A dedicated mental resource for intuitive physics.

Countless decisions and actions in daily life draw on a mental model of the physical structure and dynamics of the world - from stepping carefully around a patch of slippery pavement to stacking delicate produce in a shopping basket. People can make fast and accurate inferences about how physical interactions will unfold, but it remains unclear whether we do so by applying a general set of physical principles across scenarios, or instead by reasoning about the physics of individual scenarios in an ad-hoc fashion. Here, we hypothesized that humans possess a dedicated and flexible mental resource for physical inference, and we tested for such a resource using a battery of fine-tuned tasks to capture individual differences in performance. Despite varying scene contents across tasks, we found that performance was highly correlated among them and well-explained by a unitary intuitive physics resource, distinct from other facets of cognition such as spatial reasoning and working memory.

Do striking biases in mass inference reflect a flawed mental model of physics?

To engage with the physical world, we rely on our intuitive sense of how objects will behave when we act on them or they interact with each other. Objects' latent properties such as mass and hardness determine how their physical interactions will unfold, and people have a keen ability to infer these latent properties by observing physical events. For example, we can precisely discriminate the relative masses of two objects when we see them collide. However, such inferences are sometimes subject to marked biases. When inferring mass from an observed collision, people consistently overestimate the mass of an incoming object that strikes a stationary one. Why? A number of plausible accounts have been put forward, variously arguing that the bias arises from rule-based reasoning, oversimplified stimuli, or noisy perceptual estimates of the scene dynamics. The implications of these views stand in stark contrast to one another: systematic biases may reveal a fundamental deficiency in the mental model of physical behavior, or they may be an expected consequence of reasoning over imperfect information. Here, we investigated all three accounts within a unified paradigm, presenting videos of real-world bowling ball collisions. We found that using richly detailed stimuli did not eliminate biases in mass inference. However, individual differences in the biases were task-specific and well-explained by noisy perceptual estimates rather than oversimplified physical inference mechanisms. Our findings collectively point toward an intuitive physics system that implements Newtonian principles but is subject to the quality of the information it operates on. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

When it all falls down: the relationship between intuitive physics and spatial cognition.

Our intuitive understanding of physical dynamics is crucial in daily life. When we fill a coffee cup, stack items in a refrigerator, or navigate around a slippery patch of ice, we draw on our intuitions about how physical interactions will unfold. What mental machinery underlies our ability to form such inferences? Numerous aspects of cognition must contribute - for example, spatial thinking, temporal prediction, and working memory, to name a few. Is intuitive physics merely the sum of its parts - a collection of these and other related abilities that we apply to physical scenarios as we would to other tasks? Or does physical reasoning rest on something extra - a devoted set of mental resources that takes information from other cognitive systems as inputs? Here, we take a key step in addressing this question by relating individual differences on a physical prediction task to performance on spatial tasks, which may be most likely to account for intuitive physics abilities given the fundamentally spatial nature of physical interactions. To what degree can physical prediction performance be disentangled from spatial thinking? We tested 100 online participants in an "Unstable Towers" task and measures of spatial cognition and working memory. We found a positive relationship between intuitive physics and spatial skills, but there were substantial, reliable individual differences in physical prediction ability that could not be accounted for by spatial measures or working memory. Our findings point toward the separability of intuitive physics from spatial cognition.

Individual differences in sustained attention are associated with cortical thickness.

Several studies have examined how individual differences in sustained attention relate to functional brain measures (e.g., functional connectivity), but far fewer studies relate sustained attention ability, or cognition in general, to individual differences in cortical structure. Functional magnetic resonance imaging meta-analyses and patient work have highlighted that frontoparietal regions, lateralized to the right hemisphere, are critical for sustained attention, though recent work implicates a broader expanse of brain regions. The current study sought to determine if and where variation in cortical thickness is significantly associated with sustained attention performance. Sustained attention was measured using the gradual onset continuous performance task and the Test of Variables of Attention in 125 adult Veteran participants after acquiring two high-resolution structural MRI scans. Whole-brain vertex-wise analyses of the cortex demonstrated that better sustained attention was associated with increased thickness in visual, somatomotor, frontal, and parietal cortices, especially in the right hemisphere. Network-based analyses revealed relationships between sustained attention and cortical thickness in the dorsal attention, ventral attention, somatomotor, and visual networks. These results indicate cortical thickness in multiple regions and networks is associated with sustained attention, and add to the growing knowledge of how structural MRI can help explain individual differences in cognition.

Clinically significant cognitive dysfunction in OEF/OIF/OND veterans: Prevalence and clinical associations.

