Introduction and Overview Learning Objectives

Describe four different approaches to studying cognition

Experimental Cognitive Psychology

Behavioural data from controlled studies of normal subjects
Reaction Times – time that elapses from the onset of a stimulus until a response
Errors
Process and representational format
- Stage analysis – what are the sequence of steps for performing a task?
  - Donders (1868) – each stage receives information from the previous stage, transforms it, and sends it to the next stage
  - Dual route model of reading
    - Stage 1: recognized the letters
    - Stage 2: Access mental lexicon
    - Stage 3: say the sound
    - Time of stage 1 (vision) + time of stage 2 (mental process) + time of stage 3 (sound) = total amount of time
  - Coding analysis – what is the nature of a mental representation?

Studies of individual brain damaged patients and people with various disorders
Associations – the relationship formed between different things – able/not able to do one thing, able/not able to do another
Dissociations – able to do one thing but not another
Double Dissociations – occurs when one person can do one thing but not another, and another person can do the thing the first person couldn’t, but can’t do the thing they could

Develops computational models of cognition often to imitate results from experiments
Computational (mathematical/computer) models of cognition

Describe top-down and bottom-up processing

Bottom-up processing – processing that is directly influenced by environmental stimuli
Top-down processing – processing that is influenced by internal subject factors  Stimulus – processing – response

How do reaction times and errors help us test models of information processing?

General assumption for reaction time and information processing – the longer the response, the more processing is required
- The longer the time, the more steps
Types of errors may give rise to the nature of the steps
- Errors can indicate personal strategies of processing information (e.g. the way someone figures out how to multiply 8 by 3)
- Errors could also indicate developmental deficiencies

Discuss with examples how association and dissociation logic can be used in cognitive neuropsychology to understand cognitive processing

If I’m good at one thing (e.g. quick at visual processing), I tend to be good at another (quick at recognizing faces)
Another association – if I lose my ability to read, I also lose my ability to process faces
Can’t conclude that much as limited info
- May be due to shared functions
- May be due to anatomical similarity of processing areas (i.e. easier to damage different functions in similar areas)

 After brain injury, patient X was able to read words, but not recognize faces  Conclusions:

Perhaps there is a face processing module
Perhaps faces are just harder to process than letters – hence the same amount of degradation might affect faces more than words

After a brain injury, patient X was able to read words, but not recognize faces, while patient Y was able to recognize faces, but not read words  Conclusions:
- This suggests that there must be some aspect of processing that is not shared between the two tasks
Problems with DD logic:
- Assumes everyone uses the same cognitive architecture – e.g. maybe person Y has a special face module and patient X doesn’t
- Assumes that you can’t build new pathways or modules