Object-location Binding Research Articles

Audiovisual communication of object-names improves the spatial accuracy of recalled object-locations in topographic maps.

Knowing the correct location of a specific object learned from a (topographic) map is fundamental for orientation and navigation tasks. Spatial reference systems, such as coordinates or cardinal directions, are helpful tools for any geometric localization of positions that aims to be as exact as possible. Considering modern visualization techniques of multimedia cartography, map elements transferred through the auditory channel can be added easily. Audiovisual approaches have been discussed in the cartographic community for many years. However, the effectiveness of audiovisual map elements for map use has hardly been explored so far. Within an interdisciplinary (cartography-cognitive psychology) research project, it is examined whether map users remember object-locations better if they do not just read the corresponding place names, but also listen to them as voice recordings. This approach is based on the idea that learning object-identities influences learning object-locations, which is crucial for map-reading tasks. The results of an empirical study show that the additional auditory communication of object names not only improves memory for the names (object-identities), but also for the spatial accuracy of their corresponding object-locations. The audiovisual communication of semantic attribute information of a spatial object seems to improve the binding of object-identity and object-location, which enhances the spatial accuracy of object-location memory.

An effect of categorical similarity on object-location binding in visual working memory

An effect of categorical similarity on object-location binding in visual working memory

Influence of Landmarks on Wayfinding and Brain Connectivity in Immersive Virtual Reality Environment.

Spatial navigation is influenced by landmarks, which are prominent visual features in the environment. Although previous research has focused on finding advantages of landmarks on wayfinding via experimentation; however, less attention has been given to identifying the key attributes of landmarks that facilitate wayfinding, including the study of neural correlates (involving electroencephalogram, EEG analyses). In this paper, we combine behavioral measures, virtual environment, and EEG signal-processing to provide a holistic investigation about the influence of landmarks on performance during navigation in a maze-like environment. In an experiment, participants were randomly divided into two conditions, Landmark-enriched (LM+; N = 17) and Landmark-devoid (LM-; N = 18), and asked to navigate from an initial location to a goal location in a maze. In the LM+ condition, there were landmarks placed at certain locations, which participants could use for wayfinding in the maze. However, in the LM- condition, such landmarks were not present. Beyond behavioral analyses of data, analyses were carried out of the EEG data collected using a 64-channel device. Results revealed that participants took less time and committed fewer errors in navigating the maze in the LM+ condition compared to the LM- condition. EEG analyses of the data revealed that the left-hemispheric activation was more prominent in the LM+ condition compared to the LM- condition. The event-related desynchronization/synchronization (ERD/ERS) of the theta frequency band, revealed activation in the left posterior inferior and superior regions in the LM+ condition compared to the LM- condition, suggesting an occurrence of an object-location binding in the LM+ condition along with spatial transformation between representations. Moreover, directed transfer function method, which measures information flow between two regions, showed a higher number of active channels in the LM- condition compared to the LM+ condition, exhibiting additional wiring cost associated with the cognitive demands when no landmark was available. These findings reveal pivotal role of the left-hemispheric region (especially, parietal cortex), which indicates the integration of available sensory cues and current memory requirements to encode contextual information of landmarks. Overall, this research helps to understand the role of brain regions and processes that are utilized when people use landmarks in navigating maze-like environments.

Sex differences of cognitive load effects on object-location binding memory.

In this study, we investigated where the sex differences of object-location binding memory performance were influenced by the cognitive load. We used the fractal objects version of the 'What was where?' task to measure object memory, location memory and objection-location binding memory. Cognitive load was controlled by task difficulty presented two sessions: one session randomly displayed three or four fractal objects (Session 34) and the other session four or five objects (Session 45). The results showed that females outperformed males on object-location binding memory. Interestingly, even when the four object trials were compared between Session 34 and Session 45, in which we believed that the level of difficulty was similar while cognitive load varied, the swap error of males was significantly increased in Session 45 compared to females. In conclusion, there may be sex differences in object-location binding memory and the males could be more sensitive about the cognitive load than females.

