Semaine 2 - Goldstein, 2010, p. 43-72. Flashcards

Question

Quelle est une solution pour compenser la diminution de la capacité d’accommodation ? A. Tenir le matériel de lecture plus loin B. Porter des lunettes C. Utiliser des lentilles de contact D. A et B E. A et C F. Aucune de ces réponses

Answer 1

D. A et B « There are two solutions to this problem. One is to **hold reading material farther away**. If you’ve ever seen someone holding a book or newspaper at arm’s length, the person is employing this solution. The other solution is to **wear glasses that add to the eye’s focusing power**, so it can bring light to a focus on the retina. » (Goldstein, 2010, p. 46)

Answer 2

E. 100 cm « The near point for most 20-year-olds is at about 10 cm, but it increases to 14 cm by age 30, 22 cm at 40, and **100 cm at 60**. » (Goldstein, 2010, p. 46)

Answer 3

B. Myopie « Of course, many people who are far younger than 45 need to wear glasses to see clearly. Most of these people have **myopia**, or nearsightedness, an inability to see distant objects clearly. » (Goldstein, 2010, p. 46)

Answer 4

C. A et B « This problem can be caused by either of two factors: (1) **refractive myopia**, in which the cornea and/or the lens bends the light too much, or (2) **axial myopia**, in which the eyeball is too long. » (Goldstein, 2010, p. 46)

Answer 5

B. En rapprochant le stimulus « One way to create a focused image on the retina is to **move the stimulus closer**. This pushes the focus point farther back, and if we move the stimulus close enough, we can push the focus point onto the retina. » (Goldstein, 2010, p. 46)

Answer 6

D. Le point éloigné « The distance at which the spot of light becomes focused on the retina is called the **far point**; when the spot of light is at the far point, a myope can see it clearly. » (Goldstein, 2010, p. 46)

Answer 7

B. Les objets éloignés sont flous « Either way, images of faraway objects are not focused sharply, so **objects look blurred**. » (Goldstein, 2010, p. 46)

Answer 8

C. 70 millions « The reason for this difficulty, which affects more than **70 million Americans**, is illustrated in Figure 3.5a. » (Goldstein, 2010, p. 46)

Answer 9

B. Parce qu’elle peut voir les objets proches clairement « Although a person with myopia can see nearby objects clearly (which is why a myopic person is called **nearsighted**), objects beyond the far point are still out of focus. » (Goldstein, 2010, p. 46)

Answer 10

B. Les lunettes correctrices ou les lentilles de contact concaves « The solution to this problem is well known to anyone with myopia: **corrective eyeglasses or contact lenses**. These corrective lenses bend incoming light so that it is focused as if it were at the far point. » (Goldstein, 2010, p. 46)

Answer 11

D. En courbant la lumière entrante « These corrective lenses **bend incoming light** so that it is focused as if it were at the far point. » (Goldstein, 2010, p. 46)

Answer 12

B. Un laser à excimère « LASIK involves sculpting the cornea with a type of laser called an **excimer laser**, which does not heat tissue. » (Goldstein, 2010, p. 46)

Answer 13

B. Hyperopie « A person with **hyperopia**, or farsightedness, can see distant objects clearly but has trouble seeing nearby objects. » (Goldstein, 2010, p. 47)

Answer 14

C. Derrière la rétine « In the hyperopic eye, the **focus point for parallel rays of light is located behind the retina**, usually because the eyeball is too short. » (Goldstein, 2010, p. 47)

Answer 15

C. Parce qu’une grande accommodation est nécessaire « Nearby objects, however, are more difficult for a person with hyperopia to deal with because a great deal of **accommodation is required** to return the focus point to the retina. » (Goldstein, 2010, p. 47)

Answer 16

B. Les maux de tête « Headaches do not usually occur in young people because they can accommodate easily, but older people, who have more difficulty accommodating because of presbyopia, are more likely to experience **headaches**. » (Goldstein, 2010, p. 47)

Answer 17

B. La formation d’une image nette sur la rétine « Focusing the image clearly onto the retina is the **initial step in the process of vision**. » (Goldstein, 2010, p. 47)

Answer 18

D. Dans le cerveau « Vision occurs not in the retina, but in the **brain**, and before the brain can create vision, the light on the retina must be transformed into electricity. » (Goldstein, 2010, p. 47)

Answer 19

A. Les bâtonnets et les cônes « The receptors for vision are the **rods and the cones**. As we will see shortly, the rods and cones have different properties that affect our perception. » (Goldstein, 2010, p. 47)

Answer 20

B. Le segment externe « The key part of the rod for transduction is the **outer segment**, because it is here that the light acts to create electricity. » (Goldstein, 2010, p. 47)

Answer 21

E. Toutes ces réponses « Rod outer segments contain **stacks of discs**. Each disc contains thousands of **visual pigment molecules**. Zooming in on an individual molecule, we can see that the molecule is a long strand of protein called **opsin**. Our main concern is one particular place where a molecule called **retinal** is attached. » (Goldstein, 2010, p. 47)

Answer 22

A. L’absorption d’un photon de lumière par le rétinal « Transduction is triggered when the **light-sensitive retinal absorbs one photon of light**. » (Goldstein, 2010, p. 47)

Answer 23

C. L’isomérisation « When a photon of light hits the retinal, it changes shape, so it is sticking out from the opsin. This change in shape is called **isomerization**, and it is this step that triggers the transformation of the light entering the eye into electricity in the receptors. » (Goldstein, 2010, p. 47)

Answer 24

B. La transduction « Saying that **isomerization of the visual pigment results in transduction** is just the first step in explaining how light is transformed into electricity. » (Goldstein, 2010, p. 48)

Answer 25

E. A et C « Because isomerization of the visual pigment molecule is a chemical process, one way to approach the problem of transduction would be to **study the chemistry of visual pigments** in a chemistry or physiology laboratory… But there is also another way to approach this problem. We can learn something about the physiological process of transduction by **doing psychophysical experiments**. » (Goldstein, 2010, p. 48)

Answer 26

B. La relation PP « We can learn something about the physiological process of transduction by doing psychophysical experiments, in which we measure **relationship PP** to provide information about the underlying physiology. » (Goldstein, 2010, p. 48)

Answer 27

D. L’isomérisation du pigment visuel « Saying that **isomerization of the visual pigment results in transduction** is just the first step in explaining how light is transformed into electricity. » (Goldstein, 2010, p. 48)

Answer 28

B. En déterminant la capacité d’une personne à voir des éclairs de lumière faibles « Just as a doctor can draw conclusions about the physiology of the heart by listening to the sounds the heart is making, the psychologist Selig Hecht (Hecht, Shlaer, & Pirenne, 1942) was able to draw conclusions about the physiology of transduction by **determining a person’s ability to see dim flashes of light**. » (Goldstein, 2010, p. 49)

Answer 29

C. La méthode des stimuli constants « He accomplished this by using the **method of constant stimuli** to determine a person’s absolute threshold for seeing a brief flash of light. » (Goldstein, 2010, p. 49)

