Orientation specificity and spatial updating of memories for layouts.

This article examines the degree to which knowledge about the body's orientation affects transformations in spatial memory and whether memories are accessed with a preferred orientation. Participants learned large paths from a single viewpoint and were later asked to make judgments of relative directions from imagined positions on the path. Experiments 1 and 2 contribute to the emerging consensus that memories for large layouts are orientation specific, suggesting that prior findings to the contrary may not have fully accounted for latencies. Experiments 2 and 3 show that knowledge of one's orientation can create a preferred direction in spatial memory that is different from the learned orientation. Results further suggest that spatial updating may not be as automatic as previously thought. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Layout geometry in encoding and retrieval of spatial memory.

Two experiments investigated whether the spatial reference directions that are used to specify objects' locations in memory can be solely determined by layout geometry. Participants studied a layout of objects from a single viewpoint while their eye movements were recorded. Subsequently, participants used memory to make judgments of relative direction (e.g., "Imagine you are standing at X, facing Y, please point to Z"). When the layout had a symmetric axis that was different from participants' viewing direction, the sequence of eye fixations on objects during learning and the preferred directions in pointing judgments were both determined by the direction of the symmetric axis. These results provide further evidence that interobject spatial relations are represented in memory with intrinsic frames of reference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lack of set size effects in spatial updating: Evidence for offline updating.

Four experiments required participants to keep track of the locations of (i.e., update) 1, 2, 3, 4, 6, 8, 10, or 15 target objects after rotating. Across all conditions, updating was unaffected by set size. Although some traditional set size effects (i.e., a linear increase of latency with memory load) were observed under some conditions, these effects were independent of the updating process. Patterns of data and participant strategies were inconsistent with the common view of spatial updating as an online process. Instead, the authors concluded that participants formed enduring, long-term memory representations of the layouts at learning that were used to reconstruct spatial information about the layouts as needed (i.e., offline updating). These results support M. Amorim, S. Glasauer, K. Corpinot, and A. Berthoz's (1997) 2-system model of spatial updating that includes both online and offline updating. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental space travel: Damage to posterior parietal cortex prevents egocentric navigation and reexperiencing of remote spatial memories.

The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Carving up space at imaginary joints: Can people mentally impose arbitrary spatial category boundaries?

Empirical attempts to understand connections between abstract cognition and sensori-motor processes have pointed toward an embodied view of cognition, where cognitive activity is strongly tied to sensori-motor activity. Here the authors test the ability of the cognitive system to impose structure on the world using a well-established phenomenon in spatial cognition--biases near spatial category boundaries. Results from 5 experiments suggest that participants were unable to mentally impose a spatial category boundary without perceptual support, even when explicitly instructed to do so. The authors conclude by considering the implications of these findings for abstraction within other domains of cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transient and enduring spatial representations under disorientation and self-rotation.

Current theories of environmental cognition typically differentiate between an online, transient, and dynamic system of spatial representation and an offline and enduring system of memory representation. Here the authors present additional evidence for such 2-system theories in the context of the disorientation paradigm introduced by R. F. Wang and E. S. Spelke (2000). Several experiments replicate the finding that disorientation results in a decrease in the precision of people's estimates of relative directions. In contrast to the typical interpretation of this effect as indicating the primacy of a transient spatial system, the present results are generally more consistent with an interpretation of it as indicating a switch from a relatively precise online representation to a relatively coarse enduring one. Further experiments examine the relative precision of transient and enduring representations and show that switching between them does not require disorientation, but can also be produced by self-rotations as small as 135°. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of spatial cueing on representational momentum.

Effects of a spatial cue on representational momentum were examined. If a cue was present during or after target motion and indicated the location at which the target would vanish or had vanished, forward displacement of that target decreased. The decrease in forward displacement was larger when cues were present after target motion than when cues were present during target motion. If a cue was present during target motion, high-relevant cues (that indicated the final location of the target) led to larger decreases in forward displacement than did low-relevant cues (that indicated only the horizontal coordinate of the final location of the target). If a cue was present after target motion, there was a trend for low-relevant cues to lead to larger decreases in forward displacement than did high-relevant cues. Possible explanations involving displacement of the cue or landmark attraction are considered. Implications for the relationship of attention and representational momentum, and for whether representational momentum reflects an automatic process, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Toward a formal theory of flexible spatial behavior: Geometric category biases generalize across pointing and verbal response types.

Three experiments tested whether geometric biases--biases away from perceived reference axes--reported in spatial recall tasks with pointing responses generalized to a recognition task that required a verbal response. Seven-year-olds and adults remembered the location of a dot within a rectangle and then either reproduced its location or verbally selected a matching choice dot from a set of colored options. Results demonstrated that geometric biases generalized to verbal responses; however, the spatial span of the choice set influenced performance as well. These data suggest that the same spatial memory process gives rise to both response types in this task. Simulations of a dynamic field model buttress this claim. More generally, these results challenge accounts that posit separate spatial systems for motor and verbal responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A spatial modality effect in serial memory.

