Aim: To investigate whether rhesus monkeys can learn fear through observing it in other rhesus monkeys.
Method: Two experiments were conducted where videotapes of model monkeys behaving fearfully were shown. The videos were spliced so that it appeared that the models were reacting fearfully either to fear-relevant stimuli (such as toy snakes or a toy crocodile), or to fear-irrelevant stimuli (such as flowers or a toy rabbit). Observer groups watched one of four kinds of videotapes for 12 sessions.
Results: Observers acquired a fear of fear-relevant stimuli (toy snakes and toy crocodile), but not of fear-irrelevant stimuli (flowers and toy rabbit).
Conclusion: Rhesus monkeys can learn fear to dangerous stimuli through observing other monkeys.
More in-depth version:
Aim: To test whether monkeys can acquire fear responses by imitation of other monkeys and to see whether they are more likely to learn fear of dangerous objects than non-dangerous ones. Method: Experiment 1 -An animal laboratory experiment was conducted which involved 22 laboratory-reared rhesus monkeys aged 4-11 years (the observer monkeys). The observer monkeys were shown edited videotapes of a model responding to particular stimuli. The videotaped models were a 32-year-old wild-reared monkey and a 7-year old laboratory reared monkey who had a fear of snakes. Observers in one group watched videotapes of models reacting fearfully with toy snakes and non-fearfully with wooden blocks. Observers in a second group watched models reacting fearfully to flowers and non-fearfully to wooden blocks.
Experiment 2 – 20 laboratory-reared rhesus monkeys aged 4-17 were used. The observer monkeys watched videotapes of a model reacting fearfully to a toy crocodile and non-fearfully to a toy rabbit. Two further tapes were used showing the model reacting fearfully to the toy rabbit and non-fearfully to the toy crocodile. In both experiments fear in the observers was then assessed by the time taken to reach for food in the presence of the fear stimulus (toy snake, toy crocodile, flowers, blocks or toy rabbit).
Results: In both experiments the times taken to reach for food increased after watching the videotape when the fear stimulus was dangerous (the snake or the crocodile). The time taken increased from 9 to 27 seconds in the presence of a toy snake. In the presence of the crocodile the time taken increased from to approx 5 to 26 seconds. The time taken did not increase when the fear stimulus was not dangerous (the flowers or the toy rabbit).
Conclusion: Fear responses can be acquired by social learning, but only to potentially dangerous objects.
Evaluation of Rhesus Monkeys:
| Strengths | Weaknesses |
| + The study was conducted under laboratory conditions with carefully controlled variables and standardised procedures making the procedure replicable. -/+ As the study was conducted using monkeys this limits the generalisability of the findings to humans as monkeys do not share the same level of cognitive ability as humans. There may be more cognitions involved in the causation of phobias in humans. However as a highly evolved species was used this makes generalisations more valid than if a lower species such as rats were used. + The control over potentially confounding variables and the artificial environment which enhances control allows for conclusions to be drawn regarding cause and effect. Thus the researchers are able to conclude that the IV had an impact on the DV. + The findings of the study has contributed to psychological understanding of the cause of phobias as the results partially support the social learning theory of phobias and also provide evidence for the preparedness theory as the monkeys were able to distinguish between dangerous and non-dangerous stimuli. + By using laboratory reared monkeys as the observers the researchers were able to control for prior experiences with fear-relevant and rear-irrelevant stimuli which is an advantage over human experiments on the learning of fears. + The finding that monkeys can learn fear to specific stimuli through observation is supported by a number of studies eg. Cook et al 1985, Mineka et al 1984) indicating that the research is reliable. |
– Some issues exist with regard to ecological validity as most of the monkeys used in the study were laboratory-reared and thus they may not behave in the same way as wild monkeys. In addition the fear stimuli used were toys which posed no danger and thus the behaviour observed may have been different in the study as a result.
– In conflict with social learning theory and the findings of Cook and Mineka, phobics who seek treatment do not often report that they became frightened after witnessing someone else’s distress. Merckelbach et al, 1996, argued that there is little evidence that phobias such as claustrophobia are due to modelling or information transmission but there is quite a lot of evidence for these explanations in relation to small animal phobias and blood and injection-type phobias. – The study has some ethical implications as some would argue that research on animals should not be conducted especially if it is simply for human benefit as this constitutes ‘speciesism’. One of the monkeys involved in the study was wild-reared and thus intervention by the researchers will have impacted on natural behaviour. Quite a large number of monkeys were used in the study and the number of animals studied should be kept to a minimum. In addition monkeys are a highly evolved species and thus more distress could have been caused by caging and the study procedure than with the use of a lower species such as a rat. |