Binocular cues in the perception of distance of a point source of light

The ability to make egocentric distance estimates of a single point source of light, seen in darkness and without the cues of changing size and luminance, was investigated in sixteen observers. The attenuation required to maintain constant luminance, when the target was viewed from different distances, was shown to follow the inverse square law providing the angle subtended by the light was less than 20 s arc. Distance changes were also simulated by means of a split mirror which produced vergence cues, or by test lenses to provide accommodation cues. Over the range 0.5 to 9.2 m distance estimates were surprisingly accurate, although there was some overestimation of near and underestimation of far distances. Most observers made good judgements when only convergence cues were varied, whereas no observers made consistently good judgements when only accommodation cues were varied. The difficulties are discussed in terms of the accommodation-convergence link. When distance was simulated by changing convergence and accommodation cues, estimates were not as good as when real distance was changed. Since good estimates were made with brief target exposures, these judgements were not based on subsequent convergence or accommodation changes. It is suggested that the metric or reference against which the apparently absolute judgements were made was the efferent demand signal associated with a 'resting' position of convergence in darkness.     

Time perception,vigilance and decision theory

A statistical decision hypothesis is outlined to account for a progressive lengthening of judgments which occurs when a series of reproductions of a time interval is made without interpolation of a standard. Three experiments are reported in which it is found that this serial effect can be manipulated by hypothetical payoff conditions, that the effect still occurs when subjects are told to count while making their judgments, and that two successive judgments are sufficient to demonstrate the effect if enough subjects are used. The phenomenon is related to recent studies of vigilance in which statistical decision theory has been applied. It is suggested that serial reproductions of time intervals may perhaps be a more sensitive index of the factors underlying vigilance than the traditional measures involving long sessions with weak, sporadic signals.     

The effects of verbal cueing on implicit hand maps

The use of position sense to perceive the external spatial location of the body requires that immediate proprioceptive afferent signals be combined with stored representations of body size and shape. Longo and Haggard (2010) developed a method to isolate and measure this representation in which participants judge the location of several landmarks on their occluded hand. The relative location of judgements is used to construct a perceptual map of hand shape. Studies using this paradigm have revealed large, and highly stereotyped, distortions of the hand, which is represented as wider than it actually is and with shortened fingers. Previous studies using this paradigm have cued participants to respond by giving verbal labels of the knuckles and fingertips. A recent study has shown differential effects of verbal and tactile cueing of localisation judgements about bodily landmarks (Cardinali et al., 2011). The present study therefore investigated implicit hand maps measuring through localisation judgements made in response to verbal labels and tactile stimuli applied to the same landmarks. The characteristic set of distortions of hand size and shape were clearly apparent in both conditions, indicating that the distortions reported previously are not an artefact of the use of verbal cues. However, there were also differences in the magnitude of distortions between conditions, suggesting that the use of verbal cues may alter the representation of the body underlying position sense.     

Forecasting good or bad behaviour: A non‐transparent test of contrastive responses to cultural cues

Bicultural individuals vary in the degree to which their two cultural identities are integrated – Bicultural Identity Integration (BII). Among Asian‐Americans, for example, some experience their Asian and American sides as integrated (high BII) whereas others experience the two as divided (low BII). Past research on social judgement found that individual differences in BII affect the way biculturals respond to cultural cues or norms in their situation. Asian‐Americans with low BII tend to contrast to the cultural norm (e.g. they exhibit typically American judgements when in Asian cultural situations) rather than assimilate to them, a response observed more among high BII individuals (e.g., they exhibit typically Asian judgements when in Asian cultural situations). Research has interpreted the contrastive response as reflecting implicit identity motives, yet past studies used measures that make cultural differences salient. Conscious awareness of the experimental hypothesis could elicit contrastive responses. The present research assessed forecasts of others' behaviour in which cultural group differences are less obvious: Asians, compared to Westerners, forecast more positive behaviours from others. In three experiments with Asian‐Americans, we found the contrastive response by low BII individuals persisted. They made more positive forecasts after exposure to American versus Asian cultural cues. This suggests that the moderating role of BII on responses to cultural cues is not a matter of demand characteristics or limited to stereotypical cultural differences. Implications for bicultural identity, implicit processes, and organizational behaviour are discussed.     

