Can mental time lines co-exist in 3D space?

Writing direction influences the spatial representations of past- and future-tense forms: Evidence from eye tracking

The present study tests the hypothesis that the directionality of reading habits (left-to-right or right-to-left) impacts individuals' representation of nonspatial events. Using the blank screen paradigm, we examine whether eye movements reflect culture-specific spatial biases in processing temporal information, specifically, grammatical tense in Russian and Hebrew. Sixty-two native speakers of Russian (a language with a left-to-right reading and writing system) and 62 native speakers of Hebrew (a language with a right-to-left reading and writing system) listened to verbs in the past or future tense while their spontaneous gaze positions were recorded. Following the verb, a visual spatial probe appeared in one of the five locations of the screen, and participants responded manually to indicate its position. While participants' response latencies to the spatial probe revealed no significant effects, their gaze positions along the horizontal axis for past- and future-tensed verbs aligned with the reading and writing direction in their language. These results provide novel evidence that eye movements during auditory processing of grammatical tense are influenced by culturally specific reading and writing conventions, shifting leftward or rightward on the horizontal plane depending on the stimuli's time reference (past or future) and the participants' language (Russian or Hebrew). This spatial bias indicates a common underlying cognitive mechanism that uses spatial dimensions to represent temporal constructs.

Keeping track of time: Horizontal spatial biases for hours, days, and months

In many Western cultures, the processing of temporal words related to the past and to the future is associated with left and right space, respectively - a phenomenon known as the horizontal Mental Time Line (MTL). While this mapping is apparently quite ubiquitous, its regularity and consistency across different types of temporal concepts remain to be determined. Moreover, it is unclear whether such spatial mappings are an essential and early constituent of concept activation. In the present study, we used words denoting time units at different scales (hours of the day, days of the week, months of the year) associated with either left space (e.g., 9 a.m., Monday, February) or right space (e.g., 8 p.m., Saturday, November) as cues in a line bisection task. Fifty-seven healthy adults listened to temporal words and then moved a mouse cursor to the perceived midpoint of a horizontally presented line. We measured movement trajectories, initial line intersection coordinates, and final bisection response coordinates. We found movement trajectory displacements for left- vs. right-biasing hour and day cues. Initial line intersections were biased specifically by month cues, while final bisection responses were biased specifically by hour cues. Our findings offer general support to the notion of horizontal space-time associations and suggest further investigation of the exact chronometry and strength of this association across individual time units.

Horizontal mapping of time-related words in first and second language

The existence of a consistent horizontal spatial-conceptual mapping for words denoting time is a well-established phenomenon. For example, words related to the past or future (e.g., yesterday/tomorrow) facilitate respective leftward/rightward attentional shifts and responses, suggesting the visual-spatial grounding of temporal semantics, at least in the native language (L1). To examine whether similar horizontal bias also accompanies access to time-related words in a second language (L2), we tested 53 Russian-English (Experiment 1) and 48 German-English (Experiment 2) bilinguals, who classified randomly presented L1 and L2 time-related words as past- or future-related using left or right response keys. The predicted spatial congruency effect was registered in all tested languages and, furthermore, was positively associated with higher L2 proficiency in Experiment 2. Our findings (1) support the notion of horizontal spatial-conceptual mapping in diverse L1s, (2) demonstrate the existence of a similar spatial bias when processing temporal words in L2, and (3) show that the strength of time-space association in L2 may depend on individual L2 proficiency.

