Location memory in the real world: category adjustment effects in 3-dimensional space

Is separation represented in terms of position?

How do humans make judgments of separation (distance in a frontal plane)? According to the additive account of separation assessment, the separation between two points is inferred from the number of instances of a unit distance lying between the points. According to the subtractive account, the separation between two points is inferred from the difference between their positions in a localization system. In response to recent findings that are consistent with the additive account and inconsistent with the subtractive account, the present study explicitly tested the subtractive account. The study tested whether separations are represented in memory in terms of positions, as would be expected under the subtractive account. In two experiments the study found no support for this possibility. Although participants showed a bias to mis-recall the members of a set of separations in the direction of the average separation in the set, participants did not show a parallel bias in recalling the positions that defined the separations. Although participants were influenced in recalling the members of a set of separations by the range of the scale that was used to specify the separations, participants were not similarly influenced in recalling the positions that defined the separations.

Oblique warping: A general distortion of spatial perception

There are many putatively distinct phenomena related to perception in the oblique regions of space. For instance, the classic oblique effect describes a deficit in visual acuity for oriented lines in the obliques, and classic "prototype effects" reflect a bias to misplace objects towards the oblique regions of space. Yet these effects are explained in very different terms: The oblique effect itself is often understood as arising from orientation-selective neurons, whereas prototype effects are described as arising from categorical biases. Here, we explore the possibility that these effects (and others) may stem from a single underlying spatial distortion. We show that there is a general distortion of (angular) space in the oblique regions that influences not only orientation judgments, but also location, extent, and size. We argue that these findings reflect oblique warping, a general distortion of spatial representations in the oblique regions which may be the root cause of many oblique effects.

Methods matter: Exploring how expectations influence common actions

Behavior in controlled laboratory studies is not always representative of what people do in daily life. This has prompted a recent shift toward conducting studies in natural settings. We wondered whether expectations raised by how the task is presented should also be considered. To find out, we studied gaze when walking down and up a staircase. Gaze was often directed at steps before stepping on them, but most participants did not look at every step. Importantly, participants fixated more steps and looked around less when asked to navigate the staircase than when navigating the same staircase but asked to walk outside. Presumably, expecting the staircase to be important made participants direct their gaze at more steps, despite the identical requirements when on the staircase. This illustrates that behavior can be influenced by expectations, such as expectations resulting from task instructions, even when studies are conducted in natural settings.

Redundancy and Reducibility in the Formats of Spatial Representations

Mental representations are the essence of cognition. Yet to understand how the mind works, one must understand not just the content of mental representations (i.e., what information is stored) but also the format of those representations (i.e., how that information is stored). But what does it mean for representations to be formatted? How many formats are there? Is it possible that the mind represents some pieces of information in multiple formats at once? To address these questions, I discuss a "case study" of representational format: the representation of spatial location. I review work (a) across species and across development, (b) across spatial scales, and (c) across levels of analysis (e.g., high-level cognitive format vs. low-level neural format). Along the way, I discuss the possibility that the same information may be organized in multiple formats simultaneously (e.g., that locations may be represented in both Cartesian and polar coordinates). Ultimately, I argue that seemingly "redundant" formats may support the flexible spatial behavior observed in humans and that researchers should approach the study of all mental representations with this possibility in mind.

Serial reproduction reveals the geometry of visuospatial representations

A primary function of human vision is to encode and recall spatial information about visual scenes. We developed an experimental paradigm that reveals the structure of human spatial memory priors in unprecedented detail. We ran a series of 85 large-scale online experiments with 9,202 participants that paint an intricate picture of these priors. Our results suggest a way to understand visuospatial representations as reflecting the efficient allocation of coding resources. In a radical departure from traditional theory, we introduce a model that reinterprets spatial memory priors as reflecting an optimal allocation of perceptual resources. We validate the predictions of the model experimentally by showing that perceptual biases are correlated with variations in discrimination accuracy.

An essential function of the human visual system is to locate objects in space and navigate the environment. Due to limited resources, the visual system achieves this by combining imperfect sensory information with a belief state about locations in a scene, resulting in systematic distortions and biases. These biases can be captured by a Bayesian model in which internal beliefs are expressed in a prior probability distribution over locations in a scene. We introduce a paradigm that enables us to measure these priors by iterating a simple memory task where the response of one participant becomes the stimulus for the next. This approach reveals an unprecedented richness and level of detail in these priors, suggesting a different way to think about biases in spatial memory. A prior distribution on locations in a visual scene can reflect the selective allocation of coding resources to different visual regions during encoding (“efficient encoding”). This selective allocation predicts that locations in the scene will be encoded with variable precision, in contrast to previous work that has assumed fixed encoding precision regardless of location. We demonstrate that perceptual biases covary with variations in discrimination accuracy, a finding that is aligned with simulations of our efficient encoding model but not the traditional fixed encoding view. This work demonstrates the promise of using nonparametric data-driven approaches that combine crowdsourcing with the careful curation of information transmission within social networks to reveal the hidden structure of shared visual representations.

