Search

Filmmakers’ efforts not only advance film as an art form, they also provide insights about basic perception. This research was designed to uncover commonalities between the aesthetic appreciation of viewers of films and the perceptual capacities of observers of environmental events. We assessed whether the temporal structure of events in the environment is reflected in the temporal structure of events in film. Participants in Study 1 segmented neutral environmental events to establish a benchmark temporal structure. Study 2 compared the temporal structure of editing in amateur and professionally made films. Results from these two studies suggest a particular fractal structure common to environmental event perception and the editing structure of professional films. This hypothesis was then tested in an experiment that reedited one film so as to produce four different versions, each with a different fractal structure. These versions were evaluated by audiences in terms of aesthetics (e.g., general likability, comprehension, technical aspects of craft). The results suggest that the fractal structure typical of environmental event perception is preferred, even when it is not the original, artistically intended version. It is argued that narrative films succeed, at least in part, because their temporal structure reflects the temporal structure of environmental event perception.

An underlying bias of contemporary cognitive science is that the brain and nervous system are in the business of carrying out computations and building representations. Gibson’s ecological approach...

In addressing the character of the haptic system, James Gibson (1966) noted, “The study of useful sensitivity, as distinguished from theoretically basic sensitivities, is only just beginning” (p. 116). Whereas the preceding 150 years had gotten mired in an inventory of isolated sensations, the ensuing 50 years have revealed a good deal about the capabilities of a perceptual system that detects information about the self, the environment, and self-environment relations by means of muscular effort. That research is summarized with special attention to the kind of medium that could ground the useful dimensions of haptic sensitivity.

The emerging understanding of the behavioral transitions that accompany the ascending and descending method of limits is in terms of "functional distance" - the degree to which a perceiver is disengaged from ordinary exploratory activities. Increasing functional distance results in negative hysteresis in contrast to the classical positive hysteresis more typical of ongoing activity. In the present study of human gait transitions on a treadmill, the functional distance between a perceiver and ordinary exploratory activities was manipulated in two ways: (1) "Active" participants, walking or running on a treadmill, were asked to anticipate the gait that would be required if treadmill speed were increased or decreased; and (2) "passive" participants, standing off a moving treadmill, were asked to report the gait they would use if they were on the treadmill at its current speed. As expected, the increase of functional distance from (1) to (2) reduced the amount of classical hysteresis and promoted negative hysteresis, that is, a lower transition speed for walk-to-run transitions (ascending trials) than for run-to-walk transitions (descending trials). These results complement empirical findings in other behavioral transition experiments. More broadly, they signify the role of perception-action cycles for grounding natural on-going perception. In particular, they support the assertion that perception and action are intertwined and that lack of information about an impending action has consequences for perceptual judgments.

Research on dynamic touch has shown that when a rod strapped to the shoulders is wielded via axial rotations, flexions-extensions, and lateral bending of the trunk, participants can selectively perceive whole rod length and partial rod length (e.g., a leftward segment) with precision comparable to wielding by hand (Palatinus, Carello & Turvey, 2011). The present research addressed whether this haptic ability is preserved in quiet standing, when postural control is limited to center of pressure (COP) fluctuations at the mm/ms scale, and, if so, whether the intentions ("perceive partial," "perceive whole") are distinguishable within the fluctuations. Given standard manipulations of rod length and attached mass, participants provided significantly distinct, appropriately scaled, whole and partial estimates of rod length. COP displacement time series were subjected to multifractal, detrended fluctuation analysis. The resultant spectrum of fractal scaling exponents for gradually different-sized fluctuations revealed that "perceive partial" was manifest as larger exponents for progressively smaller fluctuations than "perceive whole." Our results indicate (a) that the significant mechanical variables for haptically perceiving object extent are available in the small scale of normal body sway, and (b) that these seemingly "passive" movements reflect the intention of the perceiver.

