Out of sight,out of mind: Occlusion and eye closure destabilize moving bistable structure-from-motion displays

Our brain constantly tries to anticipate the future by using a variety of memory mechanisms. Interestingly, studies using the intermittent presentation of multistable displays have shown little perceptual persistence for interruptions longer than a few hundred milliseconds. Here we examined whether we can facilitate the perceptual stability of bistable displays following a period of invisibility by employing a physically plausible and ecologically valid occlusion event sequence, as opposed to the typical intermittent presentation, with sudden onsets and offsets. To this end, we presented a bistable rotating structure-from-motion display that was moving along a linear horizontal trajectory on the screen and either was temporarily occluded by another object (a cardboard strip in Exp. 1, a computer-generated image in Exp. 2) or became invisible due to eye closure (Exp. 3). We report that a bistable rotation direction reliably persisted following occlusion or interruption only (1) if the pre- and postinterruption locations overlapped spatially (an occluder with apertures in Exp. 2 or brief, spontaneous blinks in Exp. 3) or (2) if an object’s size allowed for the efficient grouping of dots on both sides of the occluding object (large objects in Exp. 1). In contrast, we observed no persistence whenever the pre- and postinterruption locations were nonoverlapping (large solid occluding objects in Exps. 1 and 2 and long, prompted blinks in Exp. 3). We report that the bistable rotation direction of a moving object persisted only for spatially overlapping neural representations, and that persistence was not facilitated by a physically plausible and ecologically valid occlusion event.     

Fitts’ Law is modulated by movement history

Fitts’ Law is one of the most robust and well-studied principles in psychology. It holds that movement time (MT) for target-directed aiming movements increases as a function of target distance and decreases as a function of target width. The purpose of this study was to determine whether Fitts’ Law is affected not only by the demands of the target on the current trial but also by the requirements for performance on the previous trial. Experiments 1 and 2 examined trial-to-trial effects of varying target width; Experiment 3 examined trial-to-trial effects of varying target distance. The findings from Experiments 1 and 2 showed that moving a finger or cursor towards a large object on a previous trial shortened the movement time on the current trial, whereas the opposite occurred with a small object. In contrast, target distance on the previous trial had no effect on movement time on the current trial. These findings suggest that performance on trial n has a clear and predictable effect on trial n+1 (at least for target width) and that Fitts’ Law as it is normally expressed does not accurately predict performance when the width of the target varies from trial to trial.     

No advantage for remembering horizontal over vertical spatial locations learned from a single viewpoint

Previous behavioral and neurophysiological research has shown better memory for horizontal than for vertical locations. In these studies, participants navigated toward these locations. In the present study we investigated whether the orientation of the spatial plane per se was responsible for this difference. We thus had participants learn locations visually from a single perspective and retrieve them from multiple viewpoints. In three experiments, participants studied colored tags on a horizontally or vertically oriented board within a virtual room and recalled these locations with different layout orientations (Exp. 1) or from different room-based perspectives (Exps. 2 and 3). All experiments revealed evidence for equal recall performance in horizontal and vertical memory. In addition, the patterns for recall from different test orientations were rather similar. Consequently, our results suggest that memory is qualitatively similar for both vertical and horizontal two-dimensional locations, given that these locations are learned from a single viewpoint. Thus, prior differences in spatial memory may have originated from the structure of the space or the fact that participants navigated through it. Additionally, the strong performance advantages for perspective shifts (Exps. 2 and 3) relative to layout rotations (Exp. 1) suggest that configurational judgments are not only based on memory of the relations between target objects, but also encompass the relations between target objects and the surrounding room—for example, in the form of a memorized view.     

The strategic control of prospective memory monitoring in response to complex and probabilistic contextual cues

Participants use simple contextual cues to reduce deployment of costly monitoring processes in contexts in which prospective memory (PM) targets are not expected. This study investigated whether this strategic monitoring pattern is observed in response to complex and probabilistic contextual cues. Participants performed a lexical decision task in which words or nonwords were presented in upper or lower locations on screen. The specific condition was informed that PM targets (“tor” syllable) would occur only in words in the upper location, whereas the nonspecific condition was informed that targets could occur in any location or word type. Context was blocked such that word type and location changed every 8 trials. In Experiment 1, the specific condition used the complex contextual cue to reduce monitoring in unexpected contexts relative to the nonspecific condition. This pattern largely was not evidenced when the complex contextual cue was probabilistic (Experiment 2). Experiment 3 confirmed that strategic monitoring is observed for a complex cue that is deterministic, but not one that is probabilistic. Additionally, Experiments 1 and 3 demonstrated a disadvantage associated with strategic monitoring—namely, that the specific condition was less likely to respond to a PM target in an unexpected context. Experiment 3 provided evidence that this disadvantage is attributable to impaired noticing of the target. The novel findings suggest use of a complex contextual cue per se is not a boundary condition for the strategic, context-specific allocation of monitoring processes to support prospective remembering; however, strategic monitoring is constrained by the predictive utility of the complex contextual cue.     

