Emotion is at the heart of who we are as people.  It is a reflection of our mental state.  For the AP exam you will have to be aware of three different theories that try to explain how and why we have emotions.

James-Lange Theory of Emotion

William James and Carl Lange theorized that we feel emotion because of biological changes caused by stress.  So if I jump out and scare the behoovies out of you, your heart begins to race and that bodily change causes you to feel fear.

Cannon-Bard Theory of Emotion

Walter Cannon and Philip Bard doubted the James-Lange order of events.  They stated that if you are really excited or scared, you body reacts with the same changes (elevated heart and respiratory rate etc…).  They theorized that the biological change and the cognitive awareness of the emotional state occurred simultaneously.  Cannon believed that the thalamus (switchboard in the brain) send information from the environment simultaneously to the autonomic nervous system (for body changes) and cerebral cortex (emotional state).  Cannon had a good concept but he overestimated the role of the thalamus and underestimated other brain structures such as the amygdala, in the formation of emotion. 

Two-Factor Theory of Emotion

Stanley’s Schacter’s two-factor theory explains emotions in a more complete way that the other two theories mentioned above.  Two-factor theory demonstrates that emotion depends on the interaction between two factors, biology and cognition. The idea behind this theory is that you first experience physiological arousal (biology) and then find a label in our mind (cognition) to explain the emotion.  For example, if you are feeling unwell, you may deduce the illness from the symptoms.  This theory explains that your biological state will interpret emotions differently.  If I go for a jog and you lay in bed, my heart rate is more elevated.  Then somebody jumps out and scares us.  I will experience greater fear because my heart rate is already elevated and when I interpret what my body is feeling, it will feel like a worse fear.  The same goes for feelings of love.  If you want to experience more passionate feelings, tell your boyfriend/girlfriend how you feel just after you have worked out.


I really did not know where to put stress so I guess it kind of fits under emotion.  Obviously too much stress is bad for us (although the Yerkes-Dodson Law says some is OK for optimum performance). 

Psychologists often use factors such as reaction to stress to divide up people’s personality types.  One such division is Type A and Type B personalities.  Type A personality is a set of characteristics that includes being impatient, excessively time-conscious, insecure about one’s status, highly competitive, hostile and aggressive, and incapable of relaxation. Type A individuals are often highly achieving workaholics who multi-task, drive themselves with deadlines, and are unhappy about the smallest of delays. The have been described as stress junkies. The Type B personality, in contrast, is patient, relaxed, and easy-going. There is also a Type AB mixed profile for people who cannot be clearly categorized.

What is important to know about these personality types is that Type A personalities not only feel more stress, but they are at higher risk for coronary heart disease.

Measuring Stress

Two psychologists (there names are Thomas Holmes and Richard Rahe- but I have never seen their names on the AP- which of course means that you will remember them), came up with a test that measures stress in your lives.  The test is called the Social Readjustment Rating Scale (SRRS) and measures stress using life-change units (LCUs).  Everytime you get married, graduate college, get a new job, buy an apartment etc…., you increase your LCU’s and thus increase your stress levels.  A person who scores high on the SRRS by having too many LCUs is more likely to have stress-related diseases than a person with a low score.

Seyle’s General Adaptation Syndrome

Han’s Seyle’s is the big daddy in the filed of stress and formulated a stage theory that he says animals (including us) go through in stressful times.  It is a three stage process:

  1. Alarm reaction: Heart rate increases, blood is diverted away from other body functions to muscles needed to react.  The organism readies itself to meet the challenge through activation of the sympathetic nervous system.

  2. Resistance: The body remains physiologically ready (high heart rate and so on..).  Hormones are released to maintain this state of readiness.  If the resistance stage lasts too long, the body can deplete its resources.

  3. Exhaustion: The parasympathetic nervous system returns our physiological state to normal.  We can be more vulnerable to disease in this stage especially if our resources were depleted by an extended resistance stage.