Are verbal and visual information processed the same way?
No
The verbal vs visual experiment with shapes shows its not processed the same.
What is change blindness?
inability to notice salient (cues that stand out) changes in the visual scene
We may feel our brain captures all the cues in the visual environment, but we don’t
When are humans not good at representation of visual information
change blindness - we can’t notice salient cues changing in the visual scene
boundary extension - when we remember a visual scene, we tend to remember a wider angle of the view
When are humans good at representation of visual information
Good at recognising visual scene - the 10000 picture experiment
When do changes stand out or not stand out?
Changes that affect the meaning/gist of the image are more salient (they stand out more)
Changes that affect superficial details are often missed.
When we perceive a visual scene, two types of representations seem to be formed
– Representation of the meaning of the scene
– Representation of surface properties of the scene
(visual details, colour, etc.)
Which one is more likely to be remembered
- The meaning (or the gist) of the scene is very well represented
- The surface properties are not
What is attention?
Attention = mechanism that selects some pieces of information for further processing, out of all available inputs.
- By paying attention to X:
o You effectively choose to process X more deeply.
o At the same time, you ignore other information.
What is attentional bottleneck
A point in the path from sensation to action where people cannot process all the information in parallel
The point where you get overwhelmed in the process and it becomes to much information so you need to focus your attention
Two types of attentional theories
Early selection theories
Late selection theories
Vary depending on how early or late they think
the bottleneck is
What is fille theory (type of early selection theory)
The point of the bottleneck happens early in the stream
Even at the very first sensation stage, the bottleneck happens already - we cant sense all the pieces of information simultaneously, we have to select information for further processing
filter = instead of taking information from the environment, it takes info as it is being filtered through
How was the filler theory (early attentional theory) proposed
Proposed via the dichotic listing task
Participants wear headphones; two different messages played simultaneously (one to each ear).
Instructions:
Attend to one ear (shadowed ear) and repeat that message out loud.
Ignore the other ear.
Findings:
The attended message is remembered well.
The unattended message is poorly remembered (as if it didn’t exist).
This supports early selection (filter blocks unattended input).
Problems with the dichotic listening task
Some information about the unattended message is processed
– Some non-semantic aspects of the message (e.g., whether the voice was male or female) are remembered later
– This does not support the filter theory
Example of this is the Cocktail party effect
– You can hear your name mentioned in a crowded bar,
even when you are talking with someone else - indicates sematic components can slip through
What is the attenuation theory (type of early selection theory)
The same as the filter theory, but instead it’s conceptualised as a leaky filter - information is not fully blocked, it is attenuated (turned down)
Important/meaningful signals (like your name) can still break through.
So early selection still occurs, but the filter is partial, not absolute
What is late selection theory
selection (bottleneck) occurs late in the processing
All things are processed on a semantic level but then only some are chosen for conscious awareness
Bottleneck or selection can occur as late as the response or action stage
Comparing Early vs Late Selection
Setup:
- Same dichotic listening task.
- Participants attend to one ear and shadow that message.
New twist:
- Target words are embedded in the messages.
- Target words can appear in:
- The attended (shadowed) ear.
- The unattended ear.
Task: detect target words, wherever they occur.
Results:
- Target words in attended channel: ~87% detected.
- Target words in unattended channel: only about 8% detected.
Interpretation:
Attending vs ignoring has a large effect, consistent with an early attentional bottleneck (attenuation filter).
What are the two types of attention
voluntary vs reflexive
What is voluntary attention
Top down, goal-directed
What we normally think of when we think of attention
When you choose what to pay attention to
Goal directed because you pay attention to somethingng in order to achieve something - example studying
What is reflexive attention
bottom up, stimulus driven
Attention captured automatically by sudden or salient stimuli.
e.g., sudden loud noise in class.
You don’t intend to attend to it; your system is hijacked because it might be important/dangerous.
Comparison of voluntary vs reflexitive
Voluntary attention:
You control where and how long to allocate attention.
No strong inherent time window.
Reflexive attention:
Driven by stimulus, not your goals.
Has strong temporal dynamics (early facilitation, later inhibition of return).
What is feature integration theory
- Attention acts as a glue that binds features of everyday objects together as one to form a unified object
Without attention you can still register features correctly but you cant bind them together
Dual task performance
- Asks the question, can we do two tasks at once?
- You can effectively do two tasks at once however, there are limits to this cognitive ability
Stroop task