Interactions between endogenous and exogenous attention during vigilance

The ability to remain vigilant over long periods of time is critical for many everyday tasks, but controlled studies of visual sustained attention show that performance declines over time when observers are required to respond to rare stimulus events (targets) occurring in a sequence of standard stimulus events (nontargets). When target discrimination is perceptually difficult, this vigilance decrement manifests as a decline in perceptual sensitivity. We examined whether sudden-onset stimuli could act as exogenous attentional cues to improve sensitivity during a traditional sustained attention task. Sudden-onset cues presented immediately before each stimulus attenuated the sensitivity decrement, but only when stimulus timing (the interstimulus interval [ISI]) was constant. When stimulus timing was variable, exogenous cues increased overall sensitivity but did not prevent performance decline. Finally, independent of the effects of sudden onsets, a constant ISI improved vigilance performance. Our results demonstrate that exogenous attention enhances perceptual sensitivity during vigilance performance, but that this effect is dependent on observers’ being able to predict the timing of stimulus events. Such a result indicates a strong interaction between endogenous and exogenous attention during vigilance. We relate our findings to a resource model of vigilance, as well as to theories of endogenous and exogenous attention over short time periods.     

First impressions: gait cues drive reliable trait judgements

Personality trait attribution can underpin important social decisions and yet requires little effort; even a brief exposure to a photograph can generate lasting impressions. Body movement is a channel readily available to observers and allows judgements to be made when facial and body appearances are less visible; e.g., from great distances. Across three studies, we assessed the reliability of trait judgements of point-light walkers and identified motion-related visual cues driving observers' judgements. The findings confirm that observers make reliable, albeit inaccurate, trait judgements, and these were linked to a small number of motion components derived from a Principal Component Analysis of the motion data. Parametric manipulation of the motion components linearly affected trait ratings, providing strong evidence that the visual cues captured by these components drive observers' trait judgements. Subsequent analyses suggest that reliability of trait ratings was driven by impressions of emotion, attractiveness and masculinity.     

Effects of head orientation on gaze perception: How positive congruency effects can be reversed

Several past studies have considered how perceived head orientation may be combined with perceived gaze direction in judging where someone else is attending. In three experiments we tested the impact of different sources of information by examining the role of head orientation in gaze-direction judgements when presenting: (a) the whole face; (b) the face with the nose masked; (c) just the eye region, removing all other head-orientation cues apart from some visible part of the nose; or (d) just the eyes, with all parts of the nose masked and no head orientation cues present other than those within the eyes themselves. We also varied time pressure on gaze direction judgements. The results showed that gaze judgements were not solely driven by the eye region. Gaze perception can also be affected by parts of the head and face, but in a manner that depends on the time constraints for gaze direction judgements. While “positive” congruency effects were found with time pressure (i.e., faster left/right judgements of seen gaze when the seen head deviated towards the same side as that gaze), the opposite applied without time pressure.     

Effects of head orientation on gaze perception: how positive congruency effects can be reversed

Several past studies have considered how perceived head orientation may be combined with perceived gaze direction in judging where someone else is attending. In three experiments we tested the impact of different sources of information by examining the role of head orientation in gaze-direction judgements when presenting: (a) the whole face; (b) the face with the nose masked; (c) just the eye region, removing all other head-orientation cues apart from some visible part of the nose; or (d) just the eyes, with all parts of the nose masked and no head orientation cues present other than those within the eyes themselves. We also varied time pressure on gaze direction judgements. The results showed that gaze judgements were not solely driven by the eye region. Gaze perception can also be affected by parts of the head and face, but in a manner that depends on the time constraints for gaze direction judgements. While “positive” congruency effects were found with time pressure (i.e., faster left/right judgements of seen gaze when the seen head deviated towards the same side as that gaze), the opposite applied without time pressure.     

Within compound Associations Mediate the Retrospective Revaluation of Causality Judgements

The role of within-compound associations in the retrospective revaluation of causality judgements was investigated in a two-stage procedure in which the subjects were asked to learn whether or not different food stimuli caused an allergic reaction in hypothetical patients. In the compound-cue stage a number of compound cues, each consisting of a competing stimulus and a target stimulus, were associated with the reaction across a series of trials, whereas in the single-cue stage the subjects had the opportunity to learn which of the competing cues, when presented alone, caused the reaction. Each target stimulus was presented with the same competing cue across all compound trials in the consistent condition, but with a different competing cue on each trial in the varied condition. In a forward procedure, in which the single-cue stage preceded compound cue training, judgements of the causal effectiveness of the target stimuli were reduced or blocked by training them in compound with a competing cue that had been previously paired with the reaction. Moreover, the magnitude of this reduction was comparable in the consistent and varied conditions. This was not true, however, when the single- and compound-cue stages were reversed in the backward procedure. Judgements for target cues compounded with competing cues that were subsequently paired with the reaction were reduced only in the consistent condition. If it is assumed that stronger associations were formed between the competing and target stimuli during the compound-cue stage in the consistent condition than in the varied condition, this pattern suggests that the retrospective revaluation of causality judgements can be mediated by the formation of within-compound associations.     

