The role of the left dorsolateral prefrontal cortex in attentional bias.

The DLPFC is thought to be critically involved in maintaining attention away from behaviourally irrelevant information, and in the establishment of attentional control settings. These play an important role in the phenomenon of top-down bias to features in the visual field - also known as attentional bias. This paper probes the involvement of the left DLPFC in attentional bias by manipulating its cortical excitability via tDCS and then analysing these effects following an induced attentional bias towards the colour green. Although both anodal and cathodal tDCS over the left DLPFC decrease distractibility caused by biased but irrelevant objects, further interrogation of our data reveals theoretically differential mechanisms for each type of stimulation. Anodal tDCS appears to increase cognitive control over attentional bias-related items that are behaviourally irrelevant, allowing for their efficient disregard. In contrast, cathodal tDCS appears to lessen the overall effect of the induced attentional bias, potentially by reducing the influence of top-down modulated attentional control settings thus preventing the implementation of the control setting favouring green items. These results suggest a potential causal role of the left DLPFC in the cognitive mechanism underlying attentional bias.

Fearing the wurst: Robust approach bias towards non-vegetarian food images in a sample of young female vegetarian eaters.

Previous studies have shown that humans show an implicit approach bias toward food related items which is moderated by hunger and properties of the food items displayed (such as their palatability and calorie content). However, little is known about if and how this approach bias is moderated by food preferences and/or diet choices. In this study, we compared approach-avoidance biases in a group of young female omnivore and vegetarian eaters towards images of vegetarian and non-vegetarian food items using a manikin stimulus-response compatibility task. While vegetarian eaters showed a slightly larger approach bias for vegetarian than for non-vegetarian food stimuli, this bias was of similar size to that observed in the omnivorous group. Most interestingly, vegetarian eaters' approach bias towards non-vegetarian food pictures also did not differ from that of the omnivorous group, despite vegetarians rating those pictures as much less pleasant. Our findings suggest that approach biases towards food items are quite robust and do not rapidly change with dietary practice. However, despite approach biases often guiding behaviour, vegetarian eaters successfully withstand these implicit action tendencies and avoid non-vegetarian produce. Potential implications of this finding for the addiction literature are discussed.

Light social drinkers are more distracted by irrelevant information from an induced attentional bias than heavy social drinkers.

It is well established that alcoholics and heavy social drinkers show a bias of attention towards alcohol-related items. Previous research suggests that there is a shared foundation of attentional bias, which is linked to attentional control settings. Specifically, attentional bias relates to a persistent selection of a Feature Search Mode which prioritises attentional bias-related information for selection and processing. However, no research has yet examined the effect of pre-existing biases on the development of an additional attentional bias. This paper seeks to discover how pre-existing biases affect the formation of a new, additional attentional bias. Twenty-five heavy and 25 light social drinkers, with and without a pre-existing bias to alcohol-related items, respectively, had an attentional bias towards the colour green induced via an information sheet. They then completed a series of one-shot change detection tasks. In the critical task, green items were present but task-irrelevant. Irrelevant green items caused significantly more interference for light than heavy social drinkers. This somewhat counter intuitive result is likely due to heavy drinkers having more experience in exerting cognitive control over attentional biases, something not previously observed in investigations of the effects of holding an attentional bias. Our findings demonstrate for the first time that an established attentional bias significantly modulates future behaviour.

Altering attentional control settings causes persistent biases of visual attention.

Attentional control settings have an important role in guiding visual behaviour. Previous work within cognitive psychology has found that the deployment of general attentional control settings can be modulated by training. However, research has not yet established whether long-term modifications of one particular type of attentional control setting can be induced. To address this, we investigated persistent alterations to feature search mode, also known as an attentional bias, towards an arbitrary stimulus in healthy participants. Subjects were biased towards the colour green by an information sheet. Attentional bias was assessed using a change detection task. After an interval of either 1 or 2 weeks, participants were then retested on the same change detection task, tested on a different change detection task where colour was irrelevant, or were biased towards an alternative colour. One experiment included trials in which the distractor stimuli (but never the target stimuli) were green. The key finding was that green stimuli in the second task attracted attention, despite this impairing task performance. Furthermore, inducing a second attentional bias did not override the initial bias toward green objects. The attentional bias also persisted for at least two weeks. It is argued that this persistent attentional bias is mediated by a chronic change to participants' attentional control settings, which is aided by long-term representations involving contextual cueing. We speculate that similar changes to attentional control settings and continuous cueing may relate to attentional biases observed in psychopathologies. Targeting these biases may be a productive approach to treatment.