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Sensory and Perception: Understanding How Our Brain Interprets the World

Updated: Mar 9

Do you ever wonder how we are able to experience the world around us? The process of sensation refers to the way in which our sensory organs detect and respond to sensory information from the environment. Sensation involves the detection of physical stimuli such as light, sound waves, and touch, and the conversion of these stimuli into neural signals that can be interpreted by the brain. Perception, on the other hand, refers to the way in which we organize, interpret, and make sense of the sensory information we receive. Perception involves not only the detection of sensory information but also the processing and interpretation of that information in order to create a meaningful experience of the world around us.

Our brains make sense of the things we sense by using a process of detecting and analyzing incoming information. This helps us create a meaningful experience of the world around us. Sensory thresholds are really important in this process. The absolute threshold is the smallest amount of stimulation needed to notice something. The difference threshold (also called the just noticeable difference) is the smallest detectable difference between two things. Weber's law says that the difference threshold is related to how big the stimulus is. This means that the bigger the stimulus, the bigger the difference needs to be for us to notice it. Knowing about these sensory thresholds helps us understand how our brains process information and create our understanding of the world.

An example of sensory thresholds in action could be when you're trying to listen to someone speak in a noisy environment. Your brain needs to be able to detect the sound of the person's voice above the background noise in order for you to understand what they're saying. This is where the concept of the absolute threshold comes in - there's a minimum amount of sound needed for you to detect the person's voice. The difference threshold also comes into play if, say, the person starts speaking more softly or more loudly. The difference between the new level of sound and the original level needs to be large enough for your brain to detect the change. Weber's law applies here as well - if the person is speaking very loudly, to begin with, a small change in their volume may not be noticeable, but if they're speaking softly, even a slight change could be noticeable.

Did you know that our eyes don't "see" and our ears don't "hear"? Instead of directly experiencing the world around us, our sensory organs detect physical stimuli and turn them into signals that the brain processes and interprets. This process is called transduction. Adaptation is how our senses adjust to changes in the environment over time. By constantly adapting, we can keep detecting and interpreting sensory information even as our surroundings change. Transduction and adaptation work together to create a rich and complex experience of the world. However, our perception of the world is shaped by our senses and can be influenced by things like context, attention, and expectation. Our senses help us to understand and experience the world around us. Vision, audition, and touch are three important sensory processes that allow us to detect and make sense of light, sound, and touch. Vision involves detecting and interpreting light waves that enter our eyes. Our eyes have special cells called photoreceptors that send signals to the brain when they detect light, allowing us to see colors and shapes. Hearing, or audition, involves detecting and interpreting sound waves that enter our ears. Our ears have special cells called hair cells that send signals to the brain when they detect sound, allowing us to hear music, speech, and warning signals. Touch involves detecting and interpreting pressure, temperature, and pain sensations on our skin. Our skin has special cells called sensory receptors that send signals to the brain when they detect these sensations, allowing us to feel textures, hot and cold, and pain. These sensory processes are crucial for everyday tasks such as communication, recognition, and staying safe. If someone has difficulty with their senses, they may struggle with these tasks and need support to navigate the world around them.

The human body has an intricate system of senses that allows us to perceive and navigate the world around us. Two important senses that contribute to our orientation and movement are the vestibular organ and the kinesthetic sense. The vestibular organ, located in the inner ear, is responsible for detecting changes in head position and movement. This helps us maintain balance and orientation in space. The kinesthetic sense, on the other hand, is the sense of body position and movement. It allows us to know where our body is in space and how it is moving. Together, these senses help us navigate our surroundings and coordinate our movements.

Skin senses, including pressure and sensitivity, temperature, and pain, are also crucial for our everyday functioning. Pressure and sensitivity are detected by specialized sensory receptors in the skin that respond to pressure and touch. This allows us to feel sensations such as texture, shape, and pressure. Temperature is detected by specialized receptors that respond to changes in temperature, allowing us to sense hot and cold. Pain, on the other hand, is detected by specialized pain receptors that respond to tissue damage or inflammation. Interestingly, the perception of pain can be modulated by the nervous system through a phenomenon called pain gating. This allows us to reduce the intensity of pain by activating other sensory pathways or distracting ourselves from the pain.

