Eye Movements Reveal Mental Looking Through Time

Spontaneous eye movements reflect the representational geometries of conceptual spaces

Functional neuroimaging studies indicate that the human brain can represent concepts and their relational structure in memory using coding schemes typical of spatial navigation. However, whether we can read out the internal representational geometries of conceptual spaces solely from human behavior remains unclear. Here, we report that the relational structure between concepts in memory might be reflected in spontaneous eye movements during verbal fluency tasks: When we asked participants to randomly generate numbers, their eye movements correlated with distances along the left-to-right one-dimensional geometry of the number space (mental number line), while they scaled with distance along the ring-like two-dimensional geometry of the color space (color wheel) when they randomly generated color names. Moreover, when participants randomly produced animal names, eye movements correlated with low-dimensional similarity in word frequencies. These results suggest that the representational geometries used to internally organize conceptual spaces might be read out from gaze behavior.

Vertical Mental Timeline Is Not Influenced by VisuoSpatial Processing

The results examining the direction (bottom-to-top vs. top-to-bottom) of the mental vertical timeline are not conclusive. The visuospatial processing of temporal stimuli along vertical space could influence this time representation. This study aimed to investigate whether and how the visuospatial processing stage modulated the vertical timeline in an online temporal categorization task. In three studies, Italian university students (N = 150) responded more quickly to words expressing the past with a down arrow key, and more quickly to words expressing the future with an up arrow key, irrespective of whether the words were located in the top, middle, or bottom space (Experiment 1), or were presented downward (from top to bottom; Experiment 2A) or upward (from bottom to top Experiment 2B). These results suggest that the representation of time was not influenced by the visuospatial processing. The daily experience with verticality (e.g., to reach the attic, the lift goes up) could explain the bottom-to-top direction of the mental timeline.

Joint spatial-temporal association of response codes (STEARC) effect: Mental timelines embodied interpersonally

A co-action task was used to explore the effect of social interactions on temporal judgements, in comparison with an individual-task condition. In Experiment 1, the co-actors sat either individually (individual condition) or alongside a partner (joint condition) in front of a monitor and then responded to time-related words (e.g. yesterday, tomorrow). In Experiment 2, co-actors sat separately in front of two monitors and categorized the words either individually or jointly. Participants' response times to past- and future-related words in the individual conditions of both experiments had no significant difference. However, in the joint conditions, the responses were faster when the past-time words were mapped toward the participants on the left than when future-time words were mapped toward them. Our data support the existence of a specific mapping between past-time-left space and future-time-right space. This suggests that the two cooperators probably shared a similar mental timeline.

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.

A Review of Studies Supporting Metaphorical Embodiment

This paper presents a review of studies that have provided evidence supporting metaphorical embodiment. These studies are divided into three categories of behavioral, neuroimaging, and corpus studies. After summing up the findings of these studies, it is concluded that metaphorical embodiment is supported by these three lines of research. This is followed by a review of a number of studies that have measured sensorimotor and action effector strengths of various concepts. Then, the idea of sensorimotor and action effector strength of concepts is linked to metaphorical embodiment to present the main idea of the paper. Based on the findings of studies that have measured sensorimotor and action effector strengths of concepts, it is suggested that the degree of involvement of sensorimotor systems in mental simulation of metaphoric actions may not be at the same level in all metaphors. It depends on the sensorimotor strength of the base of the metaphor in various modalities. If the base of a metaphor has a high degree of perceptual strength in a certain modality, that modality plays the most important role in the processing of that metaphor, while other modalities take less important roles. In other words, depending on the sensorimotor strengths of the base of a metaphor in various modalities, those modalities have various levels of importance in the processing of that metaphor. If the base of the metaphor is weak in all modalities, modal resources can come into play to process that metaphor.

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.

Space-Time Congruency Effects Using Eye Movements During Processing of Past- and Future-Related Words

In Western cultures where people read and write from left to right, time is represented along a spatial continuum that goes from left to right (past to future), known as the mental timeline (MTL). In language, this MTL was supported by space-time congruency effects: People are faster to make lexical decisions to words conveying past or future information when left/right manual responses are compatible with the MTL. Alternatively, in cultures where people read from right to left, space-time congruency effects go in the opposite direction. Such cross-cultural differences suggest that repeated writing and reading dynamic movements are critically involved in the spatial representation of time. In most experiments on the space-time congruency effect, participants use their hand for responding, an effector that is associated to the directionality of writing. To investigate the role of the directionality of reading in the space-time congruency effect, we asked participants to make lateralized eye movements (left or right saccades) to indicate whether stimuli were real words or not (lexical decision). Eye movement responses were slower and higher in amplitude for responses incompatible with the direction of the MTL. These results reinforce the claim that repeated directional reading and writing movements promote the embodiment of time-related words.

