COG Lecture 2 - Attention 1

• Cognitive psychology aims to understand metal processes that allow people to make sense of their environment, decide how to react, and implement decisions
• Human cognition can be conceptualized as a flow of information, psychologists can measure cognition by measuring signal processing
• Cognitive psychology allows psychologists to operationalize and measure abstract concepts like attention, memory, perception, planning, reasoning, and motivation

Fodor and Modularity

• Human cognitions are organized into discrete mental modules each fulfilling a specific function
• Horizontal faculties are general competencies used across domains, such as long term memory
• Vertical faculties are domain specific cognitive functions and processes, such as language production or object recognition
• Modules don't need to interact with other psychological processes to operate, making them independent
• Modules are similar across humans and function fast and obligatory, occurring without conscious thought
• Cognition involves both horizontal and vertical faculties

Methods for Identifying Modules

• Single dissociation allows researchers to infer that two functions are independent to some degree, but does not rule out partial relation
• Double dissociation enables specific brain function inferences and functional localization, demonstrating separate functions
• The two tasks are mediated by different functional mechanisms
• Task X is controlled by area A
• Task Y is controlled by area B

Cognitive Neuropsychology

• Brain damage explains normal cognition by reverse engineering cognition and function localisation, but typically investigates single cases
• Patient HM (Scoville & Milner 1957) underwent neurosurgery to cure epilepsy but experienced severe anterograde amnesia, and was unable to form new memories
• Patient HM's short term memory was ok, and could learn new skills
• Long Term Memory (LTM), Short Term Memory (STM) and procedural memory must be different systems
• Patient HM revolutionized understanding of memory function

Limitations of studying cognitive neuropsychology

• Defining "normal" performance can be difficult if there is limited prior knowledge of the patient's pre-injury state
• Functional reorganization relates to the nervous system adapting its structure to new situations, potentially adopting compensatory strategies
• Its difficult to determine the time-course of information processing, and that damage is rarely focal, leading to patients being different

Attention

• Attention is taking possession by the mind in clear and vivid form, of one out of what seems several simultaneously possible objects or trains of thought
• Focalization and concentration of consciousness are essential to attention
• Select one specific thought or object, make it clear in the mind, and concentrate awareness on it

The Importance of Attention

• Attention allows the processing of relevant sensory signals and deciding which signals need action due to limited cognitive resources
• Attention refers to input and central processes

Attention as a Module?

• Thinking of as "Attentional Network" or "Attentional System" is better, where several different modules and processes interact to guide behaviour
• Posner & Peterson (1990; 2012) 3 components of the attention system:
  • Alerting: Regulates arousal level
  • Orienting: Prioritizes relevant sensory signals (input module)
  • Executive: Conscious control of central behaviour process

Evidence for distinct components of attention

• Double dissociation occurs
• Hemispatial Neglect: causes reduced awareness of stimuli on one side of space, but no loss of sensory loss
  • Show deficits in orienting attention, particularly in the contralesional side of space
  • Maintain intact executive control of attention for perceived stimuli
• Alien Hand Syndrome (AHS): a condition in which a person experiences their limbs acting seemingly on their own
  • Demonstrate intact orienting of attention to stimuli
  • Experience impaired executive control and affected limb movement

How Orienting Works

• Attentional orienting filters and prevents information in the unattended channel from being processed
• "Cocktail Party" effect (Cherry 1953) allows focus on one specific conversation amidst background noise
• Cherry developed the "Shadowing" paradigm (dichotic listening) to study the cocktail party effect

Dichotic Listening Task

• Played different word lists to left and right ear
• Participants repeat words from one ear (attended ear) based on experimenter instruction, such as focusing on only one ear
• Recall performances are lower for words presented to the unattended ear
• Participants cannot recall words presented to the unattended ear
• Selective nature of attention and the limited capacity of cognitive processing
• Participants fail to detect language changes or backward words

Broadbent's Filter Theory (1958)

• Information about physical properties, such as tone, pitch, or loudness, are processed pre-attentively
• This information is used for channel selection by choosing the source of input to process
• Attended information is processed, while unattended information is lost
• This accounts for the findings of Cherry's Shadowing Experiments

Criticism for Broadbent's theory

• It cannot account for the analysis of information from unattended ear
• Breakthrough occurs when a person's name is mentioned in the unattended ear (Moray 1959)
• Breakthrough also occurs when a word from the unattended ear makes sense of a message in the attended ear (Treisman 1960)

Treisman & Geffen (1967) Attenuation Theory

• Filter limits the stimulus information amount that can be processed
• Attended stimuli is analyzed in detail
• Attenuated processing in unattended channel, instead of being extinguished
• Breakthrough occurs when stimuli can be identified using limited information, such as a beep in spoken language

What is attended?

• Spotlight of theory - Posner (1980)
• Focus attention through space
• Zoom-lens model - Eriksen & St James
• Focused attention using flexible spotlight and tightly focused detail
• Spotlight is not required at fovea
• It can move in the absence of eye movement (Posner, Snyder, Davidson, 1980)

Spatial Cueing Task

• Involves fixating on the centre screen, a cue orients the participant towards one or other side
• Participant must respond as quickly as possible to the appearance of a target in any 3 types of trial:
  • Valid: Target appears at cued location
  • Invalid: Target appears opposite cued location
  • Neutral: Cue does not indicate any location
• Reaction times are faster in the valid cue condition and the longest in the invalid cue condition
• Effects the same for both central and peripheral cues

Covert vs Overt Attention

• Overt Attention:
  • When there is movement of the eyes to fixate on location of interest
• Cover Attention:
  • When orienting attention to a location that is not being fixated

Spatial Cueing Task Results

• Peripheral cues can automatically capture attention rapidly (exogenous attention)
• Central cues require more lime to affect attention, needing the need for processing

Two Systems of Orienting

• Exogenous (vs. Endogenous)
  • (Orient to salient location)
  • Involuntary
  • Stimulus-driven
  • Fast (Max effect at 150ms)
  • Transient
  • Effects the Inferior Parietal Lobe and right ventral frontal regions
  • Inhibitory after-effect
• Endogenous (vs. Exogenous)
  • (Orient to task relevant location)
  • Voluntary
  • Goal-Directed
  • Slow (Max after 300ms)
  • Sustained
  • Effects the Superior Parietal Lobe (bilateral)

Feature Integration Theory (Treisman & Gelade, 1980)

• Integrates attention information in the processing model perception
• Visual features are split and coded in parallel, and proposed by attention acting like 'glue' that binds the figures together into objects
• Attended features bind together to form objects, whereas unattended features do not
• This is proven by visual search

Visual Search

• Includes both feature and conjunction search.
• Feature Search
  • A visual search task where the target is defined by a single feature
• Conjunction Search
  • Visual search task where target is defined by a feature combination
• Single-feature targets (positive trials)
  • Reaction time remains relatively constant with all sizes/display levels
• Conjunctive targets:
  • (Slow) serial search with larger display sizes
• Features like colour and shape are processed separately and need attention ('attentive' stage) to turn coherent

Illusory Conjunctions

• (Treisman & Schmidt (1982): demonstrated illusory conjunction errors occur when features of different objects combine incorrectly
• In the end the participant mixes up the object being studied

Overview of Selective Attention

• Two methods of selecting
  • Posner Spotlight (select a desired sensory location)
  • Pre-attentive method (salient location in a cluttered environment)
• Posner vs Treisman
  • Posner - selects the sensory location
  • Treisman - describes how objects are formed