How does culture shape our concepts? Across many cultures, people conceptualize time as if it flows along a horizontal timeline, but the direction of this implicit timeline is culture specific: Later times are on the right in some cultures but on the left in others. Here we investigated whether experience reading can determine the direction and orientation of the mental timeline, independent of other cultural and linguistic factors. Dutch speakers performed space-time congruity tasks with the instructions and stimuli written in either standard, mirror-reversed, or rotated orthography. When participants judged temporal phrases written in standard orthography, their reaction times were consistent with a rightward-directed mental timeline, but after brief exposure to mirror-reversed orthography, their mental timelines were reversed. When standard orthography was rotated 90° clockwise (downward) or counterclockwise (upward), participants' mental timelines were rotated, accordingly. Reading can play a causal role in shaping people's implicit time representations. Exposure to a new orthography can change the direction and orientation of the mental timeline within minutes, even when the new space-time mapping directly contradicts the reader's usual mapping. To account for this representational flexibility, we propose the hierarchical mental metaphors theory, according to which culturally conditioned mappings between space and time are specific instances of a more general mapping, which is conditioned by the relationship between space and time in the physical world. Conceptualizations of time are culture specific at one level of analysis but may be universal at another.

Across cultures, people conceptualize time as if it flows along a horizontal timeline, but the direction of this implicit timeline is culture-specific: in cultures with left-to-right orthography (e.g., English-speaking cultures) time appears to flow rightward, but in cultures with right-to-left orthography (e.g., Arabic-speaking cultures) time flows leftward. Can orthography influence implicit time representations independent of other cultural and linguistic factors? Native Dutch speakers performed a space-time congruity task with the instructions and stimuli written in either standard Dutch or mirror-reversed Dutch. Participants in the Standard Dutch condition were fastest to judge past-oriented phrases by pressing the left button and future-oriented phrases by pressing the right button. Participants in the Mirror-Reversed Dutch condition showed the opposite pattern of reaction times, consistent with results found previously in native Arabic and Hebrew speakers. These results demonstrate a causal role for writing direction in shaping implicit mental representations of time.

In human and non-human animals, conceptual knowledge is partially organized according to low-dimensional geometries that rely on brain structures and computations involved in spatial representations. Recently, two separate lines of research have investigated cognitive maps, that are associated with the hippocampal formation and are similar to world-centered representations of the environment, and image spaces, that are associated with the parietal cortex and are similar to self-centered spatial relationships. We review evidence supporting cognitive maps and image spaces, and we propose a hippocampal-parietal network that can account for the organization and retrieval of knowledge across multiple reference frames. We also suggest that cognitive maps and image spaces may be two manifestations of a more general propensity of the mind to create low-dimensional internal models. Organizing Knowledge in Low-Dimensional SpaceEvery second, our brains process an amazing amount of information, perceive a dynamic and complex sensory environment, and spontaneously generate countless thoughts. Making sense of this vast amount of data must rely on some structure and organizational principles [1,2]. Determining exactly what these organizational principles are has proved to be a formidable challenge [3][4][5]. However, convergent evidence from neural, cognitive, and information sciences is pointing toward a fascinating hypothesis: that the human brain may organize knowledge into low-dimensional spaces (see Glossary) that we can easily navigate, explore, and manipulate as we, for example, navigate a familiar environment, explore a picture in a frame, or manipulate an object in our hands [1,2,6,7]. In other words, the neural machinery that evolved to map objects and structure events in the physical world may have been recycled to map and structure knowledge within our minds [6].Although this idea, broadly taken, has a venerable tradition [8][9][10][11], research in cognitive science and neuroscience has only recently provided solid empirical ground for this view. We review here evidence suggesting that the neurocognitive structures and algorithms that are recruited to represent and navigate space are also recruited to represent and navigate (nonspatial) conceptual knowledge. In particular, we focus on, and contrast, world-centered cognitive maps (that are usually associated with the hippocampal formation) and self-centered image spaces (usually associated with the parietal cortex). We then attempt to integrate cognitive maps and image spaces with the mechanisms of a hippocampal-parietal network, inspired by current models of spatial navigation and based on complementary reference frames (allocentric and egocentric). Finally, we discuss the role of low-dimensional conceptual spaces in cognition. World-Centered Cognitive Maps and the Hippocampal FormationA long history of neuropsychological studies with amnesic patients [12,13] and more recent neuroimaging experiments [14] have shown that the hippocampal formation (i.e., the hippoca...