Do isoluminant color changes capture attention?

Four experiments are reported in which the effects of peripheral cues on visual orienting were investigated. In the luminance condition, the cues consisted of a peripheral change in stimulus luminance. In the isoluminance condition, the cues consisted of an isoluminant color change, using the transient tritanopic technique. In Experiments 1 and 2, it was found that peripheral luminance cues captured attention, whereas peripheral isoluminance cues did not. In Experiments 3 and 4, the participants detected a peripheral target that was also isoluminant with the background. Under these conditions, it was found that both luminance and isoluminance cues captured attention. The results are discussed in terms of the roles of the dorsal and ventral streams in visual orienting, and it is concluded that our findings provide partial support for the contingent involuntary orienting hypothesis of C. Folk and colleagues.     

Fast and frugal versus regression models of human judgement

Following Brunswik (1952), social judgement theorists have long relied on regression models to describe both an individual's judgements and the environment about which such judgements are made. However, social judgement theory is not synonymous with these compensatory, static, structural models. We compared the characterisations of physicians' judgements using a regression model with that of a non-compensatory process model (called fast and frugal). We found that both models fit the data equally well. Both models suggest that physicians use few cues, that they disagree among themselves, and that their stated cue use is discrepant with the models' stated cue use. However, the fast and frugal model is easier to convey to physicians and is also more psychologically plausible. Implications for how social judgement theorists conceptualise the process of vicarious functioning are discussed.     

Generation difficulty and memory for source

The role of the word predictability from sentence context for reality monitoring and external source monitoring was examined in two experiments. In a reality-monitoring task, discrimination of an internal source was better in the hard than in the easy condition. It is probable that extra cognitive operations engaged during word generation in the hard condition were effective cues for reality-monitoring judgements. In contrast, in an external source-monitoring task (recognition memory of item's colour), the hard condition resulted in worse source memory for generated words than did the easy condition. This result is consistent both with an item-context trade-off hypothesis and a processing hypothesis. Greater effort involved at the time of generation might limit resources available for encoding of an external source. It is also possible that for generated words, the hard condition promoted conceptual processing instead of perceptual processing; therefore the item's colour was not effectively encoded.     

Does binocular disparity or familiar size information override effects of relative size on judgements of time to contact?

Previous studies indicate that non-tau sources of depth information, such as pictorial depth cues, can influence judgements of time to contact (TTC). The effect of relative size on such judgements, the size-arrival effect, is particularly robust. However, earlier studies of the size-arrival effect did not include binocular disparity or familiar size information. The effects of these cues on relative TTC judgements were measured. Results suggested that disparity can eliminate the size-arrival effect but that the amount of disparity needed to do so is greater than typical stereoacuity thresholds. In contrast, familiar size eliminated the size-arrival effect even when disparity information was not available. Furthermore, disparity contributed more to performance when familiar size was present than when it was absent. Consistent with previous studies, TTC judgements were influenced by multiple sources of information. The present results suggested further that familiar size is one such source of information and that familiar size moderates the influence of binocular disparity information.     

Pictorial encoding effects and memory confusions in the Deese-Roediger-McDermott paradigm: evidence for the activation of spontaneous imagery

The purpose of the experiments reported in this paper was to examine the possible role of spontaneous imagery and list-specific cues on pictorial encoding effects induced by the Deese-Roediger-McDermott (DRM) task. After viewing pictures and words referring to thematically related materials, by way of a picture/word source-judgement task, participants were asked to remember the way in which these materials were presented. Participants reported "seeing" pictures of items that were presented as words, an effect predicted by the imaginal activation hypothesis in its suggestion that incidental images experienced during encoding will later be mistaken as memories for pictures. Whether participants made the same picture misattributions on related lures (or non-presented related items) depended on the way in which the lures' respective thematic lists were experienced during encoding (Experiments 1 and 2), pointing to the effects of list-specific cues in picture/word judgements. These findings have intriguing implications for interpretations of picture-encoding effects induced by the DRM task. The findings also speak to the use of DRM false-memory rates when marshalling evidence against the use of imagery in applied settings.     

