Exam 7: Selecting an Appropriate Method

Those who play the card game Poker try to hide the quality of their hand. This is the basis for the term, "poker face" -- indicating that the player successfully conceals how good a poker hand he or she has. But can the quality of a hand be seen from other behavior? Researchers prepared 20 video clips of players placing a bet in the World Series of Poker tournament. Seventy-eight college students viewed the clips and rated the quality of the poker hand based on behaviors of the players. The students were randomly assigned to three groups. None of the students knew how to play poker. One group was shown video clips that were of the player's head only, another group was shown video clips that were of the player's upper body only, and the third group was shown video clips that were of the player's arm movement only. The correlations between the quality of the poker hand and the student rating were near zero for the upper body and face only videos, but the correlation between the student rating and the quality of poker hand was relatively large and positive for the arm movement only videos. The researchers concluded that arm movement cues were better indicators of the quality of the poker hands of experienced poker players than head or upper body movements. (Perhaps they need to develop "poker arms!")

The black woodpecker is the second largest woodpecker species in the world and therefore it must nest in large trees. To see whether modern forestry practices (clear cutting) pose a threat to the black woodpecker, investigators studied the nest-site selection in a large forest. The investigators used radio telemetry to monitor 219 birds to see where they built nests. The investigators used the data to estimate the proportion of woodpecker nests that were in clear cut areas.

Political advertisements on television are very frequent in election years. These political ads boost citizens' involvement, their interest in the election, and awareness of current issues. In recent years, candidates' advertising seems to focus on criticizing and discrediting their opponents rather than promoting their own ideas and solutions to problems. Is it possible that positive and negative advertising alters voter participation? During a recent electoral cycle, investigators randomly assigned California voters to one of two groups. The voters in one group were shown a "positive" 30-second advertisement about candidates that were actually running for office. Another group of voters was shown a 30-second negative ad. After the ads were shown, the voters were asked about their voting intentions and general level of involvement in the campaign. Sixty-four percent of those who watched a positive ad intended to vote. Fifty-eight percent of those exposed to the negative versions of the campaign said they were likely to vote. The researchers concluded that the proportion of people who intend to vote was significantly lower for those who see a negative ad.

In some dogs, tail-chasing is a repetitive behavior that is expressed as circling with the dog's attention directed towards its tail. Tail-chasing is reported more frequently in certain dog breeds, and some veterinarians believe this behavior may have a genetic basis. It is also possible that there re biochemical factors leading to the behavior. In a clinical study, 15 dogs of various breeds exhibiting tail-chasing behavior were identified. After a fasting period of 12 to 16 hours, blood samples were taken from each dog and total cholesterol was measured. Blood samples were also taken from fifteen dogs that did not exhibit tail-chasing behavior. Tail chasing dogs had significantly higher mean total cholesterol than dogs who did not chase their tails.