1. Spatial Neglect and its Extension to Abstract Cognition
Unilateral Spatial Neglect (USN) is classically defined as the inability to attend or respond to stimuli presented in the space contralateral to the side of the lesion (generally, right hemisphere left neglect). In the TIM, USN is interpreted as the collapse of the Intrinsic Fractionation of a dimension, rendering that space non-existent as a structural category for the Soma.
A. The Mental Time Line (MTL)
Time, an abstract concept, is managed by our brain by anchoring it to familiar spatial structures. This representation is the Mental Time Line (MTL). In Western culture:
- The Past (Before) is conventionally associated with left space.
- The Future (After) is associated with right space.
This association is powerfully reinforced by the practice of reading and writing (the eye proceeds from left to right to process the temporal sequence of the text).
B. The Manifestation of Temporal Neglect
If left space collapses due to USN, and if this space is the template for the Past, then the Past itself should become partially inaccessible or neglected.
Patients with USN exhibit Temporal Neglect characterized by:
- Difficulty Processing the Past: They tend to make systematic errors that favor the Future dimension (right side) at the expense of events located in the Past (left side).
- Truncated Representation: As demonstrated by Bisiach’s task for space, the Ego Cogitans (EC) cannot generate a complete mental timeline. The Cognitive Morphogenesis of a temporal sequence is impaired, resulting in a line that begins “in the center” or is heavily biased toward the Future.
- Impact on Prognostica Mens (PM): The Predictive Mens (PdM) (part of the PM) may fail to generate predictions (Future) or plans (Action) that require a complete and stable recall of past experiences as a basis for simulation.
2. The Critical Role of Literacy: The Cultural Convention
The phenomenon of temporal neglect raises a crucial question: is the Left \right Past association a universal feature of the brain, or is it a learned Cultural Convention? Analysis of illiterate subjects answers this question by distinguishing primitive failure from functional failure.
A. The S-T Anchoring in the TIM
According to the TIM, the acquisition of reading and writing (from left-to-right) imposes a Hierarchical Conditionality on the brain:
- The Intrinsic Left/Right Dichotomy (primitive QS hardware) is co-opted to represent the Abstract Past/Future Dichotomy (EC evolutionary software).
- This Extrinsic Relational Interaction (writing/reading) stabilizes and rigidifies the S-T (Spatial-Temporal) anchoring.
B. The Experiment with Illiterate Subjects and Its Relevance
Studies conducted on illiterate subjects with spatial neglect have been essential for isolating the influence of culture:
- Absence of Rigid Mapping in Healthy Subjects: In healthy illiterate subjects (who lack the L/R reading convention), the Past $\leftrightarrow$ Left association is often absent or very weak. Their Mental Time Line (MTL) is not rigidly lateralized; they may represent time vertically, radially, or in other non-linear directions.
- Protection from Temporal Neglect: When illiterate patients develop left spatial neglect (failure of Intrinsic Fractionation), their representation of time is not systematically dragged into the spatial deficit. They show a significant reduction or absence of temporal neglect for past events compared to literate patients.
C. Implications for Cognitive Morphogenesis (EC)
These findings indicate that the primitive damage of neglect (the collapse of Intrinsic Fractionation) is necessary but not sufficient to produce temporal neglect:
- Literate Subjects: Intrinsic Fractionation collapses. Cognitive Morphogenesis fails to construct a complete Past because the Past has been rigidly anchored to left space by cultural convention.
- Illiterate Subjects: Intrinsic Fractionation collapses. Cognitive Morphogenesis succeeds in constructing the Past using alternative (non-horizontally spatialized) schemata or anchors, as the strong Hierarchical Conditionality (writing) was not present.
3. The Absence of Temporal Neglect: Functional Failure (Gerstmann Syndrome)
It is equally instructive to note the absence of systematic temporal neglect in Gerstmann Syndrome (GS).
A. Structural Integrity (TIM)
As established, GS is not a failure of the absolute Intrinsic Fractionation of the Soma, but a failure in the Extrinsic Relational Interaction and Hierarchical Conditionality for the mapping of Entities and Symbols.
- The Spatial Matrix is Intact: The Left/Right spatial dichotomy is structurally preserved and functional; the GS patient does not deny the existence of left space but has problems relating it to other systems.
- Absence of Primary Collapsus: Since the primitive spatial collapse (which would engulf the temporal representation) does not occur, the Mental Time Line (MTL) remains structurally complete, even if its symbolic expression or use in a mapping task (e.g., writing sequences) may be disorganized due to Agraphia or Acalculia.
4. Conclusions: The Embodied and Social Nature of Time
The presence/absence of temporal neglect illuminates the architectural principles of the TIM:
- Structural Priority (USN): The failure of Intrinsic Fractionation (the primitive damage) has the potential to destroy abstract categories (Time) that have been rigidly anchored to it.
- Cultural Modulation (Literacy): The Hierarchical Conditionality of culture (reading/writing) is what makes time vulnerable to spatial damage. The absence of this convention in the illiterate protects their temporal cognition, demonstrating that Cognitive Morphogenesis is a process that is not only biological but also social and acquired.
Temporal neglect is not merely a clinical curiosity but powerful evidence that our cognition of time is embodied and that the most abstract concepts are built upon the most primitive spatial divisions—but only if extrinsic interactions (like literacy) have established that hierarchical mapping.