The Variability of Mental Timeline in Vertical Dimension

People often use concrete spatial terms to represent abstract time. Previous studies have shown that mental timeline (MTL) is represented along a horizontal axis. Studies of the mental timeline have demonstrated that compared with English speakers, Mandarin speakers are more likely to think about time vertically (up-down) than horizontally (left-right/front-back). Prior studies have suggested that MTL in the up and down dimensions originated from temporal-spatial metaphors in language. However, there are still a large number of perceptual experiences in the up and down dimensions, such as visual and sensorimotor experience. Then does the visual experience in daily life affect the MTL in the vertical dimension? This study is aimed to investigate whether visual experience can promote or activate the opposite direction of MTL from implicit and explicit levels. The results showed that when the time information in the task was not prominent, the direction of vertical MTL cannot be affected by ascending or descending perceptual experience. While when the time information was prominent, whether the task was implicit or explicit, compared with the control group, watching the top-down scene significantly increased the top-down direction selection, while in the implicit task, watching the bottom-up scene made the top-down MTL disappear. To the best of our knowledge, our study provides the first evidence that the flexibility of space–time associations in vertical dimension extends beyond explicit and embraces even implicit levels. This study shows that the vertical MTL is activated in certain conditions and could be affected by the visual experience.

The vertical space-time association

The space-time interaction suggests a left-to-right directionality in the mind's representation of elapsing time. However, studies showing a possible vertical time representation are scarce and contradictory. In Experiment 1, 32 participants had to judge the duration (200, 300, 500, or 600 ms) of the target stimulus that appeared at the top, centre, or bottom of the screen, compared with a reference stimulus (400 ms) that always appeared in the centre of the screen. In Experiment 2, 32 participants were administered the same procedure, but the reference stimulus appeared at the top, centre, or bottom of the screen and the target stimulus was fixed in the centre location. In both experiments, a space-time interaction was found with an association between short durations and bottom response key as well as between long durations and top key. The evidence of a vertical mental timeline was further confirmed by the distance effect with a lower level of performance for durations close to that of the reference stimulus. The results suggest a bottom-to-top mapping of time representation, more in line with the metaphor "more is up."

Processing of an ambiguous time phrase in posttraumatic stress disorder: Eye movements suggest a passive, oncoming perception of the future

Metaphorically, the future can be perceived as approaching us (time-moving metaphor) or as being approached by us (ego-moving metaphor). Also, in line with findings that our eyes look more up when thinking about the future than the past, the future's location can be conceptualized in upwards terms. Eye movements were recorded in 19 participants with PTSD and 20 healthy controls. Participants with PTSD showed downward and healthy controls upward eye movements while processing an ego/time-moving ambiguous phrase, suggesting a passive (time-moving) outlook toward the future. If replicated, our findings may have implications for the conceptualization and treatment of PTSD.

“Next Wednesday’s Meeting has been Moved Forward Two Days”

Abstract. If time is conceived of as a river, we either have the perspective of seeing ourselves as moving downstream toward the future (e.g., “We are approaching the future,” called ego moving), or we have the perspective of the future as moving upstream toward us (e.g., “The future is approaching,” called time moving). Most ego- and time-moving studies have been conducted by using an English ego/time-moving ambiguous question to implicitly measure a person’s current time perspective (ego vs. time moving). In the current study, we replicate previous findings that in (Standard) German the time-perspective question is not ambiguous, while showing as a new finding that it is ambiguous in Swiss German. We attribute this difference to different normative uses in these two German variants. To our knowledge, this study is the first to investigate dialectal differences in relation to cognitive processing of ego-/time-moving metaphors. Psychological and linguistic implications are discussed.

Do Writing Directions Influence How People Map Space onto Time?