Answer 30

B. Quelle est la probabilité que deux photons entrent dans le même récepteur ? « Hecht asked the following question: **What is the likelihood that any two of these photons would enter the same receptor**? The answer to this question is “very small.” » (Goldstein, 2010, p. 49)

Answer 31

E. Très faible « Hecht asked the following question: What is the likelihood that any two of these photons would enter the same receptor? The answer to this question is **“very small.”** » (Goldstein, 2010, p. 49)

Answer 32

B. Pour comprendre la transduction « Hecht wasn’t satisfied just to show that a person sees a light when 7 visual pigment molecules are activated. He also wanted to determine how many visual pigment molecules must be isomerized to activate a single rod receptor. » (Goldstein, 2010, p. 49)

Answer 33

A. 1 molécule « Hecht’s conclusions can be summarized as follows: 2. A rod receptor can be activated by the isomerization of just **1 visual pigment molecule**. » (Goldstein, 2010, p. 50)

Answer 34

C. L’approche psychophysique « The beauty of Hecht’s experiment is that he used the **psychophysical approach**, measuring relationship PP in Figure 3.8, to draw conclusions about the physiological operation of the visual system. » (Goldstein, 2010, p. 50)

Answer 35

A. La cascade enzymatique « Therefore, the sequence of reactions triggered by the activated visual pigment molecule is called the **enzyme cascade**. » (Goldstein, 2010, p. 50)

Answer 36

Allumer une allumette pour déclencher un feu d’artifice « Just as lighting one match to a fuse can trigger a fireworks display consisting of thousands of points of light, isomerizing one visual pigment molecule can cause a chemical effect that is large enough to activate the entire rod receptor. » (Goldstein, 2010, p. 50)

Answer 37

C. Transformer la lumière en électricité « Vision can occur only if the rod and cone visual pigments **transform the light entering the eye into electricity**. » (Goldstein, 2010, p. 50)

Answer 38

B. La sensibilité à la lumière « We will show how the properties of visual pigments help determine how **sensitive we are to light**, by comparing perception determined by the rod receptors to perception determined by the cone receptors. » (Goldstein, 2010, p. 50)

Answer 39

C. Plus de bâtonnets que de cônes. « Il y a beaucoup plus de bâtonnets que de cônes dans la rétine périphérique parce que la plupart des récepteurs de la rétine sont situés là et parce qu’il y a environ 120 millions de bâtonnets et 6 millions de cônes. » (Goldstein, 2010, p. 50)

Answer 40

B. Contient uniquement des cônes. « Il y a une petite zone, la fovéa, qui ne contient que des cônes. » (Goldstein, 2010, p. 50)

Answer 41

A. 50,000. « La fovéa est si petite (environ de la taille de ce “o”) qu’elle ne contient qu’environ 1 pour cent, soit 50,000, des 6 millions de cônes dans la rétine. » (Goldstein, 2010, p. 50)

Answer 42

B. Sur la fovéa. « Lorsque nous regardons directement un objet, son image tombe sur la fovéa. » (Goldstein, 2010, p. 50)

Answer 43

La taille d’un “o”. « La fovéa est si petite (environ de la taille de ce “o”)… » (Goldstein, 2010, p. 50)

Answer 44

B. 6 millions. « …il y a environ 120 millions de bâtonnets et 6 millions de cônes. » (Goldstein, 2010, p. 50)

Answer 45

A. La dégénérescence maculaire « A condition called **macular degeneration**, which is most common in older people, destroys the cone-rich fovea and a small area that surrounds it. This creates a “blind spot” in central vision, so when a person looks at something he or she loses sight of it. » (Goldstein, 2010, p. 51)

Answer 46

B. La rétinite pigmentaire « Another condition, called **retinitis pigmentosa**, is a degeneration of the retina that is passed from one generation to the next… This condition first attacks the peripheral rod receptors and results in poor vision in the peripheral visual field. » (Goldstein, 2010, p. 51)

Answer 47

C. Une cécité complète « Eventually, in severe cases, the foveal cone receptors are also attacked, resulting in **complete blindness**. » (Goldstein, 2010, p. 51)

Answer 48

A. Là où le nerf optique quitte l’œil « There is one area in the retina where there are no receptors […] where the **optic nerve leaves the eye**. Because of the absence of receptors, this place is called the blind spot. » (Goldstein, 2010, p. 51)

Answer 49

A. 50,000 « The fovea is so small (about the size of this “o”) that it contains only about 1 percent, or **50,000**, of the 6 million cones in the retina. » (Goldstein, 2010, p. 51)

Answer 50

C. 120 millions « There are many more rods than cones in the peripheral retina because most of the retina’s receptors are located there and because there are about **120 million rods** and 6 million cones. » (Goldstein, 2010, p. 51)

Answer 51

B. Parce qu’elle est située sur le côté de notre champ visuel. « One reason is that the blind spot is located off to the side of our visual field, where objects are not in sharp focus. » (Goldstein, 2010, p. 52)

Answer 52

A. Parce que notre cerveau la remplit. « But the most important reason that we don’t see the blind spot is that some mechanism in the brain “fills in” the place where the image disappears. » (Goldstein, 2010, p. 52)

Answer 53

C. Avec une perception qui correspond au motif environnant. « The brain does not fill in the area served by the blind spot with “nothing”; rather, it creates a perception that matches the surrounding pattern. » (Goldstein, 2010, p. 52)

Answer 54

C. Pour préserver leur vision nocturne. « One of the myths explored was that pirates wore eye patches to preserve night vision in one eye. » (Goldstein, 2010, p. 52)

Answer 55

A. En utilisant des cache-œil pendant 30 minutes. « They did some different tasks with an eye that had just previously been covered with a patch for 30 minutes. » (Goldstein, 2010, p. 52)

Answer 56

B. Ils ont complété les tâches plus rapidement avec l’œil couvert. « It isn’t surprising that they completed the tasks much more rapidly when using the eye that had been patched. » (Goldstein, 2010, p. 52)

Answer 57

B. Deux phases. « However, as you experience your eye’s increasing sensitivity in the dark, it is probably not obvious that your eyes increase their sensitivity in two distinct stages: **an initial rapid stage and a later, slower stage**. These two stages are revealed by measurement of the dark adaptation curve—a plot of how visual sensitivity changes in the dark, beginning with when the lights are extinguished. » (Goldstein, 2010, p. 53)

Answer 58

A. L’adaptation des récepteurs en cône. « We will now describe three ways of measuring the dark adaptation curve, to show that the initial rapid stage is due to adaptation of the cone receptors and the second, slower stage is due to adaptation of the rod receptors. **We will first describe how to measure a two-stage dark adaptation curve that is caused by both the rods and the cones.** We will then measure the dark adaptation of the cones alone and of the rods alone and show how the different adaptation rates of the rods and the cones can be explained by differences in their visual pigments. » (Goldstein, 2010, p. 53)