Binding object features to locations: Does the “spatial congruency bias” update with object movement?

One of the fundamental challenges of visual cognition is how our visual systems combine information about an object's features with its spatial location. A recent phenomenon related to object-location binding, the "spatial congruency bias," revealed that two objects are more likely to be perceived as having the same identity or features if they appear in the same spatial location, versus if the second object appears in a different location. The spatial congruency bias suggests that irrelevant location information is automatically encoded with and bound to other object properties, biasing perceptual judgments. Here we further explored this new phenomenon and its role in object-location binding by asking what happens when an object moves to a new location: Is the spatial congruency bias sensitive to spatiotemporal contiguity cues, or does it remain linked to the original object location? Across four experiments, we found that the spatial congruency bias remained strongly linked to the original object location. However, under certain circumstances-for instance, when the first object paused and remained visible for a brief time after the movement-the congruency bias was found at both the original location and the updated location. These data suggest that the spatial congruency bias is based more on low-level visual information than on spatiotemporal contiguity cues, and reflects a type of object-location binding that is primarily tied to the original object location and that may only update to the object's new location if there is time for the features to be re-encoded and rebound following the movement.

Out of place, out of mind: Schema-driven false memory effects for object-location bindings.

Events consist of diverse elements, each processed in specialized neocortical networks, with temporal lobe memory systems binding these elements to form coherent event memories. We provide a novel theoretical analysis of an unexplored consequence of the independence of memory systems for elements and their bindings, 1 that raises the paradoxical prediction that schema-driven false memories can act solely on the binding of event elements despite the superior retrieval of individual elements. This is because if 2, or more, schema-relevant elements are bound together in unexpected conjunctions, the unexpected conjunction will increase attention during encoding to both the elements and their bindings, but only the bindings will receive competition with evoked schema-expected bindings. We test our model by examining memory for object-location bindings in recognition (Study 1) and recall (Studies 2 and 3) tasks. After studying schema-relevant objects in unexpected locations (e.g., pan on a stool in a kitchen scene), participants who then viewed these objects in expected locations (e.g., pan on stove) at test were more likely to falsely remember this object-location pairing as correct, compared with participants that viewed a different unexpected object-location pairing (e.g., pan on floor). In recall, participants were more likely to correctly remember individual schema-relevant objects originally viewed in unexpected, as opposed to expected locations, but were then more likely to misplace these items in the original room scene to expected places, relative to control schema-irrelevant objects. Our theoretical analysis and novel paradigm provide a tool for investigating memory distortions acting on binding processes. (PsycINFO Database Record

Object-location binding across a saccade: A retinotopic spatial congruency bias.

Despite frequent eye movements that rapidly shift the locations of objects on our retinas, our visual system creates a stable perception of the world. To do this, it must convert eye-centered (retinotopic) input to world-centered (spatiotopic) percepts. Moreover, for successful behavior we must also incorporate information about object features/identities during this updating - a fundamental challenge that remains to be understood. Here we adapted a recent behavioral paradigm, the "spatial congruency bias," to investigate object-location binding across an eye movement. In two initial baseline experiments, we showed that the spatial congruency bias was present for both gabor and face stimuli in addition to the object stimuli used in the original paradigm. Then, across three main experiments, we found the bias was preserved across an eye movement, but only in retinotopic coordinates: Subjects were more likely to perceive two stimuli as having the same features/identity when they were presented in the same retinotopic location. Strikingly, there was no evidence of location binding in the more ecologically relevant spatiotopic (world-centered) coordinates; the reference frame did not update to spatiotopic even at longer post-saccade delays, nor did it transition to spatiotopic with more complex stimuli (gabors, shapes, and faces all showed a retinotopic congruency bias). Our results suggest that object-location binding may be tied to retinotopic coordinates, and that it may need to be re-established following each eye movement rather than being automatically updated to spatiotopic coordinates.

