Perception 3,3 Flashcards

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1
Q

One purpose of perception is to inform us about what is out there in the environment?

What is the perception foundations?

A

Of information from the environment

For visual perception this information is light

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2
Q

Diagram of information

explain

A

Information from the light entering the eye and the electrical signals to the brain is crucial for perceiving any object in the environment

because without it, the object will not be represented in the nervous system

The sequence of events from eye to brain is called bottom up processing

starts at the “bottom” or beginning of the system, when environmental energy stimulates the receptors.

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3
Q

What is bottom up processing?

A

Processing that starts with information received by the receptors. This type of processing is also called data-based processing.

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4
Q

What else needs to be involved other than the information from light entering eye?

A
  • perception needs more information than what is provided by activation of the receptors and bottom-up processing.
  • Perception also involves factors such as a person’s knowledge of the environment, the expectations people bring to the perceptual situation, and their attention to specific stimuli. This additional information is the basis of top-down processing—processing that originates in the brain, at the “top” of the perceptual system (see Figure 3.10).
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5
Q

What is top down processing?

A

Processing that involves a person’s knowledge or expectations. This type of processing has also been called knowledge-based processing.

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6
Q

Diagram of top donw and bottom up processing?

A
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7
Q

Figure 3.11

example of top-down processing involved in perceiving objects

A
  • An example of how top-down processing is involved in perceiving objects is illustrated in Figure 3.11. Depending on whether you interpret the central stimulus as a part of a row or a column, you will either perceive it as the letter S (as part of a row of letters) or as the number 5 (as part of a column of numbers).
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8
Q

Infleunce of context has been demonstrated in study by oliva and torrabla 2007

multiple personalities of a blob

A
  • Participants in their study were asked to identify a blurred object in a scene (the “blob”).
  • Results showed that even though the “blobs” in all the pictures were identical, they were perceived as different objects (for example, a shoe on a person bending down, or a car or person on the street) depending on its orientation and the context within which they were seen.
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9
Q

How does top down processing influence speech perception?

Watching Spanish TV channel

A
  • If you don’t speak Spanish you won’t understand anything the people are saying. In fact, the dialogue will sound like an unbroken string of sound, except occasionally when a familiar word like gracias or casa pops out.
  • Your perception will reflect the fact that the sound signal for speech is generally continuous, and when there are breaks in the sound, they do not necessarily occur between words. You can see this in Figure 3.13 by comparing the place where each word in the sentence begins with the pattern of the sound signal.
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10
Q

What about when sometime understands Spanish watching this?

vs english

A

perceives this unbroken string of sound as individual, meaningful words in a conversation. Because of their knowledge of the language, they are able to tell when one word ends and the next one begins, a phenomenon called speech segmentation.

listener familiar only with English and another listener familiar with Spanish can receive identical sound stimuli but experience different perceptions means that each listener’s experience with language (or lack of it!) is influencing his or her perception. The continuous sound signal enters the ears and triggers signals that are sent toward the speech areas of the brain (bottom-up processing); if a listener understands the language, that knowledge (top-down processing) creates the perception of individual words.

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11
Q

What is speech segmentation?

A

The process of perceiving individual words within the continuous flow of the speech signal.

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12
Q

Perception of pain is an example of how top down processing influences

A

perception

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13
Q

What model sued in 1950s and 1960s to explain pain?

A

Direct pathway model

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14
Q

How did direct pathway model worked?

A

pain occurs when receptors in the skin called nociceptors are stimulated and send their signals in a direct pathway from the skin to the brain (Melzack & Wall, 1965). This is a bottom-up process because it depends on stimulation of the receptors

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15
Q

What is definition of direct pathway model?

A

Model of pain perception that proposes that pain signals are sent directly from receptors to the brain.

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16
Q

What happened in 1960s that differ from direct pathway model?

A

researchers began noting situations in which the level and even the presence of pain was affected by factors in addition to stimulation of the skin.

e.g

  • athlete who finishes his race despite a broken toe, which he only feels and becomes aware of after the final sprint.
  • Or, think about patients who chronically suffer from intense pain despite not having any clear physical damage to their bodies.
  • Finally, and perhaps you have experienced this yourself, think about the moments that you started to feel pain only after you saw (and paid attention to) the bleeding wound at the side of your leg.
17
Q

Modern researchers shown that pain can be influenced by?

A

what a person expects, how the person directs his or her attention, and whether distracting stimuli are present (Wiech, Ploner, & Tracey, 2008).

18
Q

Hospital study surigcal piatents were told what to expect and instructed to relax to alleviate the pain

what is shown?

