Perception - Approaches

Perception

Approaches to the study of sensation and perception

Structuralism

Approach established by Wundt (1830-1920)

– States that perceptions are created by combining elements called sensations

– Popular in mid to late 19th century

Wundt studied conscious experience by examining its structure or components parts (sensations, feelings) using individuals who were trained in introspection. This "school of psychology" became known as structuralism.

Structuralism is the theoretical approach established by Wihelm Wundt who established the first scientific psychology lab in Germany in 1879. In keeping with the recognition of the day that all matter was composed of more elementary particles, structuralism claimed that perceptions were created by adding up individual elements called sensations. Although this theory is no longer used, it is important historically because the Gestalt approach arose in response to its inadequacies.

A structuralist square. The structuralist approach claims that each dot creates a sensation, and the combination of these sensations produces the perception of a square.

Empiricist approach

Empiricism is a philosophical school of thought that orginiated in the 17 th and 18 th centuries. Empiricists, such as Thomas Hobbes, John Locke, and George Berkley, claimed that the knowledge we have about the world is based wholly on the experiences provided by our senses. In fact, you may be familiar with John Locke's notion that the mind was a tabula rasa , or blank slate, when a child was born. Although the traditional empiricist view is extreme, especially considering modern knowledge about the influence of genetics on experience, a modified view is useful to the study of certain domains of sensation and perception. For example, a contemporary view focuses on the role of experience in things like depth perception, speech perception, and taste preferences.

Gestalt Approach

The Gestalt psychologists were a group of German psychologists working in the early 1900's. The name of the movement is derived from the German word "Gestalten" meaning form. The Gestalt psychologists recognized that structuralism could not explain many perceptal phenomena. In response, they proposed that perception is based on the organization of stmuli into holistic and meaningful forms. They are well-known for the phrase "the whole is different than the sum of its parts." They proposed several "laws" (really heuristics or "rules of thumb") that are referred to as the Gestalt laws of perceptual organization. The Gestalt approach is still used in areas that emphasize perceptual organization.

A Gestalt square. According to this approach, it is the organization of the dots that causes us to perceive a square.

Ecological Approach

James. J. Gibson published his first paper in 1929, proposing his ecological or direct approach to perception. He advocated for the study of perception in natural environments, rather than laboratories. The main claim of this theory is that we directly gather information from the environment and that contains all of the necessary information for perception and further processing is unnecessary. Gibson's theory guides much of the research into motion perception and navigation in real environments.

Information Processing approach

Behavourist approach

Gibsonian approach

Sensation & Perception - When we smell a fragrant flower, are we experiencing a sensation or a perception? In everyday language, the terms "sensation" and "perception' are often used interchangeably.

Sensations can be defined as the passive process of bringing information from the outside world into the body and to the brain. The process is passive in the sense that we do not have to be consciously engaging in a "sensing" process. Perception can be defined as the active process of selecting, organizing, and interpreting the information brought to the brain by the senses.

A) HOW THEY WORK TOGETHER:

1) Sensation occurs:

a) sensory organs absorb energy from a physical stimulus in the environment.

b) sensory receptors convert this energy into neural impulses and send them to the brain.

2) Perception follows:

a) the brain organizes the information and translates it into something meaningful.

B) But what does "meaningful" mean? How do we know what information is important and should be focused on?

1) Selective Attention - process of discriminating between what is important & is irrelevant, and is influenced by motivation.

2) Perceptual Expectancy - how we perceive the world is a function of our past experiences, culture, and biological makeup.

Wundt and colleagues, like student Edward Titchener, used a method called introspection to learn what was going through people's heads as they completed various tasks. Wundt was especially interested in how people processed sensory stimuli, and he was the first to draw a distinction between sensation, or a stimulus' effect on one of our senses, and perception, or our brain's interpretation of the stimulus.

Empiricist Approach

 

EMPIRICISM

ALL KNOWLEDGE OBTAINED THROUGH SENSES - NOT INHERITED

Science uses an empirical approach.

Empiricism (founded by John Locke) states that the only source of knowledge comes through our senses – e.g. sight, hearing etc.

This was in contrast to the existing view that knowledge could be gained solely through powers of reason and logical argument (known as rationalism).  Thus empiricism is the view that all knowledge is based on, or may come from experience.

The empirical approach through gaining knowledge through experience quickly became the scientific approach and greatly influenced the development of physics and chemistry in the 17th and 18th centuries.

The idea that knowledge should be gained through experience, i.e. empirically, turned into a method of enquiry that used careful observation and experiments to gather facts and evidence.

The nature of scientific enquiry may be thought of at two levels:

1. that to do with theory and the foundation of hypotheses.

2. and actual empirical methods of enquiry (i.e. experiments, observations)

The prime empirical method of enquiry in science is the experiment.

The key features of the experiment are control over variables (independent, dependent and extraneous), careful objective measurement and establishing cause and effect relationships.

• empiricism:

– experience from the senses is the only source of knowledge

• Hobbes (1588–1678) believed that everything that could ever be known or even imagined had to be

learned through the senses.

• Locke (1632–1704) sought to explain how all thoughts, even complex ones, could be constructed

from experience with a collection of sensations – tabula rasa

• Berkeley (1685–1753) studied ways in which perception is limited by the information available to us through our eyes.

– all of our knowledge about the world comes from experience, even if perception is limited

– “distance of objects”

–infer distances from cues in the image

– “To be is to be perceived”

Basic Concepts (Gibson)

Distal object--Grandma’s face

Informational medium--Reflected light from Grandma’s face

Proximal stimulation--Photon absorption in the rod and cone cells of the retina

Perceptual object --Grandma’s face

Gestalt psychology was founded by German thinkers Max Wertheimer, Wolfgang Kohler and Kurt Koffka and focused on how people interpret the world. The Gestalt perspective formed partially as a response to the structuralism of Wilhelm Wundt, who focused on breaking down mental events and experiences to the smallest elements. Max Wertheimer noted that rapid sequences of perceptual events, such as rows of flashing lights, create the illusion of motion even when there is none. This is known as the phi phenomenon. Motion pictures are based upon this principle, with a series of still images appearing in rapid succession to form a seamless visual experience.

According to Gestalt psychology, the whole is different than the sum of its parts. Based upon this belief, Gestalt psychologists developed a set of principles to explain perceptual organization, or how smaller objects are grouped to form larger ones. These principles are often referred to as the "laws of perceptual organization."

However, it is important to note that while Gestalt psychologists call these phenomena "laws," a more accurate term would be "principles of perceptual organization." These principles are much like heuristics, which are mental shortcuts for solving problems.