The nasal cycle is a chaotic ultradian rhythm with a period ranging fr
om about 75 to 200 minutes. It has been shown to correlate highly with
EEG amplitude in the contralateral hemisphere at virtually all freque
ncies, suggesting a connection between this rhythm and laterality of b
rain function. During a three-week period, five participants estimated
airflow from both nostrils every 30 minutes during waking hours. Esti
mates were recorded on Likert scales and analyzed in three distinct ph
ases: (1) reconstructing two-dimensional attractors by lagging and emb
edding; (2) computing Fourier frequency analyses; and (3) estimating f
ractal dimensions. Attractor reconstructions demonstrate noticeable or
der when compared to Monte Carlo reconstructions of the same data sets
, and dimension estimates are in the fractal range. The attractor reco
nstruction, in combination with the frequency analyses, show distinct
individual differences in the structure of the nasal cycle. The advant
ages of chaotic systems analyses over traditional behavioral statistic
s are discussed.