Multiple attentional control settings at distinct locations without the confounding of repetition priming

An attentional control setting (ACS), which is based on the task goal, induces involuntary attentional capture by a stimulus possessing a target-defining feature. It is unclear whether ACSs are maintained for multiple targets defined as conjunctions of a color and location. In the present study we examined the possibility of local ACSs for dual targets defined as combinations of color and location, using different paradigms: visual search in Experiment 1, and spatial cueing in Experiment 2. In Experiment 1, a distractor captured attention only when its features matched the ACSs. Likewise, in Experiment 2, a significant attentional capture effect was found only with a matching cue, whose color and location were in line with the conjunction of the target definition. Importantly, the identical pattern of attentional capture was also obtained for a neutral-color target, which was unlikely to be primed by any color of the cue. Thus, these findings imply that the attentional bias depending on the match between the cue and target did not result from cue–target repetition priming. The present study highlights that top-down attentional control can be set flexibly to accomplish a complex task goal efficiently.     

The mere exposure effect for visual image

Mere exposure effect refers to a phenomenon in which repeated stimuli are evaluated more positively than novel stimuli. We investigated whether this effect occurs for internally generated visual representations (i.e., visual images). In an exposure phase, a 5 × 5 dot array was presented, and a pair of dots corresponding to the neighboring vertices of an invisible polygon was sequentially flashed (in red), creating an invisible polygon. In Experiments 1, 2, and 4, participants visualized and memorized the shapes of invisible polygons based on different sequences of flashed dots, whereas in Experiment 3, participants only memorized positions of these dots. In a subsequent rating phase, participants visualized the shape of the invisible polygon from allocations of numerical characters on its vertices, and then rated their preference for invisible polygons (Experiments 1, 2, and 3). In contrast, in Experiment 4, participants rated the preference for visible polygons. Results showed that the mere exposure effect appeared only when participants visualized the shape of invisible polygons in both the exposure and rating phases (Experiments 1 and 2), suggesting that the mere exposure effect occurred for internalized visual images. This implies that the sensory inputs from repeated stimuli play a minor role in the mere exposure effect. Absence of the mere exposure effect in Experiment 4 suggests that the consistency of processing between exposure and rating phases plays an important role in the mere exposure effect.     

Numerosity estimates for attended and unattended items in visual search

The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants’ only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.     

The concreteness effect on judgments of learning: Evaluating the contributions of fluency and beliefs

Researchers have often determined how cues influence judgments of learning (JOLs; e.g., concrete words are assigned higher JOLs than are abstract words), and recently there has been an emphasis in understanding why cues influence JOLs (i.e., the mechanisms that underlie cue effects on JOLs). The analytic-processing (AP) theory posits that JOLs are constructed in accordance with participants’ beliefs of how a cue will influence memory. Even so, some evidence suggests that fluency is also important to cue effects on JOLs. In the present experiments, we investigated the contributions of participants’ beliefs and processing fluency to the concreteness effect on JOLs. To evaluate beliefs, participants estimated memory performance in a hypothetical experiment (Experiment 1), and studied concrete and abstract words and made a pre-study JOL for each (Experiments 2 and 3). Participants’ predictions demonstrated the belief that concrete words are more likely to be remembered than are abstract words, consistent with the AP theory. To evaluate fluency, response latencies were measured during lexical decision (Experiment 4), self-paced study (Experiment 5), and mental imagery (Experiment 7). Number of trials to acquisition was also evaluated (Experiment 6). Fluency did not differ between concrete and abstract words in Experiments 5 and 6, and it did not mediate the concreteness effect on JOLs in Experiments 4 and 7. Taken together, these results demonstrate that beliefs are a primary mechanism driving the concreteness effect on JOLs.     

