alternative theories and criticisms, and (5) the future of load theory. We argue that the key next step for load theory will be the application of the model to real-world tasks. The potential benefits of applied attention research are numerous, and there is tentative evidence that applied research would provide strong support for the theory itself, as well as real-world benefits related to activities in which attention is crucial, such as driving and education

The Role of Working Memory Load in Distractor Suppression

The well-established Load Theory of Attention and Cognitive Control (Load Theory) has sparked research over two decades. There are two integral components of Load Theory, i.e. ‘cognitive load’ and ‘perceptual load’ with the former concept receiving less attention in the literature. The core assumptions of Load Theory, with an emphasis on ‘cognitive load’,have been systematically investigated in this thesis using electroencephalography (EEG) and transcranial magnetic stimulation(TMS). The current research uncovered robust working memory (WM) effects in the healthy youngeradult populationwhich partially supported Load Theory. Experiment 1 revealed that the WM load effect on distractor processing increases when more items were held in WM but can plateau at a certain set-size(i.e.,3 items). In Experiment 2, the direction of distractor interference was inconsistent across the behavioural measures of reaction times and error rates, with the latter in support of Load Theory. In contrast, therewas strong electrophysiological evidence (i.e.,the N2pc and Pd components) for increased susceptibility to peripheral distractors under low WM load conditions (remembering one item). The behavioural effects of Experiments1and 2 which partially supported Load Theory, were not replicated with a TMS protocol (Experiment 3). There were significant effects, partially supporting Load Theory, when the spatial position of distractor and a subsequent target item was considered. Altogether, the findings have contributed to a clearer understanding of WM load effects, especially in terms of the attentional processes involved in distractor processing within a single-task setting. The results have provided recommendations of factors which were omitted in Load Theory such as the distinction of functions (updating and shifting) rather than positing a general executive load. This understanding can inform future research specifically targeting visual processing, WM and selective attention processes which can be extrapolated to everyday situations where attention to detail is crucial

Task Switching and Distractibility

In this thesis I examined the effects of task switching on people’s ability to ignore irrelevant distractors. Load theory proposes that distractor interference critically depends on the availability of executive control to minimise the effects of irrelevant stimuli (e.g. Lavie, 2000). Much work on task switching suggests that task switching demands executive control in order to prepare for and implement a switch between tasks (e.g. Monsell, 2003; Rubinstein, Meyer, & Evans, 2001). I therefore hypothesised that the executive demand of a task switch will result in reduced ability to reject irrelevant distractors in selective attention tasks. The research reported provided support for this hypothesis by showing that task switching results in greater distractor interference as measured with the “flanker task” (e.g. Eriksen & Eriksen, 1974) and with the attentional capture task (e.g. Theeuwes, 1990), even when there was no overlap between the stimuli and responses for the two tasks, and when task-repeated and switch trials were presented within the same block (in AAABBB designs). This research also showed that dissociable executive demands were involved in switching tasks (AAABBB), compared with mixing tasks (ABAB versus AAA), and these executive demands were found to control rejection of distractors in the flanker task and attentional capture task, respectively. In addition, task switching reduced internal distraction by task-unrelated thoughts. The contrast between the effects of task switching on internal versus external sources of distraction further supported the involvement of executive control in task switching. Finally, individual differences in operational span capacity predicted the magnitude of task switching costs and flanker interference effects, suggesting the involvement of executive control in both abilities. Overall, this research highlights a new consequence of task switching on selective attention and distractibility, supporting predictions derived from prevalent views on the role of executive control in task switching and selective attention