A
  • the patients requested fewer painkillers following surgery and were sent home 2.7 days earlier than patients who were not provided with this information. Studies have also shown that a significant proportion of patients with pathological pain get real relief from taking a placebo, a pill that they believe contains painkillers but that, in fact, contains no active ingredients (Finniss & Benedetti, 2005; Weisenberg, 1977, 1999). In another study, it was found that the activity of serious gaming (active distraction) could reduce pain behaviour and subjective distress in children undergoing wound care (Nilsson, Enskär, Hallquist, & Kokinsky, 2013).
19
Q

What is a placebo?

A

A pill or procedure that patients believe delivers active ingredients (usually pain killers), but which contains no active ingredient.

20
Q

Most theories try to explain the pain-reducing effects of placebos highlight the role of expectation.

e.g

A
  • it is possible that when people expect less pain (due to placebos), their attention is refocused on other things than the pain, which, in turn, may cause people to experience less pain.
21
Q

Considering how a placebo works and diverting their attention to other things other than pain

how do expectations operate?

A
  • Operate as a form of cognitive control by influencing and redirecting attention
22
Q

What is cognitive or attention control an example of?

A

an executive process which involves the prefrontal lobe (note that the term “control” does not necessarily mean that one is conscious of it).

23
Q

Another way without saying expectations without the mediating role of executive attention.

e.g

A

expectations created by the placebo may stimulate the release of endogenous opioids (a pain reducing neurotransmitter) (Wager, Scott, & Zubieta, 2007).

24
Q

What did Buhle and colleagues 2012 aimed to find out these two possible mechanisms would most unrlie the placebo effect

How did they do this?

A
  • They used a type of reasoning that is often applied in cognitive psychology research, drawing on the fact that we have only a limited set of resources that we often have to share and divide over different tasks or functions.
25
Q

What two things Buhle reasoned?

A
  1. if the analgesic effect of placebo-induced expectations depends on executive attention processes in the prefrontal lobe (explanation 1), then keeping these executive processes busy with another task would lead to a smaller placebo effect.
  2. if the placebo effect does not draw on the same limited resources of the prefrontal lobe (explanation 2), then such additional task would not interfere with the (direct) effect of expectation, and may even cause an extra analgesic effect.
26
Q

What does analgesic mean?

A

Drug to relieve pain

27
Q

How did Buhle set up their experiment?

A

he task they chose to keep the executive processes busy was a working memory task, requiring participants to judge whether a presented letter was the same or different from the letter presented three trials before (3-back test, see Figure 3.14).

28
Q

What does this figure show on Buhle’s procedure?

A
  • All participants in control session and placebo session on two separate days
  • Each session , moderate thermal pain was applied in two blocks and two blocks without WM task
  • After each block and after the heat stimulus had returned to baseline
  • Aparticipant had than rated their pain that experienced
29
Q

What does this figure show from Buhle’s procedure?

A
  • both the placebo treatment and the WM task produced clear analgesic effects and that these effects were almost perfectly additive
  • placebo analgesia did not affect performance on the working memory task.
  • analgesic effects of placebos and distraction work via different and separate mechanisms.
30
Q

What did Buhle concluded?

A
  • expectations created by a placebo do not work via the executive attention system in the prefrontal lobe but instead are more likely to directly influence pain perception (thus support for explanation two). The practical implication of these findings is clear, namely that reduction of pain feelings can be achieved best by placebo treatment AND distraction of the person in pain.
31
Q

Important of Chapter 3 examples

A
  • context affects our perception of the blob; how knowledge of speech affects our ability to create words from a continuous speech stream; and how expectation and attention can influence a person’s experience of pain—illustrate that perception is created not only by signals from the environment (bottom-up processing) but also by what the individual brings to it (top-down processing).
32
Q

Humans are better at identifying ambiguous stimuli such as blurred photos because humans

A

can resolve ambiguities by top-down processing.

The human advantage over computers in identifying ambiguous, degraded, or blurred stimuli is due, in part, to the additional top-down knowledge available to humans.

33
Q

Sofia is fluent in English and German and when she listens to a speaker using either of those two languages, she is able to identify distinct words. However, she has only recently begun learning Hebrew and when she listens to a speaker, she finds it difficult to identify any words, even simple words she recognizes in isolation. Sofia is best described as experiencing issues with

A

speech segmentation.

When someone has experience with a language, he or she is able to tell when one word ends and the next one begins, a phenomenon called speech segmentation. Without that knowledge and experience, the words seem to blend together.

34
Q

Lucas is helping a friend move and slams his hand between the door frame and a large couch. He continues his labours without seeming to notice it until someone points out that his hand is dripping blood on the newly-cleaned carpet. Suddenly his hand hurts quite a bit. This is most accurately described as reflecting the effects of _____ on pain perception.

A

Attention

Attention can have an effect on the perception of pain and when a person’s attention is directed away from a painful injury, pain may be lessened.