At one level, the scientific enterprise engaged in by Guy Van Orden was about how to analyze reaction time data. At another level it was an attempt to understand the kind of system that one is dealing with in a reaction time (RT) experiment—the system that accords with the instructions that the experimenter gives, produces the responses to the particular class of stimuli that the experimenter presents, at latencies that the experimenter measures and analyzes. That there can be any question about the essential nature of the system under study is perhaps surprising given the long and influential history of RT research and the relative simplicity and transparency of the RT task. In this brief note we hope to show that the question is deserved and that on close inspection the nature of the RT task is, indeed, surprising.

We investigated fractality in the segmentation of cinematic and live events. Four movies from distinct genres were first analyzed and found to be fractal, albeit in different regions of the fractal range. In Experiment 1, viewers parsed the films' events, attending to short or long timescales, using a button box to indicate break points. The temporal structure of film viewing was found to be fractal regardless of the scale of attention and to reflect the differing fractal editing structure of the films. Experiment 2 found event segmentation to be fractal in a natural setting, a basketball game, as well. An additional parallel between reel and real events was uncovered: fractal indices were at the higher end of the range for both the film genre intended to be anxiogenic and the more suspenseful portion of the basketball game. We argue that the fractal structure of perception reflects the fractal structure of events whether the events are in film or in nature. We speculate that fractal structure has implica...

Gibson's (1966, 1979/1986) ecological approach to perception, action, and cognition is patently non-representational and non-computational. In the place of these commonly assumed neural endowments, ecological psychology seeks to expose the laws that underlie intelligent capabilities. It is argued that this is the goal for understanding the directed behavior of not just humans, not just animals, and not just the living. We argue that an approach to intelligence that is physically grounded is completely consistent with—and is even a natural consequence of—the central tenets of ecological psychology. We identify two dozen guidelines for seeking intelligence in first principles.

Dynamic touching is effortful touching. It entails deformation of muscles and fascia and activation of the embedded mechanoreceptors, as when an object is supported and moved by the body. It is realized as exploratory activities that can vary widely in spatial and temporal extents (a momentary heft, an extended walk). Research has revealed the potential of dynamic touching for obtaining non-visual information about the body (e.g. limb orientation), attachments to the body (e.g. an object's height and width) and the relation of the body both to attachments (e.g. hand's location on a grasped object) and surrounding surfaces (e.g. places and their distances). Invariants over the exploratory activity (e.g. moments of a wielded object's mass distribution) seem to ground this ‘information about’. The conception of a haptic medium as a nested tensegrity structure has been proposed to express the obtained information realized by myofascia deformation, by its invariants and transformations. The tensegrity proposal rationalizes the relative indifference of dynamic touch to the site of mechanical contact (hand, foot, torso or probe) and the overtness of exploratory activity. It also provides a framework for dynamic touching's fractal nature, and the finding that its degree of fractality may matter to its accomplishments.

The haptic subsystem of dynamic touch expresses a novel form of part–whole selective perception. When wielding a nonvisible rod grasped at some intermediate point along its length, an individual can attend to and report the length of a part of the rod (e.g., the segment forward of the hand) or the length of the whole rod. Both perceptions relate to the rod's mass moments about the point of grasp but in systematically different ways. Previous demonstrations of this part–whole selectivity have been in respect to rods grasped by hand or attached to a foot. The authors demonstrated the part–whole selectivity for nonvisible rods attached to the shoulder girdle and wielded primarily by movements of the trunk with benchmark performance provided by the same rods grasped and wielded by hand. Their results suggest that part–whole selectivity is a haptic capability general to the body.

LW, an individual with a stroke-related motor impairment, was asked to perceive the lengths of rods of different mass distributions by dynamic touch. His impairment dictated that wielding was primarily about the shoulder rather than the wrist. Although perceived rod lengths were in the range of actual rod lengths, scaling to the objects' mass moments was atypical for both the affected and unaffected limbs. A group of healthy young adults asked to mimic his wielding style yielded the same atypical scaling. The typical scaling was restored when LW's wielding was fixed about a mechanical axis. Discussion considered what frame of reference is suitable for revealing an object's mass moments relevant to a given task. In particular, it appears that individuals can exploit alternative forms of interaction with environmental objects that leave invariant the parameters specifying to-be-perceived properties. Perception by dynamic touch is not a function of particular neuromuscular patterns but of information made av...

