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Signal detection studies measure an individual’s ability to detect certain stimuli. They involve exposure to stimuli at varying magnitudes and ask subjects to detect any changes in their perceptual experience of the stimuli (i.e. the just-noticeable difference). Perceiving magnitude differences in stimuli depends on the type of sensory experience (e.g. touch or sound) and is based on proportional rather than absolute amounts.
Imagine a hypothetical study that asked participants to perceive changes in amplitude of a sound stimulus. In this experiment, the researchers wanted to know how much the amplitude needed to change in order for an individual to detect a difference. They decided to test the just-noticeable difference at three different amplitudes: low, medium, and high. Participants in each category listened to the initial sound, and then the amplitude was increased or decreased slightly until participants detected a difference.
Imagine that this study used a forced choice design in which participants had to select "the same" or "different" after hearing a pair of sounds at different amplitudes. As the amplitude of the comparison sound increased, which type of signal detection response would be most likely, regardless of the initial sound?
In forced-choice signal detection method, responses can be classified into four categories: miss (failing to identify a changed stimulus), false alarm (identifying an unchanged stimulus as changed), correct rejection (identifying an unchanged comparison as the same as the initial stimulus), or hit (correctly identifying a comparison stimulus that differs from the initial stimulus). As the amplitude is increased, it is also more likely that the subject would be able to correctly identify a changed stimulus. The greater the discrepancy in magnitude for the two sounds, the more likely the participant will get a hit.
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Which of the following is an example of sensory adaptation?
Sensory adaptation is the gradual alteration in sensitivity with prolonged stimulation or the absence of stimulation. Being able to see the candle flame is an example of "absolute threshold," which is the minimum intensity of a stimulus for humans to be able to detect the stimulus fifty percent of the time. Last, needing more of a drug to feel its effects is an example of tolerance.
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What is the definition of a "just-noticeable difference"?
Just-noticeable difference (JND) is the amount that a stimulus needs to change for someone to be able to notice it at least half the time. For example, the JND needed to perceive that a light is brighter is a two percent change in the brightness of the light’s illumination. This means that when the brightness goes up by two percent, we would be able to notice a difference half of the time or more.
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As a part of a research study, Carlos was presented with a sound. He was instructed to press "S" (for “same”) every time that he heard the same sound, and to press "D" (for “different”) every time he heard a different sound. At the end of the test, Carlos was informed that he correctly pressed "S" for every same sound, but incorrectly identified many of the different sounds as “same sounds.” Carlos' ability to detect signals would be described as which of the following?
Sensitivity is the ability to detect a true signal. Carlos correctly identified all of the "S" sounds; however, he missed many of the "D" sounds, indicating that his selectivity is poor. In medicine, doctors desire that screening instruments (e.g. mammograms as a screening for breast cancer) have high sensitivity so that no cases or symptoms are missed. Selectivity is less important for screening.
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Signal detection studies measure an individual’s ability to detect certain stimuli. They involve exposure to stimuli at varying magnitudes and ask subjects to detect any changes in their perceptual experience of the stimuli (i.e. the just-noticeable difference). Perceiving magnitude differences in stimuli depends on the type of sensory experience (e.g. touch or sound) and is based on proportional rather than absolute amounts.
Imagine a hypothetical study that asked participants to perceive changes in amplitude of a sound stimulus. In this experiment, the researchers wanted to know how much the amplitude needed to change in order for an individual to detect a difference. They decided to test the just-noticeable difference at three different amplitudes: low, medium, and high. Participants in each category listened to the initial sound, and then the amplitude was increased or decreased slightly until participants detected a difference.
Which of the following choices best describes amplitude?
In the passage, amplitude refers to loudness. On the other hand, frequency refers to pitch while timbre refers to quality/purity of sound.
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Perception is the process that occurs when the brain processes sensory stimuli and translates them in a way that a person can understand. Perception is not usually a conscious process; furthermore, sensing a particular stimulus is a different process than the interpretation (i.e. perception) of that stimulus.
