Neural Mechanisms of Reward-by-Cueing Interactions: ERP Evidence

Inhibition of return (IOR) refers to the phenomenon that a person is slower to respond to targets at a previously cued location. The present study aimed to explore whether target-reward association is subject to IOR, using event-related potentials (ERPs) to explore the underlying neural mechanism. Each participant performed a localization task and a color discrimination task in an exogenous cueing paradigm, with the targets presented in colors (green/red) previously associated with high- or low-reward probability. The results of both tasks revealed that the N1, Nd, and P3 components exhibited differential amplitudes between cued and uncued trials (i.e., IOR) under low reward, with the N1 and Nd amplitudes being enhanced for uncued trials compared to cued trials, and the P3 amplitude being enhanced for cued trials vs. uncued trials. Under high reward, however, no difference was found between the amplitudes on cued and uncued trials for any of the components. These findings demonstrate that targets that were previously associated with high reward can be resistant to IOR and the current results enrich the evidence for interactions between reward-association and attentional orientation in the cueing paradigm.

The Modulation of Exogenous Attention on Emotional Audiovisual Integration

Although emotional audiovisual integration has been investigated previously, whether emotional audiovisual integration is affected by the spatial allocation of visual attention is currently unknown. To examine this question, a variant of the exogenous spatial cueing paradigm was adopted, in which stimuli varying by facial expressions and nonverbal affective prosody were used to express six basic emotions (happiness, anger, disgust, sadness, fear, surprise) via a visual, an auditory, or an audiovisual modality. The emotional stimuli were preceded by an unpredictive cue that was used to attract participants’ visual attention. The results showed significantly higher accuracy and quicker response times in response to bimodal audiovisual stimuli than to unimodal visual or auditory stimuli for emotional perception under both valid and invalid cue conditions. The auditory facilitation effect was stronger than the visual facilitation effect under exogenous attention for the six emotions tested. Larger auditory enhancement was induced when the target was presented at the expected location than at the unexpected location. For emotional perception, happiness shared the biggest auditory enhancement among all six emotions. However, the influence of exogenous cueing effect on emotional perception seemed to be absent.

The early attentional pancake: Lack of selection in depth for rapid exogenous cueing

There have been conflicting findings on the degree to which exogenous/reflexive visual attention is selective for depth, and this issue has important implications for attention models. Previous findings have attempted to find depth-based cueing effects on such attention using reaction time measures for stimuli presented in stereo goggles with a display screen. Results stemming from such approaches have been mixed, depending on whether target/distractor discrimination was required. To help clarify the existence of such depth effects, we have developed a paradigm that measures accuracy rather than reaction time in an immersive virtual-reality environment, providing a more appropriate context of depth. Four modified Posner Cueing paradigms were run to test for depth-specific attentional selectivity. Participants fixated a cross while attempting to identify a rapidly masked letter that was preceded by a cue that could be valid in depth and side, depth only, or side only. In Experiment 1, a potent cueing effect was found for side validity and a weak effect was found for depth. Experiment 2 controlled for differences in cue and target sizes when presented at different depths, which caused the depth validity effect to disappear entirely even though participants were explicitly asked to report depth and the difference in virtual depth was extreme (20 vs 300 meters). Experiments 3a and 3b brought the front depth plane even closer (1 m) to maximize effects of binocular disparity, but no reliable depth cueing validity was observed. Thus, it seems that rapid/exogenous attention pancakes 3-dimensional space into a 2-dimensional reference frame.