In 1709, Berkeley hypothesized of the human that distance is measurable by ‘the motion of his body, which is perceivable by touch’. To be sufficiently general and reliable, Berkeley's hypothesis must imply that distance measured by legged locomotion approximates actual distance, with the measure invariant to gait, speed and number of steps. We studied blindfolded human participants in a task in which they travelled by legged locomotion from a fixed starting point A to a variable terminus B, and then reproduced, by legged locomotion from B, the A–B distance. The outbound (‘measure’) and return (‘report’) gait could be the same or different, with similar or dissimilar step sizes and step frequencies. In five experiments we manipulated bipedal gait according to the primary versus secondary distinction revealed in symmetry group analyses of locomotion patterns. Berkeley's hypothesis held only when the measure and report gaits were of the same symmetry class, indicating that idiothetic distance measurement is gait-symmetry specific. Results suggest that human odometry (and perhaps animal odometry more generally) entails variables that encompass the limbs in coordination, such as global phase, and not variables at the level of the single limb, such as step length and step number, as traditionally assumed.

The effect of prism adaptation on movement is typically reduced when movement at test (with prisms removed) is different from movement at training. Previous research [J. Fernandez-Ruiz, C. Hall-Haro, R. Diaz, J. Mischner, P. Vergara, J. C. Lopez-Garcia, Learning motor synergies makes use of information on muscular load, Learning & Memory 7 (2000) 193-198] suggests, however, that some adaptation is latent and only revealed through further testing in which the movement at training is fully reinstated. Movement in their training trials was throwing overhand to a vertical target with a mass attached to the arm. The critical test trials involved the same act initially without the attached mass and then with the attached mass. In replication, we studied throwing underhand to a horizontal target with left shifting prisms and a dissociation of the throwing arm's mass and moment of inertia. The two main results were that the observed latent aftereffect (a) depended on the similarity of training and test moments of inertia, and (b) combined with the primary aftereffect to yield a condition-independent sum. Discussion focused on a parallel between prism adaptation and principles governing recall highlighted in investigations of implicit memory: whether given training (study) conditions lead to good or poor persistence of adaptation (memory performance) at test depends on the conditions at test relative to the conditions at training (study).

Two experiments evaluated change in the perception of an environmental property (object length) in each of 3 perceptual modalities (vision, audition, and haptics) when perceivers were provided with the opportunity to experience the same environmental property by means of an additional perceptual modality (e.g., haptics followed by vision, vision followed by audition, or audition followed by haptics). Experiment 1 found that (a) posttest improvements in perceptual consistency occurred in all 3 perceptual modalities, regardless of whether practice included experience in an additional perceptual modality and (b) posttest improvements in perceptual accuracy occurred in haptics and audition but only when practice included experience in an additional perceptual modality. Experiment 2 found that learning curves in each perceptual modality could be accommodated by a single function in which auditory perceptual learning occurred over short time scales, haptic perceptual learning occurred over middle time scales, a...

The actualization of a simple affordance task—grasping and moving wooden planks of different sizes using either one or two hands—was assessed in the context of taskrelevant (plank sequence, plank presentation speed) and task-irrelevant (cognitive load) manipulations. In Experiment 1, fast (3 s/plank) and self-paced (≈5 s/plank) presentation speeds revealed hysteresis; the transition point for ascending series was greater than the transition point for descending series. Hysteresis was eliminated in the slowest presentation speed (10 s/plank). In Experiment 2, hysteresis was exaggerated by a cognitive load (counting backward by seven) for both fast and slow presentation speeds. These results suggest that behavioral responses to the attractor dynamics of perceived affordances are processes that require minimal cognitive resources.