Answer 59

B. L’adaptation des récepteurs en bâtonnet. « We will now describe three ways of measuring the dark adaptation curve, to show that the initial rapid stage is due to adaptation of the cone receptors and the second, slower stage is due to adaptation of the rod receptors. **We will first describe how to measure a two-stage dark adaptation curve that is caused by both the rods and the cones.** We will then measure the dark adaptation of the cones alone and of the rods alone and show how the different adaptation rates of the rods and the cones can be explained by differences in their visual pigments. » (Goldstein, 2010, p. 53)

Answer 60

A. La courbe d’adaptation à l’obscurité. « These two stages are revealed by measurement of the dark adaptation curve—a plot of how visual sensitiv[1]ity changes in the dark, beginning with when the lights are extinguished. **We will now describe three ways of measuring the dark adaptation curve**, to show that the initial rapid stage is due to adaptation of the cone receptors and the second, slower stage is due to adaptation of the rod receptors. » (Goldstein, 2010, p. 53)

Answer 61

B. Ajuster l’intensité d’une lumière clignotante. « In all of our dark adaptation experiments, we ask our observer to adjust the intensity of a small, fl ashing test light so that he or she can just barely see it. **This is similar to the psychophysical method of adjustment that we described in Chapter 1** (see page 14). In the first experiment, our observer looks at a small fi xation point while paying attention to a fl ashing test light that is off to the side (Figure 3.18). » (Goldstein, 2010, p. 53)

Answer 62

C. Sur la fovéa. « Because the observer is looking directly at the fi xation point, **its image falls on the fovea**, and the image of the test light falls in the periphery. Thus, the test light stimulates both rods and cones. » (Goldstein, 2010, p. 53)

Answer 63

B. Deux phases. « The dark adaptation curve indicates that the observer’s sensitivity increases in two phases. **It increases rapidly for the first 3 to 4 minutes after the light is extinguished and then levels off**; it begins increasing again at about 7 to 10 minutes and continues to do so until about 20 or 30 minutes after the light was extinguished (red curve in Figure 3.19). » (Goldstein, 2010, p. 53)

Answer 64

E. 100 000 fois plus grande. « The sensitivity at the end of dark adaptation, labeled dark-adapted sensitivity, is about **100,000 times greater than the light-adapted sensitivity** measured before dark adaptation began. » (Goldstein, 2010, p. 53)

Answer 65

D. 7 à 10 minutes. « It increases rapidly for the first 3 to 4 minutes after the light is extinguished and then levels off; **it begins increasing again at about 7 to 10 minutes** and continues to do so until about 20 or 30 minutes after the light was extinguished (red curve in Figure 3.19). » (Goldstein, 2010, p. 53)

Answer 66

B. En regardant directement la lumière de test « To measure dark adaptation of the cones alone, we have to ensure that the image of the test light stimulates only cones. **We achieve this by having the observer look directly at the test light** so its image will fall on the all-cone fovea, and by making the test light small enough so that its entire image falls within the fovea. » (Goldstein, 2010, p. 53)

Answer 67

C. Pour que son image tombe entièrement dans la fovéa « We achieve this by having the observer look directly at the test light so its image will fall on the all-cone fovea, and **by making the test light small enough so that its entire image falls within the fovea**. The dark adaptation curve determined by this procedure is indicated by the green line in Figure 3.19. » (Goldstein, 2010, p. 53)

Answer 68

C. La ligne verte « We achieve this by having the observer look directly at the test light so its image will fall on the all-cone fovea, and by making the test light small enough so that its entire image falls within the fovea. **The dark adaptation curve determined by this procedure is indicated by the green line** in Figure 3.19. » (Goldstein, 2010, p. 53)

Answer 69

B. L’activité des bâtonnets « This curve, which refl ects only the activity of the cones, matches the initial phase of our original dark adaptation curve but does not include the second phase. **Does this mean that the second part of the curve is due to the rods?** We can show that the answer to this question is “yes” by doing another experiment. » (Goldstein, 2010, p. 54)

Answer 70

C « As soon as the light is extinguished, **the sensitivity of both the cones and the rods begins increasing**. However, because our vision is controlled by the receptor system that is most sensitive, the cones, which are more sensitive at the beginning of dark adaptation, determine the early part of the dark adaptation curve. » (Goldstein, 2010, p. 54)

Answer 71

A « However, because our vision is controlled by the receptor system that is most sensitive, **the cones, which are more sensitive at the beginning of dark adaptation, determine the early part of the dark adaptation curve**. But what is happening to the sensitivity of the rods during this early part of dark adaptation? » (Goldstein, 2010, p. 54)

Answer 72

C « But what is happening to the sensitivity of the rods during this early part of dark adaptation? **The rods are increasing their sensitivity in the dark during the cone part of the dark adaptation curve**. After about 3 to 5 minutes, the cones are finished adapting, so their curve levels off. » (Goldstein, 2010, p. 54)

Answer 73

B « The rods are increasing their sensitivity in the dark during the cone part of the dark adaptation curve. **After about 3 to 5 minutes, the cones are finished adapting**, so their curve levels off. Meanwhile, the rods’ sensitivity continues to increase, until by about 7 minutes of dark adaptation the rods have caught up to the cones and then become more sensitive than the cones. » (Goldstein, 2010, p. 54)

Answer 74

C « After about 3 to 5 minutes, the cones are finished adapting, so their curve levels off. **Meanwhile, the rods’ sensitivity continues to increase, until by about 7 minutes of dark adaptation the rods have caught up to the cones and then become more sensitive than the cones**. Once the rods become more sensitive, they begin controlling the person’s vision, and the course of rod dark adaptation becomes visible. » (Goldstein, 2010, p. 54)

Answer 75

C « Once the rods become more sensitive, they begin controlling the person’s vision, and the course of rod dark adaptation becomes visible. **The place where the rods begin to determine the dark adaptation curve is called the rod–cone break**. Why do the rods take about 20 to 30 minutes to reach their maximum sensitivity (point R on the curve), compared to only 3 to 4 minutes for the cones (point C)? » (Goldstein, 2010, p. 54)

Answer 76

A, C, E « Why do the rods take about 20 to 30 minutes to reach their maximum sensitivity (point R on the curve), compared to only 3 to 4 minutes for the cones (point C)? **The answer to this question involves a process called visual pigment regeneration**, which occurs more rapidly in the cones than in the rods. » (Goldstein, 2010, p. 54)

Answer 77

D « Why do the rods take about 20 to 30 minutes to reach their maximum sensitivity (point R on the curve), compared to only 3 to 4 minutes for the cones (point C)? **The answer to this question involves a process called visual pigment regeneration**, which occurs more rapidly in the cones than in the rods. » (Goldstein, 2010, p. 54)

Answer 78

C. Elle est isomérisée et déclenche le processus de transduction. « When light hits the light-sensitive retinal part of the visual pigment molecule, it is isomerized and triggers the transduction process. » (Goldstein, 2010, p. 55)

