(c) 7 ± 2 items

George Miller (1956) proposed that the capacity of short-term memory is approximately 7 ± 2 items (i.e., between 5 and 9 items). This is known as “Miller’s Magic Number.”

(b) Proactive interference

Proactive (forward-acting) interference occurs when previously learned information interferes with the ability to learn and remember new information.

(c) Procedural memory

Procedural memory is memory for motor skills and actions that are performed automatically. Riding a bicycle is a learned skill that, once acquired, can be performed without conscious effort.

(b) Craik and Lockhart

Craik and Lockhart (1972) proposed that memory depends not on which store information is in, but on how deeply it is processed — from shallow (physical) to deep (semantic) processing.

(b) Mnemonic technique

The method of loci involves mentally placing items to be remembered at specific locations along a familiar route. During recall, one “walks” through the route and retrieves the items at each location.

Both are types of declarative (explicit) memory — they can be consciously recalled and stated.

Proactive interference occurs when previously learned information interferes with the ability to remember newly learned information.

• Example: You recently changed your phone number. When someone asks for your new number, you accidentally give them your old number. The old number (prior learning) interferes with recalling the new one.

Retroactive interference occurs when newly learned information interferes with the recall of previously learned information.

• Example: After learning your new phone number, you now have difficulty remembering your old number. The new learning has retroactively interfered with the old memory.

Both types demonstrate that forgetting is often not due to the memory disappearing, but rather to competition from other memories.

Mnemonics are memory aids — strategies and techniques that help organise and encode information to make it easier to store and retrieve.

Two techniques:

1. Acronym: Creating a word from the first letters of items to be remembered.

   • Example: VIBGYOR — Violet, Indigo, Blue, Green, Yellow, Orange, Red (colours of the rainbow)

2. Method of Loci: Mentally placing items to be remembered at specific locations along a familiar route. To recall, one mentally “walks” through the route and retrieves the items.

   • Example: To remember a shopping list (milk, eggs, bread), imagine a bottle of milk at your front door, eggs on the staircase, and bread on the dining table.

The Atkinson-Shiffrin model (1968) proposes that memory consists of three distinct stores through which information flows sequentially:

1. Sensory Memory:

• Holds raw sensory information for a very brief period
• Duration: Less than 1 second for visual (iconic memory) and about 3–4 seconds for auditory (echoic memory)
• Capacity: Very large
• Function: Acts as a buffer; only information that is attended to passes to the next stage
• Information not attended to is quickly lost

2. Short-Term Memory (STM):

• Temporary storage for information currently being processed
• Duration: About 15–30 seconds without rehearsal
• Capacity: 7 ± 2 items (Miller’s Magic Number)
• Encoding: Primarily acoustic (sound-based)
• Can be maintained through rehearsal (repeating the information)
• Chunking can increase effective capacity by grouping items into meaningful units
• Information encoded through elaborative rehearsal moves to LTM

3. Long-Term Memory (LTM):

• Relatively permanent storage with potentially unlimited capacity
• Duration: From minutes to a lifetime
• Encoding: Primarily semantic (meaning-based)
• Types include episodic (personal events), semantic (facts), and procedural (skills)
• Retrieval requires appropriate cues; information may not be permanently lost — just inaccessible

Flow of information: External stimulus → Sensory memory → (attention) → STM → (encoding/rehearsal) → LTM → (retrieval) → STM

Evaluation:

• The model provides a clear, testable framework
• Criticised for being too simplistic — STM is now understood as “working memory” with multiple components

Forgetting is the inability to retrieve information that was previously encoded and stored in memory.

1. Trace Decay Theory:

• Memories create a physical or chemical trace in the brain
• If these traces are not used or rehearsed, they gradually weaken and fade over time
• Most applicable to short-term memory
• Ebbinghaus’s Forgetting Curve: Most forgetting happens rapidly after learning (within the first hour), and then the rate of forgetting slows down
• Criticism: Does not explain why old memories can sometimes be retrieved after long periods

2. Interference Theory:

• Forgetting occurs because other memories interfere with retrieval
• Proactive interference: Old memories interfere with the recall of new ones
  • E.g., Your old address makes it hard to remember your new one
• Retroactive interference: New memories interfere with the recall of old ones
  • E.g., After learning a new password, you forget the old one
• Interference is greater when the competing materials are similar

3. Retrieval Failure:

• Information is in LTM but cannot be accessed because the appropriate cues are absent
• Encoding specificity principle (Tulving): Retrieval is most successful when the conditions at retrieval match the conditions at encoding
• Context-dependent memory: Recall is better in the same physical environment where learning occurred
• State-dependent memory: Recall is better when the internal state (mood, physiological condition) matches
• Tip-of-the-tongue (TOT) phenomenon: The feeling of knowing the information but being unable to retrieve it

4. Motivated Forgetting (Repression):

• Proposed by Freud — painful or traumatic memories may be pushed into the unconscious mind
• Controversial — difficult to verify scientifically

Strategies to reduce forgetting: Regular review, spaced practice, deep processing, using mnemonics, adequate sleep.

(a) Both A and R are true and R is the correct explanation of A

According to the levels of processing theory (Craik & Lockhart), information processed at a deeper (semantic) level — focusing on meaning — results in stronger, more durable memories than information processed at a shallow level (focusing on physical appearance or sound). The reason correctly explains why deep processing enhances memory.

(i) Strategy A (reading three times in one day) is the least effective for long-term retention because:

• It involves massed practice (cramming), which leads to rapid forgetting
• The processing is likely to be shallow (maintenance rehearsal — repeating without thinking about meaning)
• According to Ebbinghaus’s forgetting curve, information not deeply encoded is forgotten rapidly

(ii) Strategy B uses the acronym technique — a mnemonic device where the first letters of items are combined to form a memorable word.

(iii) Strategy C involves deep (semantic) processing, as Priya is engaging with the meaning of the material through discussion and connecting it to real-life examples. This is effective because:

• Elaborative rehearsal creates more connections (associations) with existing knowledge
• According to the levels of processing theory, semantic processing leads to the strongest and most durable memories

(iv) Spaced practice (distributed learning):

• Instead of studying everything in one session, Priya should study the material over multiple shorter sessions spread across several days
• Psychological basis: Research consistently shows that spaced practice leads to better long-term retention than massed practice (the spacing effect). This allows time for memory consolidation and reduces interference between sessions.

(i) This is proactive interference — the old password (Delhi123) is interfering with the recall of the new password (Mumbai456). Previously learned information is disrupting new learning.

(ii) This is retroactive interference — the new password (Mumbai456) is now interfering with the recall of the old password (Delhi123). Newly learned information is disrupting the recall of previously learned information.

(iii) This example illustrates that forgetting is often not because memories have been permanently erased from the brain, but because other memories compete with and interfere with retrieval. The type of interference depends on the direction:

• Old → New = Proactive
• New → Old = Retroactive

Both the old and new passwords were stored in memory, but they interfered with each other’s retrieval at different points in time.