A team of perception researchers decided to test the difference between sensation and perception by testing the reading speed of a paragraph in three conditions. In the first condition, the researchers correctly spelled the words in the sentences. In the second condition, they had the same words with the letters randomly jumbled within each word; however, the first and last letter of each word remained in the correct position. In the third condition, researchers used the same words and randomly jumbled every letter in each word, including the first and last letters. Sample sentences from the paragraphs are below:
1). Mary crossed the street to purchase a cookie after lunch.
2). Mray csorsed the sretet to pruachse a ckooie atfer lnuch.
3). Rmya rsocsed het teerst to curaepshs a okocei feart culhn.
The researchers timed how long it took for the participants to correctly say a sentence fluently. They found that participants in condition three took significantly more time to read the sentence fluently, whereas they found no significant difference in the average amount of time it took participants to read the passage in condition one compared to condition two.
The observation that participants did not differ in reading time between conditions one and two illustrates that humans rely on which of the following principles when reading?
Top-down and bottom-up processing are both examples of feature analysis, which allows us to detect specific elements and assemble them into a more complex visual form. A top-down process is a progression from the whole to the details (in this case, from the whole word to the individual letters). Bottom-up processing is the opposite; it is the progression from individual elements to the whole. Because participants in condition two were still reading as quickly as those in condition one, it suggests that in reading, humans process the whole word rather than each individual letter (i.e. top-down process).
The Phi Phenomenon is the illusion of movement created by presenting visual stimuli in rapid succession (e.g. a cartoon flip book). Inattentional blindness occurs when someone is hyper-focused on one stimulus and unable to take in other information.
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Perception is the process that occurs when the brain processes sensory stimuli and translates them in a way that a person can understand. Perception is not usually a conscious process; furthermore, sensing a particular stimulus is a different process than the interpretation (i.e. perception) of that stimulus.
A team of perception researchers decided to test the difference between sensation and perception by testing the reading speed of a paragraph in three conditions. In the first condition, the researchers correctly spelled the words in the sentences. In the second condition, they had the same words with the letters randomly jumbled within each word; however, the first and last letter of each word remained in the correct position. In the third condition, researchers used the same words and randomly jumbled every letter in each word, including the first and last letters. Sample sentences from the paragraphs are below:
1). Mary crossed the street to purchase a cookie after lunch.
2). Mray csorsed the sretet to pruachse a ckooie atfer lnuch.
3). Rmya rsocsed het teerst to curaepshs a okocei feart culhn.
The researchers timed how long it took for the participants to correctly say a sentence fluently. They found that participants in condition three took significantly more time to read the sentence fluently, whereas they found no significant difference in the average amount of time it took participants to read the passage in condition one compared to condition two.
Suppose the researchers were also interested in the amount of time it took the participants in each condition to read each letter fluently (as opposed to each word). In order to test this phenomenon, participants across conditions were instructed to read each letter aloud as quickly and as correctly as possible. They found no group differences in letter reading speed or accuracy. Based on these results, the researchers would most likely conclude which of the following?
If participants in all three conditions did not differ in letter reading speed, but they differed in word reading speed, then it suggests that reading is not just decoding letters. In other words, top-down processes are at play. In a top-down process, the brain uses a-priori knowledge of the world to form percepts or mental impressions about what a stimulus might be.
Given that participants in condition three were reading slower, it could be that their reading ability was poorer to begin with (i.e. a confounding variable); however, because they can read letters just as fluently as the other groups, it is unlikely that the groups differ in reading ability.
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Perception is the process that occurs when the brain processes sensory stimuli and translates them in a way that a person can understand. Perception is not usually a conscious process; furthermore, sensing a particular stimulus is a different process than the interpretation (i.e. perception) of that stimulus.
A team of perception researchers decided to test the difference between sensation and perception by testing the reading speed of a paragraph in three conditions. In the first condition, the researchers correctly spelled the words in the sentences. In the second condition, they had the same words with the letters randomly jumbled within each word; however, the first and last letter of each word remained in the correct position. In the third condition, researchers used the same words and randomly jumbled every letter in each word, including the first and last letters. Sample sentences from the paragraphs are below:
1). Mary crossed the street to purchase a cookie after lunch.
2). Mray csorsed the sretet to pruachse a ckooie atfer lnuch.
