Understanding Psychology (10th Ed)

146 Chapter 
5 
States of Consciousness
can make us feel edgy, slow our reaction time, and lower our performance on aca-
demic and physical tasks. In addition, we put ourselves, and others, at risk when we 
carry out routine activities, such as driving, when we’re very sleepy (Anderson & 
Home, 2006; Morad et al., 2009; Philip et al., 2005) (also see Figure 5). 
The Function and Meaning 
of Dreaming
I was sitting at my desk when I remembered that this was the day of my chemistry fi nal! I 
was terrifi ed, because I hadn’t studied a bit for it. In fact, I had missed every lecture all 
semester. In a panic, I began running across campus desperately searching for the class-
room, to which I’d never been. It was hopeless; I knew I was going to fail and fl unk out 
of college.
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t-score
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Sleep No 
Sleep 
 Neuroscience in Your Life:
Why Are You Cranky? 
Your Brain Is Too Awake
FIGURE 5 
One explanation about why we need sleep is that we need to restore and repair 
various systems in our brains. One such system is the one that regulates our emotions. In the 
MRI scan, the amygdala, which helps process emotions, shows less activation (seen in reds and 
oranges) when viewing emotional pictures when participants had enough sleep compared to 
when they were sleep deprived, suggesting that participants responded more emotionally 
when they had less sleep. 
(Source: Walker and van der Helm 2009.)
FIGURE 6 
Although dreams tend to be 
subjective to the person having them, 
there are common elements that 
frequently occur in everyone’s dreams. 
Why do you think so many common 
dreams are unpleasant and so few are 
pleasant? Do you think this tells us 
anything about the function of dreams?