Human Sensation, Perception, and Memory

Posted on Dec 4, 2024 in Psychology and Sociology

The Thresholds of Sensations

Limits of Human Perception

Human capacity to receive stimuli is limited. We cannot perceive certain things, such as infrared light or ultrasound. Our senses have thresholds:

  • Absolute Threshold: The minimum amount of stimulus needed to detect something (lower threshold) and the maximum stimulus we can receive (upper threshold).
  • Differential Threshold: The difference in stimulus intensity needed to perceive an increase or decrease from a prior stimulus.

Sensation and Perception

Defining Sensation

Sensation is detecting anything through the senses (sight, hearing, touch, smell, taste, and internal sensations like movement, balance, and discomfort). It is the raw detection of a stimulus, without meaning.

Defining Perception

Perception is processing sensory data to give it meaning. It’s recognizing and interpreting an object, a constructive process of organization.

Theories of Sensation and Perception

  • Associationist Theories: Perception is a set of sensations linked by the subject’s experience.
  • Gestalt Theory: Perception is not a sum of sensations, but the immediate grasp of whole objects. We perceive organized sets, later separating individual sensations through abstraction.

Memory

Defining Memory

Memory is the ability to encode, store, and retrieve past sensory experiences, knowledge, and behaviors.

Considerations on Memory

  • Access to the past
  • Basis of knowledge
  • Central archive
  • Saving mechanism
  • Basis of personal identity

Stages of Memory

  1. Encoding
  2. Storage (Freud, Huxley, and Hebb’s theories)
  3. Retrieval (spontaneous and voluntary)
  4. Recall (recognition and location)

Classifying Memory

  1. Time (short-term, medium-term, long-term)
  2. Understanding of the object (mechanical and meaningful)
  3. Fidelity of memory (recognition, reproduction, eidetic)

Memory Disorders

Amnesia, senile amnesia, hypermnesia, ecmnesia, paramnesia

Imagination

Defining Imagination

Imagination is the capacity to present images in consciousness without current sensory input.

Types of Imagination

  • Reproductive imagination
  • Creative imagination

Characteristics of Images

  • Weaker and less intense than original perceptions
  • Fewer details than original perceptions
  • Images bypass the present reality, allowing us to place ourselves in an imagined reality

Imagination, Perception, and Desire

Conscious Desire-Related Images

  • Eidetic
  • Iconic
  • Fantasy (motor response phenomenon)

Unconscious Desire-Related Images

  • Hypnagogic
  • Dreamlike
  • Hallucinatory

Three Essays on Sexual Theory (1905)

Freud’s Theory of Libido

This work addresses sexual aberrations, child sexuality, puberty, fetishism, libido types, and female sexuality.

Key Points

  • Sexuality exists before puberty.
  • Sexuality is not solely for procreation; children’s sexuality exists but cannot lead to reproduction, sometimes manifesting as perversions (transitional forms of sexuality).
  • Repression of child sexuality and perversions can lead to neuroses.

Freud’s Instinct Theory

Instinkt vs. Triebes

Freud distinguishes between instinkt (innate appetites common to a species) and Triebes (individual appetites driving a subject towards an object).

Evolution of Freud’s Theory

Initially, Freud proposed self-preservation instincts and sexual instincts (libido). Later, he considered self-preservation as libido directed towards oneself. Finally, from 1920, he proposed life instincts (Eros) and death instincts (Thanatos).

Eros and Thanatos

Eros

Eros, the life instinct, is a binding force driving the creation of units. It manifests in love, sexual activity, and maintaining physical and mental unity.

Thanatos

Thanatos, the death instinct, is a drive towards disintegration and a return to an inorganic state. It manifests in sadism, masochism, and suicide.

Three Phases of Freudian Psychoanalysis

  1. Determining the causes and cures for neuroses.
  2. Developing a general theory of the psyche (metapsychology) with topical, dynamic, and economic perspectives.
  3. Becoming a general theory of culture, analyzing and interpreting the unconscious and the role of sexuality.

Metapsychology and the First Topical

Freud’s first topical divides the psychic apparatus into three levels:

  • Unconscious
  • Preconscious
  • Conscious

The unconscious is inaccessible but filled with repressed desires. These desires, disguised as symptoms or dreams, try to enter consciousness through the preconscious, which is censored by the conscious.