Across many cultures people conceptualize time as extending along a horizontal Mental Time

Space and time are intimately linked in the human mind, but different theories make different predictions about the nature of this relationship. Metaphor Theory (MT) predicts an asymmetric relationship between space and time. By contrast, A Theory of Magnitude (ATOM) does not predict any cross-dimensional asymmetry, since according to ATOM spatial and temporal extents are represented by a common neural metric for analog magnitude. To date, experiments designed to contrast these theories support MT over ATOM, in adults and children. Yet, proponents of ATOM have questioned whether some of the observed cross-dimensional asymmetries could be task-related artifacts. Here we conducted a test of the asymmetric relationship between space and time in children's minds, equating the perceptual availability of spatial and temporal information in the stimuli more stringently than in previous experiments in children. Results showed the space-time asymmetry predicted by MT. For the same stimuli (i.e., snails racing along parallel paths), spatial information influenced temporal judgments more than temporal information influenced spatial judgments. These results corroborate previous findings in Greek children and extend them to children who speak Dutch and Brazilian Portuguese. The space-time asymmetry in children's judgments is not due to task-related differences in the perceptual availability of spatial and temporal information in the stimuli; rather, it appears to be a consequence of how spatial and temporal representations are associated in the child's mind.

Is vision necessary for the development of the categorical organization of the Ventral Occipito-Temporal Cortex (VOTC)? We used fMRI to characterize VOTC responses to eight categories presented acoustically in sighted and early blind individuals, and visually in a separate sighted group. We observed that VOTC reliably encodes sound categories in sighted and blind people using a representational structure and connectivity partially similar to the one found in vision. Sound categories were, however, more reliably encoded in the blind than the sighted group, using a representational format closer to the one found in vision. Crucially, VOTC in blind represents the categorical membership of sounds rather than their acoustic features. Our results suggest that sounds trigger categorical responses in the VOTC of congenitally blind and sighted people that partially match the topography and functional profile of the visual response, despite qualitative nuances in the categorical organization of VOTC between modalities and groups.

What is the relationship between spatial language and abstract concepts? When people talk about abstract things that they can never see or touch, they often use spatial metaphors (e.g., a long vacation, a high price, a close friendship). According to theories of metaphorical mental representation, linguistic metaphors reflect underlying mental metaphors. Yet, behavioral experiments show that this is only one of the possible relationships between spatial metaphors in language and our spatial conceptualizations of abstract domains. In some cases, linguistic metaphors not only reflect speakers' thoughts, they also change those thoughts, such that people who use different linguistic metaphors rely on correspondingly different mental metaphors. Alternatively, spatial metaphors in language may reflect the way people conceptualize an abstract domain in some circumstances, but not in others. Finally, spatial language may reflect the way an abstract domain is typically conceptualized by some people, but not by others. There is no single relationship between spatial language and abstract concepts. Discovering whether (and under what conditions) a linguistic metaphor corresponds to a mental metaphor can illuminate the ways in which our interactions with the physical and social environment shape our mental lives. WIREs Cogn Sci 2014, 5:139-149. doi: 10.1002/wcs.1271 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.

How are space and time represented in the human mind? Here we evaluate two theoretical proposals, one suggesting a symmetric relationship between space and time (ATOM theory) and the other an asymmetric relationship (metaphor theory). In Experiment 1, Dutch-speaking participants saw 7-letter nouns that named concrete objects of various spatial lengths (tr. pencil, bench, footpath) and estimated how much time they remained on the screen. In Experiment 2, participants saw nouns naming temporal events of various durations (tr. blink, party, season) and estimated the words' spatial length. The implicit length encoded in object nouns modulated time estimates, but the implicit duration encoded in event nouns did not affect estimates of spatial length. Nouns that named short objects were judged to remain on the screen for a shorter time, and nouns that named longer objects to remain for a longer time. By contrast, variations in the duration of the event nouns' referents had no effect on judgments of the words' spatial length on the screen. This asymmetric pattern of cross-dimensional interference cannot be attributed to differences in the discriminability or perceptual salience of space and time in the stimuli. Results support metaphor theory and challenge ATOM.