Portions
- Types of Attention: Selective attention and Divided attention
- Theories of Attention: (a) Theories of Selective Attention: Broadbent’s model & Triesmann’s model, (b) Theories of Divided Attention: Kahneman’s model
- Perceptual Processes: Perception: Meaning and Definition
- Gestalt laws of Perceptual Organisation
- Depth Perception: Monocular and Binocular cues for depth perception
- Constancy: Size Constancy, Brightness Constancy
- Movement Perception: Real and Apparent Motion
- Visual illusions: Muller-Lyer Illusion, Moon Illusion
- Extra Sensory Perception
Attention
Meaning
[! QUESTION] What is Attention? Attention is a cognitive process of selectively concentrating on a discrete aspect of information, whether considered subjective or objective, while ignoring other perceivable information
[! TLDR] TLDR; Concentrating on one task while ignoring other stimuli (filtering) Prioritize stimuli based on goals and needs
Factors Affecting Attention
| Internal aka subjective | External |
|---|---|
| Interest | Nature |
| Motive | Intensity |
| Mental Set | Size |
| Past Exp | Contrast |
| Emotions | Repetition |
| Habits | Novelty |
| Aim | Location |
| Meaningfulness of material | Movement |
Mnemonic
MMM, PIE AH? → Internal CRIMSoN NL → External
Internal Factors
AKA Subjective factors. Depend from person to person.
- Interest |
- Motive | basic needs and motives > other ones; what we want to do; task at hand
- Mental Set | readiness to respond; expecting a stimulus
- Past Experiences |
- Emotions |
- Habits |
- Aim |
- Organic state| Hunger, sleep, etc
External Factors
- Nature | Pic >>> Words
- Intensity | Louder >> Softer
- Size | Larger >> Smaller
- Repetition | More times >> Less times
- Contrast | Stark difference, can be in colours or concepts
- Novelty | Something new, out of place
- Location | Center >> other places
- Movement | Moving >> Static
Types of Attention
1. Based on Needs
a) Sustained Attention it is the ability to pay attention to only one task by consciously concentrating on that task only for a long time enough and by avoiding all other forms of distractions or deviations. Eg - reading a book, memorizing a chapter or following a classroom lecture.
b) Selective Attention: In this case, the listener chooses to pay attention to only a specific stimulus which is present in the environment while ignoring the other stimuli. This kind of attention does not depend on the stimulus but depends essentially on the attentive capabilities of an observer. Choosing to focus on a friend’s voice (while in a crowd with them)
c) Divided Attention: In case of divided attention, the user pays attention to two or more tasks at the same time and is also sometimes regarded as Multi-tasking which involves juggling between two or more than two tasks at the same time. Divided attention uses a lot of mental focus; ergo person may get exhausted very quickly. Function is impaired. Split our attention
d) Alternating Attention: Though this attention can be closely related to divided attention, but is different as in case of divided attention we split our attention between two tasks, while in case of alternating attention, the entire attention is shifted from one task to another or is done alternately.
2. Based on Volition
a) Voluntary (aka volitional) requires will and determination not spontaneous conscious effort goal based eg - doing math
b) Involuntary (aka non-volitional) does not involve any role of will instinctual spontaneous enforced attention eg - mom hearing baby
Auditory - ability to pay attention to auditory stimuli, related to temporal Visual - visual stimuli, related to spatial
Models Of Attention
Selective
1. Broadbent’s Model of Selective Attention | Early Selection Theory
graph LR
one[Attended Stimuli]--> A
two[Unattended Stimuli]--> A
A[Sensory Register] --Attended--> B(Selective Filter)
L[Selective filter removes <br> the unattended stimuli <br> completely]
A--Unattended-->B
B --> |Bottleneck| C(Working Memory)
C --> D(Other Cognitive Functions)
All stimuli is registered in the sensory register, and then they go through the selective filter which filters out based on physical characteristics After selective filter, meaning is assigned to the stimuli and then processed
selection of stimuli for processing occurs before stimulus identification (Early Selection)
Bottleneck theory - individuals have a limited amount of attentional resources that they can use at one time
2. Treisman’s Model | Attenuation Theory
Attenuation - the lessening or weakening in the intensity, value, or quality of a stimulus
unattended messages are attenuated or processed weakly but not entirely blocked from further processing Thus, a significant word (e.g., the person’s name) would have a low threshold and, when mentioned, would be recognized even if that person’s attention is concentrated elsewhere (Cocktail Party Effect)
graph LR
one[Attended <br> Stimuli]--> A
two[Unattended <br> Stimuli]--> A
A[Sensory <br> Register] --Attended--> B(Attenuator)
L[Attenuator weakens <br> the stimuli and <br> sends it to the <br> dictionary unit]
A--Unattended-->B
B --> |Attended| C(Dictionary <br> Unit)
B -.-> |Weakened <br> Unattended| C
C --> D(Other Cognitive Functions)
style L fill:#ebccff;
Divided
3. Kahneman’s Model
Daniel Kahneman Attention is scarce. Some tasks require more, some less. We can do multiple tasks at once as long as it is within the capacity of attention. mental “juggling” mental efforts total available processing capacities depends on arousal and other factors Central Allocation Policy
You can do several things at once, but only if they are easy and undemanding. More than once as long as it is within the processing capacity available
Easy or diff Similarity of tasks Practice
graph RL
1[Inputs]--> A
A[Arousal] --> B(Central <br> Processor)
B --> C(Evaluation of demand)
C --> R(Response)
subgraph three [Allocation of Resources]
ed[Enduring Disposition / Automatic ]
mi[Momentary Intention]
ed --> B
mi --> B
end
m[Attentional Capacity depends on arousal]
C --> A
C --> B
Interference is the term used to describe when a
person has a hard time attending to two stimuli at a
time. We see interference when the brain is only able
to process a certain amount of information
Momentary intention:
A conscious decision to
allocate attention to certain aspects of the
environment.