Space-time mapping on the sagittal axis in congenital blindness

Previous evolutionary perspectives proposed that the space-time mapping on the sagittal axis originates from visuo-locomotion coupling when walking/running forward. Accordingly, the congenitally blind could not have developed a sagittal mental timeline if the latter depends on such a visuo-locomotion coupling. However, this conclusion was reached in only a single empirical study (Rinaldi et al. in J Exp Psychol General 147:444-450, 2018), and its theoretical underpinnings are not entirely convincing as locally static and continuous auditory input undergoes a relatively similar change as function of self-locomotion, but this type of sensory-locomotion coupling is spared even in congenital blindness. Therefore, the present study systematically explored whether the congenitally blind show space-time mappings on the sagittal axis using different paradigms in three experiments. In Experiment 1, using a typical implicit RT task, the congenitally blind showed the same preferred space-time mapping in the sagittal dimension as normally sighted participants did. In Experiment 2, this space-time mapping occurred even automatically when temporal relations were task-irrelevant in a naming task. In Experiment 3, in an explicit space-time mapping task, the congenitally blind were more likely to locate the past behind and the future in front of their bodies. Moreover, most blind participants used spatial metaphors for their space-time mapping on the sagittal axis. These results supported the conclusion that the congenitally blind have a sagittal mental timeline, and that their sensory-locomotion coupling experience was either more similar to that of sighted participants or not critical for the space-time mapping. The present study, thus, also helps to clarify the origin of the sagittal mental timeline.

Does walking/running experience shape the sagittal mental time line?

A growing body of evidence suggested that time could be separately represented either on the lateral or sagittal axis. And the lateral mental time line has an origin associated with sensorimotor experience, e.g., reading/writing. However, it is still not clear whether the sagittal mental time line also originates from sensorimotor experience, e.g., walking/running. To address this question, we examined how the movement experience affected the space-time mapping on the lateral and sagittal axes using the virtual reality technique in two experiments. The results showed that the virtual movement experience had significant effects on the space-time mapping on the lateral axis (Experiment 1), but not on the sagittal axis (Experiment 2). This finding supported that the space-time mapping on the lateral axis does originate from sensorimotor experience, while the space-time mapping on the sagittal axis more likely originates from spatial metaphors in languages or other cultural experiences.

Face Age is Mapped Into Three-Dimensional Space

People can represent temporal stimuli (e.g., pictures depicting past and future events) as spatially connoted dimensions arranged along the three main axes (horizontal, sagittal, and vertical). For example, past and future events are generally represented, from the perspective of the individuals, as being placed behind and in front of them, respectively. Here, we report that such a 3D representation can also emerge for facial stimuli of different ages. In three experiments, participants classified a central target face, representing an individual at different age stages, as younger or older than the reference face of 40 years. Manual responses were provided with two keys placed along the horizontal axis (Experiment 1), the sagittal axis (Experiment 2), and the vertical axis (Experiment 3). The results indicated that the younger faces were represented on the left/back/top side of the space, whereas the older faces were represented on the right/forward/bottom side of the space. Furthermore, in all experiments, the latencies decreased with the absolute difference between the age of the target face and that of the reference face (i.e., a distance effect). Overall, this work suggests that the spatial representation of time includes social features of the human face.

When time stands upright: STEARC effects along the vertical axis

According to the spatial-temporal association of response codes (STEARC) effect, time can be spatially represented from left to right. However, exploration of a possible STEARC effect along the vertical axis has yielded mixed results. Here, in six experiments based on a novel paradigm, we systematically explored whether a STEARC effect could emerge when participants were asked to classify the actual temporal duration of a visual stimulus. Speeded manual responses were provided using a vertically oriented response box. Interestingly, although a top-to-bottom time representation emerged when only two temporal durations were employed, an inverted bottom-to-top time representation emerged when a denser set of temporal durations, arranged along a continuum, was used. Moreover, no STEARC effects emerged when participants classified the shapes of visual stimuli rather than their temporal duration. Finally, three additional experiments explored the STEARC effect along the horizontal axis, confirming that the paradigm we devised successfully replicated the standard left-to-right representation of time. These results provide supporting evidence for the notion that temporal durations can be mapped along the vertical axis, and that such mapping appears to be relatively flexible.

