A bottom–up model of spatial attention predicts human error patterns in rapid scene recognition

Humans demonstrate a peculiar ability to detect complex targets in rapidly presented natural scenes. Recent studies suggest that (nearly) no focal attention is required for overall performance in such tasks. Little is known, however, of how detection performance varies from trial to trial and which stages in the processing hierarchy limit performance: bottom–up visual processing (attentional selection and/or recognition) or top–down factors (e.g., decision-making, memory, or alertness fluctuations)? To investigate the relative contribution of these factors, eight human observers performed an animal detection task in natural scenes presented at 20 Hz. Trial-by-trial performance was highly consistent across observers, far exceeding the prediction of independent errors. This consistency demonstrates that performance is not primarily limited by idiosyncratic factors but by visual processing. Two statistical stimulus properties, contrast variation in the target image and the information-theoretical measure of “surprise” in adjacent images, predict performance on a trial-by-trial basis. These measures are tightly related to spatial attention, demonstrating that spatial attention and rapid target detection share common mechanisms. To isolate the causal contribution of the surprise measure, eight additional observers performed the animal detection task in sequences that were reordered versions of those all subjects had correctly recognized in the first experiment. Reordering increased surprise before and/or after the target while keeping the target and distractors themselves unchanged. Surprise enhancement impaired target detection in all observers. Consequently, and contrary to several previously published findings, our results demonstrate that attentional limitations, rather than target recognition alone, affect the detection of targets in rapidly presented visual sequences

Thalamic inputs to dorsomedial striatum are involved in inhibitory control: evidence from the five-choice serial reaction time task in rats

Rationale Corticostriatal circuits are widely implicated in the top-down control of attention including inhibitory control and behavioural flexibility. However, recent neurophysiological evidence also suggests a role for thalamic inputs to striatum in behaviours related to salient, reward-paired cues. Objectives Here, we used designer receptors exclusively activated by designer drugs (DREADDs) to investigate the role of parafascicular (Pf) thalamic inputs to the dorsomedial striatum (DMS) using the five-choice serial reaction time task (5CSRTT) in rats. Methods The 5CSRTT requires sustained attention in order to detect spatially and temporally distributed visual cues and provides measures of inhibitory control related to impulsivity (premature responses) and compulsivity (perseverative responses). Rats underwent bilateral Pf injections of the DREADD vector, AAV2-CaMKIIa-HA-hM4D(Gi)-IRES-mCitrine. The DREADD agonist, clozapine N-oxide (CNO; 1 μl bilateral; 3 μM) or vehicle, was injected into DMS 1 h before behavioural testing. Task parameters were manipulated to increase attention load or reduce stimulus predictability respectively. Results We found that inhibition of the Pf-DMS projection significantly increased perseverative responses when stimulus predictability was reduced but had no effect on premature responses or response accuracy, even under increased attentional load. Control experiments showed no effects on locomotor activity in an open field. Conclusions These results complement previous lesion work in which the DMS and orbitofrontal cortex were similarly implicated in perseverative responses and suggest a specific role for thalamostriatal inputs in inhibitory control

Testing a load theory framework for food-related cognition

The way we process rewarding stimuli is widely held to play a key role in normal and abnormal behavior. Biased processing of food—arguably the most primal form of reward—has been strongly implicated in the obesity crisis. Paradoxically, however, existing evidence suggests that both too much and too little attention can potentially lead to overeating. Here we sought to explain this contradiction within the framework of the load theory of attention, while also elucidating the relatively understudied role of memory biases. In 3 experiments, we presented food and nonfood images as irrelevant distractors during a letter search task with high and low levels of perceptual load, followed by a forced choice recognition task. As predicted, increasing perceptual load consistently powerfully reduced distraction by food and nonfood images alike. Similarly, food images encountered under high perceptual load were less likely to be recognized in a surprise memory test. Unexpectedly, however, there was a striking absence of attentional bias to food above and beyond salient nonfood stimuli, either within-subjects or in relation to traits implicated in food-biases. By contrast, a food memory bias was consistently observed across participants, and appeared independent of attentional biases. Food memory was consistently heightened in individuals with high levels of trait disinhibition (a measure of opportunistic eating). Our findings suggest that attention and memory for food and nonfood are similarly impacted by perceptual load. We discuss implications of the load theory framework for the wider literature on food-related cognition and for real world eating behaviors

Does overloading cognitive resources mimic the impact of anxiety on temporal cognition?

