Seligman, M., & Maier, S., (1967). Failure to Escape Traumatic Shock.
Arhe Vaninetti
Research Methods and Statistics, PSY301, Pacific University, Oregon
February 21, 2023
Martin E. Seligman began his research on dogs’ Pavlovian responses by initially establishing the concept of learned helplessness, with former research partner J. Bruce Overmier in 1967. Seligman & Meier (1967) continues this research and introduces the concept of control as the vehicle with which dogs could associate with the ability to escape. In Experiment I, Seligman & Meier initially chose 30 ‘mongrel’ dogs that weighed between 25 and 29 pounds. It is important to note that some dogs were removed as subjects because of their ability to learn to escape the shocks, because they were not large enough for the harnesses, or because they died during the experiment, which left the researchers with 24 total subjects divided into 8 groups, with 3 dogs in each group.
The control apparatus was a large cage with a hammock in the middle, where the dogs’ four legs would dangle through to the ground. In front of the dog was a panel with which the dog could terminate the shock. The researchers divided the dogs into an “escape” group that could terminate the shock, and a “yoked” group that couldn’t escape—even when pressing the panel. They used brass electrodes stuck on the bottom of the dogs’ feet to transmit the 6.0 milliamp shocks. Once the dogs were used to the shock (and understood that it hurt), the researchers moved the dogs to a two-compartment cage with an adjustable half-wall barrier that was adjusted to the dogs’ shoulder height. The escape group dogs were placed one-by-one into the shocking shuttle box, and after 5 minutes of adapting to the new space, Seligman & Meier administered the shocks. If the escape group dog jumped over the barrier, then it effectively escaped the shocks. If the dog failed to escape, then the shocks went on continuously for 60 seconds until the trial was terminated. In the yoked group, the dogs received the same initial exposure to the shock in the hammock, with the exception that pressing the panel did not terminate the shocks. When placed into the shuttle box, the same method was used as the escape group, including the shoulder height barrier.
As detailed in the results of Seigman & Meier’s (1967) study, the dogs in the escape group learned how to terminate the shocks in the hammock with increasing efficiency. When the escape group was placed into the shocking shuttle box, the mean number of failures out of 10 trials was 2.63. When the yoked group was adjusted to the hammock, they stopped panel pressing after around 30 trials. In the shuttle box, the yoked group was tested to see how often they escaped, and Seligman & Meier found that the mean failures to escape out of 10 trials was 7.25. Within the discussion, the researchers noted that while some yoked dogs would occasionally successfully escape, they would soon revert back to passive acceptance of the shocks. Furthermore, the yoked dogs, when tested 7 days later in the shuttle box, would still exhibit acceptance of the shock and a failure to escape.
In Experiment II, the method was identical, but the groups were as follows: the Preescape group, which received escape training in the shuttle box, an inescapable shock session in the hammock, and then another session in the shuttle box; the No Pregroup that received an inescapable shock session in the hammock, and then the shuttle box session; and the No Inescapable group which received training in the shuttle box, a no shock session in the hammock, and then a session in the shuttle box.
The results for Experiment II show that the No Pregroup group showed significant failure to escape in the shuttle box trials. Seligman & Meier suggest that a form of learned helplessness and a lack of pre-exposure to the possibility of escape. Finally, the researchers propose a third kind of learning—that which is independent of individual events but applied, nonetheless. This suggestion adds onto the existing acquisition and extinction of learning theory, as well as added further insight into the meaning of learned helplessness.
The largest critique of this experiment was the intensity and duration of the shocks. With a 6.0 milliamp shock, there was intense pain in the dogs, especially considering their lack of understanding. Furthermore, as mentioned in the study, if the dogs in the No Pregroup group failed to escape on every trial, they would be forced to endure 2,000 seconds of shock, or over 33 minutes. Why this was allowed after the 1966 Animal Welfare Act is unknown.