Answer 79

D. Blanchiment du pigment visuel. « This separation causes the retina to become lighter in color, a process called visual pigment bleaching. » (Goldstein, 2010, p. 55)

Answer 80

D. La rétine d’une grenouille après illumination. « This bleaching is shown in Figure 3.20, which shows a picture of a frog retina that was taken moments after it was illuminated with light. » (Goldstein, 2010, p. 55)

Answer 81

B. Le pigment se régénère. « Luckily, even in the light, as some molecules are absorbing light, isomerizing, and splitting apart, molecules that have been split apart are undergoing a process called visual pigment regeneration in which the retinal and opsin become rejoined. » (Goldstein, 2010, p. 55)

Answer 82

C. Pour permettre la vision continue. « This would be a bad situation because we need intact visual pigment molecules to see. » (Goldstein, 2010, p. 55)

Answer 83

B. 6 minutes « Rushton’s measurements showed that cone pigment takes **6 minutes** to regenerate completely, whereas rod pigment takes more than 30 minutes. » (Goldstein, 2010, p. 55)

Answer 84

E. 30 minutes « Rushton’s measurements showed that cone pigment takes 6 minutes to regenerate completely, whereas **rod pigment takes more than 30 minutes**. » (Goldstein, 2010, p. 55)

Answer 85

B. Les pigments visuels se régénèrent « If you were to turn out the lights, then **bleached visual pigment would continue to regenerate**, but there would be no more isomerization, so eventually your retina would contain only intact (unbleached) visual pigment molecules. » (Goldstein, 2010, p. 55)

Answer 86

A. Plus la concentration est élevée, plus la sensibilité est faible « Our sensitivity to light depends on the **concentration of a chemical**—the visual pigment. » (Goldstein, 2010, p. 55)

Answer 87

B. 6 minutes « He found that the rate of **cone dark adaptation matched the rate of cone pigment regeneration**. » (Goldstein, 2010, p. 55)

Answer 88

E. 30 minutes « He found that the rate of cone dark adaptation matched the rate of cone pigment regeneration and the rate of **rod dark adaptation matched the rate of rod pigment regeneration**. » (Goldstein, 2010, p. 55)

Answer 89

C « A major cause of detached retinas is **traumatic injuries of the eye or head**, as when a baseball player is hit in the eye by a line drive. » (Goldstein, 2010, p. 55)

Answer 90

C « The result is that once visual pigments are bleached, so the retinal and opsin are separated, they **can no longer be recombined** in the detached part of the retina, and the person becomes blind in the area of the visual field served by this area of the retina. » (Goldstein, 2010, p. 55)

Answer 91

D « When part of the retina becomes detached, it has become separated from a layer that it rests on, called the **pigment epithelium**, which contains enzymes that are necessary for pigment regeneration. » (Goldstein, 2010, p. 55)

Answer 92

D « The result is that once visual pigments are **bleached, so the retinal and opsin are separated**, they can no longer be recombined in the detached part of the retina, and the person becomes blind in the area of the visual field served by this area of the retina. » (Goldstein, 2010, p. 55)

Answer 93

C « The result is that once visual pigments are bleached, so the retinal and opsin are separated, they can no longer be recombined in the detached part of the retina, and the person **becomes blind in the area of the visual field served by this area of the retina**. » (Goldstein, 2010, p. 55)

Answer 94

A « Another way to show that perception is determined by the properties of the visual pigments is to compare rod and cone spectral sensitivity—**an observer’s sensitivity to light at each wavelength across the visible spectrum**. » (Goldstein, 2010, p. 56)

Answer 95

B « To determine spectral sensitivity, we use flashes of **monochromatic light**, light that contain only a single wavelength. » (Goldstein, 2010, p. 56)

Answer 96

B « The result is the curve in Figure 3.21a, which shows that the threshold for seeing light is lowest **in the middle of the spectrum**; that is, less light is needed to see wavelengths in the middle of the spectrum than to see wavelengths at either the short- or long-wavelength ends of the spectrum. » (Goldstein, 2010, p. 56)

Answer 97

A, B, C « We determine the threshold for seeing these monochromatic lights for wavelengths across the visible spectrum (see Figure 3.1). For example, we might first determine the threshold for seeing a 420-nm (nanometer) light, then a 440-nm light, and so on, using one of the **psychophysical methods for measuring threshold** described in Chapter 1. » (Goldstein, 2010, p. 56)

Answer 98

A « To determine spectral sensitivity, we use flashes of **monochromatic light**, light that contain only a single wavelength. » (Goldstein, 2010, p. 56)

Answer 99

C « The result is the curve in Figure 3.21a, which shows that the threshold for seeing light is lowest **in the middle of the spectrum**; that is, less light is needed to see wavelengths in the middle of the spectrum than to see wavelengths at either the short- or long-wavelength ends of the spectrum. » (Goldstein, 2010, p. 56)

Answer 100

B. In terms of sensitivity versus wavelength «The ability to see wavelengths across the spectrum is often plotted not in terms of threshold versus wavelength as in Figure 3.21a, but in terms of **sensitivity versus wavelength**. We can convert threshold to sensitivity with the following equation: sensitivity = 1/threshold.» (Goldstein, 2010, p. 56)

Answer 101

E. By dividing 1 by threshold «We can convert threshold to sensitivity with the following equation: **sensitivity = 1/threshold**. When we do this for the curve in Figure 3.21a, we obtain the curve in Figure 3.21b, which is called the spectral sensitivity curve.» (Goldstein, 2010, p. 56)

Answer 102

A. By having people look directly at the test light «We measure the cone spectral sensitivity curve by **having people look directly at the test light**, so that it stimulates only the cones in the fovea, and presenting test flashes of wavelengths across the spectrum.» (Goldstein, 2010, p. 56)

Answer 103

C. By measuring sensitivity after the eye is dark adapted «We measure the rod spectral sensitivity curve by **measuring sensitivity after the eye is dark adapted** (so the rods control vision because they are the most sensitive receptors) and presenting test flashes off to the side of the fixation point.» (Goldstein, 2010, p. 56)

Answer 104

C. 500 nm «The cone and rod spectral sensitivity curves, shown in Figure 3.22, show that the rods are most sensitive to light of **500 nm** and the cones being most sensitive to light of 560 nm.» (Goldstein, 2010, p. 56)

Answer 105

D. 560 nm «The cone and rod spectral sensitivity curves, shown in Figure 3.22, show that the rods are most sensitive to light of 500 nm and the cones being most sensitive to light of **560 nm**.» (Goldstein, 2010, p. 56)

Answer 106

B. It increases «This difference in the sensitivity of the cones and the rods to different wavelengths means that as vision shifts from the cones to the rods during dark adaptation, we become relatively more **sensitive to short-wavelength light**—that is, light nearer the blue and green end of the spectrum.» (Goldstein, 2010, p. 56)