The Effect of Object Distinctiveness on Object-Location Binding in Visual Working Memory

Visual working memory (VWM) is prone to interference from individual items competing for its limited capacity. At least two sources of such interference can be described: poor between-item distinctiveness (an inability to discriminate between items sharing common features) and imperfect binding (a problem with determining which of the remembered features belonged to which object). Here we investigate the links between distinctiveness and binding in VWM. In Experiment 1, we tested how object distinctiveness affects object recognition memory and memory for object-location conjunctions. In Experiment 2, we compared object-location binding under high and low distinctiveness with memory for locations when binding is not required. Object recognition decreased with low object distinctiveness, while the precision and the number of stored locations did not depend on either distinctiveness or the need for binding. However, the proportion of object-location swaps increased as object distinctiveness decreased, which might be caused by forgetting of objects. In general, our data support the idea of relatively independent object and location representations in VWM, and the independence of memory distinction and binding.

Object-location binding: Does spatial location influence high-level judgments of face images?

Object-location binding: Does spatial location influence high-level judgments of face images?

Supplemental Material for Out of Place, Out of Mind: Schema-Driven False Memory Effects for Object-Location Bindings

Supplemental Material for Out of Place, Out of Mind: Schema-Driven False Memory Effects for Object-Location Bindings

Visual short-term memory binding deficit in familial Alzheimer's disease

Long-term episodic memory deficits in Alzheimer's disease (AD) are well characterised but, until recently, short-term memory (STM) function has attracted far less attention. We employed a recently-developed, delayed reproduction task which requires participants to reproduce precisely the remembered location of items they had seen only seconds previously. This paradigm provides not only a continuous measure of localization error in memory, but also an index of relational binding by determining the frequency with which an object is misplaced to the location of one of the other items held in memory. Such binding errors in STM have previously been found on this task to be sensitive to medial temporal lobe (MTL) damage in focal lesion cases. Twenty individuals with pathological mutations in presenilin 1 or amyloid precursor protein genes for familial Alzheimer's disease (FAD) were tested together with 62 healthy controls. Participants were assessed using the delayed reproduction memory task, a standard neuropsychological battery and structural MRI.Overall, FAD mutation carriers were worse than controls for object identity as well as in gross localization memory performance. Moreover, they showed greater misbinding of object identity and location than healthy controls. Thus they would often mislocalize a correctly-identified item to the location of one of the other items held in memory. Significantly, asymptomatic gene carriers – who performed similarly to healthy controls on standard neuropsychological tests – had a specific impairment in object-location binding, despite intact memory for object identity and location. Consistent with the hypothesis that the hippocampus is critically involved in relational binding regardless of memory duration, decreased hippocampal volume across FAD participants was significantly associated with deficits in object-location binding but not with recall precision for object identity or localization. Object-location binding may therefore provide a sensitive cognitive biomarker for MTL dysfunction in a range of diseases including AD.

Glucose improves object-location binding in visual-spatial working memory.

RationaleThere is evidence that glucose temporarily enhances cognition and that processes dependent on the hippocampus may be particularly sensitive. As the hippocampus plays a key role in binding processes, we examined the influence of glucose on memory for object-location bindings.ObjectiveThis study aims to study how glucose modifies performance on an object-location memory task, a task that draws heavily on hippocampal function.MethodsThirty-one participants received 30 g glucose or placebo in a single 1-h session. After seeing between 3 and 10 objects (words or shapes) at different locations in a 9 × 9 matrix, participants attempted to immediately reproduce the display on a blank 9 × 9 matrix. Blood glucose was measured before drink ingestion, mid-way through the session, and at the end of the session.ResultsGlucose significantly improves object-location binding (d = 1.08) and location memory (d = 0.83), but not object memory (d = 0.51). Increasing working memory load impairs object memory and object-location binding, and word-location binding is more successful than shape-location binding, but the glucose improvement is robust across all difficulty manipulations. Within the glucose group, higher levels of circulating glucose are correlated with better binding memory and remembering the locations of successfully recalled objects.ConclusionsThe glucose improvements identified are consistent with a facilitative impact on hippocampal function. The findings are discussed in the context of the relationship between cognitive processes, hippocampal function, and the implications for glucose’s mode of action.