A pilot study of how the past, present, and future are represented in three-dimensional space

Numerous studies have shown that the representation of temporal concepts is associated with spatial features such as position and size. In a conventional task called the "Circle Test (CT)," participants are asked to express the relative importance of the past, present, and future and to demonstrate relationships among them by drawing three circles representing the past, present, and future. Studies on various participants, including refugees, patients living with serious illnesses, and adolescents, have used it to understand the temporal perspectives of different test takers. On the other hand, several studies have suggested that concepts of time are represented in three-dimensional (3D) space. It is expected that temporal concepts of the past, present, and future could be recorded using a 3D drawing task. Here we created a 3D version of CT (the "Sphere Test [ST]") to investigate the sagittal representation of time and to record the relative time importance and relatedness, allowing for the shielding relationships and the laws of perspective. We conducted experiments with university students to compare the results from the CT and the ST. Our results suggested that not all on-screen overlapping can be interpreted as representing a connection between two time zones in 3D space. We also found correlations between the chosen sizes of the three circles in the CT and ST, i.e., the on-screen sizes of the past and present circles were positively correlated. In contrast, we observed no correlation between the on-screen sizes of the future circles in the two tests. The alignment pattern along the sagittal axis showed different patterns from the horizontal and vertical axes. In conclusion, this study sheds new light on the third dimension of the spatial representation of time and may help us understand the relationship between temporal perspectives and other factors, including mental health.

Metonymic event-based time interval concepts in Mandarin Chinese-Evidence from time interval words

Starting from the overwhelming view that time is metaphorically conceptualized in terms of space, this study will, on the one hand, take the time interval words into minute analysis to confirm our view of event conceptualization of time at a more basic level along with space-time metaphoric conceptualization of time at a relational level. In alignment with the epistemology of the time-space conflation of the Chinese ancestors, our view is supported by the systematic examination of evidence related to the cultural origins of the conceptualization of time, through a scrutiny of the original meanings and construction of words related to intervals of time in Mandarin Chinese. This study offers a new explanation of how: (1) the conceptualization of time in Chinese is realized through metonymic cognition and (2) words related to specific intervals of time are coined based on the metonymic conceptualization of related events or a corresponding event schema. Five major types of event-based metonymies are identified, and their interactive functions are illustrated. Based on this evidence, we argue that the double nature of both metaphoric and metonymic time conceptualization in Mandarin Chinese lies in the fact that time interval words can be used in its time categorial sense or as a time entity which suggests the etymological origins of Chinese as ideograph. It is concluded therefore that the event-based metonymy conceptualization of time can provide better insights into the characteristics of Chinese modes of thinking and its influences on the perception of and interaction with the world. This study can also serve as good evidence for the shaping effect of language on cognition.

Spatial conceptual mapping of words with temporal semantics

Unlike concrete words related to sensory perception (e.g., hear, sun), abstract words (including the words with temporal semantics, e.g., year, tomorrow) do not have direct embodied sensory correlates. Nevertheless, existing research indicates that abstract concepts’ representations make regular reference to sensorimotor processes, e.g., visual perception. For example, regular expressions such as “the future is ahead” or “the flow of time” are common in different languages reflecting a relatively universal nature of space-time correspondences. Moreover, these regular correspondences are commonly demonstrated in experimental studies; for example — by registering attentional displacement during processing of past and future related words. Here, the main theoretical approaches as well as existing experimental data documenting neurocognitive foundations of space-time representations are reviewed. A detailed overview of research on spatial-conceptual mapping of time concepts in three-dimensional visual space is offered. We also consider features of space-time associations that reflect linguistic and socio-cultural differences. In conclusion, the main areas of current and future that will allow an integration of the existing data within a common theoretical framework are defined.

Mental representation of autobiographical memories along the sagittal mental timeline: Evidence from spatiotemporal interference

Time is usually conceived of in terms of space: many natural languages refer to time according to a back-to-front axis. Indeed, whereas the past is usually conceived to be "behind us", the future is considered to be "in front of us." Despite temporal coding is pivotal for the development of autonoetic consciousness, little is known about the organization of autobiographical memories along this axis. Here we developed a spatial compatibility task (SCT) to test the organization of autobiographical memories along the sagittal plane, using spatiotemporal interference. Twenty-one participants were asked to recall both episodic and semantic autobiographical memories (EAM and SAM, respectively) to be used in the SCT. Then, during the SCT, they were asked to decide whether each event occurred before or after the event presented right before, using a response code that could be compatible with the back-to-front axis (future in front) or not (future at back). We found that performance was significantly worse during the non-compatible condition, especially for EAM. The results are discussed in light of the evidence for spatiotemporal encoding of episodic autobiographical memories, taking into account possible mechanisms explaining compatibility effects.