Psychology 2135A/B Chapter Notes - Chapter 5: Inattentional Blindness, Knitting, Hemispatial Neglect
27 May 2018
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Psych 2135
May 28- June 1, 2018
Chapter 5: Paying Attention
Selective attention
- William James: attention is the taking possession by the mind, in clear and vivid form, of
one out of what seem several simultaneously possible objects or trains of thought
Dichotic listening
- Participants wore headphones and heard one input in the left ear and a different input
in the right ear
o Participants are instructed to pay attention to one of these inputs – the attended
channel – and told simply to ignore the message in the other ear – the
unattended channel
o To make sure participants were listening, they were usually given a task called
shadowing
o If you listen to one channel and repeat it word for word (shadowing) you will
almost have no recollection of what the alternative message is even saying
- More recent studies have documented a similar pattern with visual inputs
- Apparently, physical attributes of the unattended channel are heard, even though
participants are oblivious to its actual content
Some unattended inputs are detected
- If youe told to liste to the atteded iput ad the uatteded iput is a seies of
names, including your own, you will hear it research shows
o Words with personal importance are often, but not always, noticed
Perceiving and the limits on cognitive capacity
- One explanation for the above results is that you somehow block processing of the
iputs youe ot iteested i
- This was central to early theories of attention
o These theories suggest that you erect a filter that shields you from potential
distractors
- This means you are able to promote the processing of desired stimuli
- Inattentional blindness
o It seems plausible that this activity would require some initiative and some
resources from you and evidence suggests that it does
o The failure to see as Mack and Rock argue, is caused by the fact that participants
were not expecting any shapes to appear and were not in any way prepared for
them
o Therefore, perception requires more than merely having a stimulus in front of
your eyes – it requires some work
- Change blindness
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o Observers inability to detect changes in scenes theye looking directly at
o In some experiments, participants are shown pairs of pictures separated by a
brief blank interval
- Early versus late selection
o According to the early selection hypothesis, the attended input is privileged from
the start, so that the unattended input receives little analysis and so is never
perceived
o According to the late selection hypothesis, all inputs receive relatively complete
analysis and the selection occurs after the analysis is finished
o Perhaps the selection occurs just before the stimuli reach consciousness and so
we become aware only of the attended input
o Or perhaps the selection occurs later still – so that all inputs make it briefly into
consciousness, but then selection occurs, so that only the attended input is
remembered
o On the one side, there are cases in which people seem unaware of distractors
but are nevertheless influenced by them – a case of late selection
o On the other side, though, we can also find evidence for early selection with
distractor stimuli falling out of the stream of processing at a very early stage
▪ Studies confirm that the brain activity for attended inputs is
distinguishable from that for unattended inputs just 80ms or so after the
stimulus presentation
▪ Another example is that recordings from neurons in area V4 of the visual
cortex show that these neurons are more responsive to attended inputs
than unattended ones
o Therefore, attention can literally change what we perceive
Selective priming
- Why dot people peeie the stiuli ight i fot of the?
- The proposal is that you can literally prepare yourself for perceiving by priming the
relevant detectors
o I othe ods, you soeho eah ito the etok ad delieately atiate
just those detectors that you believe will soon be needed
o Priming can also come from what your expectations about what the stimulus will
be
o As a result, when stimulus is presented, it falls on unprepared, unprimed and
unresponsive detectors
- Lets also suppose piig ist fee, so you eed to sped soe effot o alloate some
resources in order to do the priming, and these resources are in limited supply
- But why then does attention sometimes leak so that you do hear some aspects of the
unattended input?
o If it is something personal to you, this stimulus is already primed
- Two types of priming
o The idea before us has three components: that perception is vastly facilitated by
the priming of relevant detectors, that priming is sometimes stimulus driven by
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
William james: attention is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. If you listen to one channel and repeat it word for word (shadowing) you will almost have no recollection of what the alternative message is even saying. More recent studies have documented a similar pattern with visual inputs. Apparently, physical attributes of the unattended channel are heard, even though participants are oblivious to its actual content. If you(cid:859)(cid:396)e told to liste(cid:374) to the atte(cid:374)ded i(cid:374)put a(cid:374)d the u(cid:374)atte(cid:374)ded i(cid:374)put is a se(cid:396)ies of names, including your own, you will hear it research shows: words with personal importance are often, but not always, noticed. One explanation for the above results is that you somehow block processing of the i(cid:374)puts you(cid:859)(cid:396)e (cid:374)ot i(cid:374)te(cid:396)ested i(cid:374)