Whose hand is this? Differential responses of right and left extrastriate body areas to visual images of self and others’ hands

The extrastriate body area (EBA) is involved in perception of human bodies and nonfacial body parts, but its role in representing body identity is not clear. Here, we used on-line high-frequency repetitive transcranial magnetic stimulation (rTMS) to test the role of EBA in self–other distinction. In Experiments 1 and 2 we compared rTMS of right EBA with stimulation of left ventral premotor cortex (vPM), whereas in Experiment 3 we compared stimulation of right and left EBA. RTMS was applied during a hand laterality task in which self or others’ hand images were presented in first- versus third-person view (Experiments 1 and 3), or while participants had to explicitly recognize their own hands (Experiment 2) presented in first- versus third-person view. Experiment 1 showed that right EBA stimulation selectively speeded judgments on others’ hands, whereas no effect of left vPM stimulation was found. Experiment 2 did not reveal any effect of rTMS. Experiment 3 confirmed faster responses on others’ hands while stimulating right EBA and also showed an advantage when judging self with respect to others’ hands during stimulation of left EBA. These results would demonstrate that EBA responds to morphological features of human body contributing to identity processing.     

Cue quality and criterion setting in recognition memory

Previous studies on how people set and modify decision criteria in old-new recognition tasks (in which they have to decide whether or not a stimulus was seen in a study phase) have almost exclusively focused on properties of the study items, such as presentation frequency or study list length. In contrast, in the three studies reported here, we manipulated the quality of the test cues in a scene-recognition task, either by degrading through Gaussian blurring (Experiment 1) or by limiting presentation duration (Experiment 2 and 3). In Experiments 1 and 2, degradation of the test cue led to worse old-new discrimination. Most importantly, however, participants were more liberal in their responses to degraded cues (i.e., more likely to call the cue “old”), demonstrating strong within-list, item-by-item, criterion shifts. This liberal response bias toward degraded stimuli came at the cost of increasing the false alarm rate while maintaining a constant hit rate. Experiment 3 replicated Experiment 2 with additional stimulus types (words and faces) but did not provide accuracy feedback to participants. The criterion shifts in Experiment 3 were smaller in magnitude than Experiments 1 and 2 and varied in consistency across stimulus type, suggesting, in line with previous studies, that feedback is important for participants to shift their criteria.     

Imagining the near and far future: The role of location familiarity

Plausible personal events envisioned as occurring in the near future tend to be reported as more vivid than those set in the far future. Why is this? The present set of three experiments identified one’s familiarity with the location in which the event is placed as critical in this regard. Specifically, Experiment 1 demonstrated that amongst a wide range of phenomenological characteristics, clarity of location appears to drive the overall difference in vividness between events imagined to take place in the near and the far future. Experiments 2 and 3 were designed to further elucidate this finding. Experiment 2 demonstrated that near future events are more likely than far future events to be imagined in familiar locations. Experiment 3 showed that future events set in familiar locations tend to be imagined with greater clarity than those set in unfamiliar locations. The results of all three experiments converge on the conclusion that the difference in vividness of events imagined as occurring in the near and far future is mediated by one’s familiarity with the location in which the event is imagined to occur.     

No evidence for binding of items to task-irrelevant backgrounds in visual working memory

When representing visual features such as color and shape in visual working memory (VWM), participants also represent the locations of those features as a spatial configuration of the locations of those features in the display. In everyday life, we encounter objects against some background, yet it is unclear whether the configural representation in memory obligatorily constitutes the entire display, including that (often task-irrelevant) background information. In three experiments, participants completed a change detection task on color and shape; the memoranda were presented in front of uniform gray backgrounds, a textured background (Exp. 1), or a background containing location placeholders (Exps. 2 and 3). When whole-display probes were presented, changes to the objects’ locations or feature bindings impacted memory performance—implying that the spatial configuration of the probes influenced participants’ change decisions. Furthermore, when only a single item was probed, the effect of changing its location or feature bindings was either diminished or completely extinguished, implying that single probes do not necessarily elicit the entire spatial configuration. Critically, when task-irrelevant backgrounds were also presented that may have provided a spatial configuration for the single probes, the effect of location or bindings was not moderated. These findings suggest that although the spatial configuration of a display guides VWM-based recognition, this information does not necessarily always influence the decision process during change detection.     

