Attention

Questions for this section How do we selectively attend to one stimuli while not attending to others? What role does inhibition play in this process? What are the limits of attention? That is, how much can we attend to at once? Under what conditions can we attend to more than one stimulus? What effect does practice have on the three questions above?

Selective Attention Refers to our ability to focus on one stimulus, while tuning out the rest. Shadowing and dichotic listening tasks. Attended vs. unattended channel. Basic findings from these paradigms: Ss are good at shadowing AC. Poor memory for UC. Physical info. can be remembered/reported from UC.

Broadbent’s Early Selection Model Initial results from shadowing and dichotic listening paradigms provided the foundation for Broadbent’s Early Selection Model. In this model, attention acts as a “filter” that is used to keep irrelevant information from reaching the limited capacity processor (short- term memory).

Broadbent’s model of attention What finding would be particularly damaging to this model?

Late-selection Data began to mount that hurt early selection: Moray (1959) “Cocktail Party Effect” Treisman (1960) Corteen and Wood (1972) Late selection theorists take a position 180 degrees opposite of Broadbent. They argue that all stimuli are processed, and then attention is applied.

Late selection assumptions No “filter” that acts on sensory cues. STM and LTM are not separate “places.” STM is seen as the active subset of LTM. All incoming stimuli make contact w/ cognitive units in LTM. Limited capacity attention comes after LTM, not before it.

Norman’s Pertinence Model

The Role of Inhibition Certainly we activate representations for the stimuli are attending to. What to we do with the representations of the stimuli we are not attending to? Negative Priming Effect

Examples of trials in a negative priming experiment L Y L Q Trial N or Trial N+1 Y F NAME THE GREEN LETTER Ignored Repetition Control IR RT TRIAL N+1 ~ 620 msec C RT TRIAL N+1 ~ 600 msec This 20 msec difference in RT is the NEGATIVE PRIMING EFFECT

EXPLAINING THE NEGATIVE PRIMING EFFECT ACTIVATION LYYLLQ Before Trial N After Trial N (IR) After Trial N (C) ACTIVATION Y (IR) (C) Activation immediately before Trial N+1

Limitations on Attention You don’t need a cognitive psychologist to tell you that you can only attend to limited amount of info. You need them to tell you WHY. Attention as a mental resource. Kahneman (1973). What are mental resources?

Divided Attention Why can we sometimes divide our attention between two stimuli wo/ performance decrement, but other times we cannot? General vs. specific resources. Brooks (1968). Wickens (1984). Controlled vs. automatic processing. Some tasks do not require our attention (more later).

BROOKS (1968) Ss told to imagine a block letter (example below) or a sentence such as “A bird in the hand is worth two in the bush.” In letter condition, the have to indicate whether each corner is outside or inside. In sentence condition they indicate whether each word is a noun/verb or not. They indicated their responses verbally or by pointing to “yes” and “no.” RT for Yes and No responses SayPoint Block1025 Sentence149

Practice One might argue that all novel tasks are performed w/ controlled attention. How does task performance become automatic? Schneider and Shiffrin (1977) Visual search task. Thousands of trials per subject. Consistent Mapping (CM) and Variable Mapping (VM)

Schneider and Shiffrin (1977) In CM condition, targets and distractors never changed. For example, the only targets a subject might see are T, Y, B, N, and the distractors might always be, Q, K, P, V, W, X. In VM condition, targets and distractors changed on every trial. Over the course of thousands of trials, how do you think RT performance would look for subjects in these two groups? Why?

Summary of Schneider and Shiffrin’s Data Trial # Reaction Time CM VM

Automaticity Automatic processes are: Ballistic (can’t stop it from happening or from finishing once it starts). Do not require intention (whether you want it to occur or not does not matter). May occur wo/ awareness. Stroop Effect

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