Phantom limb sensations are a unique phenomenon that can occur after the amputation of a limb. Even though the limb is no longer there, some people still experience sensations such as pain, tingling, or itching in the missing limb. This is thought to be due to changes in the brain and nervous system that occur after amputation. While phantom limb sensations can be uncomfortable, they can also be treated with various therapies and techniques.

Overall, our bodily senses play a crucial role in our daily functioning, allowing us to navigate our surroundings and interact with the world in a meaningful way. Understanding how these senses work and how they can be affected can help us better appreciate the complexity of our bodies and how they perceive the world around us. Chemical senses refer to the way our body detects and interprets chemical molecules in our environment. There are three types of chemical senses: taste, smell, and pheromone detection.

Taste is the ability to detect and interpret different flavors, such as sweet, sour, salty, and bitter. Our taste buds, located on the tongue, are responsible for detecting these flavors. Taste plays a crucial role in our daily lives, as it helps us identify food that is safe to eat and enjoyable to consume. Our sense of taste can also be influenced by factors such as age, genetics, and cultural background.

Smell, also known as olfaction, is the ability to detect and interpret different odors. Our olfactory system is located in the nose and consists of specialized cells that detect different odor molecules. The smell can influence our behavior and emotions, as certain scents can trigger memories and elicit specific emotional responses. For example, the smell of freshly baked cookies may trigger feelings of nostalgia and happiness.

Pheromone detection is the ability to detect and interpret chemical signals that are released by other members of our species. Pheromones are detected by specialized cells in the nose and can influence our behavior and physiology. For example, pheromones released by a female moth can attract male moths for mating. In humans, pheromone detection is still a topic of research, but some studies suggest that pheromones may play a role in attraction and mate selection. Perception: The meaning of neural messages transmitted from sensory receptors to the brain is not inherent, but rather requires organization and interpretation in the process known as perception. This process is largely universal among humans, as a unique interpretation of sensory input would result in an absence of a commonly perceived reality. However, cultural background, learning experiences, motivations, and emotions can influence individual perceptions. For instance, while a knife is generally perceived similarly among all humans due to the innate ways in which visual information is organized, it may hold different perceptual significance to each person based on their personal experiences with a similar knife. Later on, we will explore the shared innate organizational properties of all humans and briefly touch upon the individuality of perceptions. While the distinction between sensation and perception is theoretically straightforward, in practice it can be challenging to differentiate between the two. Visual perception, for example, begins in the eye's complex neural structures before sensory messages are transmitted to the brain. Thus, the distinction between sensation and perception is largely arbitrary, but it allows for an easier understanding of the processing of information by sense organs and the brain. Question: Is it possible for perception to cause individuals to perceive images and sounds differently through their eyes and ears? For instance, when one person finds someone attractive while another finds them less attractive, is this difference due to variations in taste or perception? Might it be conceivable that each individual receives different shapes of sensory information? Answer: Perception can indeed make people perceive images and sound differently through their eyes and ears. While sensory organs like the eyes and ears detect and transmit raw sensory information to the brain, it is the brain that interprets and makes sense of this information to create perception. This interpretation and organization of sensory information can vary from person to person based on their past experiences, emotions, cultural background, and other individual factors. Therefore, it is possible that two people looking at the same object or listening to the same sound may perceive it differently due to differences in their perception. The example of finding someone attractive or less attractive could be due to a combination of both taste and perception. Taste refers to an individual's preferences or aesthetic sense, while perception refers to how the brain processes sensory information to create a meaningful understanding of the world. Therefore, it is possible that each person receives and processes sensory information differently, leading to different perceptions of the same stimuli. Perception is the process of interpreting and organizing sensory information to create a meaningful understanding of the world around us. Examples of perception include: The Gestalt principles are a set of guidelines that explain how our brains organize sensory information into meaningful patterns and shapes, such as similarity, proximity, closure, and continuity. For instance, when we observe a picture of a group of individuals, our minds tend to group people who look alike or are positioned closely together. Understanding Gestalt principles can have a significant impact on our daily lives by helping us comprehend complicated information, such as recognizing faces or interpreting data visualizations. 1- Figure-ground is a Gestalt principle of perception that refers to the way in which our brains separate visual information into objects that stand out (the figure) and the background against which they appear (the ground). This principle helps us to perceive and make sense of complex visual scenes by allowing us to focus on the objects of interest while ignoring the irrelevant background.