Anxiety alters how we perceive the world and can alter aspects of cognitive performance. Prominent theories of anxiety suggest that the effect of anxiety on cognition is due to anxious thoughts "overloading" limited cognitive resources, competing with other processes. If this is so, then a cognitive load manipulation should impact performance of a task in the same way as induced anxiety. Thus, we examined the impact of a load manipulation on a time perception task that we have previously shown to be reliably impacted by anxiety. In contrast with our prediction, across 3 studies we found that time perception was insensitive to our load manipulation. Our results do not therefore support the idea that anxiety impacts temporal cognition by overloading limited cognitive resources, at least as induced by a commonly used load manipulation. Thus, anxiety might affect temporal cognition in a unique way, via an evolutionary-preserved defense survival system, as suggested by animal-inspired theories of anxiety, rather than competing for limited attentional resources. (PsycInfo Database Record (c) 2020 APA, all rights reserved)

Putting attention in the spotlight: the influence of APOE genotype on visual search in mid adulthood

The Apolipoprotein E e4 allele is associated with greater cognitive decline with age, yet effects of this gene are also observed earlier in the lifespan. This research explores genotype differences (e2, e3, e4) in the allocation of visuospatial attention in mid-adulthood. Sixty-six volunteers, aged 45–55 years, completed two paradigms probing the active selection of information at the focus of attention (a dynamic scaling task) and perceptual capacity differences. Two methods of statistical comparison (parametric statistics, Bayesian inference) found no significant difference between e4 carriers and the homozygous e3 group on either the dynamic scaling or perceptual load task. E2 carriers, however, demonstrated less efficient visual search performance on the dynamic scaling task. The lack of an e4 difference in visuospatial attention, despite previous suggestion in the literature of genotype effects, indicates that select attentional processes are intact in e4 carriers in mid-adulthood. The association of e2 genotype with slower visual search performance complicates the premised protective effects of this allele in cognitive ageing

Semantic Congruency Modulates the Effect of Attentional Load on the Audiovisual Integration of Animate Images and Sounds

Attentional processes play a complex and multifaceted role in the integration of input from different sensory modalities. However, whether increased attentional load disrupts the audiovisual (AV) integration of common objects that involve semantic content remains unclear. Furthermore, knowledge regarding how semantic congruency interacts with attentional load to influence the AV integration of common objects is limited. We investigated these questions by examining AV integration under various attentional-load conditions. AV integration was assessed by adopting an animal identification task using unisensory (animal images and sounds) and AV stimuli (semantically congruent AV objects and semantically incongruent AV objects), while attentional load was manipulated by using a rapid serial visual presentation task. Our results indicate that attentional load did not attenuate the integration of semantically congruent AV objects. However, semantically incongruent animal sounds and images were not integrated (as there was no multisensory facilitation), and the interference effect produced by the semantically incongruent AV objects was reduced by increased attentional-load manipulations. These findings highlight the critical role of semantic congruency in modulating the effect of attentional load on the AV integration of common objects

Visual selective attention is equally functional for individuals with low and high working memory capacity: Evidence from accuracy and eye movements

Selective attention and working memory capacity (WMC) are related constructs, but debate about the manner in which they are related remains active. One elegant explanation of variance in WMC is that the efficiency of filtering irrelevant information is the crucial determining factor, rather than differences in capacity per se. We examined this hypothesis by relating WMC (as measured by complex span tasks) to accuracy and eye movements during visual change detection tasks with different degrees of attentional filtering and allocation requirements. Our results did not indicate strong filtering differences between high- and low-WMC groups, and where differences were observed, they were counter to those predicted by the strongest attentional filtering hypothesis. Bayes factors indicated evidence favoring positive or null relationships between WMC and correct responses to unemphasized information, as well as between WMC and the time spent looking at unemphasized information. These findings are consistent with the hypothesis that individual differences in storage capacity, not only filtering efficiency, underlie individual differences in working memory

Perceptual load and enumeration: Distractor interference depends on subitizing capacity

Attention is limited, both in processing capacity (leading to phenomena of “inattentional blindness”) and in the capacity for selective focus (leading to distraction). Load theory (e.g., Lavie, 1995) accounts for both limitations by proposing that perceptual processing has limited capacity but proceeds automatically and in parallel on all stimuli within capacity. Here we tested these claims by applying load theory to the phenomenon of “subitizing”: the parallel detection and individuation of a limited number of items, established in enumeration research. We predicted that distractor interference will be found within but not beyond a person’s subitizing capacity (measured as the transition from parallel to serial slope). Participants reported the number of target shapes from brief displays while ignoring irrelevant cartoon-image distractors. As predicted, distractor cost on enumeration performance was found within subitizing capacity and eliminated in larger set sizes. Moreover, individual differences results demonstrated that distractor effects depended on an individual’s capacity (i.e., their serial-to-parallel transition point), rather than on set size per se. These results provide new evidence for the load theory hypotheses that perceptual processing is automatic and parallel within its limited capacity, while extending it to account for selective attention during enumeratio

The Contralateral Delay Activity Tracks the Sequential Loading of Objects into Visual Working Memory, Unlike Lateralized Alpha Oscillations

Visual working memory temporarily represents a continuous stream of task-relevant objects as we move through our environment performing tasks. Previous work has identified candidate neural mechanisms of visual working memory storage; however, we do not know which of these mechanisms enable the storage of objects as we sequentially encounter them in our environment. Here, we measured the contralateral delay activity (CDA) and lateralized alpha oscillations as human subjects were shown a series of objects that they needed to remember. The amplitude of CDA increased following the presentation of each to-be-remembered object, reaching asymptote at about three to four objects. In contrast, the concurrently measured lateralized alpha power remained constant with each additional object. Our results suggest that the CDA indexes the storage of objects in visual working memory, whereas lateralized alpha suppression indexes the focusing of attention on the to-be-remembered objects