Which of the following does not represent a common example of an extraneous variable?

Students at Northwestern University studied many of Ebbinghaus's original lists in an attempt to replicate his studies of memory. After many trials with many lists, the students found

a. an effect opposite to that found by Ebbinghaus. b. no effect of interference, probably due to improved learning techniques. c. proactive interference that was similar to that experienced by Ebbinghaus. d. that even real words began to look like nonsense syllables.

A specialist in communication was describing a nonverbal gesture a person makes to emphasize or accent words, yet does not have a specific meaning. Which form of nonverbal communication was she describing?

a) adaptors b) emblems c) regulators d) illustrators