Delayed Match Retrieval: a novel anticipation-based visual working memory paradigm.

We tested 8- and 10-month-old infants' visual working memory (VWM) for object-location bindings - what is where - with a novel paradigm, Delayed Match Retrieval, that measured infants' anticipatory gaze responses (using a Tobii T120 eye tracker). In an inversion of Delayed-Match-to-Sample tasks and with inspiration from the game Memory, in test trials, three face-down virtual 'cards' were presented. Two flipped over sequentially (revealing, e.g. a swirl pattern and then a star), and then flipped back face-down. Next, the third card was flipped to reveal a match (e.g. a star) to one of the previously seen, now face-down cards. If infants looked to the location where the (now face-down) matching card had been shown, this was coded as a correct response. To encourage anticipatory looks, infants subsequently received a reward (a brief, engaging animation) presented at that location. Ten-month-old infants performed significantly above chance, showing that their VWM could hold object-location information for the two cards. Overall, 8-month-olds' performance was at chance, but they showed a robust learning trend. These results corroborate previous findings (Kaldy & Leslie, 2005; Oakes, Ross-Sheehy & Luck, 2006) and point to rapid development of VWM for object-location bindings. However, compared to previous paradigms that measure passive gaze responses to novelty, this paradigm presents a more challenging, ecologically relevant test of VWM, as it measures the ability to make online predictions and actively localize objects based on VWM. In addition, this paradigm can be readily scaled up to test toddlers or older children without significant modification.

The effect of gaze direction on the different components of visuo-spatial short-term memory

Cerebral asymmetries and cortical regions associated with the upper and lower visual field were investigated using shifts of gaze. Earlier research suggests that gaze shifts to the left or right increase activation of specific areas of the contralateral hemisphere. We asked whether looking at one quadrant of the visual field facilitates the recall in various visuo-spatial tasks. The different components of visuo-spatial memory were investigated by probing memory for a stimulus matrix in each quadrant of the screen. First, memory for visual images or patterns was probed with a matrix of squares that was simultaneously presented and had to be reconstructed by mouse click. Better memory performance was found in the upper left quadrant compared to the three other quadrants indicating that both laterality and elevation are important. Second, positional memory was probed by subsequently presenting squares which prevented the formation of a visual image. Again, we found that gaze to the upper left facilitated performance. Third, memory for object-location binding was probed by asking observers to associate objects to particular locations. Higher performance was found with gaze directed to the lower quadrants irrespective of lateralization, confirming that only some components of visual short-term memory have shared neural substrates.

Effects of healthy ageing on precision and binding of object location in visual short term memory.

Visual short term memory (STM) declines as people get older, but the nature of this deterioration is not well understood. We tested 139 healthy subjects (19–83 years) who were first required to identify a previously seen object and then report its location using a touchscreen. Results demonstrated an age-related decline in both object identification and localization. Deterioration in localization performance was apparent even when only 1 item had to be remembered, worsening disproportionately with increasing memory load. Thus, age-dependent memory degradation cannot be explained simply by a decrease in the number of items that can be held in visual STM but rather by the precision with which they are recalled. More important, there was no evidence for a significant decrease in object-location binding with increasing age. Thus, although precision for object identity and location declines with age, the ability to associate object identity to its location seems to remain unimpaired. As it has been reported that binding deficits in STM might be the first cognitive signs of early Alzheimer’s disease (AD), the finding that object-location binding processes are relatively intact with normal aging supports the possible suitability of using misbinding as an index measures for probing early diagnosis of AD.

Supplemental Material for Effects of Healthy Ageing on Precision and Binding of Object Location in Visual Short Term Memory

Supplemental Material for Effects of Healthy Ageing on Precision and Binding of Object Location in Visual Short Term Memory

Fractionation of visuo-spatial memory processes in bipolar depression: a cognitive scaffolding account.

