SET B — SENSORY & WORKING MEMORY

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What is iconic memory?

A brief visual sensory memory for externally presented stimuli that reflects ongoing perceptual processing in the visual cortex (occipital lobe).

What are the key properties of iconic memory?

Raw visual form before semantic meaning; Duration ≈ 250–300 ms unless masked; Extremely large capacity; Reflects continued perceptual processing after stimulus offset

What is the key functional role of iconic memory?

It reflects continued perceptual processing in visual cortex after the stimulus disappears.

Why is iconic memory described as “pre-semantic”?

Because it represents raw visual form before meaning or identification is assigned.

Why does masking eliminate iconic memory?

Because new visual input overwrites ongoing perceptual processing in visual cortex.

What is echoic memory?

Auditory sensory memory that preserves sounds for ~1–2 seconds

What is short-term (working) memory?

A limited-capacity system that temporarily holds and manipulates information.

Why did lecture frame working memory as a workspace?

Because its defining feature is manipulation and comparison of active representations

Digit load logic

If WM capacity is limited adding a digit span task should impair reasoning and comprehension

Grammatical reasoning task

A reasoning task used to test the dependence of cognition on working memory

Implication for the modal model (BH)

A single unitary short-term memory system cannot explain cognitive performance

Baddeley & Hitch (1974) – Dual-task prediction

If short-term memory is a single unitary system then holding a heavy digit load should severely impair reasoning and comprehension tasks because both storage and processing rely on the same limited-capacity store.

Baddeley & Hitch (1974) – Key finding

Holding a 6-digit memory load greatly impaired digit recall but caused only minimal slowing and accuracy loss in concurrent reasoning and comprehension tasks.

Large load = low digit recall but mostly good reasoning and comprehension too

Why were Baddeley & Hitch’s findings surprising?

A unitary short-term memory system was assumed to manage both storage and processing

Theoretical conclusion from Baddeley & Hitch (1974)

Working memory is not a single system but has specialized storage systems (e.g. phonological loop) and a separate central executive responsible for processing.

Critical distinction established by Baddeley & Hitch (1974)

The systems for storage of information and processing of information rely on semi independent systems, not a single short term store

Why did reasoning remain relatively intact under digit load?

Reasoning tasks mostly rely on central executive which stayed available even when phonological store was taken by digit storage.