Hormones and Pheromones
____ = SAQ Studies
Levels of hormones can influence our behavior and vice versa.
1.Hormones and Behaviour
Hormones are chemicals released by specific glands in the body to regulate medium- and long-
term changes in the body.
1.1 Testosterone and aggression
Testosterone is sex hormone. Thus effects sex differently.
Hormones are chemical messengers that are transported through our blood as a result of
activation of different glands in the endocrine system. These chemicals perform a number of
functions on our physiological processes. They can spark physical reactions throughout the body.
Testosterone affects the amygdala, which is a part of the brain that is associated with perception
of threat and response to threat by aggression. Amygdala, when stimulated, stimulates a response
mechanism in the body by stimulating the process of pumping adrenaline, which prepares for
fight or flight response to threat. Resulting behavior often can be aggression. Higher testosterone
levels increase amygdala sensitivity, increasing its activation. Thus, it may increase the
perception of threat and leading to higher expression of aggressive behavior.
Albert el al. (1986)
(animal experimentation on rats)
Aim: To investigate the effects of changing testosterone levels on the aggressiveness of male
rats.
Method:
They placed rats in cages and identified the alpha males. An alpha male is the leader of the
colony. The researchers identified the alpha males and they measured their aggression levels
when there was a non-aggressive rat placed in the same cage. They measured aggression by
recording behaviours such as biting.
After they measured the aggression levels they divided the alpha males into four
separate groups to undergo four separate surgeries (IV):
A. Castration
, B. Castration followed by implanting of tubes with testosterone
C. Castration followed by implanting of empty tubes
D. A “sham” castration followed by implanting of empty tubes (they were cut open but the
testicles were kept intact)
DV: They measured the change in aggression when non-aggressive rats were introduced to the
cage.
Findings:
A&C showed less aggression. B&D, who had castration but maintained their testosterone level
showed no decrease in aggression.
● As the second part of their experiment, they put castrated alpha males in the same cage as
non-alphas or subordinate males. It showed that the subordinate males rose to social
dominance and showed greater response to social threat.
Evaluation:
Strengths:
- Experiment with direct physical manipulation of IV.
- High internal validity
- This study used rats instead of humans, ensuring no possible harm done to humans.
- Rats are inexpensive, and have large litters, which allows for members of the same litter
to be assigned to different experimental conditions.
Limitation:
- May be inapplicable to humans because it is an animal experiment
- Does not consider factors distinct to humans, eg higher cognition, sociocultural factors,
when applying the results of the study to humans.
Radke et al. (2015)
Aim: to investigate the relationship between perceiving a social threat, testosterone and the
amygdala.
Method:
54 healthy female participants.
A small dose of testosterone was given to half and placebo to the other half. The participants
were scanned in an fMRI while they were shown pictures of faces with happy or angry
expressions one at a time. The participants were told to “avoid” or to “approach” the faces using
a joystick. When the joystick was pushed one way, the stick made the picture gradually bigger
and vice versa. The “approaching” of angry faces was designed to model the social threat of an
angry person approaching them.
____ = SAQ Studies
Levels of hormones can influence our behavior and vice versa.
1.Hormones and Behaviour
Hormones are chemicals released by specific glands in the body to regulate medium- and long-
term changes in the body.
1.1 Testosterone and aggression
Testosterone is sex hormone. Thus effects sex differently.
Hormones are chemical messengers that are transported through our blood as a result of
activation of different glands in the endocrine system. These chemicals perform a number of
functions on our physiological processes. They can spark physical reactions throughout the body.
Testosterone affects the amygdala, which is a part of the brain that is associated with perception
of threat and response to threat by aggression. Amygdala, when stimulated, stimulates a response
mechanism in the body by stimulating the process of pumping adrenaline, which prepares for
fight or flight response to threat. Resulting behavior often can be aggression. Higher testosterone
levels increase amygdala sensitivity, increasing its activation. Thus, it may increase the
perception of threat and leading to higher expression of aggressive behavior.
Albert el al. (1986)
(animal experimentation on rats)
Aim: To investigate the effects of changing testosterone levels on the aggressiveness of male
rats.
Method:
They placed rats in cages and identified the alpha males. An alpha male is the leader of the
colony. The researchers identified the alpha males and they measured their aggression levels
when there was a non-aggressive rat placed in the same cage. They measured aggression by
recording behaviours such as biting.
After they measured the aggression levels they divided the alpha males into four
separate groups to undergo four separate surgeries (IV):
A. Castration
, B. Castration followed by implanting of tubes with testosterone
C. Castration followed by implanting of empty tubes
D. A “sham” castration followed by implanting of empty tubes (they were cut open but the
testicles were kept intact)
DV: They measured the change in aggression when non-aggressive rats were introduced to the
cage.
Findings:
A&C showed less aggression. B&D, who had castration but maintained their testosterone level
showed no decrease in aggression.
● As the second part of their experiment, they put castrated alpha males in the same cage as
non-alphas or subordinate males. It showed that the subordinate males rose to social
dominance and showed greater response to social threat.
Evaluation:
Strengths:
- Experiment with direct physical manipulation of IV.
- High internal validity
- This study used rats instead of humans, ensuring no possible harm done to humans.
- Rats are inexpensive, and have large litters, which allows for members of the same litter
to be assigned to different experimental conditions.
Limitation:
- May be inapplicable to humans because it is an animal experiment
- Does not consider factors distinct to humans, eg higher cognition, sociocultural factors,
when applying the results of the study to humans.
Radke et al. (2015)
Aim: to investigate the relationship between perceiving a social threat, testosterone and the
amygdala.
Method:
54 healthy female participants.
A small dose of testosterone was given to half and placebo to the other half. The participants
were scanned in an fMRI while they were shown pictures of faces with happy or angry
expressions one at a time. The participants were told to “avoid” or to “approach” the faces using
a joystick. When the joystick was pushed one way, the stick made the picture gradually bigger
and vice versa. The “approaching” of angry faces was designed to model the social threat of an
angry person approaching them.
