Olfactory perception and olfactory imagery: a multidimensional analysis.

Whether a system of imagery for olfaction exists is currently an unsettled issue. Moreover, the dimensions underlying odor perception have eluded researchers for many years. Two experiments bearing on these issues are presented. In one experiment, a group of 32 undergraduates rated the similarity of pairs of 16 commonplace odorants (e.g., chocolate and leather) they perceived using scratch and sniff stimuli; in another, a different group of 44 undergraduates was asked to imagine and then rate the similarity of the same pairs of odors. Multidimensional scaling of the data suggests that three-dimensional solutions with similar stimulus dimensions, such as fruitiness, strength, and familiarity, underlied the ratings of both perceived and imagined odors. By finding that similar dimensions define the psychological space of both the imagery and the perception tasks, this study suggests that imagery does indeed exist for olfaction.

Measurements of n-p correlations in the reaction of relativistic neon with uranium.

We report a preliminary measurement of coincident neutron-proton pairs emitted at 45 degrees in the interaction of 400, 530, and 650 MeV/A neon beams incident on uranium. Charged particles were identified by time of flight and momentum, as determined in a magnetic spectrometer. Neutral particles were detected using a thick plastic scintillator, and their time of flight was measured between an entrance scintillator, triggered by a charged particle, and the neutron detector. The scatter plots and contour plots of neutron momentum vs. proton momentum appear to show a slight correlation ridge above an uncorrelated background. The projections of this plane on the n-p momentum difference axis are essentially flat, showing a one standard deviation enhancement for each of the three beams energies. At each beam energy, the calculated momentum correlation function for the neutron-proton pairs is enhanced near zero neutron-proton momentum difference by approximately one standard deviation over the expected value for no correlation. This enhancement is expected to occur as a consequence of the attractive final state interaction between the neutron and proton (i.e., virtual or "singlet" deuterons). The implications of these measurements are discussed.