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First question - sorry Cognitive Science is a closed book to me so I hope someone can give me an insight into this phenomenon.

We have a child's toy that is activated by clapping of the hands. To me, I always perceive the activation of the toy to take place a split second before I perceive the sound of the hand clap - even, perhaps especially, when it is me that is doing the hand clapping.

I recognise that this must be a perception issue because the sound has to travel, perhaps 12 times the distance to the toy compared to my ears, then be processed by the electronics before the sound of the toy reaches back to me. How is it possible that I hear the sound of the toy before the sound of the handclap?

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Judging from your description I think it has to do with the predictability of a certain event (the activation of the toy in this case) after a certain action (the hand clapping), altering your perception of temporal order between the event and your action. David Eagleman has done some research on this suggesting that when one has the intention of generating a certain event that has a high probability to occur, this event can be perceived to happen earlier than the action that caused it. That maybe explains why it especially happens when you are the agent. At least that is what I got from reading this paper http://www.psych.usyd.edu.au/staff/alexh/research/papers/EaglemanHolcombeTiCS2002.pdf Feel free to correct me if you think my description is wrong.

Nevertheless, the field of time perception has generally revealed many illusions in human timing and if you are interested in more you can read the work of Benjamin Libet as well on time and conscious awareness http://www.amazon.com/Mind-Time-Consciousness-Perspectives-Neuroscience/dp/067401846X

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  • $\begingroup$ I've had a pretty good scan through the first article you cite and I think that certainly seems to be a very likely explanation of what I experience. Thank you very much! I'll read again, and more fully, when I get a better chance. The one factor I hadn't taken into account was the (relatively) slow processing power of my brain. It certainly seems plausible to me that evolution would have equipped us with a mechanism to allow us to perceive events as simultaneous when we know they did occur simultaneously by other means. $\endgroup$ – Lefty Sep 23 '14 at 21:05
  • $\begingroup$ I remain a little intrigued as to why this is the only circumstance in which I perceive this "retroactive causality" to occur. Given the huge amount of events that I've caused in my life and all of which appear to work perfectly normal forward-time. I wonder if it's the unusual nature of a sound-activated electronic device that could be something my brain isn't wired to understand. $\endgroup$ – Lefty Sep 23 '14 at 21:18
  • $\begingroup$ You make a good point about this circumstance. It could be that sometimes we don't notice some phenomena until a certain event brings them to our perception. However, if you think about it, supposing that conscious awareness is like a control system, a system such as this that has a latency of about 300 ms (as calculated by Libet) is not that bad. It could be worse $\endgroup$ – Lazaros Mitskopoulos Sep 24 '14 at 8:53
  • $\begingroup$ I suppose what I was failing to properly express in my comment is that something like a light switch is a causal relationship we learn at a very early age, we "know" that the cause/effect are linked and so our brain has learned to perceive the causal relationship. Maybe the nature of this handclap/musical-toy-response being something I first experienced in my 40's, my brain doesn't have any frame of reference in which to link the causality...? $\endgroup$ – Lefty Sep 24 '14 at 9:02
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It is possible that the acoustics of the situation can explain the perception. If the clapping of your hands acts as a highly directional sound source (I cannot quickly find any measurements of the acoustic directionality of hand claps) then it is possible that very little direct sound reaches your ears and you are only hearing the "echo" of the clap. In other words the sound waves propagate from your hands to a reflecting surface like a wall and then to your ears. Depending on how far away these reflecting surfaces are could mean the sound reaches the toy substantially before it reaches your ears. A way to test this would be to see if your perception changes in an anechoic chamber where there are no reflecting surfaces. If you do not have an anechoic chamber in your basement, and I pity you if you don't, then you can go outside away from any buildings and walls.

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  • $\begingroup$ Your scepticism does you credit - that was exactly the sort of explanation that I assumed for a few years but various different experiments proved that the answer was unlikely to be in the world of physics (where I'm more comfortable) but in my own perception. For example, I turned my back on the toy and placed it between 10 and 15 feet away from me then clapped my hands in front of my face. However, you have added another dimension - I wonder if I perceive the clap later due to echoes making the envelope of the sound longer...? $\endgroup$ – Lefty Sep 24 '14 at 11:35
  • $\begingroup$ As it happens, I DO have an anechoic chamber in my basement ;) but I haven't tried the experiment in there or in the garden. I will do that. Also I've been meaning to try recording the experiment and see how I perceive it "once removed". Keep forgetting to do that... $\endgroup$ – Lefty Sep 24 '14 at 11:39
  • $\begingroup$ OK, I've just gone into the garden and tested. The phenomenon still exists but may be slightly reduced, difficult to tell. I also tried video recording it (indoors) and, as I watch it I'm quite surprised to say that it still happens on the recording! A few more experiments are needed I think.... $\endgroup$ – Lefty Sep 24 '14 at 11:53

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