PERCEPTION

What is perception?

Perception is defined as experiences resulting from the stimulation of the senses.

What illustrates how perception can change?

based on added information.

What is the inverse projection problem?

the task of determining the object responsible for a particular image on the retina.

What does 'viewpoint invariance' refer to?

people’s ability to recognize an object even when it is seen from a different viewpoint.

What type of processing involves a sequence of events from eye to brain?

Bottom-up processing.

What is 'top-down processing'?

Processing that originates in the brain at the top of the perceptual system.

What principle states we perceive objects that are most likely to have caused the stimuli?

The likelihood principle.

What key concept did Helmholtz contribute to perception?

the concept of unconscious inference, suggesting our perceptions result from assumptions we make about the environment.

What is the principle of good continuation?

Points that, when connected, result in straight or smoothly curving lines are seen as belonging together.

What is the law of pragnanz?

, or principle of simplicity, states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible.

What are semantic regularities?

Are characteristics associated with the function carried out in different types of scenes.

What does Bayesian inference involve?

Using prior prior and likelihood to estimate the probability of an outcome.

What brain area is heavily involved in face recognition?

The Fusiform Face Area.

What are the two processing streams in the brain related to perception and action?

The what pathway (ventral) related to perception and the where/action pathway (dorsal).

What do mirror neurons do?

respond both when observing an action and when executing that action, helping to determine the goal or intention behind the action.

How does movement facilitate perception?

it reveals aspects of objects that are not apparent from a single viewpoint.

What is 'speech segmentation'?

The ability to tell when one word in a conversation ends and the next begins.

What does the principle of similarity state?

states that similar things tend to appear grouped together.

Why is designing a perceiving machine difficult?

Because stimuli on receptors are often ambiguous, objects can be hidden or blurred, and they look different from various viewpoints.

In what year  scientists thought they could build a machine with human-like vision in just a few years. But early systems were very slow and could barely identify simple objects.

1950s

_____ is the ability to tell when one word in a conversation ends and the next begins.

Speech segmentation.

In what year did the International Journal of Computer Vision, the first journal devoted solely to computer vision, was founded. Researchers were still struggling to solve basic visual problems, using complex math to understand things that are easy for humans.

1987

In what year did the thirteen robotic vehicles are lined up in the Mojave Desert in California for the Defense Advanced Projects Agency (DARPA) Grand Challenge. The tasks was to drive 150 miles from starting point to Las VEGAS, using only gps coordinates to define the course and computer vision to avoid obstacles.

2004

WHY IS IT SO DIFFICULT TO DESIGN A PERCEIVING MACHINE?

1. The stimulus on the receptors is ambiguous

2. Objects can be hidden or blurred

3. Objects look different from different viewpoints

4. Scenes containing high-level information

Examples of top down processing

1. Perceiving objects

2. Hearing words in a sentence

- the likelihood that one sound will follow another within a word

Transitional probabilities

- The process of learning about transitional probabilities and about other characteristics of language.

Statistical learning

He was a physicist who made important contributions to fields as diverse as thermodynamics, nerve physiology, visual perception, and aesthetics.

Hermann von Helmholtz

- we perceive the object that is most likely to have caused the pattern of stimuli we have received.

likelihood principle

our perceptions are the result of unconscious assumptions, or inferences, that we make about the environment.

unconscious inference

The gestalt approach to perception originated, in part, as a reaction to Wilhelm Wundt’s

structuralism.

- he wondered how the structuralist idea that experience is created from sensations could explain the illusion of movement he observed in a stroboscope

Max Wertheimer

- an optical illusion in which stationary objects viewed in quick succession or in relation to moving objects appear to be in motion.

Apparent Movement

Wertheimer’s conclusions from the phenomenon of apparent movement

1. Apparent movement cannot be explained by sensations because there is nothing in the dark space between the flashing lights.

2. The whole is different than the sum of its parts

- points that, when connected, result in straight or smoothly curving lines are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path.

principle of good continuation

- every stimulus pattern is seen in such a way that the resulting structure is as simple as possible

law of pragnanz

- similar things appeared to be grouped together.

principle of similarity

gestalt psychologist realized that perception is based on more than just the pattern of light and dark on the retina, perception is determined by specific______.

organizing principle.

- characteristics of the environment that occurs frequently

Regularities in the environment

- regularly occuring physical properties of the environment. (sky, trees and plants).

Physical regularities

- people can perceive horizontals and verticals more easily than other orientations.

Oblique effect

- we usually assume that light is coming from above, because light in our environment, including the sun and most artificial light, usually comes above.

light-from-above assumption

One of the reasons humans are able to perceive and recognize objects and scenes so much better than computer-guided robots is that

our system is adapted to respond to the physical characteristics of our environment, such as the orientations of objects and the direction of light

- characteristics associated with the function carried out in different types of scenes

semantic regularities

- knowledge of what a given scene typically contains

Scene schema

- our initial belief about the probability of an outcome

prior probability

-the extent to which the available evidence is consistent with the outcome.

likelihood

researchers have used______ to develop computer-vision systems that can apply knowledge about the environment to more accurately translate the pattern of stimulation on their sensors into conclusions about the environment.

Bayesian Inference

- states that characteristics that enhance an animal’s ability to survive and, therefore, reproduce will be passed on to future generations

Theory of natural selection

- refers to the ability of the brain to change and adapt its structure and function based on experience.

Experience-dependent plasticity

- an area in the temporal lobe that contains many neurons that respond best to faces

Fusiform Face Area

Moving reveals aspects of the objects that are _______ from a single viewpoint.

not apparent

seeing an object from different viewpoint provides added information that results in ______ perception, especially for objects that are out of the ordinary

more accurate

is also important because of the coordination that continually occurs between perceiving stimuli and taking action toward these stimuli.

movement

- the study of the effect of removing parts of the brain in animals

brain ablation

- the study of the behavior of people with brain damage.

neuropsychology

- the challenge of recognizing and remembering objects in different contexts. It involves a task where an individual must identify objects among others.

Object discrimination problem

- where pathway (dorsal/back)

parietal

-what pathway (ventral/lower part)

Temporal

used the neuropsychological approach (studying the behavior of people with brain damage) to reveal two streams, one involving the temporal lobe and the other involving the parietal lobe

David Milner and Melvyn Goodale (1995)

- action pathway

Parietal

- perception pathway

Temporal

—neurons that respond both when a monkey observes someone else grasping an object such as food on a tray and when the monkey itself grasps the food

MIRROR NEURONS

What is the purpose of mirror neurons?

they are involved in determining the goal or intention behind the action

- forms the basis of unconscious inference and helps interpret sensory information (e.g., recognizing words in a conversation).

Knowledge

-uses knowledge to predict and make sense of the world (e.g., identifying objects like a book or loaf of bread)

Inference

-shape how we perceive and interact with the world, as seen in the size-weight illusion, where larger objects seem lighter due to prior predictions about size and weight

Prediction