Abstract. The causal role of a unidirectional orthography in shaping speakers’ mental representations of time seems to be well established by many psychological experiments. However, the question of whether bidirectional writing systems in some languages can also produce such an impact on temporal cognition remains unresolved. To address this issue, the present study focused on Japanese and Taiwanese, both of which have a similar mix of texts written horizontally from left to right (HLR) and vertically from top to bottom (VTB). Two experiments were performed which recruited Japanese and Taiwanese speakers as participants. Experiment 1 used an explicit temporal arrangement design, and Experiment 2 measured implicit space-time associations in participants along the horizontal (left/right) and the vertical (up/down) axis. Converging evidence gathered from the two experiments demonstrate that neither Japanese speakers nor Taiwanese speakers aligned their vertical representations of time with the VTB writing orientation. Along the horizontal axis, only Japanese speakers encoded elapsing time into a left-to-right linear layout, which was commensurate with the HLR writing direction. Therefore, two distinct writing orientations of a language could not bring about two coexisting mental time lines. Possible theoretical implications underlying the findings are discussed.

Karma or Immortality: Can Religion Influence Space-Time Mappings?

People implicitly associate the "past" and "future" with "front" and "back" in their minds according to their cultural attitudes toward time. As the temporal focus hypothesis (TFH) proposes, future-oriented people tend to think about time according to the future-in-front mapping, whereas past-oriented people tend to think about time according to the past-in-front mapping (de la Fuente, Santiago, Román, Dumitrache, & Casasanto, 2014). Whereas previous studies have demonstrated that culture exerts an important influence on people's implicit spatializations of time, we focus specifically on religion, a prominent layer of culture, as potential additional influence on space-time mappings. In Experiment 1 and 2, we observed a difference between the two religious groups, with Buddhists being more past-focused and more frequently conceptualizing the past as ahead of them and the future as behind them, and Taoists more future-focused and exhibiting the opposite space-time mapping. In Experiment 3, we administered a religion prime, in which Buddhists were randomly assigned to visualize the picture of the Buddhas of the Past (Buddha Dipamkara) or the Future (Buddha Maitreya). Results showed that the pictorial icon of Dipamkara increased participants' tendency to conceptualize the past as in front of them. In contrast, the pictorial icon of Maitreya caused a dramatic increase in the rate of future-in-front responses. In Experiment 4, the causal effect of religion on implicit space-time mappings was replicated in atheists. Taken together, these findings provide converging evidence for the hypothesized causal role of religion for temporal focus in determining space-time mappings.

Mapping of non-numerical domains on space: a systematic review and meta-analysis

The spatial numerical association of response code (SNARC) effect is characterized by low numbers mapped to the left side of space and high numbers mapped to the right side of space. In addition to numbers, SNARC-like effects have been found in non-numerical magnitude domains such as time, size, letters, luminance, and more, whereby the smaller/earlier and larger/later magnitudes are typically mapped to the left and right of space, respectively. The purpose of this systematic and meta-analytic review was to identify and summarise all empirical papers that have investigated horizontal (left-right) SNARC-like mappings using non-numerical stimuli. A systematic search was conducted using EMBASE, Medline, and PsycINFO, where 2216 publications were identified, with 57 papers meeting the inclusion criteria (representing 112 experiments). Ninety-five of these experiments were included in a meta-analysis, resulting in an overall effect size of d = .488 for a SNARC-like effect. Additional analyses revealed a significant effect size advantage for explicit instruction tasks compared with implicit instructions, yet yielded no difference for the role of expertise on SNARC-like effects. There was clear evidence for a publication bias in the field, but the impact of this bias is likely to be modest, and it is unlikely that the SNARC-like effect is a pure artefact of this bias. The similarities in the response properties for the spatial mappings of numerical and non-numerical domains support the concept of a general higher order magnitude system. Yet, further research will need to be conducted to identify all the factors modulating the strength of the spatial associations.

Recombinant Enaction: Manipulatives Generate New Procedures in the Imagination, by Extending and Recombining Action Spaces

Manipulation of physical models such as tangrams and tiles is a popular approach to teaching early mathematics concepts. This pedagogical approach is extended by new computational media, where mathematical entities such as equations and vectors can be virtually manipulated. The cognitive and neural mechanisms supporting such manipulation-based learning-particularly how actions generate new internal structures that support problem-solving-are not understood. We develop a model of the way manipulations generate internal traces embedding actions, and how these action-traces recombine during problem-solving. This model is based on a study of two groups of sixth-grade students solving area problems. Before problem-solving, one group manipulated a tangram, the other group answered a descriptive test. Eye-movement trajectories during problem-solving were different between the groups. A second study showed that this difference required the tangram's geometrical structure, just manipulation was not enough. We propose a theoretical model accounting for these results, and discuss its implications.