TOEFL Experts Reading Practice 34
Does the sound of music have a color to you? Can you taste the sight of a particular shade of blue? Few people can. For most of us, the five primary senses—sight, hearing, taste, smell, and touch—are distinct categories; our brains process these sensory experiences as separate from one another and fundamentally unique. But for certain people known as “synesthetes,” things are not so straightforward. For these people, the stimulation of one sense may trigger the activation of one or more other senses.
Just how prevalent synesthesia is remains unknown. Estimates range from 1 in 20 people to 1 in 25,000 people. The most common type of synesthesia is called “grapheme-color synesthesia,” or seeing different letters as different colors. Still, there are many people who experience other forms of overlapping senses. One such person was the American composer Leonard Bernstein, who reported that when he listened to music, the timbre1 of various sounds appeared to him visually as varied colors.
Other synesthetes may even have multiple forms of the condition at once. Twentieth-century Russian journalist Solomon Shereshevsky, for example, is reputed to have had a spectacular memory—he could memorize a speech word for word after hearing it only once, and could remember a complicated math formula within a strikingly short time frame. The method by which he did so was synesthesia, which for him existed among all five senses.
How does synesthesia work? In recent decades, scientists have been able to uncover the neurological basis for some kinds of synesthesia. Grapheme-color synesthetes, for example, display uncharacteristic neural activity in the color-based region of the visual cortex of their brains while reading, while people who are not grapheme-color synesthetes do not.
The genetic basis of synesthesia, however, remains somewhat of a mystery. In the early days of genetic research into the phenomenon, scientists hypothesized that the gene that brought about synesthesia was a dominant one located on the X chromosome. This was believed in part because the phenomenon appeared to be more common among women than men.
This belief has changed, however, as new research has challenged it. While there does appear to be a genetic basis of some sort, as revealed by the unusual brain activity associated with the condition, several developments have undermined the hypothesis that a dominant gene on the X chromosome is the precise genetic mechanism. One such development is that while early studies showed that more women than men are synesthetes, more recent and rigorous studies have suggested a more even distribution between the sexes. Furthermore, synesthesia can skip a generation, which means that if there is a gene for synesthesia, it cannot be a dominant gene, because dominant genes are not able to skip generations.
A study of a pair of identical female twins, one of whom is synesthetic and one of whom is not, raised further questions about the genetic basis of the phenomenon. Identical twins have the same genetic code—all of their genes are identical. For one to be synesthetic and the other not to be, therefore, is peculiar. The study raised the possibility of whether synesthesia can be environmentally triggered or suppressed. At the very least, it suggested there might be some explanation beyond the simple inheritance or non-inheritance of a synesthesia-causing gene.
But there is little evidence that synesthesia can be manipulated by one’s environment. Efforts to “train” people to be synesthetes have been unsuccessful compared to actual synesthetes. While people can “teach” their brains to correlate certain letters with certain colors, for instance, the neural activity in their brains remains distinct from that of people who are naturally synesthetic.
A likely possibility is that the genetic basis for synesthesia does indeed lie on the X chromosome, as predicted by early researchers, and that the twin study can be explained by a phenomenon called “X-inactivation.” X-inactivation is the process by which one of a female’s two X chromosomes is rendered essentially inactive by the other X chromosome. X-inactivation occurs randomly and at the cellular level during the earliest stages of development of the female. In other words, one X chromosome may be active in one cell (while the other one is silenced), but in the neighboring cell, the situation is reversed. This genetic phenomenon could explain the twin study, because it leads to a different expression of the same genes in two female twins, which is precisely what was observed.
timbre1: the particular quality or tenor of sound or music, distinguishing, say, violins from trumpets playing the same note
Does the sound of music have a color to you? Can you taste the sight of a particular shade of blue? Few people can. For most of us, the five primary senses—sight, hearing, taste, smell, and touch—are distinct categories; our brains process these sensory experiences as separate from one another and fundamentally unique. But for certain people known as “synesthetes,” things are not so straightforward. For these people, the stimulation of one sense may trigger the activation of one or more other senses.
Just how prevalent synesthesia is remains unknown. Estimates range from 1 in 20 people to 1 in 25,000 people. The most common type of synesthesia is called “grapheme-color synesthesia,” or seeing different letters as different colors. Still, there are many people who experience other forms of overlapping senses. One such person was the American composer Leonard Bernstein, who reported that when he listened to music, the timbre1 of various sounds appeared to him visually as varied colors.
Other synesthetes may even have multiple forms of the condition at once. Twentieth-century Russian journalist Solomon Shereshevsky, for example, is reputed to have had a spectacular memory—he could memorize a speech word for word after hearing it only once, and could remember a complicated math formula within a strikingly short time frame. The method by which he did so was synesthesia, which for him existed among all five senses.
