WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

WE REALLYCAN TELL IF WE ARE BEING WATCHED

Stories about how people somehow know when they are being watched have been going around for years. However, few attempts have been made to investigate the phenomenon scientifically. Now, with the completion of the largest ever study of the so-called staring effect, there is impressive evidence that this is a recognizable and (13) ______ sixth  sense. The study (14) _______ hundreds of children. For the experiments, they sat with their eyes (15) _______ so they could not see, and with their backs to other children, who were told to either stare at them or look away. Time and time again the results showed that the children who could not see were able to (16) _______ when they were being stared at. In a total of more than 18,000 trials (17) ________ worldwide, the children (18) ________ sensed when they were being watched almost 70% of the time. The experiment was repeated with the (19) ________precaution of putting the children who were being watched outside the room, separated from the starers by the windows. This was done just in case there was some (20) ________ going on with the children telling each other whether they were looking or not.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.

RIGHT-HAND DOMINANCE

Humans are disproportionately right-handed. Scientists have not been able to agree over the exact percentages of right versus left- handers because there is no accepted standard for identifying which hand is dominant. For example, some people who write or throw with theirright hands may perform other tasks with their left hands or may kick a ball with their left foot. Absent an objective measure, therefore, the range of estimates is wide. Right-handers are said to make up 85% to 95% of all people and left-handers 5%-15%, while the remaining tiny percentageare ambidextrous, so they can use both hands with equal ability.

Perhaps the most unusual fact about right-hand dominance is how little we know about its causes. Several theories have been proposed. Some evidence exists that the phenomenon is genetic, but genetics cannot agree on the process by which handedness may be passed on by inheritance. Social and cultural forces can also cause a preference for one hand, as when teachers or parents force a naturally left-handed child to use their right hand. And it has been observed by anthropologist that left-handedness tends to be less common in restrictive societies and more common in permissive ones. But no consensus has been reached on howthat could occur.

The most credible explanations center on functions inside the brain. It has been shown that the brain’s two hemispheres control the opposite side of the body. It has been suggested that the nerves in the brain cross over at neck level to the other side of the body so that the right half of the brain governs the left side of the body while the left half governs the right side. Scientists believe that the left half of the brain evolved in such a way as to predominate over the right half. As a result, the right side of the body is controlled by the more influential left hemisphere, causing the right side to be more adept at physical tasks. But when a person is born with a dominant right hemisphere, that person will be left-handed. Some researchers have argued that some left-handedness may have a pathological origin, having been caused by brain trauma during birth.

A theory grounded in evolution is the “warrior and his shield theory”. This theory explains that right-handedness evolved over time to be dominant because a right-handed warrior would hold his shield in his left hand to protect his heart and to leave his right hand to  free to hold a weapon. A left-handed warrior, in contrast, would hold his weapon in his left hand and his shield in his right, leaving his heart exposed. Thus a right-handed warrior, with his heart protected against enemy attacks, was more likely to survive. By the process of natural selection, the trait for right-handedness became favored over that for left-handedness.

Another theory focuses on the naturally asymmetrical arrangement of the human body. Such asymmetry is evidenced by the observable facts that the right side of the face is slightly different from the left, that one leg is stronger or longer than the other, and that one foot is larger than the other one. Right-handedness, the theory proposes, is just another example of this natural asymmetry.

(A) A consequence of right-hand dominance is that most common consumer products are geared to right-handers only, leaving left-handers to struggle to adapt to designs not made with them in mind. (B) Some of these include scissors, doorknobs, locks, screwdrivers, automobile fixtures, refrigerators, can openers, clothes buttons, and fasteners, and musical instruments. (C) The result of this design bias can be more than mere inconvenience. (D) Some left-handed soldiers shooting rifles designed for right-handers have sustained eye and head injuries from ejected shell casings.

Hand dominance does not seem to occur in non-human animal species. While some individual animals can be seen developing a preference for one hand or the other, there is no evidence that this preference is common to the species as a whole, as it is in humans. Some scientists claim to have observed such dominance in animals but only in controlled settings, such as a zoo or laboratory, and only when the animals are performing manual tasks that do not mirror howthey use their hands in the wild.