Previous studies of neurocognitive performance in bipolar disorder (BD) have demonstrated impairments in visuo-spatial memory. The aim of the present study was to use an object-location memory (OLM) paradigm to assess specific, dissociable processes in visuo-spatial memory and examine their relationship with broader neurocognitive performance. Fifty participants (25 patients with BD in a current depressive episode and 25 matched healthy controls) completed the OLM paradigm which assessed three different aspects of visuo-spatial memory: positional memory, object-location binding, and a combined process. Secondary neurocognitive measures of visuo-spatial memory, verbal memory, attention and executive function were also administered. BD patients were significantly impaired on all three OLM processes, with the largest effect in exact positional memory (d = 1.18, p < 0.0001). General deficits were also found across the secondary neurocognitive measures. Using hierarchical regression, verbal learning was found to explain significant variance on the OLM measures where object-identity was present (the object-location binding and combined processes) and accounted for the group difference. The group difference in precise positional memory remained intact. This study demonstrates that patients with bipolar depression manifest deficits in visuo-spatial memory, with substantial impairment in fine-grain, positional memory. The differential profile of processes underpinning the visuo-spatial memory impairment suggests a form of 'cognitive scaffolding', whereby performance on some measures can be supported by verbal memory. These results have important implications for our understanding of the functional cognitive architecture of mood disorder.

Verbal labeling, gradual decay, and sudden death in visual short-term memory.

Zhang and Luck (Psychological Science, 20, 423-428, 2009) found that perceptual memories are lost over time via sudden death rather than gradual decay. However, they acknowledged that participants may have instead lost memory for the locations of objects. We required observers to recall only a single object. Although the paradigm eliminated the need to maintain object-location bindings, the possibility that observers would use verbal labels increased. To measure the precision of verbal labeling, we included explicit verbal-labeling and label-matching trials. We applied a model that measured the contributions of sudden death, gradual decay, and verbal labeling to recall. Our model-based evidence pointed to sudden death as the primary vehicle by which perceptual memories were lost. Crucially, however, the sudden-death hypothesis was favored only when the verbal-labeling component was included as part of the modeling. The results underscore the importance of taking into account the potential role of verbal-labeling processes in investigations of perceptual memory.

Item-location binding in working memory: Is it hippocampus-dependent?

A general consensus is emerging that the hippocampus has an important and active role in the creation of new long-term memory representations of associations or bindings between elements. However, it is less clear whether this contribution can be extended to the creation of temporary bound representations in working memory, involving the retention of small numbers of items over short delays. We examined this by administering a series of recognition and recall tests of working memory for colour-location binding and object-location binding to a patient with highly selective hippocampal damage (Jon), and groups of control participants. Jon achieved high levels of accuracy in all working memory tests of recognition and recall binding across retention intervals of up to 10s. In contrast, Jon performed at chance on an unexpected delayed test of the same object-location binding information. These findings indicate a clear dissociation between working memory and long-term memory, with no evidence for a critical hippocampal contribution to item-location binding in working memory.

Forgetting What Was Where: The Fragility of Object-Location Binding

Although we frequently take advantage of memory for objects locations in everyday life, understanding how an object’s identity is bound correctly to its location remains unclear. Here we examine how information about object identity, location and crucially object-location associations are differentially susceptible to forgetting, over variable retention intervals and memory load. In our task, participants relocated objects to their remembered locations using a touchscreen. When participants mislocalized objects, their reports were clustered around the locations of other objects in the array, rather than occurring randomly. These ‘swap’ errors could not be attributed to simple failure to remember either the identity or location of the objects, but rather appeared to arise from failure to bind object identity and location in memory. Moreover, such binding failures significantly contributed to decline in localization performance over retention time. We conclude that when objects are forgotten they do not disappear completely from memory, but rather it is the links between identity and location that are prone to be broken over time.