When we are faced with new situations, we draw on our previous experiences stored in memory, in other words, our social knowledge. The content of those experiences and knowledge and how easily we can retrieve it will affect what types of social judgments we make and how we behave in social situations. If you are attending your first day of class, for exam­ple, in order to act appropriately you draw on social knowledge that tells you “how to behave in a class­room.” This process includes having available stored representations of the social world or memories of past events, how to apply those memories to various situations, and easy access to the memories.

We draw on implicit theories of personality (our personal theories of how personality works) to make judgments, for example, about how a professor should act in a classroom. If the professor’s behavior is incon­sistent with our implicit theory of how he or she should act, this will affect the impression we form of the professor. If a professor dresses in shorts and makes casual references to the party he attended last night, this may violate our implicit theory that profes­sors are reserved and work all the time. Research sup­ports this in that implicit personality theories we have about people, in general, influence the impressions we form about specific individuals (Epstein et al., 1992; Skowronski & Carlston, 1989).

However, availability of social information in memory does not necessarily imply easy access to that information. The degree to which informa­tion in memory is easily accessible will determine the extent to which that information will guide social judgments and/or behavior. Easy access to information will be influenced by a number of vari­ables. First, accessibility depends on the strength of the information stored in memory. For example, if you have extensive past experience retrieving and
applying a particular construct, such as a personal­ity trait (aggressive), you will have a highly accessi­ble social knowledge structure representing features of this particular personality trait (e. g., dominant in social situations, highly competitive, and so on). Thus you would judge a person as “aggressive” by interpreting dominant behaviors as clearly diagnos­tic of aggressiveness. The personality trait construct would not be easily accessible for other people who do not have experience with aggressive people so that the trait of aggressiveness may not have been retrieved very often. These people would be likely to interpret the behavior very differently (Bargh, 1997; Higgins et al., 1977). For example, they may see the dominant or aggressive person as an expert in the area.

Age differences in the accessibility of social knowl­edge influence social judgments. First, as you saw in the case of impression formation, older adults rely on easily accessible social knowledge structures such as the initial impression made about an individual. Second, age differences in knowledge accessibility also depend on the extent to which people rely on source judgments, in other words, when they try to deter­mine the source of a particular piece of information. For example, suppose you and a friend were intro­duced to two new people last week. Jane is an athlete and Sereatha is a bookworm. Sereatha revealed to you that she loves to play tennis. Today, your friend asks you whether it was Jane or Sereatha that loves to play tennis. This is a source judgment.

Mather and colleagues (Mather et al., 1999; Mather & Johnson, 2003) have found that when making source judgments, older adults rely more on easily accessible knowledge than do younger adults. In the example of meeting Jane and Sereatha, older adults would be more likely to erroneously remem­ber that Jane loves to play tennis, as they would rely on an easily accessible stereotype that the athlete is more likely to love tennis than the bookworm.

Finally, older adults make more social judgment biases because they have trouble distinguishing between information that is true and information that is false (Chen, 2002; Chen & Blanchard-Fields, 2000). In studies by Chen and colleagues, older adults were instructed to disregard false information (printed in

red) and pay attention to true information (printed in black) when reading criminal reports. However, the older adults had difficulty in doing so, and thus the false information (e. g., information that exacerbated the nature of the crime) biased their judgments about how dangerous the criminal was and affected their determination of the criminal’s prison sentence.