Answer 107

B « The shift from cone vision to rod vision that causes this enhanced perception of short wavelengths during dark adaptation is called the **Purkinje shift**, after Johann Purkinje, who described this effect in 1825. » (Goldstein, 2010, p. 57)

Answer 108

A « You can experience this shift in color sensitivity that occurs during dark adaptation by **closing one of your eyes for about 5–10 minutes**, so it dark adapts, and then switching back and forth between your eyes and noticing how the blue flower in Figure 3.23 is brighter compared to the red flower in your dark-adapted eye. » (Goldstein, 2010, p. 57)

Answer 109

D « You can experience this shift in color sensitivity that occurs during dark adaptation by closing one of your eyes for about 5–10 minutes, so it dark adapts, and then switching back and forth between your eyes and noticing how the **blue flower** in Figure 3.23 is brighter compared to the red flower in your dark-adapted eye. » (Goldstein, 2010, p. 57)

Answer 110

B. 500 nm « Le pigment des bâtonnets absorbe le mieux à 500 nm, la zone bleu-vert du spectre. » (Goldstein, 2010, p. 57)

Answer 111

C. Trois « Il y a trois spectres d’absorption pour les cônes parce qu’il y a trois pigments de cônes différents, chacun contenu dans son propre récepteur. » (Goldstein, 2010, p. 57)

Answer 112

A. 419 nm « Le pigment à courte longueur d’onde (S) absorbe la lumière le mieux à environ 419 nm. » (Goldstein, 2010, p. 57)

Answer 113

C. 531 nm « Le pigment à moyenne longueur d’onde (M) absorbe la lumière le mieux à environ 531 nm. » (Goldstein, 2010, p. 57)

Answer 114

D. 558 nm « Le pigment à longue longueur d’onde (L) absorbe la lumière le mieux à environ 558 nm. » (Goldstein, 2010, p. 57)

Answer 115

E. 560 nm « Les pigments des cônes à courte, moyenne et longue longueur d’onde qui absorbent le mieux à 419, 531 et 558 nm, respectivement, se combinent pour donner un spectre de sensibilité psychophysique qui atteint son maximum à 560 nm. » (Goldstein, 2010, p. 57)

Answer 116

C « Signals generated in the receptors (R) travel to the **bipolar cells** (B) and then to the ganglion cells (G). » (Goldstein, 2010, p. 58)

Answer 117

D « The receptors and bipolar cells do not have long axons, but the **ganglion cells** have axons like the neurons in Figure 2.4. These axons transmit signals out of the retina in the optic nerve. » (Goldstein, 2010, p. 58)

Answer 118

A « In addition to the receptors, bipolars, and ganglion cells, there are two other types of neurons, the **horizontal cells and amacrine cells**, which connect neurons across the retina. » (Goldstein, 2010, p. 58)

Answer 119

D « Signals can travel between receptors through the **horizontal cells** and between bipolar cells and between ganglion cells through the amacrine cells. » (Goldstein, 2010, p. 58)

Answer 120

B « We focus specifically on the property of **neural convergence** (or just convergence for short) that occurs when one neuron receives signals from many other neurons. » (Goldstein, 2010, p. 58)

Answer 121

D « A great deal of convergence occurs in the retina because there are 126 million receptors, but only 1 million ganglion cells. Thus, on the average, each ganglion cell receives signals from **126 receptors**. » (Goldstein, 2010, p. 58)

Answer 122

C « On the average, about **120 rods** pool their signals to one ganglion cell, but only about 6 cones send signals to a single ganglion cell. » (Goldstein, 2010, p. 58)

Answer 123

A « On the average, about 120 rods pool their signals to one ganglion cell, but only about **6 cones** send signals to a single ganglion cell. » (Goldstein, 2010, p. 58)

Answer 124

D « Many of the foveal cones have “private lines” to ganglion cells, so that each ganglion cell receives signals from only one cone, with **no convergence**. » (Goldstein, 2010, p. 58)

Answer 125

A « The greater convergence of the rods compared to the cones translates into two differences in perception: (1) the **rods result in better sensitivity** than the cones, and (2) the cones result in better detail vision than the rods. » (Goldstein, 2010, p. 58)

Answer 126

A D « The greater convergence of the rods compared to the cones translates into two differences in perception: (1) **the rods result in better sensitivity than the cones**, and (2) the **cones result in better detail vision** than the rods. » (Goldstein, 2010, p. 58)

Answer 127

B, C « One reason rod vision is more sensitive than cone vision is that **it takes less light to generate a response from an individual rod receptor than from an individual cone receptor**. But there is another reason as well: **The rods have greater convergence than the cones**. » (Goldstein, 2010, p. 58)

Answer 128

B « We saw that the release of excitatory transmitter at the synapse **increases the chances that the receiving neuron will fire**. » (Goldstein, 2010, p. 58)

Answer 129

C « The threshold for ganglion cell firing is **10 units of excitation**. That is, the ganglion cell must receive 10 units of excitation to fire. » (Goldstein, 2010, p. 58)

Answer 130

A « The ganglion cell must fire **before perception of the light can occur**. » (Goldstein, 2010, p. 58)

Answer 131

C « Thus, when intensity = 1, **neither the rod nor the cone ganglion cells fire**. » (Goldstein, 2010, p. 59)

Answer 132

C « If, however, we increase the intensity to 2, as shown in the figure, the rod ganglion cell receives 2 units of excitation from each of its 5 receptors, for a total of 10 units of excitation. This total reaches the threshold for the rods’ ganglion cell, **it fires**, and we see the light. » (Goldstein, 2010, p. 59)

Answer 133

B « Meanwhile, at the same intensity, the cones’ ganglion cells are still below threshold, each receiving only **2 units of excitation**. » (Goldstein, 2010, p. 59)

Answer 134

D « For the cones’ ganglion cells to fire, we must increase the intensity to **10**. » (Goldstein, 2010, p. 59)

Answer 135

B « The operation of these circuits demonstrates that one reason for the rods’ high sensitivity compared to the cones’ is the **rods’ greater convergence**. » (Goldstein, 2010, p. 59)

Answer 136

B « The fact that rod and cone sensitivity is determined not by individual receptors but by **groups of receptors** converging onto other neurons means that when we describe “rod vision” and “cone vision” we are actually referring to the way groups of rods and cones participate in determining our perceptions. » (Goldstein, 2010, p. 59-60)

Answer 137

B « While rod vision is more sensitive than cone vision because the rods have more convergence, the **cones have better visual acuity**—detail vision—because they have less convergence. » (Goldstein, 2010, p. 60)

Answer 138

B « When you move your eyes to look at different things in this way, what you are doing is scanning with your **cone-rich fovea** (remember that when you look directly at something, its image falls on the fovea). » (Goldstein, 2010, p. 60)

Answer 139

B « This is necessary because your **visual acuity is highest in the fovea**; objects that are imaged on the peripheral retina are not seen as clearly. » (Goldstein, 2010, p. 60)

