<p><em>Disclaimer: My answer is about recurrent dreams. I don't have any immediate sources to consult on the continuation part (and there are less references to it in literature), but I'd be very surprised if it is any different.</em></p>

<h1>Theories</h1>

<p>Firstly, there are many of theories that support the notion of recurring dreams. I know not of a single one that (explicitly or even reasonably implicitly) rejects such thing.</p>

<h1>On cognitive perception</h1>

<p>Secondly, you talk about <em>perception</em>, which in cognitive terms equates <em>conscious access</em> (rather than <em>sensing</em> in everyday language). So if you can (consciously) perceive it, it must be a genuine mental process that made it available (with the sole exception below).</p>

<h1>Subjective reports = objective measurements</h1>

<p>Thirdly, recurring dreams have been reported and studied for decades (in your case I'd probably start with [1]). Most of dream science is natively based on subjective reports. But recently, scientists have shown that monitored <strong>brain activity</strong> is <strong>in agreement</strong> with, and can <strong>even predict</strong>, those subjective reports [2].</p>

<p>So we really have all reasons to believe that what we perceive as a dream is what we actually dream.</p>

<h1>Possible exception?</h1>

<p>The one exception for this, and it is <strong>my own informed suspicion</strong>, is that we <em>may</em> still have a Déjà vu (déjâ rêvé, in the question context) while dreaming - so it may be a false sensation after all. It is <strong>the same informed suspicion</strong> that tells me that if this happens at all, it should be <strong>extremely rare</strong>.</p>

<h1>Sleep's low retention</h1>

<p>As for the latter part of your question:</p>

<blockquote>
  <p>we can't recollect the first instance of such a dream. Why is this so?</p>
</blockquote>

<p>If one is to make <strong>gross simplification</strong>, during sleep:</p>

<ul>
<li>Your <strong>long-term</strong> memory is <strong>'not available'</strong> to remember stuff.</li>
<li>Your <strong>short-term</strong> memory is even <strong>more volatile</strong> than it is while you're awake (there isn't central-executive process to exercise retention).</li>
</ul>

<p>For the same reason, we often remember a dream just after waking up, but unless salient we fail to recall it shortly after.</p>

<hr>

<p>[1] Zadra, Antonio, and D. C. Donderi. <em>Nightmares and bad dreams: their prevalence and relationship to well-being.</em> Journal of abnormal psychology 109.2 (2000): 273.</p>

<p>[2] Horikawa, Tomoyasu, et al. <em>Neural decoding of visual imagery during sleep.</em> Science 340.6132 (2013): 639-642.</p>

CC BY-SA 3.0
2015-11-24T00:03:43.153Z
2015-11-24T01:32:19.960Z
2015-11-24T01:32:19.960Z
Izhaki
<p>During lucid dreaming, we sometimes feel that it is a repetition of (or in someway related to) a previous dream, but when we wake up, we can't recollect the first instance of such a dream. Why is this so?</p>

CC BY-SA 3.0
2015-11-23T20:30:29.813Z
What type of psychological or neurological experiment would you expect to be able to answer this question?
Seanny123
CC BY-SA 3.0
2015-11-24T00:04:17.930Z
@Seanny123 see Horikawa et al. in my answer.
Izhaki
CC BY-SA 3.0
2015-11-24T00:17:54.777Z
@Izhaki that's an amazing answer!
Seanny123
CC BY-SA 4.0
2022-11-04T15:35:33.813Z
FWIW I know the experience you're talking about. I have dreams that reference previous dreams, but it's only after waking that I realize that the _memory_ of the previous dream is a fabrication rather than an actual dream. In the dream it _felt_ like a memory. Or at least that is the strong perception. I guess it's possible that I really did have the dream but the long-term memory isn't available to me upon awakening.
John Berryman
<memory><dreams>
Do dreams repeat/continue? Or is it just a perception that a dream repeated?
Roomba
# Do dreams repeat/continue? Or is it just a perception that a dream repeated?

(Asked by: username_0 on 2015-11-22)

During lucid dreaming, we sometimes feel that it is a repetition of (or in someway related to) a previous dream, but when we wake up, we can't recollect the first instance of such a dream. Why is this so?

**Tags:** memory, dreams

> **Comments:**
> **username_1**: What type of psychological or neurological experiment would you expect to be able to answer this question?  
> **username_2**: @username_1 see Horikawa et al. in my answer.  
> **username_1**: @username_2 that's an amazing answer!  
> **username_3**: FWIW I know the experience you're talking about. I have dreams that reference previous dreams, but it's only after waking that I realize that the _memory_ of the previous dream is a fabrication rather than an actual dream. In the dream it _felt_ like a memory. Or at least that is the strong perception. I guess it's possible that I really did have the dream but the long-term memory isn't available to me upon awakening.  

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## 1 answers

### Answer by username_2 on 2015-11-24. Score: 6

*Disclaimer: My answer is about recurrent dreams. I don't have any immediate sources to consult on the continuation part (and there are less references to it in literature), but I'd be very surprised if it is any different.*

# Theories

Firstly, there are many of theories that support the notion of recurring dreams. I know not of a single one that (explicitly or even reasonably implicitly) rejects such thing.

# On cognitive perception

Secondly, you talk about *perception*, which in cognitive terms equates *conscious access* (rather than *sensing* in everyday language). So if you can (consciously) perceive it, it must be a genuine mental process that made it available (with the sole exception below).

# Subjective reports = objective measurements

Thirdly, recurring dreams have been reported and studied for decades (in your case I'd probably start with [1]). Most of dream science is natively based on subjective reports. But recently, scientists have shown that monitored **brain activity** is **in agreement** with, and can **even predict**, those subjective reports [2].

So we really have all reasons to believe that what we perceive as a dream is what we actually dream.

# Possible exception?

The one exception for this, and it is **my own informed suspicion**, is that we *may* still have a Déjà vu (déjâ rêvé, in the question context) while dreaming - so it may be a false sensation after all. It is **the same informed suspicion** that tells me that if this happens at all, it should be **extremely rare**.

# Sleep's low retention

As for the latter part of your question:

> we can't recollect the first instance of such a dream. Why is this so?

If one is to make **gross simplification**, during sleep:

* Your **long-term** memory is **'not available'** to remember stuff.
* Your **short-term** memory is even **more volatile** than it is while you're awake (there isn't central-executive process to exercise retention).

For the same reason, we often remember a dream just after waking up, but unless salient we fail to recall it shortly after.

---

[1] Zadra, Antonio, and D. C. Donderi. *Nightmares and bad dreams: their prevalence and relationship to well-being.* Journal of abnormal psychology 109.2 (2000): 273.

[2] Horikawa, Tomoyasu, et al. *Neural decoding of visual imagery during sleep.* Science 340.6132 (2013): 639-642.


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