How does synesthesia work? In recent decades, scientists have been able to uncover the neurological basis for some kinds of synesthesia. Grapheme-color synesthetes, for example, display uncharacteristic neural activity in the color-based region of the visual cortex of their brains while reading, while people who are not grapheme-color synesthetes do not.
The genetic basis of synesthesia, however, remains somewhat of a mystery. In the early days of genetic research into the phenomenon, scientists hypothesized that the gene that brought about synesthesia was a dominant one located on the X chromosome. This was believed in part because the phenomenon appeared to be more common among women than men.
This belief has changed, however, as new research has challenged it. While there does appear to be a genetic basis of some sort, as revealed by the unusual brain activity associated with the condition, several developments have undermined the hypothesis that a dominant gene on the X chromosome is the precise genetic mechanism. One such development is that while early studies showed that more women than men are synesthetes, more recent and rigorous studies have suggested a more even distribution between the sexes. Furthermore, synesthesia can skip a generation, which means that if there is a gene for synesthesia, it cannot be a dominant gene, because dominant genes are not able to skip generations.
A study of a pair of identical female twins, one of whom is synesthetic and one of whom is not, raised further questions about the genetic basis of the phenomenon. Identical twins have the same genetic code—all of their genes are identical. For one to be synesthetic and the other not to be, therefore, is peculiar. The study raised the possibility of whether synesthesia can be environmentally triggered or suppressed. At the very least, it suggested there might be some explanation beyond the simple inheritance or non-inheritance of a synesthesia-causing gene.
But there is little evidence that synesthesia can be manipulated by one’s environment. Efforts to “train” people to be synesthetes have been unsuccessful compared to actual synesthetes. While people can “teach” their brains to correlate certain letters with certain colors, for instance, the neural activity in their brains remains distinct from that of people who are naturally synesthetic.
A likely possibility is that the genetic basis for synesthesia does indeed lie on the X chromosome, as predicted by early researchers, and that the twin study can be explained by a phenomenon called “X-inactivation.” X-inactivation is the process by which one of a female’s two X chromosomes is rendered essentially inactive by the other X chromosome. X-inactivation occurs randomly and at the cellular level during the earliest stages of development of the female. In other words, one X chromosome may be active in one cell (while the other one is silenced), but in the neighboring cell, the situation is reversed. This genetic phenomenon could explain the twin study, because it leads to a different expression of the same genes in two female twins, which is precisely what was observed.
timbre1: the particular quality or tenor of sound or music, distinguishing, say, violins from trumpets playing the same note
→(P4) How does synesthesia work? In recent decades, scientists have been able to uncover the neurological basis for some kinds of synesthesia. Grapheme-color synesthetes, for example, display uncharacteristic neural activity in the color-based region of the visual cortex of their brains while reading, while people who are not grapheme-color synesthetes do not.
→(P4) How does synesthesia work? In recent decades, scientists have been able to uncover the neurological basis for some kinds of synesthesia. Grapheme-color synesthetes, for example, display uncharacteristic neural activity in the color-based region of the visual cortex of their brains while reading, while people who are not grapheme-color synesthetes do not.
→(P6) This belief has changed, however, as new research has challenged it. While there does appear to be a genetic basis of some sort, as revealed by the unusual brain activity associated with the condition, several developments have undermined the hypothesis that a dominant gene on the X chromosome is the precise genetic mechanism. One such development is that while early studies showed that more women than men are synesthetes, more recent and rigorous studies have suggested a more even distribution between the sexes. Furthermore, synesthesia can skip a generation, which means that if there is a gene for synesthesia, it cannot be a dominant gene, because dominant genes are not able to skip generations.
→(P6) This belief has changed, however, as new research has challenged it. While there does appear to be a genetic basis of some sort, as revealed by the unusual brain activity associated with the condition, several developments have undermined the hypothesis that a dominant gene on the X chromosome is the precise genetic mechanism. One such development is that while early studies showed that more women than men are synesthetes, more recent and rigorous studies have suggested a more even distribution between the sexes. Furthermore, synesthesia can skip a generation, which means that if there is a gene for synesthesia, it cannot be a dominant gene, because dominant genes are not able to skip generations.
→(P6) This belief has changed, however, as new research has challenged it. While there does appear to be a genetic basis of some sort, as revealed by the unusual brain activity associated with the condition, several developments have undermined the hypothesis that a dominant gene on the X chromosome is the precise genetic mechanism. One such development is that while early studies showed that more women than men are synesthetes, more recent and rigorous studies have suggested a more even distribution between the sexes. Furthermore, synesthesia can skip a generation, which means that if there is a gene for synesthesia, it cannot be a dominant gene, because dominant genes are not able to skip generations.
- Synesthesia is a neurological phenomenon by which a small percentage of people have blended sensory experiences.