University:
Loyola University Maryland
Course:
PY 222 | Cognitive Psychology
Academic year:

2023
Views:

348

Pages:

4
Author:

esfredint7qo

Cognitive Psychology Today’s Topic: Short-term-memory (Week 4) After today’s lecture, you will learn about: 1. The similarities and differences between short-term memory and working memory. 2. The methods used to measure STM and WM capacity. 3. The key theoretical models that explain how STM and WM work. Atkinson & Shiffrin’s model of memory (1968) There are 3 types of memory: 1. Sensory memory 2. Short-term memory 3. Long-term memory Sensory memory • stores information that we receive from the environment – visual information in an iconic store – auditory information in an echoic store • has large capacity (full perceptual detail is preserved) • but decays rapidly Short-term memory • only limited information from sensory memory is transferred to STM – c.f. Broadbent’s model of attention from Lecture 3/FoC Ch 3 – information not attended to will be lost • STM has limited capacity Long-term memory • rehearsal is necessary to transfer information in STM to LTM – information in STM easily displaced by new incoming sensory information – rehearsal = “subvocal repetition of verbal material” Evaluation This is very dated model! But it is relevant for setting the theoretical framework for memory research. Nevertheless we should also be aware of its shortcomings. 1. Not true that unattended information is never processed into STM: We know from research in attention (Ch3/L3) that unattended stimuli can be processed without our awareness. 2. Only allows 1-way flow of information from SM -> STM -> LTM: We know from research in perception (Ch2/L2) that bottom up and top down information (i.e., knowledge stored in LTM) can interact to influence perceptual processing. 3. Focus on storage capacity vs. processing of stimuli 4. Coarse-grained view of LTM (unitary store, rehearsal as the only form of learning permitted): Next lecture we will learn more about the LTM and see that it is a lot more complex than Atkinson & Shiffrin suggested Measuring STM capacity How many items of information can we store? How long can the information stay? How many? Memory span is the number of items that one can recall immediately in the correct order of its presentation. General approach: Present items in a random (non-meaningful) order, see how many can be recalled. In these studies, the items could be letters, digits, words… 7+2 or 4+1? According to Miller (1956), the STM capacity is about 7 items, plus or minus 2. According to Cowan (2001), it is about 4 items, plus or minus 1. Who is right? Items or Chunks? Miller’s estimate could be an overestimation because people are able to form chunks from grouping letters/digits as a single unit, and leverage on them to increase their span. For example: AYECTETPE (9 items) vs. AYE_CTE_TPE (3 chunks) Cowan (2001)’s experimental design (with fast presentation of digits and unpredictable recall points) prevented participants from forming chunks and leveraging on their LTM. Not all chunks are the same! Example 1: Word length effect Larger word span for short words than long words. Example 2: Cultural differences in digit span Chinese speakers have a larger digit span than English speakers.