Nonvisual perceptions of a wielded object's spatial properties are based on the quantities expressing the object's mass distribution, quantities that are invariant during the wielding. The mechanoreceptors underlying the kind of haptic perception involved in wielding - referred to as effortful, kinesthetic, or dynamic touch - are those embedded in the muscles, tendons, and ligaments. The present experiment's focus was the selectivity of this muscle-based form of haptic perception. For an occluded rod grasped by the hand at some intermediate position along its length, participants can attend to and report selectively the rod's full length, its partial lengths (fore or aft of the hand), and the position of the grip. The present experiment evaluated whether participants could similarly attend selectively when wielding by foot. For a given rod attached to and wielded by foot or attached to (i.e. grasped) and wielded by hand, participants reported (by magnitude production) the rod's whole length or fractional length leftward of the point of attachment. On measures of mean perceived length, accuracy, and reliability, the degree of differentiation of partial from full extent achieved by means of the foot matched that achieved by means of the hand. Despite their neural, anatomical, and experiential differences, the lower and upper limbs seem to abide by the same principles of selective muscle-based perception and seem to express this perceptual function with equal facility.

According to the International Classification of Functioning, Disability and Health, effective rehabilitation requires interventions that go beyond minimizing pathological conditions and associated symptoms. The scope of practice must include promoting an individual's activity within relevant contexts. We argue that best practice requires decisions that are not only evidence-based but also theory-based. Perception and action theories are essential for interpreting evidence and clinical phenomena as well as for developing new interventions. It is our contention that rehabilitation goals can best be achieved if inspired by the ecological approach to perception and action, an approach that focuses on the dynamics of interacting constraints of performer, task and environment. This contrasts with organism-limited motor control theories that have important influence in clinical practice. Parallels between such theories and the medical model of care highlight their fundamental inconsistency with the current understanding of functioning. We contend that incorporating ecological principles into rehabilitation research and practice can help advance our understanding of the complexity of action and provide better grounding for the development of effective functional practice. Implications and initial suggestions for an ecologically grounded functional practice are outlined.

(2006). Symmetry and Duality: Principles for an Ecological Psychology, II. Ecological Psychology: Vol. 18, No. 4, pp. 239-242.

The sensibility associated with muscles contributes little to the conceptual content of current psychology. In part, this is because perceptions achieved through the muscle sense typically go unnoticed. Nonetheless, researchers have discovered a rich variety of muscle-based perceptual capabilities—such as those relating to held objects, probed objects, and body segments—that seem to depend on quantities well known in physics, quantities that reflect how the mass of an object or limb is distributed. The conceptual and technical issues posed by these capabilities warrant study by psychologists interested in the general problems of space perception, action, and selective attention.

Reading-disabled children often have accompanying deficits in motor coordination. Rather than assuming impairment of a shared neural mechanism, we conjecture that coordination difficulties that undermine normal speech would also undermine development of phonological awareness, which is necessary for reading fluency. Nonimpaired readers who vary in fluency, therefore, should also covary in coordination. Reliable interrelationships between phonological decoding skills and the speed and variability of sequentially tapping the fingers of one hand (either dominant or nondominant) were, indeed, found for college undergraduates. Reading measures that do not emphasize phonological decoding did not show the same connection. Characterizing phonological decoding as a skill and the long-term consequences of failure to master that skill suggest that it could benefit from practice even in high-literacy populations.

Various object properties are perceptible by wielding. We asked whether the dynamics of wielding differed as a function of the to-be-perceived property. Wielding motions were analyzed to determine if they differed under the intention to perceive or not perceive rod length (experiment 1), to perceive object height versus object width (experiment 2), and to perceive the length forward of where the rod was grasped versus the position of the grasp (experiment 3). Perceiving these different properties is known to depend on different components of the object's inertia tensor. Analyses of the subtle recurrent patterns in the phase space of the hand motions revealed differences in wielding across the different perceptual intentions. Haptic exploratory procedures may exhibit distinct exploratory dynamics.

The hypothesis that the earliest representations in visual processing of print are activated word-specific units leads to the expectation that homophonic priming (HP) should be greater for word pairs than pseudohomophone pairs. Ten experiments with naming disconfirmed this hypothesis. At interstimulus intervals of 0, 129, 516, and 930 ms, HP for pseudohomophones (e.g., HOEZ-hoze vs. HOGZ-hoze) equaled HP for words (e.g., KNOWS-nose vs. KNEES-nose). The complementary finding of negative HP with pseudohomophones relative to positive HP with words was found in an additional investigation of lexical decision. The results confirm a critical early stage in visual word recognition, in which words are represented in purely phonological form, and implicate equal speeds in dual-route models for nonlexical and lexical processing.