Answer 140

C « When you move your eyes to look at different things in this way, what you are doing is scanning with your cone-rich fovea (remember that when you look directly at something, **its image falls on the fovea**). » (Goldstein, 2010, p. 60)

Answer 141

B « This is necessary because your visual acuity is highest in the fovea; **objects that are imaged on the peripheral retina are not seen as clearly**. » (Goldstein, 2010, p. 60)

Answer 142

E « Visual acuity can be measured in a number of ways, one of which is to determine how far apart two dots have to be before a space can be seen between them. We make this measurement by presenting a pair of closely spaced dots and asking whether the person sees one or two dots. We can also measure acuity by determining how large the elements of a checkerboard or a pattern of alternating black and white bars must be for the pattern to be detected. Perhaps the most familiar way of measuring acuity involves the eye chart in an optometrist’s or ophthalmologist’s office. » (Goldstein, 2010, p. 60)

Answer 143

B « In the demonstration above, we showed that **acuity is better in the fovea** than in the periphery. » (Goldstein, 2010, p. 60)

Answer 144

B « Because you were light adapted, the comparison in this demonstration was between the foveal cones, which are **tightly packed**, and the peripheral cones, which are more widely spaced. » (Goldstein, 2010, p. 60)

Answer 145

B « Comparing the foveal cones to the rods results in even greater differences in acuity. We can make this comparison by **measuring how acuity changes during dark adaptation**. » (Goldstein, 2010, p. 60)

Answer 146

B « The picture of the bookcase in Figure 3.27 simulates the **change in acuity that occurs during dark adaptation**. » (Goldstein, 2010, p. 60)

Answer 147

E « Visual acuity can be measured in a number of ways… Perhaps the most familiar way of measuring acuity involves the eye chart in an optometrist’s or ophthalmologist’s office. » (Goldstein, 2010, p. 60)

Answer 148

C « The books on the top shelf represent the **details we see when viewing the books in the light**, when our cones are controlling vision. » (Goldstein, 2010, p. 61)

Answer 149

B « The books on the middle shelf represent how we might perceive the **details midway through the process of dark adaptation**, when the rods are beginning to determine our vision. » (Goldstein, 2010, p. 61)

Answer 150

A « The books on the bottom shelf represent the **poor detail vision of the rods**. » (Goldstein, 2010, p. 61)

Answer 151

B « The poor detail vision of the rods is why it is difficult to read in dim illumination. » (Goldstein, 2010, p. 61)

Answer 152

B « The firing of the single rod ganglion cell provides no hint that two separate spots were presented. » (Goldstein, 2010, p. 61)

Answer 153

D « The firing of the two adjacent cone ganglion cells could have been caused by a single large spot. » (Goldstein, 2010, p. 61)

Answer 154

C « The output of the cones signals two separate spots, because there is a silent ganglion cell between the two that are firing. » (Goldstein, 2010, p. 61)

Answer 155

D « Thus, the rods’ convergence decreases their ability to resolve details. » (Goldstein, 2010, p. 61)

Answer 156

A « We have seen that the large amount of convergence that occurs in the rods results in **high sensitivity**, and the low amount of convergence of the cones results in high acuity. » (Goldstein, 2010, p. 61)

Answer 157

B « We have seen that the large amount of convergence that occurs in the rods results in high sensitivity, and the **low amount of convergence of the cones results in high acuity**. » (Goldstein, 2010, p. 61)

Answer 158

A « When we are looking directly at something under high illumination, **cone vision, aided by low neural convergence, enables us to see details**, as in the top shelf of the bookcase in Figure 3.27. » (Goldstein, 2010, p. 61)

Answer 159

E « When we are looking at something under low illumination, **rod vision, aided by high neural convergence, enables us to make out things that are dimly illuminated**, but we see few details, as in the bottom shelf of the bookcase. » (Goldstein, 2010, p. 61)

Answer 160

B « When we are looking at something under low illumination, rod vision, aided by **high neural convergence**, enables us to make out things that are dimly illuminated, but we see few details, as in the bottom shelf of the bookcase. » (Goldstein, 2010, p. 61)

Answer 161

C « We are now going to look at some perceptual effects of inhibition by focusing on lateral inhibition—inhibition that is transmitted across the retina. » (Goldstein, 2010, p. 62)

Answer 162

E « To understand how lateral inhibition can cause perceptual effects, we will look at an experiment using a primitive animal called the Limulus, more familiarly known as the horseshoe crab. » (Goldstein, 2010, p. 62)

Answer 163

C « Notice that activation of neurons A or C results in the release of inhibitory transmitter onto neuron B. » (Goldstein, 2010, p. 62)

Answer 164

B « We saw that the convergence and inhibition in this circuit caused neuron B to respond best to stimulation by a small spot of light on receptors 3, 4, and 5. » (Goldstein, 2010, p. 62)

Answer 165

B « Notice that activation of neurons A or C results in the release of inhibitory transmitter onto neuron B. » (Goldstein, 2010, p. 62)

Answer 166

C « To understand how lateral inhibition can cause perceptual effects, we will look at an experiment using a primitive animal called the Limulus, more familiarly known as the horseshoe crab. » (Goldstein, 2010, p. 62)

Answer 167

B. Parce que sa structure oculaire permet de stimuler des récepteurs individuels « They chose the Limulus because the structure of its eye makes it possible to stimulate individual receptors. » (Goldstein, 2010, p. 62)

Answer 168

C. La réponse de A diminue « But when they added illumination to the three nearby receptors at B, the response of receptor A decreased. » (Goldstein, 2010, p. 62)

Answer 169

C. Les cellules horizontales et amacrines « Just as the lateral plexus transmits signals laterally in the Limulus, the horizontal and amacrine cells transmit signals across the human retina. » (Goldstein, 2010, p. 62)

Answer 170

B. Améliorer la perception de la lumière et de l’obscurité « We will now see how lateral inhibition may influence how humans perceive light and dark. » (Goldstein, 2010, p. 62)

Answer 171

C. La perception de la lumière « We will now describe three perceptual phenomena that have been explained by lateral inhibition. Each of these phenomena involves the **perception of lightness**—the perception of shades ranging from white to gray to black. » (Goldstein, 2010, p. 62)

Answer 172

C. La grille de Hermann « The Hermann Grid: Seeing Spots at Intersections Notice the **ghostlike gray images** at the intersections of the white “corridors” in the display in Figure 3.32, which is called the **Hermann grid**. » (Goldstein, 2010, p. 62)

Answer 173

A. En regardant directement une intersection B. En couvrant deux rangées de carrés noirs avec du papier blanc « You can prove that this grayness is not physically present by noticing that it is reduced or vanishes when you **look directly at an intersection** or, better yet, when you **cover two rows of black squares with white paper**. » (Goldstein, 2010, p. 63)

Answer 174

B. Elles sont causées par l’inhibition latérale. « Figure 3.33 shows how the **dark spots at the intersections can be explained by lateral inhibition**. Figure 3.33a shows four squares of the grid and five receptors that are stimulated by different parts of the white corridors. » (Goldstein, 2010, p. 63)

