Cognitive ErgonomicsMega Bagus Herlambang, ST, MT

IntroductionPerceive, think, rememberHIP (Human Information

Processing) is represented by different stages :1. Perception of

information about the environment

2. Central processing or transforming that information

3. Responding to that information

HIP Model (Wickens, 1992)

MemorySensory MemoryWorking Memory (short-term memory)Long-term memory

Sensory MemoryEach sensory system has a corresponding

sensory memory which is also termed a sensory register or sensory store.

Each sensory memory briefly stores and transforms the stimuli it receives into a form that can be processed by short-term memory.

Short-term MemoryKnown as Working MemoryShort-term memory (STM) receives, holds,

and processes information from the sensory registers.

Processing in STM is necessary before information can be transferred and retained in long-term memory.

STM also retrieves information from long-term memory when needed.

Long-term MemoryLong-term memory (LTM) receives

information from short-term memory and stores it indefinitely.

LTM capacity is considered unlimited for practical purposes. 

LTM holds all of the learning and memories of our life experience. It is essentially our life "database.“

The retrieval and processing of long-term memories by STM enables us to function in the world.

Memory – Basic ProcessesEncodingMaintenanceRetrieval

Perception (1/3)Perception proceeds by analyzing the raw

features of a stimulus or event.The stimulus / event can be a word, a symbol,

a sound, etc.Every event could consist of a huge

combination of features.Perception proceeds by three processes

1. Bottom-up2. Top Down3. Unitization

Perception (2/3)We do not experience

reality exactly as it exists, but as our experience and memories cause us to perceive it. 

Our perception involves more than the receipt of sensory information.

We must attend to, select, organize, and interpret this information in order to meaningfully recognize objects and events in our environment.

Guidelines in perception (3/3)1. Maximize bottom-up processing2. Maximize automaticity & unitization3. Maximize top-down when bottom-up may be

poor

Joko susilo joko_susilo@yahoo.com 081320930912

Joko susilo joko_susilo@yahoo.com 081320930912

Joko susilo joko_susilo@yahoo.com 081320930912

Working Memory (1/3)Transient & limited holding a small amount of

information that may be rehearsed by other cognitive process.

Temporary store that keeps information active while we are using it or until we are using it.

The capacity of working memory to be around 7 2 chunks.

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Working Memory (2/3)The strength of information in working

memory decays over time, unless it’s periodically reactivated (maintenance rehearsal).

Confusability & similarity affect working memoryEGBDVC ENWRUJ

Guidelines in Working Memory (3/3)1. Minimize working memory load2. Provide visual echoes3. Minimize confusability

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4. Avoid unnecessary zeros in codes to be remembered.

5. Consider working memory limits in instructions

Before doing X and Y, do A

Do A, then do X and Y

Long-term Memory (1/4)We need a mechanism for storing information

and retrieving it at later times.The associative nature of long-term memory

is based in the brain's neural networks. It is estimated that there are over 100 billion

neurons in the brain which can form many trillions of potential interconnections.

These neurons form complex webs that enable the brain to perform as an extremely powerful, parallel processor.

Long-term Memory (2/4)The more we recall

and use specific memories or information the easier recall of the information becomes.

Overtime with repeated recall some memories undergo change.

Types of knowledge & memory (3/4)1. Declarative or explicit knowledge

a. Semantic Memory This is information that has lost its time reference. We know the information, facts, and concepts, but we

cannot remember where or when the information was acquired.

b. Episodic Memory These memories are associated with a specific time or

episode in our life and is in serial form.

2. Procedural or implicit knowledge Dynamic knowledge of how to do things in the world. Examples are: driving, biking, typing, the physical

component of writing, or playing tennis.

Forgetting (4/4)1. Encoding failure

If perceived information is not successfully encoded by working memory for entry into long-term memory, the information will be lost. 

2. Interference Interference occurs when new information interacts with previously

learned information. Retroactive : New information interferes with prior learning. Proactive : Old information interferes with new information being

learned.

3. Retrieval Failure Trace Decay

This occurs when the information in memory has not be accessed or used for a period of time.

Lost LinkageThe same principle of fading or decay from disuse applies, but it applies to the link instead of the stored memory.

Attention Resources (1/5)

Attention Resources (2/5)

Automatic Processing (3/5)Information can also be

processed with little or no allocation of attention resources.

When skills are learned to the point of automaticity, the load on working memory typically is reduced by 90%.

Tasks learned to the point of "automaticity" are not easily changed by conscious control

Cognition, attention & design (4/5)Understanding how attention works in

cognitive processing is important in human factors design.

Some pertinent conceptual questions are :1. How well can the user concentrate and

screen out conflicting messages?2. How much information can the user attend

to at one time?3. How does attending to one input affect the

user's ability to deal with another input?

Cognition, attention & design (5/5)

Mental Workload MeasurementSubjective

1. NASA-TLX (The National Aeronautical and Space Administration Task Load Index)

2. Borg Scale3. SWAT (Subjective workload assessment technique)

Objective1. Heart Rate (ECG, HRM)2. Brain signal (EEG)3. Eye flickering (Flicker test)4. Pupil diameter5. Hormone levels

Mental Fatigue ?Decreasing

Affects HR

Low coordination

TUGAS (10 poin nilai UTS)Sesuai dengan kelompok lingkungan fisik, lakukan percobaan sebagai berikut :Lakukan eksperimen sederhana sebanyak 3

aktivitas yang berbeda. 2 orang melakukan masing-masing eksperimen.

1 aktivitas mental1 aktivitas fisik1 aktivitas kombinasi (fisik + mental)Masing-masing aktivitas dilakukan selama 30 menit,

dan berurutan.Lakukan penilaian NASA-TLX dan Borg 10 Scale

untuk setiap selesai melakukan 1 aktivitas.

Lakukan analisis statistik untuk eksperimen tersebut, yakni :1. Lakukan uji korelasi antara skor NASA-TLX

dengan skor Borg.2. Lakukan analisis di tiap skala NASA-TLX,

yaitu MD, PD dst, lakukan analisis korelasi tiap skala NASA-TLX terhadap Borg scale.

3. Lakukan analisis terhadap 2 hasil di atas, dan tentukan perbedaan mendasar antara NASA-TLX dan Borg Scale, dan tentukan aplikasi masing-masing.