Imagine waking up in a dark room. You smell coffee, hear a distant radio, and feel the sheets on your skin. In a few moments, your mind has already begun to construct a representation of the world around you. This is the power of perception.

Perception is the process by which we organize and interpret sensory information to make sense of our environment. It is much more than just passively recording stimuli; it is an active and constructive process.

How Does Perception Work?

1. Sensory stimulation: It all starts with our senses receiving stimuli from the environment – light hitting the retina, sound waves reaching the ear, and so on.
2. Transduction: These physical stimuli are converted into electrical signals that our nervous system can process.
3. Neural processing: The brain processes these signals, organizing them into meaningful patterns.
4. Recognition: Finally, we recognize and interpret these patterns, giving them meaning based on our past experiences and expectations.

These elements help us make sense of complex visual scenes and are fundamental in processing the world.

Piaget and the Constructivist Theory

In Jean Piaget’s constructivist theory, perception is seen as an active process through which a child constructs their understanding of the world. Piaget believes that children are not mere passive receptors of sensory information but active participants who interpret and organize experiences according to evolving mental schemas.

The key concepts of perception according to Piaget’s constructivist theory are:

1. Schema: Piaget defines “schema” as the mental structure that allows an individual to organize and interpret information. Schemas are dynamic and adapt with experience. When children perceive the world, they do so through preexisting schemas, which evolve as they encounter new experiences.
2. Assimilation and accommodation: Perception relies on two fundamental processes:
   • Assimilation: This is the process through which children integrate new information into their existing schemas. For example, a child who has already seen a ball might perceive a new round object as a “ball” because it fits their existing schema.
   • Accommodation: When a child perceives something that does not fit into their existing schemas, they must modify or create new schemas. This is the process of accommodation. For example, when a child encounters a round fruit like an orange, they might need to modify their “ball” schema to accommodate the new perception of an edible round object.
3. Cognitive development stages:
   • Sensorimotor stage (0-2 years): During this period, the child’s perception is closely tied to their sensory and motor experiences. The child learns about the world through object manipulation and develops concepts like object permanence.
   • Preoperational stage (2-7 years): At this stage, the child begins to represent the world through language and mental images. Perception is still tied to egocentrism, and the child struggles to understand perspectives different from their own.
   • Concrete operational stage (7-11 years): Perception becomes more logical and organized. Children can consider multiple aspects of a situation and understand concepts such as conservation (the idea that quantities and volumes remain constant despite changes in shape or appearance).
   • Formal operational stage (from 12 years onward): During this phase, perception is based on the ability to think abstractly and hypothetically, allowing the child to analyze complex and variable situations.

In summary, for Piaget, perception is a process that evolves and refines with a child’s cognitive development, in a continuous cycle of assimilation and accommodation that leads to the active construction of reality.

Perception in Cognitive Theories

According to cognitive theories, perception is an active process by which the brain selects, organizes, and interprets sensory information to create a coherent representation of the world. Compared to Piaget’s constructivist theory, which views perception as a gradual construction process, cognitive theories emphasize the mental mechanisms and cognitive structures that process and transform information from the environment.

Here are some of the main concepts of perception according to cognitive theories:

1. Top-down and bottom-up processing

• Bottom-up processing: This process is based on raw sensory information received from the external world. Sensory data are processed at lower levels (e.g., recognizing lines or shapes) and then integrated into more complex representations. In other words, it starts from physical stimuli and moves towards more abstract mental processing.
• Top-down processing: In this case, perception is influenced by prior knowledge, expectations, and already stored concepts. Information from past experience or memory influences how we interpret sensory data. For example, when looking at an ambiguous image, our past experience can guide us toward a specific interpretation.

2. Attentional processes

Perception is strongly influenced by attention. Cognitive models emphasize that when receiving a large amount of sensory information, the human brain selects which stimuli to process in-depth. Attention allows us to filter out irrelevant stimuli and focus on what is important. This means that perception is not a passive reproduction of the world but a selective and focused process.

Some examples of attention theories include:

• Broadbent’s filter theory: It proposes that information is filtered early in the processing stage, allowing the focus to be on certain stimuli while others are ignored.
• Treisman’s attenuation theory: It suggests that unattended stimuli are not entirely ignored but merely attenuated, allowing us to notice some “less relevant” stimuli in certain circumstances.

3. Pattern recognition theory

An important part of perception is the ability to recognize patterns or familiar models in sensory data. Cognitive theories explain that the brain compares sensory information with stored mental patterns or representations in memory. These patterns guide our interpretation of stimuli.

• Template theory: This theory suggests that the brain has predefined models (or templates) that it compares with sensory stimuli to recognize them.
• Prototype theory: It posits that perception is based on a flexible process in which we compare stimuli to “prototypes” or ideal examples stored in memory. For example, we recognize a dog based on an abstract prototype of a dog rather than specific characteristics.
• Feature detection theory: This theory proposes that perception is based on the analysis of basic sensory features. The brain breaks down stimuli into elementary components (e.g., lines, angles) and integrates them to create more complex patterns.

In summary, cognitive theories of perception emphasize the interaction between sensory stimuli and cognitive processes, highlighting that perception is an active and complex process that goes beyond the simple reception of sensory stimuli.

4. David Marr’s Computational Theory

David Marr proposed a model of visual perception that consists of three stages of processing:

• Raw primal sketch: The first stage involves extracting the basic features of visual stimuli, such as edges, contours, and shadows.
• 2.5D primal sketch: In this phase, information is organized into a partial representation of the world based on the observer’s perspective.
• 3D model: Finally, the brain constructs a complete and stable three-dimensional representation of the object, independent of the observer’s specific viewpoint.

5. Gestalt Theory

Although positioned between cognitive psychology and perception psychology, Gestalt theory has strongly influenced the cognitive field. Gestalt proposes that we perceive objects as organized wholes rather than as the sum of their parts. The fundamental principles of Gestalt, such as proximity, similarity, closure, and continuity, describe how our brain organizes stimuli into coherent configurations.

6. Models Based on Mental Simulation:

Some more recent cognitive theories suggest that perception occurs not only through the processing of external stimuli but also through internal mental simulations. This means that the brain can simulate perceptions based on past experiences to understand new situations or imagine future experiences.

Cognitive theories view perception as an active process, where the brain processes, selects, and interprets sensory information through attentional mechanisms, mental schemas, and the interaction between sensory data (bottom-up) and past experiences (top-down). Perception is not a passive copy of reality but a dynamic process guided by cognitive structures and the expectations that the individual has developed over time.

The Importance of Perception in Everyday Life

Perception not only helps us navigate our environment but also influences our emotions and decisions. For example, the perception of time can vary depending on our activities: an hour may seem to fly by when we are engaged in something enjoyable, while it can drag on when we are bored.

Additionally, perception underpins our social interactions. Our ability to read facial expressions, tone of voice, and body language allows us to better understand others’ emotions and intentions, facilitating communication and human connection.

An area that exemplifies the observation of perception in all its potential is art, where it is primarily used as an element of research and action.

Image from Clickarte.it

Image from OpenEdition Journals – Aesthetics Journal