Enduring Disposition
An automatic influence where people direct their attention.
Summary of Models
| Model | AKA | Principle | Main Component |
|---|---|---|---|
| Broadbent’s Theory | Early Selection | Based on physical properties, filtered out before identification, bottleneck theory | selective filter |
| Treisman’s Theory | Attenuation Theory | Based on threshold, unattended stimuli is weakened but processes, cocktail party | attenuator, dictionary unit |
| Kahneman’s Theory | Divided Attention | Can do multiple things at once depending on capacity; Central Allocation Policy; IME | central processor |
Broadbent, Treisman → Selective Attention Theory Kahneman → Divided Attention Theory
Broadbent → said that filtered out by physical properties, semantic analyis is not done, meaning is not assigned to unattended stimuli,
→ Sensory Register →Selective Filter →Working Memory → Other Cog functions
Treisman → signal is weakened, everything is processed, some words have lower thresholds than others, CPE
→ Sensory Register → Attenuator → Dictionary Unit → Other Cog functions
Kahneman → CAP, can attend to multiple stimuli, each task requires diff amount of effort
→ Arousal → Central Processing Unit → Evaluation of demand → Response --------------------| -------------------- Momentary Intention - (Allocation -------------------- Enduring Disposition - of resources)
Perception
Definition - the organization, identification, and
interpretation of sensory information to
represent and understand the environment.
Sensation: the process by which our sense organs
receive information from the environment.
we gain information about the properties and elements of the environment helps us navigate and understand the world around us helps us interact w environment helps us survive
Psychophysics is the study of the relationship between the physical aspects of stimuli and our psychological experience of them
Senses - (five senses) proprioception social cues
Absolute threshold: the smallest intensity of
the stimulus that must be present for it to be
detected.
Difference threshold: the smallest level of
stimulation required to sense that a change has
occurred.
Just noticeable difference: The minimum
stimulation required to detect the difference
between the two stimuli.
Adaptation: An adjustment in sensory capacity
following prolonged exposure to stimuli.
top-down processing Perception that is guided by higher-level knowledge, experience, expectations, and motivations
bottom-up processing Perception that consists of the progression of recognizing and processing information from individual components of a stimuli and moving to the perception of the whole.
Gestalt Laws of Perceptual Organisation
Llusion
a misrepresentation of a “real” sensory stimulus an interpretation that contradicts objective “reality” as defined by general agreement universal unlike hallucinations real stimuli, wrong interpretation
Monocular and Binocular Cues
flowchart TD
Depth[Depth Perception] ---> a[monocular] & b[binocular]
n[the visual ability to perceive <br> world in 3D <br> ability to gauge <br> how far an object is ]
a --- d[one eye] --- f[bad at depth]
b --- e[two eyes] --- h[diff angles helps]
n --- m[relies on the convergence <br> of both eyes upon a <br> single object]
m --- x[navigating, determing dist, <br> avoiding, etc]
lateral displacement of the eyes that provides
two slightly different views of the same object
allowing STEREOPSIS / two images which helps
us discern depth better
| Mono Cues | Bino Cues |
|---|---|
| Relative Size size constancy - smaller = far | Retinal Disparity |
| Interposition Overlapping objects, object that overlaps = closer | Binocular Convergence |
| Linear Perspective converging of parallel lines | |
| Aerial scattering of blue light; far hill appears blue closer hill more contrast | |
| Light and Shade Highlights and shadows help us understand dimensions of object, where light is coming from, etc | |
| Ponzo Illusion |
Perceptual constancy
refers to the tendency to perceive an object you
are familiar with as having a constant shape, size, and brightness
e.g. - moon illusion
Size Const. Shape Const. Colour Const.
Real and Apparent motion
Apparent Motion -
- Phi Phenomena - bulbs in row, flashing, feels like moving
• Motion after effect (MAE)
• Induced motion - train moving next to you, you feel like you are moving • Autokinetic movement - dark room, singular light, feels like moving