To discourage players from randomly guessing whether their inputs
are the same, scoring in input-agreement games strongly penalizes incorrect guesses. One way to do this (while
maintaining a positive scoring system)
is to give an increasing number of
points for streaks of correct answers
and zero points for incorrect answers.
increase Player enjoyment
Perhaps the most important aspect of
GWAP is that the output is produced in
a way that’s designed to be enjoyable.
As noted with respect to the ESP Game,
players are not directly instructed to
enter keywords for a given image. Rather, they are told to type what they think
their partner is typing. The fact that
people enjoy the game makes them
want to continue playing, in turn producing more useful output.
It is important to note that the three
basic templates defined earlier describe the basic structure of a GWAP;
additional game mechanisms must be
added to them to increase player enjoyment. For example, much of the previous work describing game-design principles cites challenge as a key aspect of
any successful game. 11, 12, 14, 20 Challenge
translates into game features (outlined
by Malone11, 12) like timed response,
score keeping, player skill level, high-score lists, and randomness:
Timed response. Setting time limits
for game sessions introduces challenge into a game in the form of timed
response. 11, 12 Players are told to complete a designated number of problem instances within an assigned time
limit. If they accomplish it, they may
be given extra points for their performance. Timed response is effective for
introducing challenge because it estab-lishes an explicit goal that is not trivial
for players to achieve if the game is calibrated properly. 11, 12 We know from the
literature on motivation in psychology
and organizational behavior that goals
that are both well-specified and challenging lead to higher levels of effort
and task performance than goals that
are too easy or vague. 10 It is essential
that the number of tasks for players to
complete within a given time period is
calibrated to introduce challenge and
that the time limit and time remaining
are displayed throughout the game.
Score keeping. One of the most di-
rect methods for motivating players is
by assigning points for each instance
of successful output produced during
the game. For the ESP Game, 22 pairs of
it is essential that players are given points for each image for which they successfully agree on a
the number of word (which then becomes a label for
tasks for players the image). Using points increases mo- tivation by providing a clear connection
to complete within among effort in the game, performance
a given time period (achieving the winning condition), and outcomes (points). 11, 12 A score summa-
is calibrated to ry following each game also provides
players with performance feedback, 10
introduce challenge facilitating progress assessment on
and that the time score-related goals (such as beating a previous game score and completing
limit and time all task instances within the set time
remaining are limit). Player skill levels. Player skill levels,
displayed throughout or “ranks,” are another way for game
the game. developers to incorporate goal-based motivation into GWAP design. For ex-
ample, the ESP Game and Peekaboom
each have five skill levels players are
able to achieve based on the number
of points they accumulate. Each newcomer to the game initially has no
points and is assigned to the lowest
level (“newbie”) then has to earn a certain number of points to advance to the
next level.
Following each game session, players are shown their current skill level
and the number of points needed to
reach the next level. 10 Data from the
ESP Game indicates that presentation
of this skill-level information strongly
influences player motivation and behavior. Of the 200,000+ players as of
July 2008 with an account on the ESP
Game, 42% have scores that fall within
5,000 points of the rank cutoffs. Given
that these skill-level point intervals
cover less than 2% of the space of possible cumulative scores, the data suggests that many players continue playing just to reach a new rank.
High-score lists. Another method
for motivating GWAP play is the use
of high-score lists showing the login
names and score of the subset of players with the highest number of points
over a certain period of time. The score
needed by players to be listed on a
high-score list varies in terms of difficulty relative to the list’s time period,
ranging from highest scores achieved
in the past game session over the past
hour or week all the way to the history
