In a number of experimental studies we explored the so-called 'radical subjective', and rather controversial, solution of the measurement problem. This solution posits that an interaction with a conscious entity is required to complete the measurement. Thus the collapse of the wave packet is assumed to be causally linked to a conscious observation. Under the assumption that the brain is sensitive for the difference between observing a quantum (superposition) state and a classical state this

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... cal solution can be tested. A radioactive source was used to trigger beeps that first were delayed for 1 second and then were observed by a (final) observer from whom a continuous recording of brain activity was made. In about 50% of the events, another (pre) observer got feedback of this quantum event before the final observer. In those cases, presumably the pre-observer's observation resulted in collapse of the wave-packet while in the other half of the cases the final observer was 'producing' the collapse. The brain signals of the final observer for the two types of events were compared. The ambiguous results of the studies will be discussed. If consciousness is the crucial ingredient for 'collapse' to occur, then this might also give a new anthropocentric hypothesis with regard to the 'arrow of time'. The projection postulate implies a irreversible process of reduction and hence can be seen as one of the few non time-symmetric processes in physics. If consciousness is required to have a collapse then it might follow that consciousness introduces time asymmetry into physics. New neuro-cognitive models of consciousness suggest that the neural correlate of conscious experience (rather than non conscious processing) is the occurrence of massive parallel recurrent (i.e. non linear) neural activation. Thus the collapse of the wave packet would become associated with a strong non-linear process. This fits, at least in a metaphorical sense, with the theoretical results where an introduction on a non linear term in the Schrödinger equation results in an 'objective' reduction of the wave packet.