Unit 7&8- Sensation and Perception

Sensation

Sensation refers to the process of receiving information from the environment through sensory organs such as the eyes, ears, skin, nose, and tongue. It is the initial step in the process of perception, where sensory receptors detect stimuli and transmit signals to the brain for processing and interpretation. Each of these systems maintains unique neural pathways with the brain which allows them to transfer information from the environment to the brain very rapidly.

Each sensory system contains unique sensory receptors, which are designed to detect specific environmental stimuli. In essence, sensation is how we "sense" the world around us through raw data collection, without adding interpretation or meaning, which happens in the next step—perception.

Key Features of Sensation:

  • Sensory Receptors: Specialized cells that respond to particular types of stimuli, such as photoreceptors in the eyes for light or mechanoreceptors in the skin for touch.

  • Transduction: The process by which sensory receptors convert physical energy (like light or sound) into electrical signals sent to the brain.

  • Thresholds: Sensation can be influenced by the absolute threshold (the minimum level of stimulus detectable) and the difference threshold (the smallest detectable change in a stimulus).

Touch Sensation

Is thought to be the first sense that humans develop. Touch consists of several distinct sensations communicated to the brain through specialized neurons in the skin.

  • Pressure

  • temperature

  • light touch

  • vibration

  • pain

and other sensations are all part of the touch sense and are all attributed to different receptors in the skin. Often combines these signals with feedback from the muscles and tendons as we actively move and explore the world, and with proprioceptive information about the position of our tactual surfaces.

Sight Sensation

An ability to interpret the surrounding environment through vision due to the light reflected by the objects in the surrounding. Involves perceiving things through the eyes, in which the iris (which is the colored part of the eye) works like the shutter of a camera, retracting to shut out light or opening wider to let in more light. The information translated from the light is sent as electrical impulses to the brain through the optic nerve.

Hearing Sensation

This sense works via the complex labyrinth that is the human ear. Sound is funneled through the external ear and piped into the external auditory canal. Then, sound waves reach the tympanic membrane, or eardrum. There, the auditory ossicles — three tiny bones called the malleus (hammer), incus (anvil) and stapes (stirrup) — vibrate. The stapes bone, in turn, pushes a structure called the oval window in and out, sending vibrations to the organ of Corti. The impulses then travel to the brain via sensory nerves.

Smell Sensation

Humans may be able to smell over 1 trillion scents. They do this with the olfactory cleft, which is found on the roof of the nasal cavity. Nerve endings in the olfactory cleft transmit smells to the brain. Poor smelling ability in people may be a symptom of a medical condition or aging.

Taste Sensation

Usually broken down into the perception of four different tastes:

  • salty

  • sweet

  • sour

  • bitter

The sense of taste aided in human evolution, because taste helped

people test the food they ate. The five tastes can be sensed on all parts of the tongue, although the sides are more sensitive than the middle. The cells differ in their level of sensitivity, each has a specific palette of tastes with a fixed ranking, so some cells may be more sensitive to sweet, followed by bitter, sour, and salty, while others have their own rankings. The full experience of a flavor is produced only after all of the information from the different parts of the tongue is combined.

Point to Note

These sensory experiences are essential for our understanding and interaction with the world around us. The brain processes these sensory inputs, interprets them, and forms our perception of the environment, which then guides our behaviour and responses.

Perception

Perception in psychology refers to the process by which individuals interpret and make sense of sensory information received from their environment. It involves organizing, identifying, and interpreting sensory stimuli to create a meaningful understanding of the world around us. Perception is influenced by various factors, including

  • past experiences

  • cultural background

  • expectations

  • context.

Internal Influences on Perception

Internal influences on perception are factors within an individual that shape how they interpret and make sense of the world around them. These influences are rooted in an individual's cognitive, psychological, and biological characteristics. Some key internal influences on perception are:

  • Cognitive Schema: A mental framework or structure that helps individuals organize and interpret information. Schemas are shaped by past experiences, beliefs, and knowledge, influencing how we perceive and process new information

  • Perceptual Expectations: Our previous experiences, motivations, and expectations can influence how we perceive new information. These expectations guide our attention and shape our perception of stimuli.

  • Motivational Factors: Our goals, desires, and needs can influence our perception. We tend to perceive information in ways that align with our motivations and objectives.

  • Personality Traits: An individual's personality traits can shape their perception. For example, an optimistic person may perceive a situation differently than a pessimistic person.

  • Belief Systems: Our beliefs, values, and worldview can significantly influence our perception of events, people, and situations. We often interpret information in a way that aligns with our existing beliefs.

  • Emotional Influences: Emotional states, whether positive or negative, can influence how we perceive and interpret the world. Emotions can enhance or distort perception based on the emotional valence of the stimulus.

  • Long-term Memory: Past experiences stored in long-term memory can influence how we perceive and interpret current stimuli. Memory retrieval and association influence our understanding and interpretation of the present.

Point to Note

Understanding these internal influences on perception helps individuals become more aware of how their thoughts, emotions, past experiences, and cognitive processes shape their interpretations of the world. It's important for effective communication, decision-making, and fostering a better understanding of oneself and others.

Extrasensory Perception

Extrasensory Perception (ESP) refers to the purported ability to receive or perceive information through means other than the recognized senses (such as sight, hearing, touch, taste, and smell). ESP is a controversial topic and is not widely accepted in the scientific community due to a lack of empirical evidence supporting its existence.

Examples of Extrasensory Perception:

  • Telepathy: Telepathy involves the ability to perceive the thoughts or mental content of another person without the use of verbal or non-verbal communication.

  • Precognition: Precognition is the claimed ability to predict or foresee future events or outcomes before they occur through extrasensory means.

Discussion Question

  1. Discuss the role sensation in forming memories

  2. In what ways do our sensory limit or expand our experience of the world?

  3. Discuss how individuals' experiences and expectations shape their perception?

  4. How does perception affect memory and decision-making

  5. Discuss how sensation and perception work together in everyday experiences?

  6. In what ways can sensory limitations affect perception?