Human Memory Class 11 Psychology

Nature of memory

• The ability to draw on past experiences for present use is what defines memory.
• Memory can be broken down into three stages:
  • Encoding, which is the initial registration and processing of incoming information
  • Storage, during which the encoded information is retained for later use
  • Retrieval, where the stored information is accessed when needed.

The Stage Model

The model of memory proposed by Atkinson and Shiffrin is commonly referred to as the stage model. 

Memory Systems: Sensory, Short-Term and Long-Term Memories

According to the Stage Model, there are three memory systems: the Sensory Memory, the Short-term Memory, and the Long-term Memory.

Sensory Memory

• The incoming information first enters the sensory memory.
• Sensory memory has a large capacity but is very brief, lasting less than a second.
• Information from all senses is registered here as an exact replica of the stimulus.

Short-term Memory

• Information that is attended to enters the short-term memory (STM), holding small amounts for a brief period, typically 30 seconds or less.
• Information in STM is primarily encoded acoustically and may be lost if not rehearsed continuously.

Long-term Memory

• Materials that survive STM limitations enter long-term memory (LTM), which has a vast capacity and stores information semantically.
• Information in LTM is never forgotten but may be challenging to retrieve, leading to what is perceived as forgetfulness.
• Information travels from sensory memory to STM through selective attention and maintenance rehearsal. Chunking and elaborative rehearsals help information move from STM to LTM.
• Experiments testing the stage model of memory have shown mixed results regarding the distinction between STM and LTM.

Levels of Processing

In 1972, Craik and Lockhart proposed the levels of processing view, suggesting that how new information is perceived, analyzed, and understood determines how well it will be retained. Although the theory has evolved, its core idea remains the same.

Multiple Levels of Analysis

• Information can be processed at different levels, from shallow to deep.
• Shallow Processing: Involves analyzing physical or structural features of the information.
• Example: Focusing on the shape of letters in the word "cat," regardless of whether it is written in capital or small letters, or the color of the ink.
• Intermediate Level: Involves phonetic processing, where the focus is on the sounds associated with the letters.
• Example: Recognizing "cat" as a word with three specific letters and their associated sounds.
• Deep Processing: Involves semantic processing, where the meaning of the information is analyzed and understood.
• Example: Thinking of a cat as an animal with fur, four legs, a tail, and as a mammal. Imagining a cat and connecting that image to personal experiences.

Memory Retention

• Shallow and Intermediate Processing:
  • Memory produced at these levels is fragile and likely to decay quickly.
• Deep Processing:
  • Information processed at the semantic level is retained for a longer period.
  • Deep processing leads to memory that resists forgetting.

Implications for Learning

• Focus on Meaning:
  • Understanding information in terms of its meaning enhances long-term retention.
  • Rote memorization leads to shallow processing and is less effective for long-term memory.
• Elaborate the Meaning:
  • When learning new material, focus on elaborating the meaning of its contents.
  • Relate new information to other facts, concepts, and personal life experiences.

Types of Long Term Memory

• Declarative Memory pertains to information about facts, names, dates, etc. For instance, knowing that a car has four wheels or that Valentine's Day falls on the 14th of February are examples of declarative memories. Such memories can be described verbally.
• Procedural Memory refers to memories related to procedures for performing various tasks, such as driving a car or baking a cake. The contents of procedural memory are more practical and application-based, and thus, are not easily described.

Declarative Memory

Episodic Memory

Semantic Memory

Nature and Causes of Forgetting

• Information that we have stored in our long-term memory is lost somehow.
• The information that needs to be learned was not memorized sufficiently.
• Incorrect encoding of the information.

Key Theories of Forgetting:

Ebbinghaus's Experiments:

• Hermann Ebbinghaus conducted the first systematic studies on forgetting by memorizing lists of nonsense syllables (e.g., CVC trigrams like NOK or SEP).
• He measured how many trials it took to relearn the same list after varying time intervals.
• Forgetting Curve: Ebbinghaus observed that the rate of forgetting is highest in the first nine hours, especially within the first hour. After that, the rate slows down and stabilizes, as depicted in the Forgetting Curve.

Trace Decay Theory:

• Also known as the disuse theory, it suggests that memories form physical changes in the brain called memory traces.
• When these traces are not used over time, they decay and become inaccessible.
• Criticism: Experiments showed that people who remain awake after learning forget more than those who sleep, contradicting the trace decay theory.

Interference Theory:

• This theory posits that forgetting occurs because different pieces of information in the memory interfere with each other during recall.
  Types of Interference:
• Proactive Interference: Earlier learning interferes with new learning (e.g., knowing English makes it hard to learn French).
• Retroactive Interference: New learning interferes with recalling previous information (e.g., learning French makes it hard to recall English words).
  Example Experiment: Asking someone to learn two lists of nonsense syllables (A and B) and then recall list A. If list B items are recalled instead of list A, it demonstrates interference.

Retrieval Failure Theory:

• Proposed by Tulving and associates, this theory suggests that forgetting occurs due to the absence or inappropriateness of retrieval cues during recall.
• Retrieval Cues: These are aids that help recover stored information.
• Example: Memorizing a list of words from different categories. If you struggle to recall them later, providing the category names can act as effective retrieval cues, significantly improving recall.

Repressed Memories:

• Sigmund Freud suggested that traumatic experiences can be repressed into the unconscious, making them inaccessible to conscious recall.
• Psychological Amnesia: Severe stress or trauma can lead to a fugue state, where a person assumes a new identity and forgets their previous life.
• Stress-Induced Forgetting: High stress and anxiety, such as during exams, can cause temporary forgetfulness.

Enhancing Memory 

• Mnemonics using images: To remember information, create vivid and interactive images of the material. There are two types of techniques in this category:
• Keyword Method: This method identifies an English word that sounds similar to a foreign language word, which becomes the keyword. It is an easier method than rote learning.
• Method of Loci: This method helps in learning things in a specific order by visualizing familiar places or objects and associating them with the material to be remembered.
• Mnemonics using organization: This category refers to imposing a particular order on the material to be remembered. The techniques under this category are:
  • Chunking: This method involves combining smaller units to form larger chunks using organizational principles.
  • First Letter Technique: This method involves picking the first letter of each word to be remembered and arranging them logically to form another word or sentence.
  • Deep Level Processing: Processing information in terms of meaning leads to better memory. This method involves asking several questions related to the information.
  • Retrieval Cues: Providing oneself with sufficient retrieval cues makes it easier to remember information by linking it to the retrieval cues.