Rende Shui

Contralateral delay activity tracks object identity information in visual short term memory

Previous studies suggested that ERP component contralateral delay activity (CDA) tracks the number of objects containing identity information stored in visual short term memory (VSTM). Later MEG and fMRI studies implied that its neural source lays in superior IPS. However, since the memorized stimuli in previous studies were displayed in distinct spatial locations, hence possibly CDA tracks the object-location information instead. Moreover, a recent study implied the activation in superior IPS reflected the location load. The current research thus explored whether CDA tracks the object-location load or the object-identity load, and its neural sources. Participants were asked to remember one color, four identical colors or four distinct colors. The four-identical-color condition was the critical one because it contains the same amount of identity information as that of one color while the same amount of location information as that of four distinct colors. To ensure the participants indeed selected four colors in the four-identical-color condition, we also split the participants into two groups (low- vs. high-capacity), analyzed late positive component (LPC) in the prefrontal area, and collected participants subjective-report. Our results revealed that most of the participants selected four identical colors. Moreover, regardless of capacity-group, there was no difference on CDA between one color and four identical colors yet both were lower than 4 distinct colors. Besides, the source of CDA was located in the superior parietal lobule, which is very close to the superior IPS. These results support the statement that CDA tracks the object identity information in VSTM.

Tracking object number or information load in visual working memory: Revisiting the cognitive implication of contralateral delay activity

Two accounts prevail for the ERP component contralateral delay activity (CDA). One is that CDA tracks the number of objects stored in visual working memory (VWM), the more objects the higher amplitude (object number account). The other is that CDA reflects the maintained information load (information load account), the higher load the higher amplitude. The two accounts were tested by manipulating the information load and the object number of stored objects. Two or four arrows with low- or high-resolution information were remembered in separate blocks. In two experiments we found that the CDA-amplitude was higher for 4 arrows than for 2 arrows in low-resolution condition, yet no difference in high-resolution condition. Critically, there was no difference on CDA-amplitude among 2 low- and high-resolution objects, as well as 4 high-resolution objects, yet all were significantly lower than 4 low-resolution arrows. These results supported the object number account of CDA.

Coarse-to-Fine Construction for High-Resolution Representation in Visual Working Memory

Background This study explored whether the high-resolution representations created by visual working memory (VWM) are constructed in a coarse-to-fine or all-or-none manner. The coarse-to-fine hypothesis suggests that coarse information precedes detailed information in entering VWM and that its resolution increases along with the processing time of the memory array, whereas the all-or-none hypothesis claims that either both enter into VWM simultaneously, or neither does. Methodology/Principal Findings We tested the two hypotheses by asking participants to remember two or four complex objects. An ERP component, contralateral delay activity (CDA), was used as the neural marker. CDA is higher for four objects than for two objects when coarse information is primarily extracted; yet, this CDA difference vanishes when detailed information is encoded. Experiment 1 manipulated the comparison difficulty of the task under a 500-ms exposure time to determine a condition in which the detailed information was maintained. No CDA difference was found between two and four objects, even in an easy-comparison condition. Thus, Experiment 2 manipulated the memory array’s exposure time under the easy-comparison condition and found a significant CDA difference at 100 ms while replicating Experiment 1′s results at 500 ms. In Experiment 3, the 500-ms memory array was blurred to block the detailed information; this manipulation reestablished a significant CDA difference. Conclusions/Significance These findings suggest that the creation of high-resolution representations in VWM is a coarse-to-fine process.

Tracking the mismatch information in visual short term memory: an event-related potential study.

Although the mechanisms of visual short term memory (VSTM) are extensively investigated in the recent decade, how we compare the representation stored in VSTM to the perceptual input to detect and process the mismatch information remains largely unclear. The current study explored whether there is an ERP component tracking the mismatch process in VSTM by adopting a delayed matching task. To exclude non-memory factors, for instance, using perceptual representation which dominated in previous studies using this paradigm, we lengthened the blank interval between the two sequentially displayed stimuli to 4 s to ensure the first stimuli is stored in VSTM. In order to test the sensitivity of this potential neural index and its functional relation to VSTM comparison process, colored shapes were adopted as materials while both the target feature color and the irrelevant feature shape could be changed. We found both the target feature change and the irrelevant feature change elicited a more negative component N270 (or N2-enhancement) around the anterior areas, with their neural sources located at frontal lobe. These results suggest that the N270 can sensitively reflect the mismatch information between the representation in VSTM and the perceptual input. Moreover, it may reflect the limited-capacity process in the VSTM-perception comparison, in which a deliberative comparison was conducted after an unlimited-capacity comparison process.

Saccades elicit obligatory allocation of visual working memory

In daily life, visual working memory (VWM) typically works in contexts in which people make frequent saccades. Here, we investigated whether people can effectively control the allocation of VWM when making a saccade. Subjects were required to make an intervening saccade in the process of a memory task. The saccade target was either a to-be-remembered item or an extra, not-to-be-remembered item. The results showed that memory performance was poorer when a saccade was made to the extra, not-to-be-remembered item, regardless of its similarity to the memory item(s). In contrast, when memorizing the items while remaining fixated, subjects had similar memory performance whether an extra, not-to-be-remembered item was present or not. Taken together, these results demonstrated that volitional control over VWM allocation is greatly impaired when a saccade is made, indicating that VWM contains an automatic part that cooperates with eye movements and is allocated to a saccade target obligatorily.

