SOCIALIZING CONSISTENCY - Human-Computer Interaction and Management Information Systems: Foundations - page 357

(human vs. machine). Throughout, we provide theoretical grounding for the findings and describe
how these results and theories could and should inform design.
PERSONALITY: IT'S NOT ONLY ABOUT “PERSONS”
Humans (and other social animals) are extremely complex creatures. Yet social life requires inter-
action with any number of such complex beings on a daily basis. How do we cope with this
complexity? One of the ways is by simplifying our view of others through categorizations such
as personality (Nass and Moon, 2000; Nass et al., 1995). Descriptions such as extroverted vs. intro-
verted, judging vs. intuiting, kind vs. unkind, and a host of other traits provide a powerful frame-
work for understanding how other people will think, feel, and behave (Pervin and John, 2001).
Given that we assign personality to people and pets—and sometimes even inanimate objects
(such as cars)—it should come as little surprise that once a computer starts looking or talking like
a human, people will assign personality (Nass and Lee, 2001; Reeves and Nass, 1996). Interfaces
that talk (even those using non-human-sounding synthetic speech) constantly provide signals of
personality through vocal characteristics such as pitch, pitch range, volume, and speech rate (Nass
and Lee, 2001). For example, listeners rapidly and automatically interpret softer, slower, lower-
pitched speech with narrow pitch range as introverted, and louder, faster, higher-pitched speech with
wider pitch range as extroverted—regardless of whether the voice comes from a human standing
in front of the listener, a television, a telephone, or a computer (Nass and Brave, 2005; Nass and
Lee, 2001). Words themselves (whether spoken or written onscreen) also evoke personality (Nass
and Brave, 2005; Nass and Lee, 2001). For example, extroverts tend to communicate using more
words overall, use more assertive language, and make more use of emotional terms than introverts
(Kiesler, 1983; Nass and Lee, 2001).
Embodied agents that have a face and/or body (such as onscreen character and robots) can pro-
vide additional indications of personality through gestures, facial expression, and posture (Cassell,
2002; Cassell and Stone, 1999). For example, extroverts tend to stand closer to other people and face
them more directly, make larger and faster gestures, stand more upright, and make more eye contact
with others than do introverts (Isbister and Nass, 2000). Particular body types/shapes are often even
interpreted as indicators of personality. For example, mesomorphs (muscular bodies with erect
posture, like Superman) are associated with energetic and assertive personalities, ectomorphs (tall,
thin, and small-shouldered bodies, like Ichabod Crane) with fearful and introverted personalities,
and endomorphs (round, soft bodies, like Santa Claus) with gregarious and fun-loving personalities
(Sheldon, 1970).
Because personality is fundamentally a mechanism through which we understand and predict the
behaviors of others, consistency of personality is critical (Cantor and Mischel, 1979; Nass and Lee,
2001). If a social being is unpredictable, it is very difficult at a cognitive or practical level to interact
with that being. Thus, people strongly prefer to interact with others who display consistent personal-
ity cues—a phenomenon known as consistency-attraction (Nass and Lee, 2001). Inconsistent person-
alities not only require longer and more effortful processing (Fiske and Taylor, 1991), but also lead to
dislike and distrust of the inconsistent person (Cantor and Mischel, 1979; Cantor and Mischel, 1979).
Given such negative responses to inconsistent personality cues, it would seem that the same
might hold true for inconsistent personality cues in embodied computer interfaces. To find out, our
lab conducted an experiment in the context of a voice interface for online auctions (Nass and Lee,
2001).