Attentional biases in depression: Relation to disorder severity, rumination, and anhedonia

Introduction: According to cognitive models of depression, selective attentional biases (ABs) for mood-congruent information are core vulnerability factors of depression maintenance. However, findings concerning the presence of these biases in depression are mixed. This study aims to clarify the presence of these ABs among individuals with clinical and subclinical depression. Method: We compared three groups based on a semi-structured diagnostic interview and a depressive symptoms scale (BDI-II): 34 individuals with major depressive disorder (clinically depressed); 35 with a dysphoric mood but without the criteria of major depressive disorder (i.e., subclinically depressed), and 26 never been depressed individuals. We examined AB for sad and happy materials in three modified versions of the exogenous cueing task using scenes, facial expressions, and words. Brooding, anhedonia, and anxiety were also evaluated. Results: In contrast to our hypotheses, there were no ABs for negative or positive information, regardless of the task and the groups. Neither the association between AB toward negative information and brooding nor the one between AB away from positive stimuli and anhedonia was significant. Bayes factors analyses revealed that the present pattern of findings does not result from a lack of statistical power.Discussion: Our results raise questions about how common AB is in depression. From a theoretical point of view, because individuals with depression did not exhibit AB, our results also seemingly challenge the claim that AB figures prominently in the maintenance of depression. We believe the present null results to be particularly useful for future meta-research in the field.

How Does Spatial Attention Influence the Probability and Fidelity of Colour Perception?

Existing research has found that spatial attention alters how various stimulus properties are perceived (e.g., luminance, saturation), but few have explored whether it improves the accuracy of perception. To address this question, we performed two experiments using modified Posner cueing tasks, wherein participants made speeded detection responses to peripheral colour targets and then indicated their perceived colours on a colour wheel. In E1, cues were central and endogenous (i.e., prompted voluntary attention) and the interval between cues and targets (stimulus onset asynchrony, or SOA) was always 800 ms. In E2, cues were peripheral and exogenous (i.e., captured attention involuntarily) and the SOA varied between short (100 ms) and long (800 ms). A Bayesian mixed-model analysis was used to isolate the effects of attention on the probability and the fidelity of colour encoding. Both endogenous and short-SOA exogenous spatial cueing improved the probability of encoding the colour of targets. Improved fidelity of encoding was observed in the endogenous but not in the exogenous cueing paradigm. With exogenous cues, inhibition of return (IOR) was observed in both RT and probability at the long SOA. Overall, our findings reinforce the utility of continuous response variables in the research of attention.

Cue predictability does not modulate bottom-up attentional capture

Attention can be involuntarily captured by physically salient stimuli, a phenomenon known as bottom-up attention. Typically, these salient stimuli occur unpredictably in time and space. Therefore, in a series of three behavioural experiments, we investigated the extent to which such bottom-up attentional capture is a function of one's prior expectations. In the context of an exogenous cueing task, we systematically manipulated participants' spatial (Experiment 1) or temporal (Experiments 2 and 3) expectations about an uninformative cue and examined the amount of attentional capture by the cue. We anticipated larger attentional capture for unexpected compared to expected cues. However, while we observed attentional capture, we did not find any evidence for a modulation of attentional capture by prior expectation. This suggests that bottom-up attentional capture does not appear modulated by the degree to which the cue is expected or surprising.

Transcutaneous vagus nerve stimulation and emotional inhibition of return

People suffering from chronic worries pay excessive attention to emotional information. In this study we examined whether a reduced ability to inhibit attention from fearful faces (i.e. inhibition of return; IOR) can be attributed to the low vagus nerve activity observed in high worriers. Our pre-registered hypothesis was that transcutaneous auricular vagus nerve stimulation (tVNS) would enhance IOR to fearful faces. Ninety-four students who scored above a pre-determined cut-off on the Penn State Worry Questionnaire were randomly allocated to receive either tVNS (n = 45) or sham stimulation of the earlobe (n = 49). Meanwhile, to assess IOR, they performed an emotional exogenous cueing task wherein neutral and fearful faces predicted the target location at chance level. Resting levels of HRV were also collected before stimulation onset. Results showed that levels of trait worry were associated with reduced IOR, but resting levels of HRV were not. Critically, tVNS did not affect performance on the exogenous cueing task when compared to sham stimulation. These findings did not confirm the hypothesized causal role of vagus nerve activity in maintaining disrupted IOR for emotional information. They also provide evidence that high levels of worry are associated with generally reduced IOR. This points to a clear need to understand the neurobiological basis of inhibitory problems in worriers.