The short (18 items) version don't indicate any scale (cacioppo, petty & kao, 1984).
Also, no exact instructions are indicated only:
"Note. Subjects were instructed to indicate the degree of agreement or disagreement with each of the statements listed above".
Some internet version instructions that uses a 5-points Likert scale:
For each of the statements below, please indicate whether or not the statement is characteristic of you or of what you believe. For example, if the statement is extremely uncharacteristic of you or of what you believe about yourself (not at all like you) please place a "1" on the line to the left of the statement. If the statement is extremely characteristic of you or of what you believe about yourself (very much like you) please place a "5" on the line to the left of the statement. You should use the following scale as you rate each of the statements below.
nik0lai
commented
6 years ago
The original article (cacioppo & petty, 1982) has this scale
-4 - very strong agreement -3 - strong agreement -2 - moderate agreement -1 - slight agreement 0 - neither agreement nor disagreement 1 - slight disagreement 2 - moderate disagreement 3 - strong disagreement 4 - very srtrong disagreement
The short (18 items) version don't indicate any scale (cacioppo, petty & kao, 1984).
Also, no exact instructions are indicated only:
Some internet version instructions that uses a 5-points Likert scale: