Cognitive Lecture 6 PDF

Cognitive- Lecture 6 [What is attention?] "Everyone knows what attention is. It is the taking possession of the mind in the clear and vivid form of one out of what seem several simultaneous objects or trains of thought\... It implies withdrawal from some things in order to deal effectively with ot...

Cognitive- Lecture 6 [What is attention?] "Everyone knows what attention is. It is the taking possession of the mind in the clear and vivid form of one out of what seem several simultaneous objects or trains of thought\... It implies withdrawal from some things in order to deal effectively with others" (james,1890) [Three features of attention ] Selectivity- let us process specific information while ignoring (inhibiting) the rest Limited capacity- can only process so much information at once (divided attention) Sustainability- difficult to attend to the same thing over extended periods of time (sustained attention). Vigilance, alertness, mind- wandering [Attention: basic categories] **Bottom-up attention** -- when attention is directed bases on properties of sensory input (e.g. shiny objects, loud noises) **Top- down attention**- when attention is directed bases on internal states ( e.g., habits, knowledge, goals) [Voluntary vs involuntary attention ] Voluntary attention - Related to current goals - Manipulated with instructions, incentives Involuntary attention - Unrelated to current goals - Distraction, capture of attention - Manipulated with stimuli Not always opposite in practice - Only distraction when contrary to goals [Exogenous attention] - Controlled by external events (e.g. sudden changed in brightness or sound) - Rapid but brief attention [Endogenous attention ] - Controlled by internal states (knowledge, goals) - Slower- acting but long- lasting attention [Selective attention ] *Cocktail party effect- cherry 1953* The "cocktail party" effect: how does one follow a conversation at a cocktail party in a very noisy environment? Attention needs to select one message for processing and inhibit the rest You often do not hear (unaware of) the unattended messages Shadowing task: overt repetition of the info presented in one message - Content of the unattended message (unnoticed) - Change in language- unnoticed *Early selection theory (Broadbent 1958)* Parallel inputs are filtered before accessing one of them - Filtering prevents overloading of the limited capacity mechanism - Filter out inputs based on early sensory properties (e.g. location, pitch) Accounts for cocktail party effect We are unaware of the unattended info because it undergoes sensory but not semantic processing before being filtered *Challenges to early selection* - Some information from the unattended channel is notices during dichotic listening - So, some processing of the unattended message must occur - Cannot be completely filtered out [Attention theory- Treisman (1960)] - Unattended information is not fully inhibited ( as in early slection models) but attenuated after initial sensory processing - Typically, unattended information does not reach semantic processing threshold, but some types of information may (e.g. familiar or very relevant information) leading to occasional "breakthroughs"  [Late selection theory- Deutsch and Deutsch (1963)] Also tried to explain why semantic information is sometimes processed Proposal - all channels are semantically analysed following sensory processing - Filtering happens later in STM after semantic processing (hence, late selection model of attention) based on the importance of inputs - Only most important inputs are acted on and remembered [Visual attention ] *Covert vs overt attention* In vision, attention is often linked to where someone is looking -- recall fovea has most detailed vision Overt attention- gaze shift accompanies shift of attention. Covert attention- attentional shifts occur in the absence of eye movements [Is attention needed for vision?] Studies using search tasks (find an object among distractors) Parallel processing - When what you are looking for pops out from a crowd of irrelevant objects - Some visual features are processed simultaneously Serial processing - When you need to effortfully to find something - Especially when what makes targets different from distractors depends on conjunctions of features - No single visual feature that isolates target Not just one or the other: search efficiency varies on a spectrum As targets differ more from distractors, search gets easier [Attention and awareness ] Although we experience a rich and detailed world, we are aware of surprisingly little information Change blindness - Difficulty noticing changes when dynamic signals are missing Inattentional blindness - Failure to notice events that aren\'t attended Both have been demonstrated outside the lab [Attention to brain ] *Posner\'s attention networks* Alerting network - Maintaining vigilance over a period - Right frontal and parietal areas - Norepinephrine Orienting network - Directing attention - 3 operations: disengage, move, engage - Frontal, parietal and subcortical areas - Acetylcholine Executive network - Target detection and selective responding - Midline frontal areas and lateral frontal cortex - Dopamine  [Unilateral neglect ] - Deficiency in attending to one half of the visual - Typically damage in right inferior parietal lobe, with neglect of left visual hemifield - Patients do not notice stimuli in left hemifield if there is something else to attend to in the right hemifield - Deficit in attention, not vision DO BIAISED THEORY