COG Lecture 3 - Attention 2

• Cognitive psychology conceptualizes human thought as information processing
• Cognitive psychology aims to understand thought processes at a functional level
• Attention is a module that is amenable to the cognitive psychology approach
• Orienting involves a flexible, limited capacity filter limiting the amount of sensory input
• Attention spotlight can be wide/low-resolution or narrow/high resolution

Cocktail Party Effect

• Hearing your name mentioned in a crowded room is an example (99% agreed)

Broadbent's Filter Theory

• States that the filter does not use an attenuation process to partially process unattended stimuli
• The attenuation process was actually introduced by Treisman to explain the "Breakthrough" phenomenon

Illusory Conjunction

• Best described as perceiving a red square and a blue circle when only a red circle and a blue square are present (77% agreed)

Capacity of the Filter

• Sperling (1960) found that even when 12 letters were briefly flashed for 50ms, participants could only report about 4-5 items on average
• Pylyshyn & Storm (1988) found individuals could track up to five moving objects simultaneously with high accuracy (85%) in a multiple object tracking paradigm (MOT)

Fixed or Flexible Capacity?

• Baldauf & Deubel (2010) suggested attention can be flexibly distributed across multiple relevant locations simultaneously during action planning, implying attentional capacity isn't strictly limited to 4 items
• Jans, Peters & De Weerd (2010) suggested typically spatial attention is confined to a single focus

Evidences for an Early Selection

• Neisser & Becklen (1975) found that when participants had to monitor two superimposed episodes, they missed approximately 1/4 events.
• Neisser & Becklen found that attention actively selects relevant information for processing while other information may not be picked up
• In unattended channels only 21% participants noticed unexpected test events
• These studies show selective attention can cause individuals to miss obvious events when focus is elsewhere
• Change Blindness, Inattentional Blindness, and Attentional Blink collectively indicate attention acts as an early filter, which then selects information receives further processing and reaches awareness equitably

Cognitive Neuroscience Evidences for an Early Selection

• Luck, Woodman & Vogel (2000) found ERPs (tiny electrical signals) can be recorded using electrodes placed on the scalp
• Researchers focus on P1 and N1 components, which occur within the first 200 milliseconds after stimulus
• When they were attending to a stimulus, early components have amplitudes compared to when it is ignored it

Early Selection Summary

• Originally proposed by Broadbent in the 1950s, suggesting attention filters at early processing
• Based on physical characteristics of stimuli with only selected information process further for meaning
• Broadbent argued unfiltered stimuli are not processed at all
• Some evidence shows unfiltered stimuli can be processed like breakthrough and the attenuated filter which show that Irrelevant information can pass through the filter if capacity is not filled by relevant information
• Selective looking tasks shows participants often fail to notice unexpected events where Neisser and Becklen (1975) found only 21% of observers noticed an unexpected

Late Selection

• Deutsch & Deutsch (1963) suggested filtering occurs AFTER semantic processing, meaning that all stimuli is processed for meaning and only items consistent with the observers' goals are selected

Evidences for Late Selection

• Eriksen & Eriksen (1974) Flanker task presented 7 letters where participants pressed the right button for H and k and the left button for S and C
• Two conditions includes congruent conditions where Target and flankers corresponded to the same response
• Other conditions involves incongruent where target and flankers corresponded to opposite responses
• Results show RT were longer in the incongruent condition compared to the congruent condition meaning that participants showed slower reaction when flankers conflicted with the target. Suggesting that unattended stimuli are processed semantically

Example of Late Selection

• Halligan & Marshall (1988) Blindsight showed patient PS with attention to left visial field impairment
• In a test, PS indicated a house but same if they were the same
• Researchers then indicated anything wrong and PS stated NO
• In which a house you would live showed that the perference for non burning house indicates that the meaning and implications of fire is extracted from the neglected stimuli
• Which indicates that some level of processing occurs for neglected stimuli

Cognitive Neuroscience Evidence for Late Selection

• Hillyard et al. (1973):
• Results shows standard tones in attended are has a larger N1 components compared to tones presented the unattended channel
• Selective attention can modulate sensory processing at an early stage
• P300 elicited only after the signal tones and not by the standard tones
• Both types of stimuli undergo initial processing, but only task relevant stimuli receive further cognitive evaluation

So Early OR Late? Or is it Both?

• According to Lavie (1995, 2005), and Lavie et al. (2004) perceptually task has fewer resources which the attentional capacity
• Automatic processing is automatic
• Load is when it is visually complex where the focus and attention is focused on relevant information
• Low load shows capacity spills over irrelevant stimuli and process and that selection the selection process is

Lavie (1995) Perceptual Load theory

• Lavie (1995) used a visual search of a display manipulating the numbers of non-target letters.
• One variation was for A peripheral letter was incompatible for what was selected
• It was determined that detect the target in the high load compared to the low load which also consumes Attentional resources

Nuero View

• Ress ( 1997) states that The findings support Lavie's theory of attention and shows perception distractor relevant

Summary

• Hybrid models offer better account for early and late selection
• Acts at an later stage if sensory systems are not being overloaded
• Attentional selection can also be early and late and shows processing