Tracking Eye Movements during Spontaneous and Directed Refreshing

There is a growing interest in specifying the mechanisms underlying refreshing, i.e., the use of attention to keep working memory (WM) contents accessible. Here, we examined whether participants’ visual fixations during the retention interval of a WM task indicate the current focus of internal attention, thereby serving as an online measure of refreshing. Eye movements were recorded while participants studied and maintained an array of colored dots followed by probed recall of one (Experiments 1A and 1B) or all (Experiment 2) of the memoranda via a continuous color wheel. Experiments 1A and 2 entailed an unfilled retention interval in which refreshing is assumed to occur spontaneously, and Experiment 1B entailed a retention interval embedded with cues prompting the sequential refreshment of a subset of the memoranda. During the retention interval, fixations revisited the locations occupied by the memoranda, consistent with a looking-at-nothing phenomenon in WM, but the pattern was only evident when placeholders were onscreen in Experiment 2, indicating that these fixations may largely reflect random gaze. Furthermore, spontaneous fixations did not predict recall precision (Experiments 1A and 2), even when ensuring that they did not reflect random gaze (Experiment 2). In Experiment 1B, refreshing cues increased fixations to the eventually tested target and predicted better recall precision, which interacted with an overall benefit of target fixations. These results suggest that fixations during instructed, but not spontaneous, refreshing conditions account for additional variance in recall precision. Eye movements, however, do not seem suitable as an online measure of refreshing.

Functional Delineation of Prefrontal Networks Underlying Working Memory in Schizophrenia: A Cross-data-set Examination

Background: Working memory (WM) impairment in schizophrenia substantially impacts functional outcome. Although the dorsolateral pFC has been implicated in such impairment, a more comprehensive examination of brain networks comprising pFC is warranted. The present research used a whole-brain, multi-experiment analysis to delineate task-related networks comprising pFC. Activity was examined in schizophrenia patients across a variety of cognitive demands. Methods: One hundred schizophrenia patients and 102 healthy controls completed one of four fMRI tasks: a Sternberg verbal WM task, a visuospatial WM task, a Stroop set-switching task, and a thought generation task (TGT). Task-related networks were identified using multi-experiment constrained PCA for fMRI. Effects of task conditions and group differences were examined using mixed-model ANOVA on the task-related time series. Correlations between task performance and network engagement were also performed. Results: Four spatially and temporally distinct networks with pFC activation emerged and were postulated to subserve (1) internal attention, (2) auditory–motor attention, (3) motor responses, and (4) task energizing. The “energizing” network—engaged during WM encoding and diminished in patients—exhibited consistent trend relationships with WM capacity across different data sets. The dorsolateral-prefrontal-cortex-dominated “internal attention” network exhibited some evidence of hypoactivity in patients, but was not correlated with WM performance. Conclusions: Multi-experiment analysis allowed delineation of task-related, pFC-anchored networks across different cognitive constructs. Given the results with respect to the early-responding “energizing” network, WM deficits in schizophrenia may arise from disruption in the “energization” process described by Donald Stuss' model of pFC functions.

Individual differences in working memory capacity are unrelated to the magnitudes of retrocue benefits

Previous studies have associated visual working memory (VWM) capacity with the use of internal attention. Retrocues, which direct internal attention to a particular object or feature dimension, can improve VWM performance (i.e., retrocue benefit, RCB). However, so far, no study has investigated the relationship between VWM capacity and the magnitudes of RCBs obtained from object-based and dimension-based retrocues. The present study explored individual differences in the magnitudes of object- and dimension-based RCBs and their relationships with VWM capacity. Participants completed a VWM capacity measurement, an object-based cue task, and a dimension-based cue task. We confirmed that both object- and dimension-based retrocues could improve VWM performance. We also found a significant positive correlation between the magnitudes of object- and dimension-based RCB indexes, suggesting a partly overlapping mechanism between the use of object- and dimension-based retrocues. However, our results provided no evidence for a correlation between VWM capacity and the magnitudes of the object- or dimension-based RCBs. Although inadequate attention control is usually assumed to be associated with VWM capacity, the results suggest that the internal attention mechanism for using retrocues in VWM retention is independent of VWM capacity.