Answer 175

B. Aux intersections des corridors blancs. « Receptor A is stimulated by light **at the intersection of the two white corridors**, where the gray spot is perceived, and the surrounding receptors B, C, D, and E are located in the corridors. » (Goldstein, 2010, p. 63)

Answer 176

B. Ils reçoivent la même stimulation. « It is important to note that all five of these receptors **receive the same stimulation**, because they are all receiving illumination from the white areas. » (Goldstein, 2010, p. 63)

Answer 177

B. Une vue en trois dimensions de la grille. « Figure 3.33b shows a **three-dimensional view of the grid** and the receptors. This view shows each receptor sending signals to a bipolar cell. » (Goldstein, 2010, p. 63)

Answer 178

B. Les signaux envoyés par les récepteurs aux cellules bipolaires. « This view shows each receptor **sending signals to a bipolar cell**. It also shows that each of the bipolar cells sends lateral inhibition, indicated by the arrows, to receptor A’s bipolar cell. » (Goldstein, 2010, p. 63)

Answer 179

D. Les cellules bipolaires. « We are assuming, for the purposes of this example, that our perception of the lightness at A is determined by the response of its **bipolar cell**. (It would be more accurate to use ganglion cells because they are the neurons that send signals out of the retina, but to simplify things for the purposes of this example, we will focus on the bipolar cells.) » (Goldstein, 2010, p. 63)

Answer 180

A. De la quantité de stimulation reçue de son récepteur. B. De la quantité d’inhibition latérale reçue de ses cellules voisines. « The size of the bipolar cell response depends on **how much stimulation it receives from its receptor** and on the **amount that this response is decreased by the lateral inhibition it receives from its neighboring cells**. » (Goldstein, 2010, p. 63)

Answer 181

E. 100 unités. « Let’s assume that light falling on A generates a response of **100 units in its bipolar cell**. This would be the response of the bipolar cell if no inhibition were present. » (Goldstein, 2010, p. 63)

Answer 182

C. Elle est égale à un dixième de la réponse du récepteur. « The lateral inhibition sent by each receptor’s bipolar cell is **one-tenth of each receptor’s response**. » (Goldstein, 2010, p. 63)

Answer 183

C. 60 unités. « To calculate the response of A’s bipolar cell, we start with A’s initial response of 100 and subtract the inhibition sent from the other four bipolar cells, as follows: 100 - 10 - 10 - 10 - 10 = **60** (Figure 3.33c). » (Goldstein, 2010, p. 63)

Answer 184

E. 76 unités. « The output of the bipolar cell receiving signals from D will be **100 -10 - 2- 10 - 2 -10 - 2 = 76** (Figure 3.34c). » (Goldstein, 2010, p. 63)

Answer 185

E. 100 unités. « Because receptors B, C, D, and E receive the same illumination as receptor A, their response is also **100**. » (Goldstein, 2010, p. 63)

Answer 186

C « The calculation is the same as the one we just did, but with one important difference. Two of the surrounding receptors, F and H are illuminated dimly because they fall under black squares. » (Goldstein, 2010, p. 63)

Answer 187

C. À cause de l’inhibition latérale. « Because the response associated with receptor A (at the intersection) is smaller than the response associated with receptor D (in the corridor between the black squares), the intersection should appear darker than the corridor. **This is exactly what happens—we perceive grey images at the intersections. Lateral inhibition therefore explains the dark images at the intersection**. » (Goldstein, 2010, p. 64)

Answer 188

A. C « When Hartline and coworkers recorded from the nerve fiber of receptor A, as shown in Figure 3.31a, they found that illumination of that receptor caused a large response. » (Goldstein, 2010, p. 62)

Answer 189

B. « When Hartline and coworkers recorded from the nerve fiber of receptor A, as shown in Figure 3.31a, they found that illumination of that receptor caused a large response. **But when they added illumination to the three nearby receptors at B, the response of receptor A decreased** (Figure 3.31b). » (Goldstein, 2010, p. 62)

Answer 190

C. E. « When Hartline and coworkers recorded from the nerve fiber of receptor A, as shown in Figure 3.31a, they found that illumination of that receptor caused a large response. But when they added illumination to the three nearby receptors at B, the response of receptor A decreased (Figure 3.31b). **They also found that increasing the illumination of B de- creased A’s response even more (Figure 3.31c)** » (Goldstein, 2010, p. 62)

Answer 191

B. Les images grises disparaissent. « Lateral inhibition therefore explains the dark images at the intersection. **(Although the fact that these images disappear when we look at the intersection directly must be explained by some other mechanism)**. » (Goldstein, 2010, p. 64)

Answer 192

C. Les bandes de Mach. « Another perceptual effect that can be explained by lateral inhibition is **Mach bands**, illusory light and dark bands near a light–dark border. » (Goldstein, 2010, p. 64)

Answer 193

C. À gauche et à droite de la bordure claire-sombre. « You can see Mach bands in Figure 3.35 by looking **just to the left of the light–dark border** for a faint light band (at B) and **just to the right of the border** for a faint dark band (at C). » (Goldstein, 2010, p. 64)

Answer 194

A. Des bandes lumineuses et sombres illusoires. « Another perceptual effect that can be explained by lateral inhibition is Mach bands, **illusory light and dark bands** near a light–dark border. » (Goldstein, 2010, p. 64)

Answer 195

B. Elles sont des illusions. « The reason Mach bands are interesting is that, like the spots in the Hermann grid, they are an illusion—they are not actually present in the pattern of light. **If we determine the intensity across the stripes in Figure 3.35a by measuring the amount of light reflected from this pattern as we move along the line between A and D, we obtain the result shown in Figure 3.35b**. » (Goldstein, 2010, p. 64)

Answer 196

B. Elle reste constante entre A et B, puis diminue entre C et D. « The light intensity remains the same across the entire distance between A and B then drops to a lower level and remains the same between C and D. **Because the intensities remain constant across the light stripe on the left and the dark stripe on the right, the small bands we perceive on either side of the border must be illusions**. » (Goldstein, 2010, p. 64)

Answer 197

A. Une augmentation de la luminosité à gauche de la bordure. « **The upward bump at B represents the slight increase in lightness we see to the left of the border**, and the downward bump at C represents slight decrease in lightness we see to the right of the border. » (Goldstein, 2010, p. 64)

Answer 198

B. Parce que l’intensité lumineuse reste constante. « The light intensity remains the same across the entire distance between A and B then drops to a lower level and remains the same between C and D. **Because the intensities remain constant across the light stripe on the left and the dark stripe on the right, the small bands we perceive on either side of the border must be illusions**. » (Goldstein, 2010, p. 64)

Answer 199

C. Les bandes de Mach « The lateral inhibition in our circuit has therefore created a neural pattern that looks like the Mach bands we perceive. **A circuit similar to this one, but of much greater complexity, is probably responsible for the Mach bands that we see**. » (Goldstein, 2010, p. 66)