In 2 experiments, the authors tested whether the classical modality effect--that is, the stronger recency effect for auditory items relative to visual items--can be extended to the spatial domain. An order reconstruction task was undertaken with four types of material: visual-spatial, auditory-spatial, visual-verbal, and auditory-verbal. Similar serial position curves were obtained regardless of the nature of the to-be-remembered sequences, with the exception that a modality effect was found with spatial as well as with verbal materials. The results are discussed with regard to a number of models of short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Ovarian hormones and cognition in the aged female rat: I. Long-term, but not short-term, ovariectomy enhances spatial performance": Correction to Bimonte-Nelson et al. (2003).

Reports an error in "Ovarian Hormones and Cognition in the Aged Female Rat: I. Long-Term, but Not Short-Term, Ovariectomy Enhances Spatial Performance" by Heather A. Bimonte-Nelson, Rachel S. Singleton, Christopher L. Hunter, Kimber L. Price, Alfred B. Moore and Ann-Charlotte E. Granholm (Behavioral Neuroscience, 2003[Dec], Vol 117[6], 1395-1406). The fifth sentence of the abstract reads, "Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats." The sentence should read as follows: "Aged rats exhibited similar estradiol and elevated progesterone levels compared with those of young rats." (The following abstract of the original article appeared in record 2003-10460-025.) Although research suggests that ovariectomy (ovx) is detrimental to spatial cognition in young rats, little work has evaluated the cognitive effects of ovx in aged rats. The authors investigated the effects of ovx in aged rats using the water radial-arm maze. In Study 1, young rats and aged rats receiving ovx 1.5 months before testing outperformed aged rats receiving sham surgery or ovx 21 days before testing. In Study 2, young rats and aged rats receiving ovx 2.0 or 6.0 months before testing outperformed aged sham rats. Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats. The findings suggest that 1.5-6.0 months, but not 21 days, of ovx improves spatial memory in aged rats. The hypothesis that long-term ovarian hormone loss is detrimental to spatial memory in aged rats was not supported. The authors hypothesize that removal of elevated progesterone levels is related to the ovx-induced cognitive enhancement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affect influences false memories at encoding: Evidence from recognition data.

Memory is susceptible to illusions in the form of false memories. Prior research found, however, that sad moods reduce false memories. The current experiment had two goals: (1) to determine whether affect influences retrieval processes, and (2) to determine whether affect influences the strength and the persistence of false memories. Happy or sad moods were induced either before or after learning word lists designed to produce false memories. Control groups did not experience a mood induction. We found that sad moods reduced false memories only when induced before learning. Signal detection analyses confirmed that sad moods induced prior to learning reduced activation of nonpresented critical lures suggesting that they came to mind less often. Affective states, however, did not influence retrieval effects. We conclude that negative affective states promote item-specific processing, which reduces false memories in a similar way as using an explicitly guided cognitive control strategy. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Bilateral eye movements enhance the retrieval of episodic memories.

Two experiments examining effects of eye movements on episodic memory retrieval are reported. Thirty seconds of horizontal saccadic eye movements (but not smooth pursuit or vertical eye movements) preceding testing resulted in selective enhancement of episodic memory retrieval for laboratory (Experiment 1) and everyday (Experiment 2) events. Eye movements had no effects on implicit memory. Eye movements were also associated with more conservative response biases relative to a no eye movement condition. Episodic memory improvement induced by bilateral eye movements is hypothesized to reflect enhanced interhemispheric interaction, which is associated with superior episodic memory (S. D. Christman & R. E. Propper. 2001). Implications for neuropsychological mechanisms underlying eye movement desensitization and reprocessing (F. Shapiro, 1989, 2001), a therapeutic technique for posttraumatic stress disorder, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Micro- and macroreference frames: Specifying the relations between spatial categories in memory.

A substantial amount of research has demonstrated the importance of reference frames in organizing memory of object locations in both small and large environments. However, to date, little research has examined how the object locations represented in one reference frame are specified relative to object locations represented in another. In a series of 4 experiments, we demonstrate that multiple microreference frames can be established in memory for sets of objects that are spatially and semantically distinct, and that the spatial relations between these microreference frames are specified in memory by means of a more global, macroreference frame. Additionally, these experiments demonstrate that an established macroreference frame can influence which of several microreference frames will be coded in memory, but that a previously established microreference frame had no appreciable influence on the subsequent formation of a macroreference frame. These results are interpreted as indicating that the same cognitive mechanisms underlie interobject coding across multiple environmental scales. The implications for reference frame theories and theories positing hierarchical memory organization are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A diffusion model analysis of adult age differences in episodic and semantic long-term memory retrieval.

