No electrophysiological evidence for semantic processing during inattentional blindness.

A long-standing question concerns whether sensory input can reach semantic stages of processing in the absence of attention and awareness. Here, we examine whether the N400, an event related potential associated with semantic processing, can occur under conditions of inattentional blindness. By employing a novel three-phase inattentional blindness paradigm designed to maximise the opportunity for detecting an N400, we found no evidence for it when participants were inattentionally blind to the eliciting stimuli (related and unrelated word pairs). In contrast, participants noticed the same task-irrelevant word pairs when minimal attention was allocated to them, and a small N400 became evident. When the same stimuli were fully attended and relevant to the task, a robust N400 was observed. In addition to univariate ERP measures, multivariate decoding analyses were unable to classify related from unrelated word pairs when observers were inattentionally blind to the words, with decoding reaching above-chance levels only when the words were (at least minimally) attended. By comparison, decoding reached above-chance levels when contrasting word pairs with non-word stimuli, even when participants were inattentionally blind to these stimuli. Our results also replicated several previous studies by finding a "visual awareness negativity" (VAN) that distinguished task-irrelevant stimuli that participants noticed compared with those that were not perceived, and a P3b (or "late positivity") that was evident only when the stimuli were task relevant. Together, our findings suggest that semantic processing might require at least a minimal amount of attention.

Pre-stimulus alpha predicts inattentional blindness.

Pre- and post-stimulus oscillatory activity between 8 and 12 hertz, referred to as the alpha-band, correlates with conscious visual awareness of stimuli across a variety of psychophysical tasks. Within an EEG-adapted inattentional blindness task, the current study sought to examine whether this relationship holds for conscious awareness of stimuli under conditions of inattentional blindness. Noticing rates of the task-irrelevant unexpected stimulus were correlated with a significant decrease in alpha power over bilateral parietal-occipital areas during the pre-stimulus interval, and a significant decrease in alpha power over parietal-occipital regions in the right hemisphere during the post-stimulus interval. Findings are taken to imply alpha-band neural activity represents a valid correlate of consciousness that is not confounded by task relevancy or the need for report.

tACS Stimulation at Alpha Frequency Selectively Induces Inattentional Blindness.

Contemporary neurocognitive models implicate alpha oscillations as a top-down mechanism of cortical inhibition, instrumental in the suppression of information that fails to reach conscious visual awareness. This suggests that alpha-band activity may play a key role in the phenomenon of inattentional blindness, however this has not yet been empirically examined. The current study employed transcranial alternating current stimulation (tACS) over occipital cortex at alpha, theta, and sham frequencies within an inattentional blindness task to delineate whether an exogenous manipulation of alpha oscillations has a modulatory effect on visual awareness of the unexpected stimulus. Results revealed that compared to theta and sham, those exposed to alpha tACS were more likely to be inattentionally blind to the unexpected stimulus. Findings extend current theoretical views of alpha by suggesting inattentional blindness may be explained as a suppression of irrelevant information via alpha-band.

A study into the mental health of PhD students in Australia: investigating the determinants of depression, anxiety, and suicidality.

PhD students are particularly vulnerable to experiencing poor mental health. Mental health concerns that arise during their studies can not only affect their study progress but also have long-lasting impacts on their mental health after their studies. Extensive research has been conducted on the mental health of university students, but few studies have focused on PhD students and even fewer on PhD students in Australia. The present study investigated demographic, occupational, psychological, social, and relational determinants of mental health symptoms (depression, anxiety, and suicidality) in PhD students in Australia. PhD students enrolled in Australian universities were invited to complete an online survey. Results from regression analyses identified key determinants of mental health symptoms in our sample of PhD students (N = 302). In particular, higher levels of imposter thoughts, perfectionism discrepancy, and loneliness were strong predictors of depression, anxiety, and suicidality. These findings contribute to our understanding of the mental health of PhD students in Australia. Importantly, these findings inform areas of focus where potential strategies can be implemented to better protect the mental health of this population. For example, strategies that mitigate loneliness or foster effective, collaborative student-supervisor relationships.

