Spatial Perception

• Spatial Thinking explores how individuals perceive and navigate space
• Main topics include spatial perception, representation/navigation, the relationship between space, language, symbols, and the role of experience and aging in navigation

Spatial Perception

• It involves sensing an individual's position relative to objects and landmarks
• This is dependent on monocular and binocular depth cues
• Monocular cues are pictorial and obtained from a single eye
• Examples of monocular cues include occlusion, relative size, and converging lines
• Binocular cues uses the combination of information from slightly different points of view from each eye and allows depth perception, an example being stereopsis

Binocular Cues and Depth Perception

• Retinal disparity refers to the different angles from each eye allowing more of the object to be seen
• Convergence is the contraction/relaxation of eye muscles to focus on objects provides information on distance
• Animal studies have demonstrated that depth perception is experience-expectant and requires general visual experience
• The development of which includes a critical period
• Depth perception is present very early in humans

Mental Maps

• Humans, as well as other animals, form various "mental maps"
• A mental representation that is organized in relation to the existing physical-spatial environment
• One example by Kosslyn in 1973, participants studied a map and were asked questions about it from memory
• Time taken to answer questions about locations on the island was proportional to the locations' physical distance
• Suggested people were "navigating" a mental image that maintained spatial distance
• Another example shows mental maps exist in rats, from a study by Tolman et al. in 1946

Types of Mental Maps

• Three types of mental maps can be used for navigation
• Mental map of distance and direction: Path integration which involves a feeling/intuition of direction/distance/speed
• Mental map of geometry (shape) of surrounding as applied to larger scale environments
• Mental map of landmarks which highlights particular/distinctive spatial points

Path Integration

• Path integration is how ants find its way home
• Ants accomplish this feat by external cues (odor, visible landmarks, sun, etc.) or internal representation (distance, direction, etc)
• Ants that navigate by internal representations go straight to where their nests would have been before searching for it
• They can accurately navigate 500-meter journey at direction ± 2° and distance ± 10%
• Newly hatched chicks and geese succeeding at path integration tasks similar to ant tests, suggesting no real learning is needed and indicating innate path integration abilities
• Path integration doesn't require immediate vision
• Blind children at age 5 performed just as well as children who had received typical visual input throughout life
• Suggests spatial representation/path integration is not dependent on visual experience/visual learning
• While can be present in both humans and animals alike, and aided by landmarks, requires maintenance
• Includes limits and errors in estimation

Enduring Representations of Space

• There are two navigation systems that don't have the same limits as path integration
• A system for representing one's location by analyzing the shape of the environment -A system for representing other locations by analyzing the location of landmarks
• Reorientation studies in young children were studied to determine what external cues children rely on

External Cues

• If children can't use the geometrical shape of the room to find the hidden toy, they will search equally in all four corners (25%)
• If children decide to rely on the geometrical shape of the room to find the hidden toy, they will search equally in two geometrically equivalent corners (50)
• Adults and children have different reorientation results
• Adults use reorientation and have shown 57% and 41% searches
• Children often make geometrical errors and have shown 39% and 39% searches
• Younger children do not readily integrate features of the room like a red wall with the shape to reorient
• This is not because they do not notice the red wall
• Is proven by the subjects success in finding a item at the base or middle of the red wall
• Tests whether the subject can reorient by shape, feature or both
• Sensitivity to layout shape is independent of visual experiment of corners in chicks

Navigation Summary

• Guided by three distinct spatial abilities:
• Estimate position based on path integration
• Orient based on landmarks but is often unable to integrate with the shape of the layout
• Orient based on shape and is not often insensitive to all geometric properties
• Arises early in development shared with many other animals
• Limits in other animals

Brain Regions Involved

• How the brain impliments Spatial maps is through one area of great importance for navigation, the hippocampus
• Hippocampal 'Grid Cells' in the Rat fires certain cells in a spatial grid like fashion when the moves in the environment
• Different cells have slightly shifted grids
• Allows a coordinate type map of environment
• In Grid Cells of Humans, spatial distance, direction, speed, and position become calculated
• In hippocampal 'Place Cells' of rats, certain cells are fired in the hippocampus at specific locations
• Place Cells in Rats respond to either the southwest corner, bottom west boundary, or bottom north boundary
• Firing patterns of place cells maintain same relative position over changes in size/shape of environment
• Human hippoccampus is thought to contain may place cells
• Spatial Navigation Cells in the Hippocampus has shown grid cells use direction to determine position, and place cells represent enviornment shapes
• 2014 Nobel Prize in Physiology awarded to O'Keefe, Moser, and Moser

Space, Language, and Symbols

• How do abilities change over time?
• How are our spatial abilities enhanced by uniquely human symbolic and linguistic abilities?
• This includes symbolic maps and spatial language for use with reorientation
• Symbolic Map requires dual representation
• Item must be represented and compared at the same time
• May be further aided by the use of language
• In maps, pictures stand for something else
• In graspings objects in pictures, subjects are confused, till they start to understand that they aren't themselvs the objects
• Understanding the map requires a spatial representation for a given enviornment
• Between 2 and 2.5 years, understanding that picture can provide information about the scenes depicteds

Language and Spatial Representation

• Children integrate factors of shape and language
• Spatial vocabulary use predicts performance on reorientation tasks (Hermer-Vazquez et al., 2001)
• Significant relationship between production of left/right terms and performance on reorientation task
• Suggests a supportive role of spatial (left/right) language in combining landmarks and shape of the environment
• Language combines landmark and geometrical shape information
• Impairing/taxing the language system leads to impairment in reorientation

Individual Differences in Navigation

• Tested by Spiers et al., 2022
• Individual differences in VR navigation correlate with real life navigation abilities
• Spiers et al dataset had N > 3 million participants worldwide
• VR can be used to test navigation abilities on very large scale
• Navigation declines with age (from ~20 years on)
• Growing up in rural areas = better navigators
• Economic wealth of country (GDP) correlates with navigation abilities Countries with more public transit worse (e.g., European countries) compared to countries with more cars (e.g., U.S.)
• Gender differences exist for navigations skills, which is determined by gender inequality

Other Applications

• Memory Disorders (i.e., AD) characterized by deficits in hippocampal memory system
• Early behavioral symptom of getting lost/disoriented
• VR navigation game as a potential method of detection of Alzheimer's (Sea Hero Quest)
• VR navigation performance predicts early symptoms of Alzheimer's
• Neuropsychological assessments
• A potential way to detect Alzheimer's earlier

Summary

• Spatial perception/depth perception develops very early in development (see upcoming lectures)
• Spatial Action (navigation) is guided by 3 core abilities: path integration, the ability to orient based on landmarks, and the ability to orient based on the shape of the environment
• Core spatial navigation is enhanced by the uniquely human ability to use symbols and language
• Spatial navigation abilities are influenced by the environment; deficits may be a marker of disease

Explore spatial perception through monocular and binocular cues like retinal disparity and convergence. Understand how experience shapes depth perception, and spatial navigation strategies inform daily life.