Endogenous variation in estradiol in women affects the weighting of metric and categorical information in spatial location memory

Recent work has suggested that sex differences may exist in the strategies or types of cues that are utilized by men and women to remember discrete spatial locations or routes through a visual environment. The current study investigated the effects of circulating estradiol levels in women on the relative weighting of categorical versus fine-grained 'metric' information in a test of short-term memory for spatial locations, either presented within a simple geometric surround (a circular enclosure) or within more visually complex landscape scenes. Patterns of displacement error in the point location estimates made by men and women were analyzed. Results confirmed a sex difference in the weighting of metric versus categorical cues. Relative to men, women's estimates of locations were more strongly biased toward the center of the surrounding category (i.e., toward the category 'prototype'). Furthermore, objective measures of estradiol via saliva collected at the time of memory testing showed that, among naturally-cycling women, estradiol concentrations correlated in a positive, graded, fashion with the degree of emphasis that women placed on categorical information when estimating point locations. No associations were found for progesterone. These findings are consistent with a wider body of research showing that biological sex and reproductive hormone levels, including 17β-estradiol, can subtly influence performance on certain spatial tasks. This is the first study to show that circulating estradiol levels may influence the relative emphasis placed on categorical versus metric cues when remembering simple point locations.

Mapping visual spatial prototypes: Multiple reference frames shape visual memory

Categories provide a fundamental source of information used to structure our perception of the world. For example, when people reproduce the remembered location of a dot in a circle, they implicitly impose vertical and horizontal axes onto the circle, and responses are biased towards the center of each of the resulting quadrants. Such results reveal the existence of spatial prototypes, which function as Bayesian priors and which are integrated with actual memory traces. Spatial prototypes have been extensively investigated and described in previous studies, but it remains unclear what type of information is used to create spatial categories. We developed a new approach that allowed to 'image' patterns of spatial bias in detail, and map the internal representational structure of objects and space. Previous studies, using circular shapes suggested that boundaries are established based on a viewer-based frame of reference, therefore using cues extrinsic to the object. Given that a circle has radial symmetry, the axes imposed cannot come from the shape itself. Here we investigated if the same applies for shapes with clearly-defined symmetry axes and thus intrinsic frames of reference. Using rotated shapes (squares and rectangles), where extrinsic and intrinsic cues are dissociated, we observed flexible usage of multiple reference frames. Furthermore, in certain contexts, participants relied mostly on cues intrinsic to the shape itself. These results show that humans divide visual space as a function of multiple reference frames, in a flexible, and context dependent manner.

Navigation and the developing brain

As babies rapidly acquire motor skills that give them increasingly independent and wide-ranging access to the environment over the first two years of human life, they decrease their reliance on habit systems for spatial localization, switching to their emerging inertial navigation system and to allocentric frameworks. Initial place learning is evident towards the end of the period. From 3 to 10 years, children calibrate their ability to encode various sources of spatial information (inertial information, geometric cues, beacons, proximal landmarks and distal landmarks) and begin to combine cues, both within and across systems. Geometric cues are important, but do not constitute an innate and encapsulated module. In addition, from 3 to 10 years, children build the capacity to think about frames of reference different from their current one (i.e. to perform perspective taking). By around 12 years, we see adult-level performance and adult patterns of individual differences on cognitive mapping tasks requiring the integration of vista views of space into environmental space. These lines of development are continuous rather than stage-like. Spatial development builds on important beginnings in the neural systems of newborns, but changes in experience-expectant ways with motor development, action in the world and success–failure feedback. Human systems for integrating and manipulating spatial information also benefit from symbolic capacities and technological inventions.

Working memory and spatial judgments: Cognitive load increases the central tendency bias

Previous work demonstrates that memory for simple stimuli can be biased by information about the distribution of which the stimulus is a member. Specifically, people underestimate values greater than the distribution's average and overestimate values smaller than the average. This is referred to as the central tendency bias. This bias has been explained as an optimal use of both noisy sensory information and category information. In largely separate literature, cognitive load (CL) experiments attempt to manipulate the available working memory of participants in order to observe the effect on choice or judgments. In two experiments, we demonstrate that participants under high cognitive load exhibit a stronger central tendency bias than when under a low cognitive load. Although not anticipated at the outset, we also find that judgments exhibit an anchoring bias not described previously.

The Sapir-Whorf Hypothesis and Probabilistic Inference: Evidence from the Domain of Color

The Sapir-Whorf hypothesis holds that our thoughts are shaped by our native language, and that speakers of different languages therefore think differently. This hypothesis is controversial in part because it appears to deny the possibility of a universal groundwork for human cognition, and in part because some findings taken to support it have not reliably replicated. We argue that considering this hypothesis through the lens of probabilistic inference has the potential to resolve both issues, at least with respect to certain prominent findings in the domain of color cognition. We explore a probabilistic model that is grounded in a presumed universal perceptual color space and in language-specific categories over that space. The model predicts that categories will most clearly affect color memory when perceptual information is uncertain. In line with earlier studies, we show that this model accounts for language-consistent biases in color reconstruction from memory in English speakers, modulated by uncertainty. We also show, to our knowledge for the first time, that such a model accounts for influential existing data on cross-language differences in color discrimination from memory, both within and across categories. We suggest that these ideas may help to clarify the debate over the Sapir-Whorf hypothesis.

