Do humans respond to fear like animals?

Behind the Headlines

Thursday January 19 2012

Fears such as agoraphobia can be complex

The human response to fear is more primal, and animal-like, than previously thought, according to a story in the Daily Mail today. The paper reported that humans share a “primitive response to fear with other animals, despite our ability to consciously assess danger”.

The report is based on a small study that looked at how humans consciously and subconsciously respond to the possibility of danger, as represented in the study by a mild electric shock linked to a series of images. Researchers found that after a series of shocks participants rated their chances of receiving another shock as low, despite the fact that the electrical activity in their skin indicated that they subconsciously expected one. The reverse was also true, with those predicting a shock showing a lesser fear of one, subconsciously. The researchers said that these results showed that people used conscious reasoning to assess the risk of getting a shock, but that the electrical activity of their skin indicated a subconscious physiological response similar to that found in other animals.

This small study will be of interest to certain specialists and the researchers, but for the moment it has little practical relevance for people living with anxiety and phobia. While it might offer some clues to the nature of fear, the majority of phobias can be alleviated using existing treatments such as talking therapies and medication.


Where did the story come from?

The study was carried out by researchers from the University of Exeter and Canterbury Christchurch University. It was funded by Canterbury Christchurch and a doctoral training grant. The study was published in the peer-reviewed Journal of Experimental Psychology.

Perhaps unsurprisingly, this small laboratory study was not widely covered in the media. The Daily Mail’s headline, that our response to fear is “more like [that of] animals – and can overrule what we think”, can’t be proved by the study results.


What kind of research was this?

This was a laboratory-based psychological experiment looking at how humans responded when they were given a series of mild electric shocks while viewing coloured shapes on a screen. Researchers wanted to test how the participants’ conscious responses to shock compared with their physiological responses, which were measured by testing the amount of electricity transmitting through their skin.

When a person or animal forms an association between a stimulus (such as coloured shapes) and a physiological response (such as an electric shock), this is known as a “conditioned response” (CR). The Russian scientist Ivan Pavlov first discovered the phenomenon.

In humans, the conditioned, physiological response has previously been thought to be linked to conscious expectancy. In other words, if you are consciously expecting a shock, your physiological response will reflect this. However, the researchers hypothesise that the human physiological response to a stimulus may not be the same as their conscious one, and may in fact more closely resemble the response in other animals.


What did the research involve?

Researchers recruited 52 students ranging in age from 18 to 35. During a series of trials, participants sat in front of a screen on which coloured shapes sometimes appeared. Half the time, the images were accompanied by mild electric shocks, given through electrodes attached to the participants’ index fingers. For the rest of the time the image appeared but no shock was given. Participants had previously defined their own shock level to reach a level they would describe as “uncomfortable but not painful”.

During the trials, participants were asked to rate whether or not they thought a shock would be given, in response to seeing a shape on the screen. They had to press one of five buttons on a device held in their palm with numbers that represented different expectations, ranging from 1: “There will definitely not be a shock” to 5: “There will definitely be a shock.”

At the same time researchers measured participants’ “skin conductance”. This technique measures variation in the electrical activity of the skin’s sweat glands, and is an indication of the state of arousal of the sympathetic nervous system that regulates the body’s “fight or flight” response. The measurements were taken from electrodes attached to the fingers being monitored using specialist software.


What were the basic results?

Researchers found that following a series of trials involving shocks, participants were more likely to predict they would not receive a shock when the coloured image was next shown. Conversely, they generally anticipated receiving a shock if they had not had one for the last few images. This is a recognised phenomenon of expecting good luck after a run of bad luck and vice versa, and is called “the gambler’s fallacy”.

However, the measurements of skin conductance, which is related to physiological arousal, revealed the opposite pattern: after a series of images accompanied by shocks, participants’ skin conductance in response to the next image increased, suggesting they were subconsciously expecting another shock. Conductance also decreased following a series of images unaccompanied by shocks, suggesting they were less likely to expect a shock.


How did the researchers interpret the results?

The researchers said that their experiment suggests that humans have a “dual response” to stimuli that they associate with danger, and that the two responses are separate. One response is at the conscious level but the other is called “associative learning”, and more closely resembles the response of other animals. This could have practical implications for the treatment of disorders such as phobia as well as for educational practice, they argued.



This small study is of interest to specialists in the field of psychology, but doesn’t contribute much to possible treatments of conditions such as phobias and panic attacks.

While the results are certainly intriguing from an academic perspective, the context of electric shocks in a laboratory is arguably quite different to what occurs when a person has problematic fears and phobias, which can often be treated. Phobias, for example, can be treated using talking therapies such as psychotherapy, cognitive behavioural therapy and counselling. There are also medications that can be prescribed in cases where talking therapy has not proved successful.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Eeek! Human response to fear is more like animals - and can overrule what we think. Daily Mail, January 19 2012

Links to the science

McAndrew A, Jones FW, McLaren RP. et al. Dissociating expectancy of shock and changes in skin conductance: An investigation of the Perruchet effect using an electrodermal paradigm. Journal of Experimental Psychology: Animal Behavior Processes, [Advanced online publication] January 16 2012


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