Lecture 4 – Attention 1 Three questions: What is attention? Are there different types of attention? What can we do with attention that we cannot do without attention (and why can’t we)?

Lecture 4 – Attention 2 1.What is attention? No-one knows. Three metaphors: Spotlight Limited resource Glue

Lecture 4 – Attention 3 Spotlight: Attending is like shining a light. Rate of uptake of information is faster in spotlight than outside spotlight. Consequence: things attended are more likely to be perceived, or are perceived faster.

Lecture 4 – Attention 4 Limited resource Attending is like seating people at dinner – you should not invite more people than you have seats or plates. If two tasks both require attention: There is a cost to doing both at once Neither done as well as when done alone

Lecture 4 – Attention 5 Glue Basic idea: we analyze an object into features. Features are extracted without attention. Responses based on a feature don’t require attention to the stimulus object. But attention is necessary to “glue” the features back together again into an object percept.

Lecture 4 – Attention 6

Lecture 4 – Attention 7 2. Are there different types of attention? Three types: Selective Attention Divided Attention Sustained Attention

Lecture 4 – Attention 8 Selective attention Our ability to choose which of many things or locations around us we should attend to. Ability is not absolute – e.g., fire alarms compel our attention. But much of the time, we deliberately choose what to attend to.

Lecture 4 – Attention 9 Divided attention Our ability to allocate part of our attention to each of several different things. Issue: is there a cost to dividing attention? For processing efficiency, is DA = UA? Yes – for some tasks. No – for others.

Lecture 4 – Attention 10 Sustained attention Our ability to focus on one target even though the world around us may be bustling and full of change. Very important topic during WWII – study of radar operators. Important in development of cognitive psychology.

Lecture 4 – Attention 11 Metaphors vs. Types of attention: If you use a spotlight, you’re selecting what to look at. If you use a spotlight, light is a limited resource. If you have unlimited resources, you can divide attention without cost. If something demands to be selected, it interferes with sustained attention.

Lecture 4 – Attention What can we do with attention that we cannot do without attention (and why can’t we)? The answer depends upon capacity. Consider a human in a typical, everyday situation: Many stimuli available. Most important must be selected. Response must be chosen and executed.

Lecture 4 – Attention 13 Question: What will this person do? Will she attend to all stimuli? Some stimuli? How chosen? Will she respond to more than one stimulus? Which ones?

Lecture 4 – Attention 14 Kahneman’s capacity model: Probability of a stimulus being recognized is a function of: How many things must be recognized at once? How much “effort” Required for each thing? How much effort Available? If R > A, what do we do?

Lecture 4 – Attention 15 How much effort required for each thing? Varies with how familiar stimulus is to person. This varies with person’s experience. How much effort is available? Varies with person’s level of arousal. What do we do if R > A? Varies with person’s goals.

Lecture 4 – Attention 16 Notice that all these answers involve facts about the person. Stimuli can be expected or unexpected familiar or unfamiliar important or unimportant but only to a particular person. These are not qualities inherent in the stimulus itself. They are facts about the perceiver.

Lecture 4 – Attention 17 Conclusion: Attention is a complex interaction between the current environment and your life experience. So what can we do without attention?

Lecture 4 – Attention 18 Automatic processes. Automatic processing deals with attention to familiar, expected, important, simple stimuli. Paying attention to such stimuli requires almost no effort. Repeated practice at a task gives task and stimuli such familiarity that task becomes effortless.

Lecture 4 – Attention 19 Two types of automatic processes: 1.Those that we already have. e.g. – feature detection in vision (Treisman) 2. Those that we deliberately acquire. e.g. – automation of complex processing (Spelke et al.)

Lecture 4 – Attention Automatic processes we already have.

Lecture 4 – Attention 21 Treisman’s model (uses glue metaphor): We extract features of visual objects then re- combine them into perceptual objects. The recombined units are called conjunctions. Features are extracted in parallel across the visual array. Conjunctions are produced by a serial process.

Lecture 4 – Attention 22 Treisman’s evidence: Visual search task: is target letter in display? Target is X. O O O X O O

Lecture 4 – Attention 23 X X X Target is green

Lecture 4 – Attention 24 C X X X C C X C X Target is green X

Lecture 4 – Attention 25 Treisman’s evidence: Independent variables: 1.# features defining target (1 or 2) 2. # distractors in the display Result: RT almost independent of display size for feature search, not for conjunction search.

Lecture 4 – Attention 26 Treisman’s conclusion: If response can be driven by a feature, no effect of # of distractors because features can be found in parallel. If response depends upon a conjunction, effect of # of distractors implies that conjoining features to produce objects is a serial process. This is ‘gluing’ the features together and requires attention.

Lecture 4 – Attention Automatic processes we deliberately acquire.

Lecture 4 – Attention 28 Spelke, Hirst, & Neisser (1976) Subjects listened to headphones and typed message they heard. At the same time, they read a book out loud. Two input modalites – vision and hearing. Two output modalities – typing and speaking.

Lecture 4 – Attention 29 Typewriter Book Headphones “now is the…

Lecture 4 – Attention 30 Spelke’s finding: After 6 weeks, subjects could perform both tasks to a very high standard. Comprehension of story + error-free typing. This result obtains when simultaneous responses use different sets of muscles – here, typing and speaking.

Lecture 4 – Attention 31 Review: 3 Metaphors: attention as spotlight, limited resource, and glue. 3 types of attention: selective, divided, and sustained.

Lecture 4 – Attention 32 Review: Amount of effort you can expend varies with your arousal. Amount of effort it takes to recognize an object varies with object’s familiarity (which varies with your experience). If amount of effort needed exceeds amount available, we must select.

Lecture 4 – Attention 33 Review: The choice of what to select will vary with the person’s goal. If we have enough effort available, we can divide attention without cost. If we have lots of practice with a task or a stimulus, we can process automatically – without cost for other processes.

Lecture 4 – Attention 34 Attention disorders

Lecture 4 – Attention 35 1.Autism Indexical function (pointing) Shared gaze Social functions depend upon attention Simon Baron-Cohen: different interests

Lecture 4 – Attention Neglect & Extinction Result of brain damage to certain areas Neglect: failure to attend to half of space includes own body Extinction: competing stimulus produces neglect Victor Mark: failure to disengage

Lecture 4 – Attention Attention deficit disorder Poorly understood. Symptoms are real. Causes are unknown. How do we measure a deficit in something if we can’t measure “how much” anyone has? Is it an attention disorder or a learning disorder? Recall importance of person variables