• June 17, 2013

6. What is the purpose of dreaming? (proposed — Bill) discussed 29 June 2013

What is the pur­pose of dream­ing? (i.e. what evo­lu­tion­ary advan­tage would a dream­ing crea­ture have over one that does not dream?) There are many exist­ing the­o­ries, such as emo­tion­al reboot, build­ing neu­ral net­works for visu­al pro­cess­ing, etc., but there is no gen­uine con­sen­sus on the issue.

One thought on “6. What is the purpose of dreaming? (proposed — Bill) discussed 29 June 2013

  1. Com­ments on Dream­ing
    Thor May
    29 June 2013

    1. Peo­ple tend to see what they want to see and hear what they want to hear. This sta­bi­lizes their iden­ti­ty and self-con­fi­dence. Phe­nom­e­na that are sep­a­rat­ed from direct sen­so­ry input are even more liable to this process. Hence faith based reli­gion, and ergo, the inter­pre­ta­tions of dream­ing. There­fore we are unlike­ly to change anyone’s mind dur­ing this dis­cus­sion about their favourite dream­ing the­o­ries!

    2. In every cul­ture, there is an enor­mous accu­mu­la­tion of sto­ries, beliefs and habits of inter­pre­ta­tion attached to dream­ing. This stuff is a rich anthro­po­log­i­cal source for under­stand­ing pat­terns of human behav­iour. It does not nec­es­sar­i­ly give insight into a sci­en­tific under­stand­ing of dream­ing.

    3. Dream­ing can occur dur­ing var­i­ous sleep stages, but is most com­mon and intense dur­ing REM sleep. REM sleep occu­pies about 25% of sleep time, and the length of dreams increas­es from about 10 min­utes to about 20 min­utes at the end of the night.

    4. Many ani­mals sleep. Appar­ent­ly armadil­los are amongst the biggest dream­ers. The evi­dence for such dream­ing comes from brain imag­ing. It would seem then that IQ is no qual­i­fi­ca­tion for dream­ing.

    5. Long term declar­a­tive (not pro­ce­du­ral) mem­o­ry stor­age is known to depend upon pro­cess­ing by the hip­pocam­pus dur­ing sleep. Sleep deprived sub­jects have severe­ly impaired mem­o­ry. The rela­tion­ship between dream­ing and this kind of men­tal house­keep­ing is unknown, except that the the neu­ro­trans­mit­ters, nore­pin­phrine, sero­ton­in and his­t­a­mine are blocked dur­ing REM sleep, while the stress neu­ro­chem­i­cal, cor­ti­sol often increas­es in late REM sleep, and inter­fer­es with the con­ver­sion of short term mem­o­ry to long term mem­o­ry (thus 95% of dreams are for­got­ten).


    6. The fol­low­ing is my own, com­plete­ly unsup­port­ed guess at what dream­ing may be about:

    a) Our entire real­i­ty or self-iden­ti­ty is a men­tal con­struct of habits + mem­o­ries + incom­ing exter­nal sen­sa­tion.

    b) This men­tal con­struct is not a solid thing. It is a fine­ly bal­anced, self-cor­rect­ing web of orga­nized rela­tion­ships. That orga­ni­za­tion is both chem­i­cal and elec­tri­cal. The orga­ni­za­tion, I think, prob­a­bly has a lot to do with the math­e­mat­i­cal behav­iour of com­plex­i­ty itself, which tends to gen­er­ate order from dis­or­der.

    c) My guess is that the self-cor­rect­ing nature of self-iden­ti­ty depends upon the con­stant input of exter­nal sen­sa­tion. Dur­ing sleep the input of exter­nal sen­sa­tion, espe­cial­ly visu­al and bal­ance sig­nals, is dra­mat­i­cal­ly reduced. In a way this “frees the mind” to wan­der and to play with unusu­al com­bi­na­tions.

    d) The amount of men­tal wan­der­ing in dreams varies a great deal, both between peo­ple (if we are to believe reports) and with­in indi­vid­u­al expe­ri­ence.

    e) My hypoth­e­sis (again unsup­port­ed) is that the men­tal wan­der­ing with­in dream peri­ods assists the main­te­nance of the “real­i­ty illu­sion” in a wak­ing state by explor­ing alter­na­tive pos­si­ble real­i­ties, minus the dis­ci­pline of direct sen­sa­tion. Aware­ness and rejec­tion of the­se alter­na­tives by our day­time “real­i­ty illu­sion” (our iden­ti­ty) may be com­pared to set­ting nav­i­ga­tion bea­cons for safe chan­nels in a tidal river. If this is so, then dream­ing would have clear evo­lu­tion­ary val­ue for sur­vival.

    7. Allow­ing our minds to wan­der is not restrict­ed to dream­ing. Absent-mind­ed behav­iour, day dream­ing, drug induced devi­a­tions are fur­ther exam­ples. It is a mat­ter of degree. The “half-sleep” state pri­or to full sleep or full wak­ing seems to be anoth­er exam­ple of iden­ti­ty which is part­ly with­out the dis­ci­pline of exter­nal sen­sa­tion or con­scious pur­pose. For exam­ple, my 90 year old moth­er tells me that she reg­u­lar­ly wakes now with the feel­ing that one of her sis­ters is in the bed and mustn’t be dis­turbed. Eighty years ago her five sis­ters reg­u­lar­ly had to share beds. 



    sum­ma­ry of dream the­o­ries: http://en.wikipedia.org/wiki/Dream

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