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An introduction to attention. Peter König. What is attention.
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An introduction to attention Peter König
What is attention Everyone knows what attention is. It is the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneous possible objects or trains of thought. Focalization, concentration of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrain state…. – William James (1890)
Overt attention • Movements of the eyes allow selective aquisition of visual signals. • Other sensory organs equally allow selective capturing of environmental signals.
How are salient points selected? • The concept of a saliency map • “Where is the action?” • Bottom-up approach • But … !
Spotlight of attention • Helmholtz observed that we can enhance perception, if we focus our attention on a location in the visual field. • However, enhancing perception in one part of the visual field takes place at the expense of other areas.
The shadowing task I Condition 1: 65% correct Condition 2: 20% correct
Shadowing task II Somewhere Among hidden the in most the spectacular Rocky Mountains cognitive near abilities Central City is Colorado the an ability old to miner select hid one a message box from of another. Gold. We Although do several this hundred by people focusing have our looked attention for on it, certain they cues have such not as found type it style.
Broadbend‘s filter theory • Early selection. • Selection is based on physical properties of the stimulus (e.g., pitch, loudness, etc...). • Only one input channel can be processed at a time. • Semantic interpretation only after selection. • Conscious control. • It takes time to shift attention.
Late selection Attended Channel: THE GIRL WAS dogs, six, beach ... Unattended Channel: world, eight, WAITING FOR HER ... Reported: THE GIRL WAS WAITING FOR HER ...
Popout • Popout as pre-attentive processing. The more popout, the later selection!? • Can be trained!
Competing hypothesis • early selection - Broadbent (1958) proposed that physical characteristics of messages are used to select one message for further processing and all others are lost • attenuation - Treisman (1964) proposedthat physical characteristics are used to select one message for full processing and other mes-sages are given partial processing • late selection - Deutsch & Deutsch (1963) proposed that all messages get through, but that only one response can be made (late selection).
What did we learn / the next time • Overt/covert attention • When: Early, middle, late … • What: Spatial … Object oriented attention • Where: Areas, -band … Single neurons, Clinical syndromes • How: Saliency maps … Top-down models • Suggested readings: Kastner, Annual Review neurosciences, 2000; JR Anderson, Chapter 3
A definition by exclusion Awake Asleep Inattentiveness (drowsy, relaxed) Different sleep stages Alert Ignore Attend
Popout • Popout as pre-attentive processing. • The more popout, the later selection. • T among I and Y vs. T among I and Z. • Can be trained!
What did we learn? • Types of attention • Overt attention, covert attention • What can we attend to • Spatial attention, object based attention - Physical characteristics, semantic contents • Properties of attention • Mechanisms of attention • Why attention
What do we want to know? • Types of attention • What can we attend to • Properties of attention • Mechanisms of attention • Why attention
Early or late? Treisman and Geffen (1967) set about to test whether the filter was early or late in the processing stream. They had subjects shadow a message on one ear, and tap whenever they heard a certain word in either ear. When the key word appeared in the attended ear, subjects tapped 87% of the time, but when the key word appeared in the unattended ear, subjects tapped 8% of the time. This indicates that early selection is occurring.
What can we attend to? Spatially oriented attention vs. Object oriented attention Popout as a pre-attentive mechanism
Divided attention Selective and divided attention • Attention is studied by presenting participants with two or more stimuli at the same time. • This is called dual-task performance. • In selective (focused) attention tasks, people are instructed to respond to one input only. • In divided attention tasks, people are asked to process and respond to more than one input.
Divided attention • Tracking task. Can track several targets simultaneously.
Dilation in space and time • Expanding dot demo.
Physiological mechanisms • Partiel lobe lesions • Balint‘s syndrome • Attention is a gateway to consciousness.
Neuroscience <-> Psychology what do these examples tell us about the relation between mental phenomena and physical states of the brain? * unrelated ? complete independence -- too many corresponding phenomena * irrelevant ? somehow related, but without any serious implications -- unlikely, because it is possible to influence percepts by affecting neurons (TMS) * correlated ? not independent, but possibly not more than common result from unknown cause -- possible from the above, but perhaps not enough? * causal ? neuronal state determines mental state -- likely in some instances, but applicable to all mental events? is consciousness emerging from neural activity? if we would reach a complete understanding of all brain mechanisms, from the single molecule to the function of extended neural networks, would we be able to comprehensively predict mental states? A. Snyder (Centre for the Mind): Yes