On the limits of statistical learning: Intertrial contextual cueing is confined to temporally close contingencies

Since the seminal study by Chun and Jiang (Cognitive Psychology, 36, 28–71, 1998), a large body of research based on the contextual-cueing paradigm has shown that the cognitive system is capable of extracting statistical contingencies from visual environments. Most of these studies have focused on how individuals learn regularities found within an intratrial temporal window: A context predicts the target position within a given trial. However, Ono, Jiang, and Kawahara (Journal of Experimental Psychology, 31, 703–712, 2005) provided evidence of an intertrial implicit-learning effect when a distractor configuration in preceding trials N ? 1 predicted the target location in trials N. The aim of the present study was to gain further insight into this effect by examining whether it occurs when predictive relationships are impeded by interfering task-relevant noise (Experiments 2 and 3) or by a long delay (Experiments 1, 4, and 5). Our results replicated the intertrial contextual-cueing effect, which occurred in the condition of temporally close contingencies. However, there was no evidence of integration across long-range spatiotemporal contingencies, suggesting a temporal limitation of statistical learning.     

Age of avatar modulates the altercentric bias in a visual perspective-taking task: ERP and behavioral evidence

Despite being able to rapidly and accurately infer their own and other peoples’ visual perspectives, healthy adults experience difficulty ignoring the irrelevant perspective when the two perspectives are in conflict; they experience egocentric and altercentric interference. We examine for the first time how the age of an observed person (adult vs. child avatar) influences adults’ visual perspective-taking, particularly the degree to which they experience interference from their own or the other person’s perspective. Participants completed the avatar visual perspective-taking task, in which they verified the number of discs in a visual scene according to either their own or an on-screen avatar’s perspective (Experiments 1 and 2) or only from their own perspective (Experiment 3), where the two perspectives could be consistent or in conflict. Age of avatar was manipulated between (Experiment 1) or within (Experiments 2 and 3) participants, and interference was assessed using behavioral (Experiments 1–3) and ERP (Experiment 1) measures. Results revealed that altercentric interference is reduced or eliminated when a child avatar was present, suggesting that adults do not automatically compute a child avatar’s perspective. We attribute this pattern to either enhanced visual processing for own-age others or an inference on reduced mental awareness in younger children. The findings argue against a purely attentional basis for the altercentric effect, and instead support an account where both mentalising and directional processes modulate automatic visual perspective-taking, and perspective-taking effects are strongly influenced by experimental context.     

The effects of context in item-based directed forgetting: Evidence for “one-shot” context storage

The effects of context on item-based directed forgetting were assessed. Study words were presented against different background pictures and were followed by a cue to remember (R) or forget (F) the target item. The effects of incidental and intentional encoding of context on recognition of the study words were examined in Experiments 1 and 2. Recognition memory for the picture contexts was assessed in Experiments 3a and 3b. Recognition was greater for R-cued compared to F-cued targets, demonstrating an effect of directed forgetting. In contrast, no directed forgetting effect was seen for the background pictures. An effect of context-dependent recognition was seen in Experiments 1 and 2, such that the hit rate and the false-alarm rate were greater for items tested in an old compared to a novel context. An effect of context-dependent discrimination was also observed in Experiment 2 as the hit rate was greater for targets shown in their same old study context compared to a different old context. The effects of context and directed forgetting did not interact. The results are consistent with Malmberg and Shiffrin’s (Journal of Experimental Psychology: Learning, Memory, and Cognition, 31, 322–336, 2005) “one-shot” context storage hypothesis that assumes that a fixed amount of context is stored in the first 1 to 2 s of the presentation of the study item. The effects of context are independent of item-based directed forgetting because context is encoded prior to the R or F cue, and the differential processing of target information that gives rise to the directed forgetting effect occurs after the cue.     

Predictive visual search: Role of environmental regularities in the learning of context cues

Repeatedly searching through invariant spatial arrangements in visual search displays leads to the buildup of memory about these displays (contextual-cueing effect). In the present study, we investigate (1) whether contextual cueing is influenced by global statistical properties of the task and, if so, (2) whether these properties increase the overall strength (asymptotic level) or the temporal development (speed) of learning. Experiment 1a served as baseline against which we tested the effects of increased or decreased proportions of repeated relative to nonrepeated displays (Experiments 1b and 1c, respectively), thus manipulating the global statistical properties of search environments. Importantly, probability variations were achieved by manipulating the number of nonrepeated (baseline) displays so as to equate the total number of repeated displays across experiments. In Experiment 1d, repeated and nonrepeated displays were presented in longer streaks of trials, thus establishing a stable environment of sequences of repeated displays. Our results showed that the buildup of contextual cueing was expedited in the statistically rich Experiments 1b and 1d, relative to the baseline Experiment 1a. Further, contextual cueing was entirely absent when repeated displays occurred in the minority of trials (Experiment 1c). Together, these findings suggest that contextual cueing is modulated by observers’ assumptions about the reliability of search environments.     

