Year of Award


Document Type


Degree Type

Doctor of Philosophy (PhD)

Degree Name

Experimental Psychology

Department or School/College

Department of Psychology

Committee Chair

Allen Szalda-Petree

Commitee Members

Nabil Haddad, Stuart Hall, Jerry Smith, Keith Parker


University of Montana


The present study examined the effect of fluoxetine on self-control in Siamese fighting fish (Betta splendens). The subjects included 17 male Betta splendens that were exposed to varying levels of fluoxetine, a selective serotonin reuptake inhibitor that increases levels of serotonin, and instrumental choice trials were run. A subject began each trial in the start box and, when a guillotine divider door was lifted, entered one side of a divided goal box. The checkerboard side of the choice door represented either the smaller-sooner choice (SS) or the larger-later choice (LL). When the subject had entered one side of the goal box, the guillotine divider door was lowered and the subject was given food pellets, 1 pellet immediately or 3 pellets after 18 seconds, depending on which side of the choice door the subject entered. Prior to these trials, subjects experienced various levels of fluoxetine exposure (0 μMol, 7.5 μMol, or 12.5 μMol). Fish exposed to higher levels of fluoxetine were expected to show a greater preference for self-control than subjects exposed to lower levels of fluoxetine. Contrary to the hypothesis, subjects in all groups did not demonstrate a significant preference for either the smaller-sooner choice or the larger-later choice, nor did the groups differ significantly from one another in their choice preference. Subjects exposed to fluoxetine did demonstrate higher response latencies than subjects not exposed to fluoxetine, and though these differences were not significant, they suggest that fluoxetine may have impacted learning or motivation.



© Copyright 2014 Kathryn Gwen Lamp