Answer 200

A. L’effet de contraste simultané « The illusion that they are different, which is created by the differences in the areas surrounding each square, is the simultaneous contrast effect. **Your perception occurs because the two small squares are actually identical shades of gray**. The illusion that they are different, which is created by the differences in the areas surrounding each square, is the simultaneous contrast effect. » (Goldstein, 2010, p. 66)

Answer 201

A. La différence de luminosité entre les zones adjacentes « Simultaneous contrast occurs when our perception of the brightness or color of one area is affected by the presence of an adjacent or surrounding area. **The illusion that they are different, which is created by the differences in the areas surrounding each square**, is the simultaneous contrast effect. » (Goldstein, 2010, p. 66)

Answer 202

C. Un circuit de grande complexité « The lateral inhibition in our circuit has therefore created a neural pattern that looks like the Mach bands we perceive. **A circuit similar to this one, but of much greater complexity, is probably responsible for the Mach bands that we see**. Lateral Inhibition and Simultaneous Contrast » (Goldstein, 2010, p. 66)

Answer 203

A. La création d’un motif neuronal ressemblant aux bandes de Mach « The lateral inhibition in our circuit has therefore created a neural pattern that looks like the Mach bands we perceive. **A circuit similar to this one, but of much greater complexity, is probably responsible for the Mach bands that we see**. Lateral Inhibition and Simultaneous Contrast » (Goldstein, 2010, p. 66)

Answer 204

A. La différence de luminosité entre les zones adjacentes « The illusion that they are different, which is created by the differences in the areas surrounding each square, is the simultaneous contrast effect. **Your perception occurs because the two small squares are actually identical shades of gray**. The illusion that they are different, which is created by the differences in the areas surrounding each square, is the simultaneous contrast effect. » (Goldstein, 2010, p. 66)

Answer 205

B. La stimulation intense des récepteurs sous la zone claire « The receptors under the light area surrounding the square on the left are intensely stimulated, so they send a large amount of inhibition to the receptors under the left square (indicated by the large arrows). **The receptors under the dark area surrounding the square on the right are less intensely stimulated**, so they send less inhibition to the receptors under the right square (small arrows). » (Goldstein, 2010, p. 67)

Answer 206

A. Les récepteurs sous le carré de gauche reçoivent plus d’inhibition « Because the cells under the left square receive more inhibition than the cells under the right square, their response is decreased more, they fire less than the cells under the right square, and **the left square therefore looks darker**. The above explanation based on lateral inhibition makes sense and is still accepted by some researchers. » (Goldstein, 2010, p. 67)

Answer 207

C. Elle ne peut pas expliquer pourquoi la luminosité est uniforme à travers le carré « If we start at the edge of the center square on the left and move toward the middle of the square, the lightness appears to be the same, all across the square. **However, because lateral inhibition would affect the square more strongly near the edge**, we would expect that the square would look lighter near the border and darker in the center. » (Goldstein, 2010, p. 66)

Answer 208

B. L’inhibition latérale n’est pas l’unique explication du contraste simultané « The fact that this does not occur suggests that lateral inhibition cannot be the whole story behind simultaneous contrast. **In fact, psychologists have created other displays that result in perceptions that can’t be explained by the spread of lateral inhibition**. » (Goldstein, 2010, p. 67)

Answer 209

A. Un réseau de récepteurs stimulés par un motif « An explanation for simultaneous contrast that is based on lateral inhibition is diagrammed in Figure 3.40, which shows an array of receptors that are stimulated by a pattern like the one in Figure 3.39. **The receptors under the two small squares receive the same illumination**. » (Goldstein, 2010, p. 67)

Answer 210

A. Ils envoient une grande quantité d’inhibition « The receptors under the light area surrounding the square on the left are intensely stimulated, so they send a large amount of inhibition to the receptors under the left square (indicated by the large arrows). **The receptors under the dark area surrounding the square on the right are less intensely stimulated**, so they send less inhibition to the receptors under the right square (small arrows). » (Goldstein, 2010, p. 66)

Answer 211

C. La luminosité uniforme à travers le carré « If we start at the edge of the center square on the left and move toward the middle of the square, the lightness appears to be the same, all across the square. **However, because lateral inhibition would affect the square more strongly near the edge**, we would expect that the square would look lighter near the border and darker in the center. » (Goldstein, 2010, p. 67)

Answer 212

B. L’inhibition latérale n’explique pas l’illusion « But the opposite happens—rectangle B appears lighter! **Clearly, White’s illusion can’t be explained by lateral inhibition**. » (Goldstein, 2010, p. 67)

Answer 213

A. En utilisant du papier blanc pour masquer une partie de l’affichage « This is hard to believe, because the two rectangles look so different, but you can prove this to yourself by using white paper to mask off part of the display and **comparing parts of rectangles A and B**, as in Figure 3.42. » (Goldstein, 2010, p. 67)

Answer 214

B. Le rectangle B devrait apparaître plus sombre « Because area B receives more lateral inhibition than area A, an explanation based on lateral inhibition would predict that area B should appear darker, **like the left square in the simultaneous contrast display in Figure 3.40**. » (Goldstein, 2010, p. 67)

Answer 215

E. Le principe d’appartenance « What’s happening here, according to Alan Gilchrist and coworkers (1999), is that our perception of lightness in influenced by a principle called belongingness, which states that an area’s appearance is influenced by the part of the surroundings to which the area appears to belong. **According to this idea, our perception of rectangle A would be affected by the light background, because it appears to be resting on it.** Similarly, our perception of rectangle B would be affected by the dark bars, because it appears to be resting on them. » (Goldstein, 2010, p. 67)

Answer 216

B. Belongingness « What’s happening here, according to Alan Gilchrist and coworkers (1999), is that our perception of lightness is influenced by a principle called **belongingness**, which states that an area’s appearance is influenced by the part of the surroundings to which the area appears to belong. » (Goldstein, 2010, p. 67)

Answer 217

C. L’apparence d’une zone est influencée par son environnement « What’s happening here, according to Alan Gilchrist and coworkers (1999), is that our perception of lightness in influenced by a principle called belongingness, which states that an area’s appearance is influenced by the part of the surroundings to which the area appears to belong. **According to this idea, our perception of rectangle A would be affected by the light background, because it appears to be resting on it.** Similarly, our perception of rectangle B would be affected by the dark bars, because it appears to be resting on them. » (Goldstein, 2010, p. 67)

Answer 218

B. Le principe d’appartenance « **Whether or not this idea of belongingness turns out to the be correct explanation, there is no question that some mechanism other than lateral inhibition is involved in our perception of White’s illusion** and many other displays. » (Goldstein, 2010, p. 67)

Answer 219

B. Dans le cortex visuel « There is still much more processing to be done before perception occurs, and this processing happens later in the visual system, **in the visual receiving area of the cortex** and beyond. » (Goldstein, 2010, p. 67)