Organization principles in visual working memory: Evidence from sequential stimulus display

Although the mechanisms of visual working memory (VWM) have been studied extensively in recent years, the active property of VWM has received less attention. In the current study, we examined how VWM integrates sequentially presented stimuli by focusing on the role of Gestalt principles, which are important organizing principles in perceptual integration. We manipulated the level of Gestalt cues among three or four sequentially presented objects that were memorized. The Gestalt principle could not emerge unless all the objects appeared together. We distinguished two hypotheses: a perception-alike hypothesis and an encoding-specificity hypothesis. The former predicts that the Gestalt cue will play a role in information integration within VWM; the latter predicts that the Gestalt cue will not operate within VWM. In four experiments, we demonstrated that collinearity (Experiment 1) and closure (Experiment 2) cues significantly improved VWM performance, and this facilitation was not affected by the testing manner (Experiment 3) or by adding extra colors to the memorized objects (Experiment 4). Finally, we re-established the Gestalt cue benefit with similarity cues (Experiment 5). These findings together suggest that VWM realizes and uses potential Gestalt principles within the stored representations, supporting a perception-alike hypothesis.

Anger and selective attention to reward and punishment in children

Anger is a negative emotion associated with approach motivation and may influence childrens attention preference. Three experiments examined the effect of anger on the attentional biases accompanying reward versus punishment cues in Chinese 5- and 6-year-olds. Experiment 1 tested children who were prone to report angry feelings in an unfair game. Experiment 2 measured children who were rated by parents and teachers for temperamental anger. Experiment 3 explored children who reported angry feelings in a frustrating attention task with rigged and noncontingent feedback after controlling for temperament anger. Results suggested that both the angry and anger-prone children were faster to engage attention toward the reward cues than toward the punishment cues in the three experiments. Furthermore, the angry children in the frustrating attention task (and those with poor attention focusing by parental report) were slower in disengaging attention away from the reward versus punishment cues (especially after negative feedback). Results support the approach motivation of anger, which can facilitate childrens attention toward the appetitive approach-related information. The findings are discussed in terms of the adaptive and maladaptive function of anger.

Social grouping: perceptual grouping of objects by cooperative but not competitive relationships in dynamic chase.

Historically, perceptual grouping is associated with physical principles. This article reports a novel finding that social information-cooperative but not competitive relationships-can drive perceptual grouping of objects in dynamic chase. Particularly, each relationship was constructed with human-generated chasing motions (i.e., two predators and one prey), and its role on perceptual grouping was examined by grouping-induced effect-attentional consequences. The results showed that: (1) Predators can be perceived as a group due to their cooperative relationship, causing attention to automatically spread within grouped predators, thus the response to target appearing on uncued predator is also facilitated; and (2) The attentional effect on competitive predators has no difference from any condition which controls low-level motion patterns, even including the random-motion condition wherein no grouping factor was contained. These findings extend perceptual grouping into the social field, implying that social information gets involved in visual cognition at an early perceptual stage.

The working memory Ponzo illusion: Involuntary integration of visuospatial information stored in visual working memory

Visual working memory (VWM) has been traditionally viewed as a mental structure subsequent to visual perception that stores the final output of perceptual processing. However, VWM has recently been emphasized as a critical component of online perception, providing storage for the intermediate perceptual representations produced during visual processing. This interactive view holds the core assumption that VWM is not the terminus of perceptual processing; the stored visual information rather continues to undergo perceptual processing if necessary. The current study tests this assumption, demonstrating an example of involuntary integration of the VWM content, by creating the Ponzo illusion in VWM: when the Ponzo illusion figure was divided into its individual components and sequentially encoded into VWM, the temporally separated components were involuntarily integrated, leading to the distorted length perception of the two horizontal lines. This VWM Ponzo illusion was replicated when the figure components were presented in different combinations and presentation order. The magnitude of the illusion was significantly correlated between VWM and perceptual versions of the Ponzo illusion. These results suggest that the information integration underling the VWM Ponzo illusion is constrained by the laws of visual perception and similarly affected by the common individual factors that govern its perception. Thus, our findings provide compelling evidence that VWM functions as a buffer serving perceptual processes at early stages.

Social constraints from an observer’s perspective: Coordinated actions make an agent’s position more predictable

Action prediction, a crucial ability to support social activities, is sensitive to the individual goals of expected actions. This article reports a novel finding that the predictions of observed actions for a temporarily invisible agent are influenced, and even enhanced, when this agent has a joint/collective goal to implement coordinated actions with others (i.e., with coordination information). Specifically, we manipulated the coordination information by presenting two chasers and one common target to perform coordinated or individual chases, and subjects were required to predict the expected action (i.e., position) for one chaser after it became momentarily invisible. To control for possible low-level physical properties, we also established some intense paired controls for each type of chase, such as backward replay (Experiment 1), making the chasing target invisible (Experiment 2) and a direct manipulation of the goal-directedness of one chasers movements to disrupt coordination information (Experiment 3). The results show that the prediction error for invisible chasers depends on whether the second chaser is coordinated with the first, and this effect vanishes when the chasers behaves with exactly the same motions, but without coordination information between them; furthermore, this influence results in enhancing the performance of action prediction. These findings extend the influential factors of action prediction to the level of observed coordination information, implying that the functional characteristic of mutual constraints of coordinated actions can be utilized by vision.