Mineka, Davidson, & Cook Keir (1984). Observational Conditioning of Snake Fear in Rhesus Monkeys.
Arhe Vaninetti
Research Methods and Statistics, PSY301, Pacific University, Oregon
February 19, 2023
Mineka et al. (1984) aimed to study and correct previous literature on the observational conditioning of the snake fear in rhesus monkeys and to extrapolate from their findings how the research related to human subjects. In Mineka et al.’s (1984) study, the designed experiment was based on previous research by Mineka et al. (1980) where they tested the fear response of young monkeys to snakes. Mineka et al. cited this previous research as having limitations in measuring the fear responses in young monkeys due to the monkeys’ attachment to their social group, which meant that the experimenters’ tests on food latency may have been testing the monkeys’ reactions to a new environment instead. To correct this failure of validity, the researchers adopted an alternative measure of latency behavior (the Sackett Self-Selection Circus, or the Circus) that was proved to be valid. In their first empirical study, Mineka et al. used 7 wild monkeys and 9 lab-raised monkeys and trained them on the WGTA (Wisconsin General Test Apparatus), which was a series of structured exposure to neutral stimuli. After the WGTA training, 7 wild monkeys and 4 lab-raised monkeys were competent enough to continue in the experiment.
For this experiment, the wild and lab monkeys were exposed to several different stimuli, including a toy snake, yellow cord, model snake, black cord, and real snake. Detailed methodology on the WGTA set up, as well as the Circus test, can be found in Mineka et al.’s article, in which the researchers list details as small as the diameter of the real snake. After the exposure to the stimuli in both the WGTA and Circus settings, the researchers found that there was a significant main effect (p = < 0.001 for both) for the wild monkeys, but not for the lab monkeys, when presented with the snake stimuli. The researchers utilized a 2 x 6 ANOVA, and a 2 x 4 ANOVA for the WGTA and Cirus, respectively. While the WGTA examined food latency, and the Circus examined fear responses, Minkea et al. created a 2 x 2 contingency table that compared the reactions to both set ups, and indicated that a relationship between both the WGTA and the Circus was present.
In the discussion section of the first experiment, Minkea et al. found that the snake fear was not socially passed down into well-socialized young in nuclear families. With this research confirmed, the researchers began to set up the second experiment: testing whether or not the snake fear could be socially learned by the lab-reared young adult monkeys when they witnessed the fear in the wild monkeys. This second experiment had a similar set up as the first, and utilized both the WGTA and the Circus set ups. After the wild monkeys were confirmed to still be afraid of snakes, and the lab-reared monkeys were confirmed to still be unafraid of snakes, one month after the initial experiment, the researchers began the second. With 5 wild monkeys and 6 lab-reared monkeys, the researchers set up a viewing contraption for both the WGTA and the Circus where the lab-reared monkeys could watch the fear responses in the wild monkeys. The observer (lab-reared) monkeys viewed 6 sessions of the wild monkey’s responses, including 15 trials in each session. After this observational conditioning, the lab-reared monkey was then placed in the apparatus and tested on its food latency and fear responses.
Mineka et al. stated that the lab-reared monkeys all showed rapid acquisition of the snake fear response, including up to 3 months after the second experiment, demonstrating that the snake fear behavior, when measured on both the WGTA and the Circus, was socially generated after observational learning, even after prior experience with the snake stimuli.
While this experiment was well-constructed, it was lacking in the sample size. As Mineka et al. mentions, some of the monkeys were unable to adapt to the WGTA or Circus set ups, which had a great effect on the study results due to the small sample size of monkeys.