OBJECTIVE: Cognitive performance in trauma-exposed populations, such as combat Veterans, has been shown to be worse than in nonexposed peers. However, cognitive performance has typically been within the normal range (within 1 SD of normative mean), and the prevalence of clinically significant cognitive dysfunction (i.e., performance more than 1 SD below the mean on multiple measures in a domain) in younger adults with trauma exposure remains unknown. The objective of our study was to measure this. METHOD: We applied Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) cutoffs for clinically significant cognitive dysfunction (>1 SD below the mean in multiple measures within a domain) in the domains of memory, executive function, and attention to a sample of combat-exposed Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND; N = 368, mean age = 31.7 years, 90% men) Veterans. We then compared psychiatric, physiological, and neural measures, as well as functional outcomes, between those with and without cognitive dysfunction. RESULTS: Veterans with cognitive dysfunction (n = 129, 35.1%) had lower premorbid reading ability and more severe psychological distress, including increased anxiety, depression, posttraumatic stress disorder (PTSD), sleep difficulties, pain, and alcohol consumption. Those with cognitive dysfunction also had worse functional outcomes, with mild but significant disability. In contrast, we found associations between outcome and age, traumatic brain injury, physiological and neural measures to be weak or not significant. CONCLUSIONS: Together, this suggests that premorbid abilities and trauma-related psychological symptoms contribute significantly to cognitive dysfunction in OEF/OIF/OND Veterans, and that neurological insult and aging may play less of a role. Cognitive dysfunction may be at least partially ameliorated by treating trauma-related symptoms. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Randomized control trial of computer-based training targeting alertness in older adults: the ALERT trial protocol.

BACKGROUND: Healthy aging is associated with a decline in multiple functional domains including perception, attention, short and long-term memory, reasoning, decision-making, as well as cognitive and motor control functions; all of which are significantly modulated by an individual's level of alertness. The control of alertness also significantly declines with age and contributes to increased lapses of attention in everyday life, ranging from minor memory slips to a lack of vigilance and increased risk of falls or motor-vehicle accidents. Several experimental behavioral therapies designed to remediate age-related cognitive decline have been developed, but differ widely in content, method and dose. Preliminary studies demonstrate that Tonic and Phasic Alertness Training (TAPAT) can improve executive functions in older adults and may be a useful adjunct treatment to enhance benefits gained in other clinically validated treatments. The purpose of the current trial (referred to as the Attention training for Learning Enhancement and Resilience Trial or ALERT) is to compare TAPAT to an active control training condition, include a larger sample of patients, and assess both cognitive and functional outcomes. METHODS/DESIGN: We will employ a multi-site, longitudinal, blinded randomized controlled trial (RCT) design with a target sample of 120 patients with age-related cognitive decline. Patients will be asked to complete 36 training sessions remotely (30 min/day, 5 days a week, over 3 months) of either the experimental TAPAT training program or an active control computer games condition. Patients will be assessed on a battery of cognitive and functional outcomes at four time points, including: a) immediately before training, b) halfway through training, c) within forty-eight hours post completion of total training, and d) after a three-month no-contact period post completion of total training, to assess the longevity of potential training effects. DISCUSSION: The strengths of this protocol are that it tests an innovative, in-home administered treatment that targets a fundamental deficit in adults with age-related cognitive decline; employs highly sensitive computer-based assessments of cognition as well as functional abilities, and incorporates a large sample size in an RCT design. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02416401.

Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement.

Motivation and reward can have differential effects on separate aspects of sustained attention. We previously demonstrated that continuous reward/punishment throughout a sustained attention task improves overall performance, but not vigilance decrements. One interpretation of these findings is that vigilance decrements are due to resource depletion, which is not overcome by increasing overall motivation. However, an alternative explanation is that as one performs a continuously rewarded task there are less potential gains/losses as the task progresses, which could decrease motivation over time, producing a vigilance decrement. This would predict that keeping future gains/losses consistent throughout the task would reduce the vigilance decrement. In the current study, we examined this possibility by comparing two versions (continuous-small loss vs. anticipate-large loss) of a 10-minute gradual onset continuous performance task (gradCPT), a challenging go/no-go sustained attention task. Participants began each task with the potential to keep $18. In the continuous-small-loss version, small monetary losses were accrued continuously throughout the task for each error. However, in the anticipate-large-loss version, participants lost all $18 if they erroneously responded to one target that always appeared toward the end of the vigil. Typical vigilance decrements were observed in the continuous-small-loss condition. In the anticipate-large-loss condition, vigilance decrements were reduced, particularly when the anticipate-large loss condition was completed second. This suggests that the looming possibility of a large loss can attenuate the vigilance decrement and that this attenuation may occur most consistently after sufficient task experience. We discuss these results in the context of current theories of sustained attention.