Spatial and movement-based heuristics for encoding pattern information through touch.

Seven experiments investigated the heuristics people use to encode spatial pattern information through touch. Observers traced a tangible pathway with 1 hand and then answered questions about either the Euclidean line between the pathway endpoints or the pathway itself. Parameters of the Euclidean line were held constant, while characteristics of the felt pathway were manipulated. Exps I–IV showed that 72 blindfolded university students and 30 blind 18–65 yr olds increasingly overestimated the length of the Euclidean line as the length of the explored pathway increased, which indicated a movement-based heuristic for encoding distance. Exps V–VII, with 40 normal undergraduates, showed that judgments of the position of the Euclidean line did not vary with the position of the felt pathway or the extent to which it deviated from that line. Instead, results indicated that Ss relied on implicit spatial axes, which were movement independent, to judge position. Implications for theories of haptic encoding of spatial pattern and for the construction of tangible graphics displays are discussed. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early-blind subjects' spatial representation of manipulatory space: exploratory strategies and reaction to change

The present study was aimed at analysing the effects of a lack of visual experience in human subjects on the detection and identification of a spatial change brought about to a configuration of objects displayed in manipulatory space. Exploratory patterns and performance levels were recorded. Learning effects were observed in different types of change and condition of presentation only in the early-blind and blindfolded sighted groups, but not in the late-blind group. Early blindness affected both exploratory patterns and performance levels. In addition, significant correlations were found between performance level and the use of systematic patterns of exploration. These data are discussed in relation with the importance of early vision during the development of spatial cognition.     

Navigating with fingers and feet: Analysis of human (Homo sapiens) and rat (Rattus norvegicus) movement organization during nonvisual spatial tasks.

The current set of studies examines the contribution of movement segmentation to self-movement cue processing for estimating direction and distance to a start location in humans and rats. Experiments 1 and 2 examined the extent that ambulatory dead reckoning tasks can be adapted to the manipulatory scale in humans. Experiments 3 and 4 investigated the performance of rats in similar tasks at their ambulatory scale. Movement segmentation had differential effects on absolute heading error for humans and rats when only comparing performance on specific tasks; however, movement segmentation had similar effects for both species when performance was examined across all tasks. In general, magnitude of movement segmentation was associated with absolute heading error in both humans and rats. In contrast, both species modified homeward segment kinematics based on the distance to the start location in all tasks, consistent with the use of self-movement cues to estimate distance. The current study provides evidence for a role of movement segmentation in processing self-movement cues selective to direction estimation and develops a foundation for future studies investigating the neurobiology of spatial orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human sensitivity to acoustic information from vessel filling.

Acylindrical vessel's fundamental resonant frequency increases as it fills with water. In Experiment 1, observers reliably identified water level rising, falling, or not changing. In Experiment 2, observers controlled filling well using only auditory information but less well than with multimodal information. Observers controlled fills to the brim better than to a drinking level, implying anticipation of fullness. In Experiment 3, blind and blindfolded sighted observers filled vessels to the brim using only auditory information. Fills tracked vessel height and flow rate well (R?=?.93, blind; R?=?.86, sighted). Experiment 4 tested sensitivity to acoustic time-to-full (TTF), analogous to optical tau. Estimated TTF to 3 fill levels at 3 rates tracked actual TTF (group R?>?.9; individual median R?=?.82). Results supported ecological perceptual theory: Changing acoustic information affords adaptive, prospective control of vessel filling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-Related Differences in Localized Attentional Interference.

Attentional selection of an object in the visual field degrades processing of neighboring stimuli in young adults. A pair of experiments examined the effects of aging on such localized attentional interference. In Experiment 1, younger and older observers made speeded same-different judgments of target shapes that varied in spatial separation. Performance declined for both age groups as the distance between targets decreased, but an Age x Distance interaction indicated that the magnitude of this effect was larger for older adults. Experiment 2 ruled out sensory masking as an explanation for these findings. Results indicate that older observers experience losses in the ability to attend to multiple spatially proximal stimuli within the visual field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual experience, visual field size, and the development of nonvisual sensitivity to the spatial structure of outdoor neighborhoods explored by walking.

