The Parameterized Human in OIT-SIM proposes a conceptual and operational application of the OIT-SIM / OIT-TISIM spacelike 5D informational framework to the human observer. The paper interprets the human as a self-referential, memory-bearing, decision-making and action-producing measuring system. Unlike a standard measuring instrument, which receives data, compares them with calibration references and outputs a result, the human observer filters incoming information through perception, compares it with a Personal Permanent Memory structure, sediments part of it as persistent information, and acts back upon external reality. The model introduces three coupled informational circuits: an ascending input circuit, a horizontal internal comparison and memory-sedimentation circuit, and a descending decision-action circuit. It synchronizes these circuits with the spacelike OIT-SIM invariant relation dτ5D,H² = dτ4D,H² − dqI,H², where dqI,H = (keff/c)dIm,H is interpreted as a spacelike informational metric displacement, not as psychological time or a second physical time. The work also introduces coherence factors, an informational discrepancy between expected and obtained results, an internal disequilibrium variable, and a phenomenological maintenance factor. This essay does not propose a clinical model, a complete neuroscience of consciousness, or an experimentally validated physical theory of the mind. It should be read as a conceptual OIT-based model of the human observer as a self-evolving measuring instrument, in which reality modifies the human through perception and memory, while the human modifies reality through decision and action. https://orcid.org/0009-0002-3646-1493