2- Continuity is another Gestalt principle of perception that refers to the tendency to perceive visual elements in a way that is consistent with our past experiences and expectations. This principle allows us to make sense of complex visual scenes by filling in missing information and perceiving patterns that are consistent with what we expect to see.

3- Proximity is a Gestalt principle of perception that refers to the tendency to perceive objects that are close together as a single group. This principle helps us to organize visual information and to group similar objects together.

4- Similarity is another Gestalt principle of perception that refers to the tendency to perceive objects that are similar in appearance to a single group. This principle helps us to organize visual information and group objects based on their shared characteristics.

5- Closure is a Gestalt principle of perception that refers to the tendency to perceive incomplete figures as complete by filling in the missing information. This principle allows us to make sense of visual scenes that are not fully visible or are partially obscured.

Perceptual constancy is the ability to perceive objects as having a consistent size, shape, color, and brightness, even when they are viewed from different angles, under different lighting conditions, or from different distances.

There are four types of perceptual constancy:

1- Brightness constancy is the ability to perceive the brightness of an object as constant even when the lighting conditions change.

2- Color constancy is the ability to perceive the color of an object as constant even when the lighting conditions change.

3- Size constancy is the ability to perceive the size of an object as constant even when the distance between the observer and the object changes.

4- Shape constancy is the ability to perceive the shape of an object as constant even when its orientation changes. Depth Perception: Depth perception plays an essential role in our ability to perceive the distance between objects in three-dimensional space. This skill is particularly important for everyday activities like driving and navigating through our environment. We use a combination of monocular and binocular cues, such as texture gradient, perspective, and the disparity between the images received by each eye, to perceive depth. For instance, while driving, we rely on both types of cues to judge the distance between other vehicles and objects on the road. Understanding how we perceive depth can help us improve our daily activities, from pouring a glass of water to complex tasks like driving. Monocular cues can be perceived with one eye, while binocular cues require the use of both eyes. Monocular cues include: - Linear perspective: the apparent convergence of parallel lines as they recede into the distance.

- Texture gradient: the gradual change in the size and spacing of elements in a textured pattern as they recede into the distance.

- Interposition: when one object overlaps another, the one in front is perceived as closer.

- Relative size: when two objects are of equal size, the one that appears smaller is perceived as being farther away.

- Height in the visual field: objects that are higher in the visual field are perceived as being farther away.

- Light and shadow: the patterns of light and dark that result from the interaction of illumination and objects can provide cues to their relative distance.

- Accommodation: the process by which the lens of the eye changes shape to focus on objects at different distances. While Binocular cues are visual cues that require the use of both eyes together to provide information about depth and distance.

  • Binocular disparity: the difference in the images seen by the two eyes, which provides a cue to depth and distance.

  • Convergence: the degree to which the eyes turn inward to focus on an object, which provides a cue to distance.

The perception of motion involves the ability to detect, track, and interpret moving objects. The visual system relies on a variety of cues, including changes in size and shape, the direction of movement, and the surrounding context, to perceive motion accurately. Synesthesia is a neurological condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in another pathway. For example, some people with synesthesia may experience colors when they hear certain sounds or see letters and numbers as having specific colors. In the next article, we will talk about The Truth Behind the Illusion: How Our Senses Can Deceive Us Sources:

- Lahey, B. B. (2018). Psychology: An Introduction (Seventh Edition). McGraw-Hill Education.

- Wood, S. E. (2016). Mastering the World of Psychology (Fifth Edition). Pearson.

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