Subjective figure reversal in two- and three-dimensional perceptual space.

A permanently illuminated pattern of Mach's truncated pyramid can be perceived according to the experimental instruction given, either as a three-dimensional reversible figure with spontaneously changing convex and concave interpretation (in one experiment), or as a two-dimensional reversible figure-ground pattern (in another experiment). The reversal rate was about twice as slow, without the subjects being aware of it, if it was perceived as a three-dimensional figure compared to the situation when it was perceived as two-dimensional. It may be hypothetized that in the three-dimensional case, the process of perception requires more sequential steps than in the two-dimensional one.

Alternation of EEG alpha and non-alpha periods does not differ in open and closed eye condition in darkness.

In relaxed subjects sitting in darkness no difference in the duration of EEG alpha and non-alpha (mostly desynchronized) periods were found under conditions of open and closed eyes.

Men in extreme conditions: some medical and psychological aspects of the Auschwitz concentration camp.

The second world war ended many years ago. Most of those who survived the stay at the German concentration camp at Auschwitz have already died of the consequences of their imprisonment; those still alive are already in the last third of their life. Is there any point in returning to the experiences of those days? Consideration of the mental hygiene of former prisoners cautions us that perhaps we should not do it.

Visual stimulus threshold related to EEG alpha and non-alpha epochs.

In humans sitting in darkness with open eyes the presence of EEG alpha and non-alpha epochs was detected automatically and the threshold of detection of a dim visual stimulus was measured under both conditions. No differences in threshold were found. However, the reaction times for stimulus detection during alpha epochs were significantly longer than during non-alpha ones.