1. Goals for Today’s Class
To introduce “attention” as a psychological phenomenon
To contrast serial and parallel processing
To demonstrate how experimentation can be used to understand mental processes

2. What is Visual Search?
One of the most widely used methods of studying visual attention

3. Basic Method of Visual Search
Find target hidden among distractors in multi-element display

4. 2 Processes to Visual Search
Parallel vs Serial Processing
Parallel Processing = Preattentive Processing
Serial Process = Attentive Processing

5. Preattentive Processes
Processes that occur automatically
Processes that apply to all objects in our visual field
Preattentive processes allow us to take in everything around us

6. Feature Search Is there a red T in the display?
Target defined by a single feature
No attention required
Target should “pop out”

7. Attentive Processes
Attentive processes require control on the part of the perceiver
Through attentive processing, we examine one component of the visual field at a time

8. Conjunction Search Is there a red T in the display?
Target is now defined by its shape and color
This involves binding features and should demand attention
Need to attend to each item until target is found

9. Conjunction Search
When there is no single feature that sets the target apart from all of the distracters
Targets are generally more difficult to find in conjunction searches than in feature searches
Difficulty increases with the number of distracters in the display

10. Questions for Today’s Lab:
Which type of search will take longer: Feature search(using parallel processes) or Conjunction search (using serial processing)?

11. Design: 3 IVs: DV: RT task (feature or conjunction search)
display size (4, 8, or 12 items)
trial type (target present or target absent)
DV: RT

12. Response Time Data

13. Conclusions:
As the number of elements in the display increases, so does the response time
Response time is significantly greater during conjunction searches - cannot process everything at once, must process one thing at a time (serial processing)
response time is higher when target is absent