3). Rmya rsocsed het teerst to curaepshs a okocei feart culhn.
The researchers timed how long it took for the participants to correctly say a sentence fluently. They found that participants in condition three took significantly more time to read the sentence fluently, whereas they found no significant difference in the average amount of time it took participants to read the passage in condition one compared to condition two.
Suppose the researchers wanted to test the Gestalt principle of proximity. In order to do this, they might consider which of the following options?
The Gestalt principle of proximity suggests that the closer objects are to one another, the more likely they will be grouped together. This is why we leave larger spaces between words than we do letters. Testing if varying the amount of space between words impacted reading fluency would be testing proximity whereas varying color, font, or size would be testing the Gestalt principle of similarity, which posits that objects that are visually similar (in size shape or color) are likely to be grouped together.
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Perception is the process that occurs when the brain processes sensory stimuli and translates them in a way that a person can understand. Perception is not usually a conscious process; furthermore, sensing a particular stimulus is a different process than the interpretation (i.e. perception) of that stimulus.
A team of perception researchers decided to test the difference between sensation and perception by testing the reading speed of a paragraph in three conditions. In the first condition, the researchers correctly spelled the words in the sentences. In the second condition, they had the same words with the letters randomly jumbled within each word; however, the first and last letter of each word remained in the correct position. In the third condition, researchers used the same words and randomly jumbled every letter in each word, including the first and last letters. Sample sentences from the paragraphs are below:
1). Mary crossed the street to purchase a cookie after lunch.
2). Mray csorsed the sretet to pruachse a ckooie atfer lnuch.
3). Rmya rsocsed het teerst to curaepshs a okocei feart culhn.
The researchers timed how long it took for the participants to correctly say a sentence fluently. They found that participants in condition three took significantly more time to read the sentence fluently, whereas they found no significant difference in the average amount of time it took participants to read the passage in condition one compared to condition two.
Suppose the researchers wanted to also test whether reading fluency in the three conditions varied by language status (i.e., native English speaker vs. participants who learned English as a second language later in life). Whereas in the original study, participants in conditions one and two did not vary significantly in reading fluency, participants who learned English as a second language later in life were slower at reading the sentences in condition two compared to condition one. Given this effect, the researchers would be most likely to conclude which of the following?
Native English speakers would probably have much more exposure to English words from a young age; therefore, they have more a-priori knowledge (i.e. a top-down approach) of the features of English words compared to non-native speakers who probably rely more on the decoding of individual letters to form a word (i.e. a bottom-up approach). Even though fluency was poorer in condition two for non-native speakers, this does not mean that they have a reading disorder.
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Which of the following is not a cause of a conductive hearing loss?
Conductive hearing loss occurs when sound is not conducted through the external auditory canal to the tympanic membrane and the ossicles. Causes include acute otitis media, performated eardrum, impacted cerumen (earwax), or a foreign body in the external canal. A sensorineural hearing loss occurs when there is damage to the fine hairs in the cochlea caused by loud noise.
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Which of the following is not a bone of the middle ear?
The "malleus," "incus," and "stapes" are the three bones that make up the ossicles of the middle ear. Together they work to transform sound waves into mechanical vibrations. The "pinna" is not a bone at all, but rather the anatomical term for the fleshy, cartilaginous outer ear.
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Sound waves enter the outer ear and vibrate the tympanic membrane, which causes the transmission of sound waves through the ossicles to the inner ear. In what order do the ossicles vibrate?
The ossicle that attaches directly to the tympanic membrane is the malleus, or "hammer." This bone articulates with the incus, or "anvil," which then articulates with the stapes, or "stirrup" (so called because of it's resemblance to the stirrup of a saddle). The stapes in turn attaches to the oval window of the fluid-filled inner ear.
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Which of the following structures is the main sensory organ associated with hearing?
The main sensory organ of hearing is a small structure within the cochlea called the “organ of Corti.” It contains hair cells, which are sensory receptor cells capable of responding to changes in pressure of the fluid of the inner ear. The organ of Corti is sandwiched between the three fluid-filled chambers, or scalae: the scala vestibuli, the scala tympani, and the scala media.