Two experiments investigated adult age differences in episodic and semantic long-term memory tasks, as a test of the hypothesis of specific age-related decline in context memory. Older adults were slower and exhibited lower episodic accuracy than younger adults. Fits of the diffusion model (R. Ratcliff, 1978) revealed age-related increases in nondecisional reaction time for both episodic and semantic retrieval. In Experiment 2, an age difference in boundary separation also indicated an age-related increase in conservative criterion setting. For episodic old-new recognition (Experiment 1) and source memory (Experiment 2), there was an age-related decrease in the quality of decision-driving information (drift rate). As predicted by the context-memory deficit hypothesis, there was no corresponding age-related decline in semantic drift rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of the dynamic field theory and the spatial precision hypothesis: Capturing a qualitative developmental transition in spatial working memory.

This study tested a dynamic field theory (DFT) of spatial working memory and an associated spatial precision hypothesis (SPH). Between 3 and 6 years of age, there is a qualitative shift in how children use reference axes to remember locations: 3-year-olds’ spatial recall responses are biased toward reference axes after short memory delays, whereas 6-year-olds’ responses are biased away from reference axes. According to the DFT and the SPH, quantitative improvements over development in the precision of excitatory and inhibitory working memory processes lead to this qualitative shift. Simulations of the DFT in Experiment 1 predict that improvements in precision should cause the spatial range of targets attracted toward a reference axis to narrow gradually over development, with repulsion emerging and gradually increasing until responses to most targets show biases away from the axis. Results from Experiment 2 with 3- to 5-year-olds support these predictions. Simulations of the DFT in Experiment 3 quantitatively fit the empirical results and offer insights into the neural processes underlying this developmental change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A category adjustment approach to memory for spatial location in natural scenes.

Memories for spatial locations often show systematic errors toward the central value of the surrounding region. This bias has been explained using a Bayesian model in which fine-grained and categorical information are combined (Huttenlocher, Hedges, & Duncan, 1991). However, experiments testing this model have largely used locations contained in simple geometric shapes. Use of this paradigm raises 2 issues. First, do results generalize to the complex natural world? Second, what types of information might be used to segment complex spaces into constituent categories? Experiment 1 addressed the 1st question by showing a bias toward prototypical values in memory for spatial locations in complex natural scenes. Experiment 2 addressed the 2nd question by manipulating the availability of basic visual cues (using color negatives) or of semantic information about the scene (using inverted images). Error patterns suggest that both perceptual and conceptual information are involved in segmentation. The possible neurological foundations of location memory of this kind are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exhaustive and heuristic retrieval processes in person cognition: Further tests of the TRAP model.

The twofold retrieval by associative pathways (TRAP) model (L. Garcia-Marques & D. L. Hamilton, 1996) proposes that two distinct modes of retrieval typically underlie recall and frequency estimation. The model accounts for the simultaneous occurrence of greater recall of incongruent information and higher frequency estimation of congruent information. Three experiments provided further tests of the TRAP model. Experiment 1 manipulated cognitive load (at encoding and at retrieval) and the selectivity of the retrieval goal. Under either high load or a selective retrieval goal, incongruent items ceased to be better recalled. Experiment 2 manipulated the accessibility of expectancy-congruent, -incongruent, or -neutral episodes and found corresponding effects in frequency estimates. Finally, Experiment 3 showed that providing part-list retrieval cues inhibits recall but increases frequency estimates. The TRAP model predicted these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual and spatial working memory are not that dissociated after all: A time-based resource-sharing account.

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and spatial storage were combined with both visual and spatial on-line processing components in computer-paced working memory span tasks (Experiment 1) and in a selective interference paradigm (Experiment 2). The cognitive load of the processing components was manipulated to investigate its impact on concurrent maintenance for both within-domain and between-domain combinations of processing and storage components. In contrast to both domain- and process-based fractionations of visuo-spatial working memory, the results revealed that recall performance was determined by the cognitive load induced by the processing of items, rather than by the domain to which those items pertained. These findings are interpreted as evidence for a time-based resource-sharing mechanism in visuo-spatial working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remembrance of places you passed: Social spatial working memory in rats.

Pairs of rats were tested in a radial-arm maze to determine whether the spatial choices made by one rat affect the subsequent spatial choices of the other rat. In a free-choice procedure, rats showed an increased tendency to choose the location that had most recently been chosen by a foraging partner but a decreased tendency to visit locations that the foraging partner had visited earlier. Forced-choice procedures were used to better control the social stimulus and the interactions between the rats. Under some conditions, locations were chosen later in the choice sequence of a subject rat if another rat had been observed choosing that location. Odor and other physical traces of the other rat's visits were ruled out as explanations for this effect. The results demonstrate the existence of working memory for locations visited by a familiar conspecific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)