Artifact and Essence

An essential property is a property that an object possesses in every possible world in which that object exists. An individual essence is a property (or set of properties) that an object possesses in every world in which that object exists, and that no other object possesses in any possible world. Call the claim that some artifacts possess an individual essence ‘artifactual essentialism’. I will argue that artifactual essentialism is true. In doing so, I will be responding to two recent arguments by Penelope Mackie against artifactual essentialism (Mackie (2006), esp. ch. 3.). In “Individual Essence Properties”, I will rehearse the qualifications that any property must meet if it is to constitute an individual essence, and in “Artifacts and the Recycling Problem” and “Artifacts and the Tolerance Problem”, I will rehearse Mackie’s arguments against artifactual essentialism. In “Artifacts and Weak Unshareability?” and “Artifacts and Strong Unshareability?”, I will show why both of these arguments fail. In “Mona Lisa’s Essence”, I will defend the interesting claim that some artifacts possess an individual essence. In the final section I will entertain some objections to my proposal.     

Relationship between vection and motion perception in depth

This study examined the effects of cues to motion in depth – namely, stereoscopic (i.e., changing-disparity cues and interocular velocity differences) and changing-size cues on forward and backward vection. We conducted four experiments in which participants viewed expanding or contracting optical flows with the addition of either or both cues. In Experiment 1, participants reported vection by pressing a button whenever they felt it. After each trial, they also rated the magnitude of the vection (from 0 to 100). In Experiments 2 and 3, the participants rated the perceived velocity and motion-in-depth impression of the flows relative to standard stimuli, respectively. In Experiment 4, the participants rated the perceived depth and distance of the display. We observed enhancements in vection, motion-in-depth impression, and perceived depth and distance when either or both types of cues indicated motion-in-depth, as compared to those when the cues did not (Experiments 1, 3, and 4). The perceived velocity changed with cue conditions only for the high velocity condition (Experiment 2). Correlational analyses showed that the vection can be best explained by the motion-in-depth impression. This was partially supported by the multiple regression analyses. These results indicate that the enhancement of vection caused by cues is related to the impression of motion-in-depth rather than the perceived velocity and perceived three-dimensionality.     

Repetition blindness in priming in perceptual identification: Competitive effects of a word intervening between prime and target

University students named a 72-ms masked target word that was preceded by two 120-ms consecutively presented words, a prime word followed by a distractor. In Experiment 1, all words were in lowercase letters, whereas in Experiment 2, the target word was changed to uppercase letters. In both experiments there was an accuracy and latency cost (repetition blindness: RB) when the prime was the same word as the target, with the cost much less severe in Experiment 2 than in Experiment 1. A low-frequency distractor impaired target identification compared with a high-frequency distractor. Distractor frequency interacted with target frequency such that high-frequency targets preceded by low-frequency distractors had the lowest accuracy. The results are consistent with a frequency-dependent competition for access to working memory among briefly displayed words. However, there was no clear evidence that effects of target repetition on interword competition play a role in RB. The effects of a letter case change for the target are consistent with a contribution of token distinctiveness to word-order recovery in the intervening-word priming task.     

The texture of causal construals: Domain-specific biases shape causal inferences from discourse

We conducted five sets of experiments asking whether psychological and physical events are construed in broadly different manners concerning the underlying textures of their causes. In Experiments 1a–1d, we found a robust tendency to estimate fewer causes (but not effects) for psychological than for physical events; Experiment 2 showed a similar pattern of results when participants were asked to generate hypothetical causes and effects; Experiment 3 revealed a greater tendency to ascribe linear chains of causes (but not effects) to physical events; Experiment 4 showed that the expectation of linear chains was related to intuitions about deterministic processes; and Experiment 5 showed that simply framing a given ambiguous event in psychological versus physical terms is sufficient to induce changes in the patterns of causal inferences. Adults therefore consistently show a tendency to think about psychological and physical events as being embedded in different kinds of causal structures.