The “bony labyrinth” is a separate part of the inner ear that plays a role in balance and equilibrium. The “eustachian tube” is not a part of the inner ear, but rather a channel between the middle ear and the pharynx.
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Which of the following is not a function of the eustachian tube?
The eustachian tube primarily functions to equalize pressure between the middle ear and the atmosphere, remove cellular and bacterial waste from the middle ear, and to drain fluid from the middle ear into the pharynx. Cells within the inner ear produce perilymph.
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Which of following is a true statement regarding light and the human eye?
The first structure that light will encounter as it enters the eye is the cornea, a transparent protein disc designed to refract light toward the eye interior. The aqueous humor is the liquid medium between the cornea and the lens of the eye. Light will pass through the aqueous humor and the pupil before hitting the lens. The lens then focuses the light onto the back of the eye. The vitreous humor is the liquid medium between the lens and the retina at the back of the eye.
The iris is used to control the shape of the pupil, and does not contain photoreceptors. All photoreceptors are located on the retina, which lines the back wall of the eye. A small region known as the fovea centralis houses a large number of cones (photoreceptors) at the back of the eye, but is part of the greater retinal structure.
The only true statement given is that light will pass through the aqueous humor before passing through the vitreous humor.
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Diana takes the subway to and from school every day. Her family’s apartment, situated in a low-income neighborhood of New York City, is a thirty-minute walk from the subway station. During her trips to the subway, Diana loves to watch people work, play, and socialize. She feels very safe in her community because she trusts the people around her.
Diana’s mother is having trouble seeing clearly. The lens of her eye appears white and cloudy. Which of the following most likely describes this situation?
The symptoms describe a “cataract.” Cataracts form when a protein coat builds up and cause a white barrier to form that limits vision. It is normally surgically removed. “Astigmatism” is a misshapen cornea that can also cause vision problems. “Conjunctivitis” is a disorder that is made evident by the inflammation of the sclera, or white part of the eye. Last, “glaucoma” describes damage caused to the optic nerve, usually by a buildup of excess fluid in the eye.
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Which of the following is the term for the process by which the eye's lens changes shape to bring close or distant objects into focus on the retina?
The lens of the eye must be able to change its shape in order to re-focus the vision on near or far objects as the eye moves. This process is called “accommodation.” On the other hand, “convergence” is the ability of the eyes to move toward one another in order to focus on objects that are very close up. “Mydriasis” is the term for dilation of the pupil, and "contrast" is a visible quality of difference in color or brightness of objects, and not a function of the eye itself.
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In myopia, which of the following abilities is impaired?
Myopia, often called nearsightedness, is an inability to being distant objects into clear focus. This may be due either to excess curvature of the cornea or to length of the eyeball itself causing the focal point of light rays to fall in front of the retina, rather than against it.
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Which of the following terms describes the inability to focus vision on close-up objects?
“Presbyopia” is the term for the inability to focus the vision on close-up objects. It is most commonly caused by loss of elasticity of the lens of the eye as individuals age.
On the other hand, the other choices are incorrect. “Amblyopia” is a general term used to denote cases in which one eye is communicating less visual information to the brain, resulting in a loss of vision in that eye In other words, the brain learns to ignore visual stimulation from the non-dominant eye. A common cause of amblyopia is “strabismus”—commonly known as “lazy eye.” It is defined as a lack of coordination between extraocular muscles that prevents the eyes from orienting in the same direction. In this case, there will almost always be a dominant eye, and if the condition is not corrected in childhood, the non-dominant eye generally suffers permanent vision loss. “Nystagmus” is a condition of involuntary eye movement (i.e. the eye seems to shudder, generally in a horizontal plane) that may or may not be associated with visual impairment. It can have numerous etiologies, including nervous system disorders, alcohol or drug reaction, congenital defect, or inner-ear disorder.
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Which of the following structures of the eye is not responsible for the refraction and focusing of light?
Light is refracted and focused by the cornea, the anterior chamber, and the lens. The retina is a thin layer of nervous system tissue, which receives focused light patterns and transmits those patterns to the brain via photoreceptor cells.
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