Whether an object can be used to satisfy a given tool user's intention depends on, among other things, the object's inertial properties. Overcoming an object's rotational inertia is key in controlling a handheld object with respect to a given intention. Manipulating an object by means of muscular exertion is the domain of dynamic touch. Thus, the affordances of a given object as a tool should be perceivable by means of dynamic touch. In 3 experiments, we investigated the inertial variables that support perception of 2 potential affordances of handheld tools: hammer-with-ability and poke-with-ability. The results suggest that ratings of hammers are dependent on the volume of the inertial ellipsoid in such a way that supports the transference of power to the struck surface. Ratings of pokers are dependent on the same quantity but in a way that supports controllability of the poking object. Additionally, results suggest that minimal experience in a given tool-using task may "tune" tool users to the inertial ...

In the most general case, haptic perception of an object's heaviness is most likely the perception of the object's resistance to movement, determined jointly by the object's mass and mass distribution. In two experiments with occluded objects wielded freely in three dimensions, we showed additive effects on perceived heaviness of mass and the inertia tensor. Our manipulations of the inertia tensor were directed specifically at the volume and symmetry of the inertia ellipsoid, quantities that can be understood as important to controlling the level and patterning of muscular forces, respectively. Ellipsoid volume and symmetry were found to have separate effects on perceptual reports of heaviness that were invariant over different tensors. Independent sensitivities to translational inertia and particular characterizations of rotational inertia suggest specialized somatosensory attunement to the rigid body laws.

Young adults are able to perceive an implement's center of percussion (CP) or “sweet spot,” and to distinguish it from the implement's length, simply on the basis of wielding. Given the known changes in mechanoreceptors with aging, two experiments assessed these perceptual abilities in older adults (ranging in age from 62 to 89 years with an average of 69.2). They, too, distinguished length from the sweet spot simply on the basis of wielding, both for tennis rackets (Experiment 1) and for bats contrived from wooden rods with attached masses (Experiment 2). Results conformed to previous research on dynamic touch in showing that perceiving the extents of wielded objects is constrained by the moments of the objects' mass distributions. Moreover, so-called young–old plots were linear – older peoples' perceptions were predicted by younger peoples' perceptions – implicating a common underlying mechanism for the two age groups. Nonetheless, the perceived-to-actual functions were generally flatter for elderly participants. How aging might compromise the functioning of dynamic touch was discussed in terms of fractal organization and functional limitations.

(1999). Further Evidence of Perceptual Independence (Specificity) in Dynamic Touch. Ecological Psychology: Vol. 11, No. 4, pp. 269-281.

Many sports involve aligning a hitting implement with a ball trajectory such that contact is made at the implement's center of percussion or ‘sweet spot’. This spot is not visibly distinct; its perception must be haptic. Although it is functionally defined with respect to contact—it is the point of impact that produces the least vibration in the hand holding the implement—hitting success requires appreciating the location of the sweet spot prior to contact. Two experiments verified that perceivers (novices as well as expert tennis players) distinguished perception of length from perception of the position of the sweet spot simply on the basis of wielding, both for tennis rackets and for bats contrived from wooden rods with attached masses. Results conformed to previous research on dynamic touch in showing that perceiving the lengths of wielded objects, including selectively perceiving partial lengths, is constrained by inertial properties of the object.

The tau-dot hypothesis states that when tau-dot greater than or equal to -0.5, impact will be soft; when tau-dot < -0.5, impact will be "hard." Four experiments tested the usefulness of tau-dot for observers of collisions between 2 objects (rather than collisions between the observer and an object). Observers watched collisions depicted on a computer as 1 object approaching another. Results conformed to the tau-dot hypothesis and were consistent with previous research wherein observers watched collisions as participants. Results suggest that the information specifying collision severity is the rate of the relative rate of optical variation, a quantity that remains invariant over differing collision path trajectories and over differing perceivers (i.e., spectators or participants, viewing from different vantage points, moving or stationary).

