Vertical attention bias for tops of objects and bottoms of scenes.

Past research demonstrated a top-salience bias in object identification, with random shapes appearing more similar when they share the same top versus the same bottom. This is consistent with tops of natural objects and lifeforms tending to be more informative locations of intentionality and functionality, leading observers to favor attending to tops. However, this bias may also reflect a generic downward vantage tendency that occurs with more informative interactive aspects of scenes typically lying below the horizon. Two experiments test for this overall pattern of vertical attention bias (VAB) for both objects and scenes. Participants observed picture triptychs and judged if the center object or scene appeared more similar to flanking comparison figures that contain the same top versus same bottom. Experiment 1 used vertically information-balanced impoverished stimuli, either polygon objects or polygon-array scenes. Experiment 2 extended the triptych stimuli to naturalistic objects or scenes. Results generally support a VAB for object tops and scene bottoms that varies as a function of the informative aspects of visually attended stimuli. This pattern held for information-balanced objects but not scenes, however, with more ecologically valid naturalistic stimuli, VAB was large and robust, consistent with a vertical information imbalance that drives a generic downward vantage. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Children and adults exhibit a common vertical attention bias for object tops and scene bottoms.

Adults have a vertical attention bias (VAB) that directs their focus toward object tops and scene bottoms. This is consistent with focusing attention on the informative aspects and affordances of the environment, and generally favoring a downward gaze. The smaller size of children, combined with their relatively limited interactions with objects and scenes, could lead them to have diminished bias that only gradually develops. Alternatively, an early coupling of attention to action space could lead to VAB similar to adults. The current study investigates the developmental timeline of VAB, comparing 4-7-year-olds to adults. Participants (N = 50 children, 53 adults; 58% White, 22% Asian, 6% Black, 2% Native American, and 12% other) observed naturalistic photographic triptychs (48 objects, 52 scenes, all online). They made similarity judgments comparing a test figure to two flanking figures containing either the same top or same bottom. We found that (a) children and adults exhibit a common VAB for object tops and scene bottoms and (b) the adult bias is stronger than children's. Exploratory analyses revealed the same age trend within children, with VAB increasing with age, and asymptoting at the adult level at age 8. This demonstrates that despite age and body size differences that could make the environment for young children relatively disparate from adults, their perceptual system is already largely attuned to their individual interactive action space, with only minor continuing residual development. The findings support that, like adults, young children focus their attention on their action space and body level affordances, where they interact more with tops of objects and bottoms of scenes. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Carrying their own weight: Dogs perceive changing affordances for reaching.

Choices about when to transition between two modes of behaviour are determined by the fit between action capabilities and environmental properties. However, such transitions typically occur not at the absolute limits of action capabilities but rather based on the relative stability of each mode. People transition from an arm-only to an arm-plus-torso-reach, not when object distance exceeds arm length but when the stability of reaching with the arm-plus-torso exceeds that of reaching with the arm-only. To the extent that perception is supported by detection of invariant stimulation patterns, such a transition ought to reflect both the fit between action capabilities and environmental properties and the relative stability of modes regardless of species. We investigated the height at which dogs transitioned from reaching with the head-only to rearing when wearing a weighted backpack - a manipulation expected to decrease the stability of a head-only reach. As expected, the transition occurred at taller heights for tall than for short dogs but at the same ratio of treat-height-to-shoulder-height for both groups. This transition also occurred at shorter heights and smaller ratios of treat-height-to-shoulder-height when dogs wore a weighted backpack. The results suggest that stimulation patterns that support control of behaviour may be invariant across species.

Doggone affordances: Canine perception of affordances for reaching.

Performing any behavior requires perceiving affordances-whether and how that behavior can be performed. Perception of affordances exhibits action scaling-choices about when to transition between two different modes of behavior reflect the fit between action capabilities and environmental properties. The boundary between distances that are perceived to be reachable with an arm-only reach and those that are perceived to be reachable with an arm-plus-torso reach occurs at farther distances for long-armed than for short-armed people, but at the same ratio of object-distance-to-arm length for both groups. To the extent that perception of affordances is supported by detection of invariant stimulation patterns, perception of a given affordance ought to exhibit action scaling regardless of species. We investigated the heights at which dogs chose to transition from reaching with the head only to rearing (i.e., reaching with the head plus torso). This transition occurred at a taller height for tall than for short dogs, but at the same ratio of shoulder-height-to-treat-height for both groups. The results demonstrate a similarity in perception of affordances across species and suggest that perception of affordances is supported by detection of lawfully structured stimulation patterns that may be invariant across species.

Turning perception on its head: cephalic perception of whole and partial length of a wielded object.

Flexibility is a fundamental hallmark of perceptual systems. In particular, there is a great deal of flexibility in the ability to perceive properties of occluded objects by effortful or dynamic touch-hefting, wielding, or otherwise manipulating those objects by muscular effort. Perception of length of an occluded wielded object is comparable when that object is wielded by anatomical components that differ in sensitivity, dexterity, and functionality. Moreover, perception of this property is supported by an analogous sensitivity to inertial properties across such components. We investigated the ability to perceive whole and partial length of an object wielded by hand or by head. Experiment 1 found that perception of length by these anatomical components is qualitatively and quantitatively indistinguishable. Experiment 2 found that perception of length is supported by the same specific sensitivity to inertial properties in each case. Experiment 3 found that perception of whole length and partial length are each supported by specific sensitivities to inertial properties and that this is the case for both hand and by head. The results are discussed in the context of the nature of the stimulation patterns and the organization of the haptic system that are likely to support such flexibility in perception.