4.6. Perceptual Processes

In the previous section we have examined that the stimulation of sensory organs leads us to experience something such as, a flash of light or a sound, or a smell. This elementary experience, called sensation, does not provide us with any understanding of the stimulus that stimulated the sense organ. For example, it does not inform us about the source of the light, sound or fragrance. In order to make sense out of the raw material provided by the sensory system, we process it further. In doing so, we give meaning to stimuli by using our learning, memory, motivation, emotions, and other psychological processes. The process by which we recognise, interpret or give meaning to the information provided by sense organs is called perception.

Perception is a crucial process that follows sensation. While sensation is merely the detection of stimuli (like sounds or sights), perception allows us to make sense of these stimuli. When our sensory organs receive information, such as a sound, the brain does not just register it as a sound; it interprets that sound based on various factors including past experiences, emotions, and cultural context. Thus, perception transforms raw data from our environment into meaningful experiences.

Think about hearing a familiar song on the radio. Initially, your ears detect the sound (sensation), but then your brain interprets it based on your memories associated with that song, the emotions it evokes, and the context of your experiences. You might remember dancing to it at a party, making the song meaningful to you.

How do we identify an object? Do we identify a dog because we have first recognised its furry coat, its four legs, its eyes, ears, and so on, or do we recognise these different parts because we have first identified a dog? The idea that recognition process begins from the parts, which serve as the basis for the recognition of the whole is known as bottom-up processing. The notion that recognition process begins from the whole, which leads to identification of its various components is known as top-down processing.

There are two main ways our brain processes information when we perceive objects: bottom-up processing and top-down processing. Bottom-up processing starts with the details, where the brain builds up to a complete perception from individual components (like recognizing a dog by its fur and legs). In contrast, top-down processing begins with the whole concept and uses that understanding to interpret the details (for instance, identifying a dog because you already know it is a dog, even before seeing its parts clearly). Both processes interact to help us understand what we see.

Imagine you see an object covered in snow, and you only catch a glimpse of its tail. Bottom-up processing means you look closely at its features to identify it, while top-down processing means you already have in mind that it might be a dog outside, helping you quickly identify it despite not seeing the whole version.

Human beings are not just mechanical and passive recipients of stimuli from the external world. They are creative beings, and try to understand the external world in their own ways. In this process their motivations and expectations, cultural knowledge, past experiences, and memories as well as values, beliefs, and attitudes play an important role in giving meaning to the external world.

The act of perceiving is heavily influenced by who we are as individuals. Our motivations and expectations shape how we interpret stimuli. For example, if someone is hungry, they might perceive ambiguous shapes as food. Cultural background and personal experiences also dictate how we interpret what we see. Our memories can alter our perceptions, leading us to see things based on what we believe or feel.

Consider a student who is studying for a math test. If they encounter a math problem in an image while flipping through a magazine, they are more likely to perceive and recall that image based on their current focus on math, even if the image was originally about something entirely different, like a recipe.

Our visual field is a collection of different elements, such as points, lines, and colours. However, we perceive these elements as organised wholes or complete objects. The process of organising visual field into meaningful wholes is known as form perception. Several scholars have tried to answer such questions, but the most widely accepted answer has been given by a group of researchers, called Gestalt psychologists. They believe that we perceive different stimuli not as discrete elements, but as an organised 'whole' that carries a definite form.

Form perception involves organizing visual elements into a complete form. Gestalt psychology proposes that our brain instinctively organizes these elements, so instead of seeing scattered dots, we see shapes or objects. For instance, we see a bicycle as a whole entity rather than a collection of wheels, a frame, and a seat. The principles determined by Gestalt psychologists explain how and why certain combinations of stimuli are perceived as cohesive.

Imagine looking at a pile of LEGO blocks. If the blocks are random, they appear as disorganized shapes. However, if those blocks are put together to form a car or a house, your brain recognizes them as a coherent toy rather than just separate pieces, demonstrating how we naturally seek to understand order in chaos.

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