When places are explored without vision, observers go from temporally sequenced, circuitous inputs available along walks to knowledge of spatial structure (i.e., straight-line distances and directions characterizing the simultaneous arrangement of the objects passed along the way). Studies show that a life history of vision helps develop nonvisual sensitivity, but they are unspecific on the formative experiences or the underlying processes. This study compared judgments of straight-line distances and directions among landmarks in a familiar area of town by partially sighted persons who varied in types and ages of visual impairment. Those with early childhood loss of broad-field vision and those blind from birth performed significantly worse than those with early or late acuity loss and those with late field loss. Broad-field visual experience facilitates perceptual development by providing a basis for proprioceptive and efferent information from locomotion against distances and directions relative to the surrounding environment. Differences in the perception of walking, in turn, cause the observed differences in sensitivity to spatial structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic contrast perception assessed by pattern masking

The perceived contrast of a pulsed grating varies markedly with the exposure duration and spatial frequency of the grating. We studied dynamic changes in perceived grating contrast with a pattern-masking paradigm. We measured masking of a brief, localized test pattern (a D6 stimulus, 30 ms in duration) by fixed-contrast cosine grating patterns of varying duration (50-500 ms). The cosine mask pattern had spatial frequency of either 1 or 6 cycles per degree (cpd) at a contrast of 0.3. The D6 test pattern was centered on a light bar of the mask and was either positive peak contrast (same-polarity test and mask) or negative peak contrast (opposite-polarity test and mask). In Experiment 1, the test and mask had simultaneous onset. With a 6-cpd mask, the same-polarity test-threshold elevation versus mask-duration function increases monotonically. For a 1-cpd mask, the same-polarity threshold-mask-duration function is nonmonotonic, with peak masking effect produced by a grating pulse of 80-100 ms. These masking effects are closely congruent with known dynamic contrast effects. With negative tests, masking-duration functions are elevated from same-polarity functions and are essentially similar in shape for 1- and 6-cpd masks. The elevated thresholds suggest inhibitory interaction between ON and OFF pathways, with a similar time course across spatial frequency. In Experiment 2, the D6 test was delayed from mask onset by 33 ms. Positive contrasts only were employed. For 1-cpd stimuli, the delay of test greatly reduced masking at all mask durations and eliminated the nonmonotonic function. This suggests that for low-spatial-frequency patterns, perceived contrast is determined by an early peak component of the neural response. But for 6-cpd stimuli, masking of the delayed test was somewhat greater at all mask durations, consistent with a gradually increasing underlying neural response to the grating. Finally, in Experiment 3, same-polarity masking effects at both spatial frequencies were replicated with negative-contrast test and mask (OFF pathway mediation). This indicates that the ON and OFF pathways have similar response dynamics.     

Steering toward a goal by equalizing taus.

Steering toward a target can be controlled by equalizing the time-to-closure of the angle between the target and the direction of locomotion and the time-to-passage of the observer by the target. Two experiments required observers to steer through a computer-simulated environment toward a target depicted as either a floating cross that did not optically expand, a floating sphere that optically expanded or a grounded post that optically expanded. Experiment 1 revealed better performance in the post and sphere conditions, suggesting that steering is influenced by local optical expansion but not by perceived spatial target location or distance. Experiment 2 revealed differences in steering behavior between target types that suggested observers attempted to equalize time-to-closure and time-to-passage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses of observer rats (Rattus norvegicus) to complex, diet-related signals emitted by demonstrator rats.

We explored the effects of complex, food-identifying signals emitted by demonstrator Long-Evans rats (Rattus norvegicus) on food preferences of their observers. In Experiments 1 and 2, observers identified each of 2 or 3 foods their demonstrators had eaten before interacting with observers. In Experiment 3, individual observers interacted with groups of demonstrators. Some of these demonstrators had eaten one food, some another. Observers then chose between the 2 foods. The greater the proportion of demonstrators in a group that had eaten a diet, the greater the proportion of that diet the observers ate. In Experiment 4, each observer interacted over several weeks with a series of demonstrators and preferred each of the foods its demonstrators had eaten. In sum, the food preferences of observers were affected by several different types of complex, food-identifying signals like those one might expect rats to encounter outside the laboratory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of line configuration on perceived numerosity of dotted lines

