FIG. 1 shows the components of the measuring apparatus for recognizing and locating emotions and thoughts by measuring the infrared pulse radiation in the sequence of the measured value pre-processing: localization tube 1, infrared detector 2, amplifier 3, analogue/digital conversion 4, analysis program 5 and display 6, wherein the components of the measuring apparatus have the following features: the localization tube 1 receives the infrared pulses, which are produced by changes in the body heat of a creature and emitted by a small surface, and partially reflects said infrared pulses several times at the inner wall and focuses said pulses on the infrared detector 2; the infrared detector 2 which is designed to be able to receive only AC voltage signals and not DC voltage signals converts the infrared beams into electrical signals; the amplifier 3 amplifies these signals; the signals are digitized during the analogue/digital conversion 4; the analysis program 5 creates time signals, amount spectra and differential spectra for the total measuring time or for time sections in different mental dispositions of the creature being investigated and creates a characteristic mental spectrum in the pulse frequency range of approximately 0.01 to 10 Hz; the results for the different mental dispositions of the creature being investigated can be seen on the display 6 and can be compared, with the result that different emotions such as joy or sorrow can be recognized, for example. In addition to the measuring apparatus, it is possible to use a transmitter which flashes on a small body surface and whose light pulses contain infrared portions. This has the advantage of amplifying pulse frequencies which have already occurred and of allowing the pulse frequencies which have not yet appeared during mental activity to emerge.