I have difficulties to understand fear as a response to a stimuli. In my view fear occurs as a anticipation of a possible threat in the (nearby) future. Fear prepares the organism so that it can react faster to the threat (eg. fight or flight response). Thus, the order of the stimulus (threat) and the response (fear) is changed ("fear -> threat" instead of "threat -> fear"). So I would describe this connection as "preparation -> stimulus" instead of "stimulus -> response".

I would argue that stimuli which cause fear (eg. loud noise) are predictors of a threat. Thus for the reaction "loud noise -> fear" we have a second order conditioning since the association "loud noise -> threat" was created before.

In a similar way I would describe other fear conditioning processes. When for example a student develops a test anxiety, after multiple exams a student often experience (extremely) negative responds which he / she experience as a threat. Thus he / she learns the connection "exam -> threat" and responds with fear at upcoming exams in order to prepare herself / himself for the anticipated threat.

My Questions:

  • Is this a valid description of fear conditioning?
  • Is it in general possible that in classical conditioning the order "stimulus -> response" is changed to "preparation behavior -> stimulus"?
  • $\begingroup$ I can see where you are going with this but unfortunately a large portion of this question and any possible answer is going to be primarily opinion-based which is off-topic here; and, I am unsure how this question can be edited to make it suitable. $\endgroup$ Commented Jul 21, 2017 at 23:00
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    $\begingroup$ Yes, there is good evidence that fear is anticipatory rather than reactive. I can elaborate on this when I have more time. $\endgroup$
    – mrt
    Commented Jul 22, 2017 at 3:57
  • $\begingroup$ @mrt have you found any time in the last year? $\endgroup$
    – Seanny123
    Commented Jul 29, 2017 at 17:32
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    $\begingroup$ @Seanny123 Haha that's a fair question. I have some reliability with answering these things :). At the very least, here's a high-level overview that can help sort things out theoretically. But if I don't have time to answer, we can always close it and reopen when I make time. $\endgroup$
    – mrt
    Commented Jul 30, 2017 at 22:54
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    $\begingroup$ @hexadecimal Well, we're probably understanding this question from different theoretical frameworks (e.g., our definition of fear, what it means to respond vs. predict). See this paper for some ideas. $\endgroup$
    – mrt
    Commented Aug 2, 2017 at 21:02

1 Answer 1


Short answer

You are almost there. The 5F (fright/flight/fight/freeze/fawn) response to threats is an unconscious reflex which in brief follows as Threat → Fear → Response.

A lot of people cannot understand the "fawn" response and https://drarielleschwartz.com/the-fawn-response-in-complex-ptsd-dr-arielle-schwartz gives a good write-up on it.

With classical conditioning, this occurs when an unconditioned response (an unlearned reflex response e.g. salivation) is turned into a conditioned response (a learned reflex response) (Source). Therefore a conditioned response of fear would be consciously created initially through stimulus → fear → learned threat, which after successful conditioning will change to the normal unconscious 5F response.

Long answer

The 5F (fright/flight/fight/freeze/fawn) response to threats

As you can see from the info-graphic below, The 5F (fright/flight/fight/freeze/fawn response) to threats, is initiated from Threat → Brain Receiving Signals → Brain Reacts (Fright) → Cortisol and Adrenaline is released → Physical Reactions occur (see quote below) from the release of hormones → Bodily response (Fight, Flight, Freeze or Fawn)

(Fight Flight Response (Source: Wikipedia)

The reaction begins in the amygdala, which triggers a neural response in the hypothalamus. The initial reaction is followed by activation of the pituitary gland and secretion of the hormone ACTH. The adrenal gland is activated almost simultaneously, via the sympathetic nervous system, and releases the hormone epinephrine. The release of chemical messengers results in the production of the hormone cortisol, which increases blood pressure, blood sugar, and suppresses the immune system. The initial response and subsequent reactions are triggered in an effort to create a boost of energy. This boost of energy is activated by epinephrine binding to liver cells and the subsequent production of glucose. Additionally, the circulation of cortisol functions to turn fatty acids into available energy, which prepares muscles throughout the body for response. Catecholamine hormones, such as adrenaline (epinephrine) or noradrenaline (norepinephrine), facilitate immediate physical reactions associated with a preparation for violent muscular action and:

  • Acceleration of heart and lung action
  • Paling or flushing, or alternating between both
  • Inhibition of stomach and upper-intestinal action to the point where digestion slows down or stops
  • General effect on the sphincters of the body
  • Constriction of blood vessels in many parts of the body
  • Liberation of metabolic energy sources (particularly fat and glycogen) for muscular action
  • Dilation of blood vessels for muscles
  • Inhibition of the lacrimal gland (responsible for tear production) and salivation
  • Dilation of pupil (mydriasis)
  • Relaxation of bladder
  • Inhibition of erection
  • Auditory exclusion (loss of hearing)
  • Tunnel vision (loss of peripheral vision)
  • Disinhibition of spinal reflexes
  • Shaking.

All of this occurs without conscious thought as analysis of the signal doesn't takes place until after action has been taken.

Classical Conditioning

With classical conditioning (also known as Pavlovian or respondent conditioning), this occurs when an unconditioned response (an unlearned reflex response e.g. salivation) is turned into a conditioned response (a learned reflex response) after

a conditioned stimulus (CS) is paired with an unconditioned stimulus (US). Usually, the conditioned stimulus is a neutral stimulus (e.g., the sound of a tuning fork), the unconditioned stimulus is biologically potent (e.g., the taste of food) and the unconditioned response (UR) to the unconditioned stimulus is an unlearned reflex response (e.g., salivation).

A conditioned response of fear would initially be consciously created through stimulus → unpleasant sensation maybe this will have to occur 2 - 3 times or more before the next stage which is learnt fear → learned threat, which after successful conditioning will change to the normal unconscious 5F response.


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