An investigation of inattentional blindness using gaze and frequency tagging.

Inattentional blindness (IB) occurs when a salient object presented in plain sight goes unnoticed when its appearance is unexpected. Across two experiments, participants completed a classic dynamic IB task while eye movements and steady-state visual evoked potential (SSVEP) responses were continually recorded. This allowed us to measure the modulation of gaze and brain-based indices of attention during IB. While an SSVEP response to all stimuli including the unexpected object was attained, only gaze measures were able to discriminate noticers from nonnoticers. Experiment 1 used a prototypical sustained IB task and found that gaze toward the unexpected object was largely unrelated to noticing that object. Experiment 2 manipulated the contrast of the target and distractor stimuli, and instead observed a tight concordance between gazing at the unexpected object and reporting its presence. This task-based variability in gaze deployment is consistent with the broader literature and cumulatively delineates the challenges faced in translating lab-based IB research from the bench to the bedside. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Insights on overflow from failure to report tasks.

Theories of consciousness diverge on the functional requirement that a conscious state need be reportable. Some maintain that the perceptual system's capacity for consciousness exceeds that of its capacity for access. Others contend that what is accessed is all there is to consciousness. Here, we suggest a compelling case for access-free consciousness cannot be made reliant on experimental evidence where access is necessarily invoked. However, a bona fide empirical separation of consciousness and report could counter the claim that reportability, and hence access, is all there is to consciousness. We first overview recent neurophysiological findings from no-report tasks, before examining a series of studies in which participants were unable to report features of clearly visible items. These new data present a challenge for a hard "access-only" view of consciousness, as they appear to demonstrate that properties of our visual experience can remain unreportable. In so doing, we highlight the utility and underappreciated value of so-called failure to report tasks.

Learned uncertainty: The free energy principle in anxiety.

Generalized anxiety disorder is among the world's most prevalent psychiatric disorders and often manifests as persistent and difficult to control apprehension. Despite its prevalence, there is no integrative, formal model of how anxiety and anxiety disorders arise. Here, we offer a perspective derived from the free energy principle; one that shares similarities with established constructs such as learned helplessness. Our account is simple: anxiety can be formalized as learned uncertainty. A biological system, having had persistent uncertainty in its past, will expect uncertainty in its future, irrespective of whether uncertainty truly persists. Despite our account's intuitive simplicity-which can be illustrated with the mere flip of a coin-it is grounded within the free energy principle and hence situates the formation of anxiety within a broader explanatory framework of biological self-organization and self-evidencing. We conclude that, through conceptualizing anxiety within a framework of working generative models, our perspective might afford novel approaches in the clinical treatment of anxiety and its key symptoms.

Toward a theory of consciousness: A review of the neural correlates of inattentional blindness.

The neuroscientific study of consciousness involves examining candidate markers of consciousness under conditions where awareness varies. One such method for manipulating awareness is inattentional blindness. Whereas other methods of studying consciousness have been reviewed elsewhere, there has been little effort toward cataloguing work which has studied inattentional blindness using neuroscientific methodology. I address this by reviewing this body of literature, with key importance placed on how research informs a neuroscience of consciousness and the degree to which visual processing occurs in the absence of attention and awareness. Findings demonstrate clear evidence that processing up to intermediate stages (e.g. visual features, orthographic processing) occurs, even during inattentional blindness. The most commonly observed neurophysiological correlates associated with awareness include the visual awareness negativity and post-stimulus alpha suppression, whereas neuroanatomical markers include the lateral occipital cortex, the temporoparietal junction, and the intraparietal sulcus. I conclude by addressing the limitations this literature has been challenged with and offer recommendations for how future work on inattentional blindness can aid in advancing neuroscientific theories of consciousness.