Attention

  1. Introduction
  2. Early vs. Late Selection
  3. Broadbent's Model
  4. Treisman's Model
  5. Norman's Model
  6. Resolution

I. Introduction

A. The bottleneck in information processing

B. Demonstration

Read the bold print.

Somewhere Among hidden the in most the spectacular Rocky Mountains cognitive near abilities Central City is Colorado the an ability old to miner select hid one a mes sage box from of another. gold. We Although do several this hundred by people focusing have our looked attention for on it, certain they cues have such not as found type it style.

What do you remember from the regular print text? What does this tell you about selective attention?

II. Early vs. Late Selection

A. Early selection

B. Late Selection

III. Broadbent's Model

A. Properties:

  1. Early selection
  2. Selection (filtering) is based on physical properties of the stimulus (e.g., pitch, loudness, etc...).
  3. Attention is directed to information that passes the filter or to physically salient information that leads to a shift in attention.
  4. Only one input channel can be processed at a time.
  5. It takes time to shift attention.

B. Physical Analogy:

C. Supporting Evidence:

Broadbent (1954): split span experiment

Stimulus presentation

ear #1   ear#2
7          8
4          2
3          6


Responses

	condition 1:  recall by ear:  "743-826"
	condition 2:  recall in order:  "78, 42, 36"
Here are some sample trials for you to try. Try to recall some of them as in condition 1 above, and others as in condition 2.

Trial 1: binaural (aiff) (.wav)
Trial 2: binaural (aiff) (.wav)
Trial 3: male/female (aiff) (.wav)
Trial 4: male/female (aiff) (.wav)

Broadbent's Results:

Condition 1: 65% correct

Condition 2: 20% correct

D. Problems with the model:

1. "cocktail party" phenomenon

2. Moray's experiments

a) shadowing:
b) information retained from the unshadowed ear included:

IV. Treisman's Model

A. Properties:

  1. Early selection
  2. Selection (attenuation) is based on physical properties of the stimulus (e.g., pitch, loudness, etc...).
  3. Attention is directed toward information that reaches a threshold of recognition.
  4. Several inputs can be processed at a time.

B. Diagram of the model:

C. Supporting Evidence (Treisman, 1960)

Ear # 1  The body was buried on Moll Legg Island beside the
            ahead  listen  aim  somebody  North Carolina
Ear # 2  We point  veiled their  many wife  he tussles last 
            other grave  and a cross put at its head.
Listen to what this sounds like:
male/female (aiff) (.wav)
binaural (aiff) (.wav)

V. Norman's (1968) Model

A. Properties:

  1. Late selection: i.e., all stimuli are processed to stimulus recognition.
  2. Selection (pertinence) is based on the importance of the recognized item.
  3. Memory processes (e.g., rehearsal) are devoted to selected inputs.

B. Diagram of the Model

VI. Resolution

A. Treisman & Geffen (1967)

Method

Task 1: shadow message in one ear.

Task 2: subjects asked to tap pencil when they heard the target word "green."

Results:

tapping to green in shadowed ear: 87%

tapping to green in the other ear: 8%

B. Conclusions

  1. Partial selection occurs early in the information processing stream.
  2. Selection is not the result of action of a simple physical filter.
  3. The selection process is sensitive to the past experiences of the subjects and the context of the recognition task.
  4. Treisman's attenuator model captures these properties.

Return to Table of Contents.