If you are uncertain, either check with your professor or err on the side of excessive acknowledgement. Psychologists study human behavior. A person can be considered a type of machine. It is dishonest to claim course credit more than once for the same work. In addition, it deprives you of the opportunity of researching and gaining knowledge on different topics, one of the aims of a college education.
ANY paper can benefit from the comments of another reader before the work is submitted.
Nevertheless, you should ensure that this process of critical review does not go beyond generally acceptable limits to the point where an unacknowledged individual makes a significant contribution to your work. All sources cited in a paper should be listed at the end of the paper, in APA format. Here is what you need to know about compiling and formatting a reference list. It is taken from the PSYC 600 Manual. If you have further questions, see the APA Publication Manual, which the library has.