Dynamics of Internal Attention and Internally-Directed Cognition: The Attention-to-Thoughts (A2T) Model

The propensity to focus inward – internal attention – is fundamental to human mental life and internally-directed cognition (IDC) such as mindwandering and (mal)adaptive self-reflection. Yet, our understanding of the mechanisms through which internal attention shapes IDC is limited. We argue that our capacity to predict and model (mal)adaptive IDC may be significantly facilitated through understanding the complexity and dynamics of how internal attention interacts with other cognitive processes from which higher-level IDC emerges. We therefore introduce the Attention-to-Thoughts (A2T) model – a dynamic systems theory and computational model of internal attention in IDC. Through the model we aim to, first, conceptually and computationally define momentary states of this dynamic system; and, second, to simulate and predict differential temporal trajectories of this dynamic system through which IDC emerge. Through a series of experimental simulations, we explore how A2T may be used to better understand how internal attention selection is expressed from moment-to-moment; how the dynamic system of internal attention unfolds by documenting how, as a function of contextual demands for focused attention, internal attentional selection iteratively transacts with working-memory and emotion; and, in turn, how higher-level maladaptive IDC (e.g., repetitive negative thinking, cognitive dyscontrol) emerges from temporal trajectories of the dynamic system of internal attention. Finally, we highlight key conceptual, computational and methodological directions for the study of internal attention, IDC and related phenomena (e.g., mindfulness).

Simulating thoughts to measure and study internal attention in mental health

Our mind’s eye and the role of internal attention in mental life and suffering has intrigued scholars for centuries. Yet, experimental study of internal attention has been elusive due to our limited capacity to control the timing and content of internal stimuli. We thus developed the Simulated Thoughts Paradigm (STP) to experimentally deliver own-voice thought stimuli that simulate the content and experience of thinking and thereby experimental study of internal attentional processes. In independent experiments (N = 122) integrating STP into established cognitive-experimental tasks, we found and replicated evidence that emotional reactivity to negative thoughts predicts difficulty disengaging internal attention from, as well as biased selective internal attention of, those thoughts; these internal attention processes predict cognitive vulnerability (e.g., negative repetitive thinking) which thereby predict anxiety and depression. Proposed methods and findings may have implications for the study of information processing and attention in mental health broadly and models of internal attentional (dys)control in cognitive vulnerability and mental health more specifically.

Individual Differences in Working Memory Capacity Are Unrelated to the Magnitude of Benefits from Object- and Dimension-Based Retro-Cues

Previous studies have associated visual working memory (VWM) capacity with the ability to use internal attention. Internal attention’s effect on VWM has been studied mostly using object-based retro-cues, which can direct internal attention to particular objects. In addition, by using dimension-based retro-cues recent studies have found that directing internal attention to a feature dimension in VWM can improve memory recall performance. An object-based cue can direct attention to one or several objects of the memory array, while a dimension-based cue can direct attention to one visual dimension (e.g., color or orientation) of all memory items. Many studies show that retro-cues can improve VWM performance (i.e., retro-cue benefit, RCB). Although the mechanism of object-based retro-cues has been studied for over ten years, no study to date has investigated the relationship between VWM capacity and the benefits of dimension-based retro-cues. The present study aims to explore individual differences in VWM capacity and their relationship with the use of dimension- and object-based retro-cues. We first measured participants’ VWM capacity and then asked them to conduct a dimension-based cue task and an object-based cue task. In the cue taks, we used the offset index to quantify participants’ VWM performance, and we used the RCB index to quantify the magnitude of the benefits obtained from retro-cues. We found that performed better than low-VWM-capacity participants in both dimension- and object-based cue tasks. In addition, although we identified certain RCBs obtained from both dimension- and object-based cues, we did not find any significant correlation between individual VWM capacity differences and the magnitude of the RCB obtained from object- or dimension-based cues. These results suggest that VWM capacity is not related to RCBs’ magnitude, and thus VWM storage and the use of internal attention are independent mechanisms. Moreover, we found that the participants who benefitted the most from object-based retro-cues also benefitted the most from dimension-based retro-cues in color reports; ; however, this pattern was not found in the orientation report trials. This finding suggests a partly overlapping mechanism between the use of the two retro-cue types. The present study provides the first evidence of the relationship between VWM capacity and the dimension-based internal attention process.