Our commentary is focused on the idea that “freedom” takes on its full significance whenever its relativistic nature, in the short- and long terms, is taken into account. Given the transformations brought about by “globalization,” application of a general model of freedom based on ecological-economic factors clearly seems to be rather untimely. We examine this idea through egocentric and ethnocentric views of the social and environmental analyses of “freedom.”

Climate stresses and monetary resources seem to lead to different collective adaptations. However, the reference to adaptation and to ambiguous collective dimensions appears premature; populations may entertain nothing more than shared adaptiveness. At this point, the intricacy of the underlying evolutionary processes (cultural selection, fitness-utility decoupling) very much obscures any diagnosis based on correlations.

Van de Vliert's findings may be explained by the psychology of threat and bargaining. Poor people facing extreme threats must cope by surrendering individual freedom in service of shared group needs. Wealthier people are more able to flee from threats and/or resist authoritarianism, so their leaders must concede greater freedom. Incorporating these factors (plus inequality) can sharpen researchers' predictions.

Cross-cultural personality research suggests that individuals from wealthier countries tend to be more open-minded. This openness to values may support more democratic governments and the expansion of fundamental freedoms. The link between wealth and freedom is evident in cold-to-temperate climates, but not across wealthy nations in hot climates. Furthermore, temperature and economic conditions shape perceptions of national character stereotypes.

Social signaling models predict that subtle variation in climatic temperature induces systematic changes in expressed cognition. An experiment showed that perceived room temperature was associated with variability in self-descriptions, social reactions of others, and desiring differing types of social networks. The findings reflect the tendency to inflate capacity demonstrations in warmer climates as a result of the social networking opportunities they enable.

Forty-nine commentators have reviewed the theory that needs-based stresses and freedoms are shaped differently in threatening, comforting, and challenging climato-economic habitats. Their commentaries cover the white domain, where the theory does apply (e.g., happiness, collectivism, and democracy), the gray domain, where it may or may not apply (e.g., personality traits and creativity), and the black domain, where it does not apply (e.g., human intelligence and gendered culture). This response article provides clarifications, recommendations, and expectations.

The study of spatial cognition has provided considerable insight into how animals (including humans) navigate on the horizontal plane. However, the real world is three-dimensional, having a complex topography including both horizontal and vertical features, which presents additional challenges for representation and navigation. The present article reviews the emerging behavioral and neurobiological literature on spatial cognition in non-horizontal environments. We suggest that three-dimensional spaces are represented in a quasi-planar fashion, with space in the plane of locomotion being computed separately and represented differently from space in the orthogonal axis – a representational structure we have termed “bicoded.” We argue that the mammalian spatial representation in surface-travelling animals comprises a mosaic of these locally planar fragments, rather than a fully integrated volumetric map. More generally, this may be true even for species that can move freely in all three dimensions, such as birds and fish. We outline the evidence supporting this view, together with the adaptive advantages of such a scheme.

In this commentary, I propose that horizontal and vertical dimensions of space are represented together inside a common metrics mechanism located in the parietal cortex. Importantly, this network is also involved in the processing of number magnitudes and environment-directed actions. Altogether, the evidence suggests that different magnitude dimensions could be intertwined with the horizontality and verticality of our world representation.

Jeffery et al. propose a non-uniform representation of three-dimensional space during navigation. Fittingly, we recently revealed asymmetries between horizontal and vertical path integration in humans. We agree that representing navigation in more than two dimensions increases computational load and suggest that tendencies to maintain upright head posture may help constrain computational processing, while distorting neural representation of three-dimensional navigation.

Existing studies have proposed that humans preferentially memorize buildings as a collection of floors. Yet this might stem from the fact that environments were also explored by floors. We have studied this potential bias with a learning and recognition experiment. We have detected a positive influence of the learning route – by floors, and also crucially by columns – on spatial memory performances.

Additional evidence is presented concerning the anisotropy between vertical and horizontal encoding, which emerges from studies of human perception and cognition of space in plane mirror reflections. Moreover, it is suggested that the non-metric characteristic of polarization – that Jeffery et al. discuss with respect to gravity – is not limited to the vertical dimension.

Animals navigate through three-dimensional environments, but we argue that the way they encode three-dimensional spatial information is shaped by how they use the vertical component of space. We agree with Jeffery et al. that the representation of three-dimensional space in vertebrates is probably bicoded (with separation of the plane of locomotion and its orthogonal axis), but we believe that their suggestion that the vertical axis is stored “contextually” (that is, not containing distance or direction metrics usable for novel computations) is unlikely, and as yet unsupported. We describe potential experimental protocols that could clarify these differences in opinion empirically.

Jeffery et al. extensively and thoroughly describe how different species navigate through a three-dimensional environment. Undeniably, the world offers numerous three-dimensional opportunities. However, we argue that for most navigation tasks a two-dimensional representation is nevertheless sufficient, as physical conditions and limitations such as gravity, thermoclines, or layers of earth encountered in a specific situation provide the very elevation data the navigating individual needs.

In this commentary, we highlight a difficulty for metric navigation arising from recent data with grid and place cells: the integration of piecemeal representations of space in environments with repeated boundaries. Put simply, it is unclear how place and grid cells might provide a global representation of distance when their fields appear to represent repeated boundaries within an environment. One implication of this is that the capacity for spatial inferences may be limited.

The bicoded cognitive maps described by Jeffery et al. are compared to metric perceptual representations. Systematic biases in perceptual experience of egocentric distance, height, and surface orientation may reflect information processing choices to retain information critical for immediate action (Durgin et al. 2010a). Different information processing goals (route planning vs. immediate action) require different metric information.

We discuss the idea that environmental factors influence the neural mechanisms that evolved to enable navigation, and propose that a capacity to learn different spatial relationship rules through experience may contribute to bicoded processing. Recent experiments show that free-flying bees can learn abstract spatial relationships, and we propose that this could be combined with optic flow processing to enable three-dimensional navigation.

Recent research investigating the language–thought interface in the spatial domain points to representations of the horizontal and vertical dimensions that closely resemble those posited by Jeffery et al. However, the findings suggest that such representations, rather than being tied to navigation, may instead reflect more general properties of the perception of space.

Multilevel wayfinding research in environmental psychology and architecture exhibits a strong compatibility with Jeffery et al.'s “bicoded” representation of space. We identify a need for capturing verticality in spatial analysis techniques such as space syntax and argue for investigating inter-individual differences in the ability to mentally integrate the cognitive maps of separate floors in buildings.

Applying the framework proposed by Jeffery et al. to nonhuman primates moving in multilayer arboreal and terrestrial environments, we see that these animals must generate a mosaic of many bicoded spaces in order to move efficiently and safely through their habitat. Terrestrial light detection and ranging (LiDAR) technology and three-dimensional modelling of canopy movement may permit testing of Jeffery et al.'s framework in natural environments.

Jeffery et al. characterize the egocentric/allocentric distinction as discrete. But paradoxically, much of the neural and behavioral evidence they adduce undermines a discrete distinction. More strikingly, their positive proposal – the bicoded map hypothesis – reflects a more complex interplay between egocentric and allocentric coding than they acknowledge. Properly interpreted, their proposal about three-dimensional spatial representation contributes to recent work on embodied cognition.