Estimates the number of objects in a line are made in many different situations. This paper demonstrates that besides the actual number of dots, aspects of line configuration affect the perceived numerosity of dotted lines. Experiment 1 provides evidence that the highly studied "clutter effect" in distance perception research replicates to the numerosity domain so that lines made up of more segments are perceived to contain more dots. Experiments 2-5 provide nomological validity for the recently proposed "direct distance" effect in distance perceptions by showing that numerosity perceptions are higher the greater the euclidean length between the line end points and by manipulating euclidean length in three orthogonal ways: the relative length of segments (Experiment 2), the angle between segments (Experiment 3), and the general direction of segments (Experiment 4). Experiment 5 conceptually replicates the results of Experiments 2-4 utilizing stimuli-based versus memory-based judgments and a discrimination task. Experiments 6 and 7 extend the research on spatial perception by demonstrating that the use of euclidean length as a source of information is inversely related to line width, with width varied through clutter (Experiment 6) and total line length (Experiment 7). Overall, the results demonstrate that the robustness of the euclidean length effect is contingent on the salience of alternative spatial heuristics--specifically, euclidean width. Theoretical implications are discussed.     

Calibrating reach distance to visual targets.

The authors investigated the calibration of reach distance by gradually distorting the haptic feedback obtained when participants grasped visible target objects. The authors found that the modified relationship between visually specified distance and reach distance could be captured by a straight-line mapping function. Thus, the relation could be described using 2 parameters: bias and slope. The authors investigated whether calibration generalized across reach space with respect to changes in bias and slope. In Experiment 1, the authors showed that both bias and slope recalibrate. In Experiment 2, they tested the symmetries of reach space with respect to changes in bias. They discovered that reach space is asymmetric, with the bias shifting inward more readily than outward. The authors measured how rapidly the system calibrated and the stability of calibration once feedback was removed. In Experiment 3, they showed that bias and slope can be calibrated independently of one another. In Experiment 4, the authors showed that these calibration effects are not cognitively penetrable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual experience influences 12-month-old infants' perception of goal-directed actions of others.

In the present study, we investigated whether infants' own visual experiences affected their perception of the visual status of others engaging in goal-directed actions. In Experiment 1, infants viewed video clips of successful and failed goal-directed actions performed by a blindfolded adult, with half the infants having previously experienced being blindfolded. The results showed that 12-month-old infants who were previously blindfolded preferred to look longer at the demonstrator's successful actions, whereas no such preference was observed in 8-month-old infants. In Experiment 2, infants watched the same 2 actions when the adult demonstrator was not blindfolded. The responses of 12-month-old infants were the opposite of those observed in Experiment 1: They showed a preference for the failed actions. These findings suggest that previous experience influenced the subsequent perception of others' goal-directed actions in the 12-month-old infants. We favor the interpretation that the preference for the successful actions in the 12-months-old infants provided with blindfolded experience demonstrates the influence of perceptual experience on considering the visual status of others engaging in goal-directed actions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Selective associations in the observational conditioning of fear in rhesus monkeys.

Three experiments explored the issue of selective associations in the observational conditioning of fear. Experiment 1 results indicated that observer rhesus monkeys acquired a fear of snakes through watching videotapes of model monkeys behaving fearfully with snakes. In Experiment 2, observers watched edited videotapes that showed models reacting either fearfully to toy snakes and nonfearfully to artificial flowers (SN+/FL–) or vice versa (FL+/SN–). SN+/FL– observers acquired a fear of snakes but not of flowers; FL+/SN– observers did not acquire a fear of either stimulus. In Experiment 3, monkeys solved complex appetitive discriminative (PAN) problems at comparable rates regardless of whether the discriminative stimuli were the videotaped snake or the flower stimuli used in Experiment 2. Thus, monkeys appear to selectively associate snakes with fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is there feature-based attentional selection in visual search?

A new paradigm combines attentional cuing and rapid serial visual presentation to disentangle the effects of perceptual filtering and location selection. Observers search successive, superimposed arrays, in which feature values are alternated for a target numeral among letters. Two dimensions, size (small, large) and color (red, green) are tested. Selective attention to feature values is jointly manipulated by instructions, presentation probabilities, and payoffs. In Experiment 1, the attended feature provides temporal, not spatial, information; observers show no attentional costs or benefits in response accuracy. In Experiment 2, the attended feature indicates a unique location; observers show consistent attentional costs and benefits. Selective attention to a particular size or color does not cause perceptual exclusion or admission of items containing that feature; it acts by guiding search processes to spatial locations that contain the to-be-attended feature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Manipulation with no or partial vision.