Intelligenz: kein Mythos, sondern Realität

Zusammenfassung. Das Konzept der psychometrischen Intelligenz ist in der Öffentlichkeit sowie auch in Teilen der wissenschaftlichen Psychologie umstritten. Warum Intelligenz so große Abwehrreaktionen auslöst und wie die Begründungen für diese zum Stand der Intelligenzforschung stehen, wird in diesem Artikel behandelt. Dabei behandeln wir drei weit verbreitete Vorurteile: 1) Das Definitionsproblem: Es gibt viele Intelligenzen, und Psychologen können sich sowieso nicht auf eine einheitliche Definition einigen; 2) Die Abseitigkeitsannahme: Die Leistung in Intelligenztests hat nichts mit Kompetenzen im wahren Leben zu tun; 3) Die Ursachenverwirrung: Wenn Intelligenz ein in den Genen verankertes Merkmal ist, bleiben Umwelteinflüsse unwirksam. Auf Basis der aktuellen Intelligenzforschung entkräften wir alle drei Einwände: 1) Intelligenz wird heute vom Großteil der Intelligenzforscher präzise und einheitlich definiert; das Fehlen einer einheitlichen Definition ist kein aktuelles Problem der Intelligenzforschung mehr. 2) Eine Reihe von jüngeren Meta-Analysen hat überzeugend die hohen und stabilen Validitäten von Intelligenztests demonstriert: Intelligenz ist einer der besten Prädiktoren von Lern- und Berufserfolg. 3) Die moderne Verhaltensgenetik hat verdeutlicht, dass Intelligenz in den Genen verankert ist, diese aber nur in einer geistig anregenden Umwelt ihr Potenzial entfalten können. Mit diesem Artikel möchten wir Psychologen Argumente an die Hand geben, mit denen sie eine skeptische Öffentlichkeit von der Wichtigkeit der psychometrischen Intelligenzforschung überzeugen können.

Thinking about quantity: the intertwined development of spatial and numerical cognition

There are many continuous quantitative dimensions in the physical world. Philosophical, psychological, and neural work has focused mostly on space and number. However, there are other important continuous dimensions (e.g., time and mass). Moreover, space can be broken down into more specific dimensions (e.g., length, area, and density) and number can be conceptualized discretely or continuously (i.e., natural vs real numbers). Variation on these quantitative dimensions is typically correlated, e.g., larger objects often weigh more than smaller ones. Number is a distinctive continuous dimension because the natural numbers (i.e., positive integers) are used to quantify collections of discrete objects. This aspect of number is emphasized by teaching of the count word sequence and arithmetic during the early school years. We review research on spatial and numerical estimation, and argue that a generalized magnitude system is the starting point for development in both domains. Development occurs along several lines: (1) changes in capacity, durability, and precision, (2) differentiation of the generalized magnitude system into separable dimensions, (3) formation of a discrete number system, i.e., the positive integers, (4) mapping the positive integers onto the continuous number line, and (5) acquiring abstract knowledge of the relations between pairs of systems. We discuss implications of this approach for teaching various topics in mathematics, including scaling, measurement, proportional reasoning, and fractions.

Spatial estimation: a non-Bayesian alternative

A large collection of estimation phenomena (e.g. biases arising when adults or children estimate remembered locations of objects in bounded spaces; Huttenlocher, Newcombe & Sandberg, 1994) are commonly explained in terms of complex Bayesian models. We provide evidence that some of these phenomena may be modeled instead by a simpler non-Bayesian alternative. Undergraduates and 9- to 10-year-olds completed a speeded linear position estimation task. Bias in both groups' estimates could be explained in terms of a simple psychophysical model of proportion estimation. Moreover, some individual data were not compatible with the requirements of the more complex Bayesian model.

Sex differences in the weighting of metric and categorical information in spatial location memory

According to the Category Adjustment model, remembering a spatial location involves the Bayesian combination of fine-grained and categorical information about that location, with each cue weighted by its relative certainty. However, individuals may differ in terms of their certainty about each cue, resulting in estimates that rely more or less on metric or categorical representations. To date, though, very little research has examined individual differences in the relative weighting of these cues in spatial location memory. Here, we address this gap in the literature. Participants were asked to recall point locations in uniform geometric shapes and in photographs of complex, natural scenes. Error patterns were analyzed for evidence of a sex difference in the relative use of metric and categorical information. As predicted, women placed relatively more emphasis on categorical cues, while men relied more heavily on metric information. Location reproduction tasks showed a similar effect, implying that the sex difference arises early in spatial processing, possibly during encoding.