Although hearing is classically considered a temporal sense, everyday listening suggests that subtle spatial properties constitute an important part of what people know about the world through sound. Typically neglected in psychoacoustics research, the ability to perceive the precise sizes of objects on the basis of sound was investigated during the routine event of dropping wooden dowels of different lengths onto a hard surface. In two experiments, the ordinal and metrical success of naive listeners was related to length but not to the simple acoustic variables (duration, amplitude, frequency) likely to be related to it. Additional analysis suggests the potential relevance of an object's inertia tensor in constraining perception of that object's length, analogous to the case that has been made for perceiving length by effortful touch.

When a rod is grasped at a place intermediate between its ends, the nonvisible perception of length by wielding can be directed to either side of the hand. The selective perception of the lengths of rod segments relative to the hand is hypothesized to depend jointly on the rod's inertia tensor about a fixed rotation point and on the 2-valued attitude spinor connecting the rod's reference frame to the hand's. That hypothesis was tested in 3 experiments m which 8-10 subjects participated; asymmetry in the rod's mass distribution relative to the hand was induced either by the addition of a metal ring to one end or by grasping the rod at a place other than its midpoint. Planes of wielding, style of wielding, and object size were varied across the experiments. The results conformed to expectation: For a given asymmetric rod configuration, perceived length for attending to one direction from the hand (e g., above or left) differed from perceived length for attending to the other direction (below or right); for a given segment of an asymmetric rod, perception of its length did not differ as a function of us direction from the hand. In each experiment, variance in perceived partial length was accommodated by the rod's major eigenvalue and the spinor rotation angle, with rotation sense dictated by the direction of attention.

Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary bipedal gaits (e.g., walk, run) are characterized by dihedral symmetry, whereas secondary bipedal gaits (e.g., gallop-walk, gallop- run) are characterized by a lower, cyclic symmetry. This fact has been used in tests of human odometry (e.g., Turvey et al. in P Roy Soc Lond B Biol 276:4309---4314, 2009, J Exp Psychol Hum Percept Perform 38:1014---1025, 2012). Results suggest that when distance is measured and reported by gaits from the same symmetry class, primary and secondary gaits are comparable. Switching symmetry classes at report compresses (primary to secondary) or inflates (secondary to primary) measured distance, with the compression and inflation equal in magnitude. The present research (a) extends these findings from overground locomotion to treadmill locomotion and (b) assesses a dynamics of sequentially coupled measure and report phases, with relative velocity as an order parameter, or equilibrium state, and difference in symmetry class as an imperfection parameter, or detuning, of those dynamics. The results suggest that the symmetries and dynamics of distance measurement by the human odometer are the same whether the odometer is in motion relative to a stationary ground or stationary relative to a moving ground.

“Quiet standing” is standing without intended movement. To the naked eye, a person “quiet standing” on a rigid surface of support is stationary. In the laboratory quiet standing is indexed by behavior (at the millimeter scale) of the center of pressure (COP), the point location of the vertical ground reaction force vector (GRF). We asked whether quiet standing is lateralized and whether the COP dynamics of the right and left legs differ. In answer, we reexamined a previous quiet standing experiment (Kinsella-Shaw et al. in J Mot Behav 38:251–264, 2006) that used dual, side-by-side, force plates to investigate effects of age and embedding environment. All participants, old (M age = 72.2 ± 4.90 years) and young (M age = 22.8 ± 0.83 years), were right handed and right footed. Cross-recurrence quantification of the anterior–posterior and mediolateral coordinates of each COP revealed that, independent of age, and with no right GRF bias, right-leg coordination was (1) more dynamically stable and less noisy than left-leg coordination and (2) more responsive to changes in degree of visible structure. The results are considered in the context of theories of laterality inclusive of lateralized differences in postural dynamics.

Two experiments examined perception of the extent of a target rod that is contacted and wielded by a second probe rod. The equations that define the dynamics of the probe-target system suggest a higher order moment of inertia as the relevant perceptual variable. The particular inertial term implicates parameters of both the target and probe rod. Experiment 1 manipulated the inertia of the target rod and Experiment 2 manipulated the inertia of the probe rod. In both experiments, perceived length was a function of the complex inertial term. Results were discussed in terms of haptic perception at a distance, the equivalence of inert and neural appendages, and the scaling of perceived to actual variables.