The present research investigated the role of vision in closed- and open-loop processing during manipulation. In Experiment 1, participants performed common manipulatory tasks with 100% accuracy in less than 1 s without vision. In Experiment 2, the effects of extensive practice of a peg-in-hole task were examined within 4 functionally significant stages of manipulation. Performance was consistently faster with than without vision in the prereach, grasp, and transport + insert stages; reverse effects were observed during the reach stage. In Experiment 3, the effects of practice with partial vision were examined: Participants initially learned the peg-in-hole task with full vision and then transferred to learning the same task with vision available only during 1 functional stage. Overall, performance was fastest when vision was limited to the prereach and reach stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are central cholinergic paths involved in habituation of exploration and distraction?

Experiment 1 tested the generality of Carlton's hypothesis that central muscarinic cholinergic pathways are involved in habituation of exploration. The effects of 3 muscarinic antagonists were tested in a holeboard, under 2 test conditions, i.e. with objects absent or present. Both the frequency and the duration of head-dipping were used as measures of exploration. Scopolamine prevented habituation only of the frequency of head-dipping, and only when objects were present. Atropine and benzhexol did not impair the habituation of either frequency of duration of head-dipping in either test condition. The impairment of habituation seemed therefore to be specific to scopolamine, and to the more complex test condition, and thus there was little to justify the suggestion that central cholinergic paths were generally involved. Experiment 2 investigated the effects of muscarinic antagonists on habituation of distraction. None of the drugs affected the distraction to tones, nor the subsequent habituation to these stimuli. Central cholinergic paths do not therefore seem to be involved in habituation of this behavioral response.     

Age-related deficits in guided search using cues.

The ability of young and older adults to engage in guided conjunction search was tested in 2 experiments. In the cued condition, a picture of the target was presented before the search. In the noncued condition, there was no picture of the target. In Experiment 1, the cue was presented for 200 ms; the magnitude of the cuing effect (noncued response time - cued response time) was greater for the young than for the older observers. In Experiment 2 (older observers only), the cue duration was doubled, and older observers had a larger magnitude of cuing effect than found in Experiment 1 but not as large as what would be expected under generalized slowing. The results indicated that older observers had difficulty with interpreting the cue and setting search parameters when the target varied across trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using temporal information to construct, update, and retrieve situation models of narratives.

Four experiments explored how readers use temporal information to construct and update situation models and retrieve them from memory. In Experiment 1, readers spontaneously constructed temporal and spatial situation models of single sentences. In Experiment 2, temporal inconsistencies caused problems in updating situation models similar to those observed previously for other dimensions of situation models. In Experiment 3, merely implied temporal order information was inferred from narratives, affecting comprehension of later sentences like explicitly stated order information. Moreover, inconsistent temporal order information prevented the creation and storage in memory of an integrated situation model. In Experiment 4, a temporal inconsistency increased processing time even if readers were unable to report the inconsistency. These results confirm the significance of the temporal dimension of situation models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial updating of locations specified by 3-D sound and spatial language.

Blind and blindfolded sighted observers were presented with auditory stimuli specifying target locations. The stimulus was either sound from a loudspeaker or spatial language (e.g., "2 o'clock, 16 ft"). On each trial, an observer attempted to walk to the target location along a direct or indirect path. The ability to mentally keep track of the target location without concurrent perceptual information about it (spatial updating) was assessed in terms of the separation between the stopping points for the 2 paths. Updating performance was very nearly the same for the 2 modalities, indicating that once an internal representation of a location has been determined, subsequent updating performance is nearly independent of the modality used to specify the representation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Space-time dependencies in psychophysical judgment of extent and duration: Algebraic models of the tau and kappa effects.

The tau effect is a functional dependence of spatial judgments, normally judgments of length, on the temporal context, whereas the kappa effect is a corresponding dependence of temporal judgments on the spatial context. The evidence for both effects in vision, hearing, and touch and with a variety of psychophysical procedures (absolute and relative judgments, reproduction adjustment) is reviewed. A number of theories of tau and kappa are briefly discussed. Consistent with several researchers, the present authors suggest that in a formal sense, Ss impute uniform motion to discontinuous displays. A general algebraic model of the psychological process is developed. The evidence is consistent with a model in which spatial or temporal judgments in context are a weighted average of the given interval, temporal or spatial, and the expected time or distance that would be traversed at a given velocity. Consequently, it is argued that the functional relations between distance, duration, and velocity provide a natural context for distance and duration judgments. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)