The role of inhibitory control and ADHD symptoms in the occurrence of involuntary thoughts about the past and future: An individual differences study

In everyday life, people often experience involuntary thoughts about their personal past and future events in response to incidental cues in the environment. Yet, despite the abundance of such cues, our consciousness is not constantly flooded by these involuntary autobiographical memories (IAMs) and involuntary future thoughts (IFTs). The main goal of the present study was to further investigate the possibility that cognitive inhibitory control keeps these involuntary cognitions at bay. To test this inhibition hypothesis, we conducted a large-scale study (n = 157) in which groups of participants with different levels of inhibitory control (low, medium, high) and individuals with ADHD spectrum symptoms were engaged in a laboratory vigilance task in which the frequency of IFTs and IAMs was assessed. Contrary to predictions, although participants across groups differed significantly in terms of their individual inhibitory control capacity, the number of IFTs and IAMs reported during the vigilance task was comparable. In addition, individuals with the ADHD spectrum symptoms did not report more spontaneous thoughts compared to other groups. Together, these findings lend little support for the idea that inhibition is a key mechanism that regulates the occurrence of IAMs and IFTs in everyday life. Other possible mechanisms and avenues for future research are discussed.     

Achromatic color matching as a function of apparent target orientation,target and background luminance,and lightness or brightness instructions

In two experiments, achromatic color matches for a fixed target, under constant illumination, were compared under conditions where the target appeared perpendicular to illumination direction and coplanar with the background (monocular viewing) and where the target appeared nonperpendicular to illumination direction and noncoplanar with the background (binocular viewing). Contrary to the coplanar ratio hypothesis, which predicts a “lightening” of the target seen coplanar with a darker background, a general “darkening” of the target occurred for both white (N9.5/) and black (N3/) backgrounds and for both dark (N5.5/) and light (N6.5/) targets. This darkening effect was greatest for the darker target and black background, and approximately equal for other combinations of target value and background. The direction of the darkening effect is consistent with the albedo hypothesis, which assumes an inferential correction for changes in conditions of illumination. However, variation in the magnitude of the darkening effect is problematical, and cannot be easily explained by any existing theory. In both experiments, instructions to judge “lightness” or “brightness” failed to produce any substantial differences in performance, although postexperimental questioning suggested that subjects had a verbal understanding of these concepts. Apparently, under reduction conditions, subjects lack cues to illumination and make only lightness matches, regardless of instructions.     

Judgements of relative direction: The effect of task instructions on spatial recall

One of the most widely used tasks in the spatial memory literature is the judgement of relative direction (JRD) test. The present investigation examined the hypothesis that standard JRD task demands bias spatial recall. In two experiments, participants' recall of small-scale layouts as measured by standard JRD tests (in which the relationship between objects was employed to establish imagined orientations within the learned scene) was compared with recall as measured by novel JRD tasks. The novel tasks emphasized either the internal front/back and left/right axes of individual objects (Experiment 1) or extrinsic spatial cues (Experiment 2). Spatial recall was found to reflect the reference cues emphasized by the JRD task in Experiment 1 and by the novel task in Experiment 2. The finding that directional judgements tended to reflect a frame of reference aligned with the set of cues emphasized by task demands suggests that the nature of the task employed to test knowledge can have an effect on spatial recall.     

Cross-modal effects of subliminal verbal stimuli

Abstract.— In a cross-modal version of an experiment by Smith et al. (1959), the effects of subliminal auditory cue words upon judgements of a supraliminal visual stimulus (a neutral face), were examined. Support was found for the hypothesis that material in an unattended channel is fully analysed for meaning, and may be integrated with material in an attended channel when it is relevant to the ongoing task. Contrary to expectations, the effects of the subliminal cues were found to carry over to trials on which the face was presented without concurrent auditory stimulation, thus providing support for the Poetzl phenomenon.     

Is subjective shortening in human memory unique to time representations?

Three experiments compared forgetting of the duration of a bar-like visual stimulus with forgetting of its length. The main aim of the experiments was to investigate whether subjective shortening (a decrease in the subjective magnitude of a stimulus as its retention interval increased) was observable in length judgements as well as in time judgements, where subjective shortening has been often observed previously. On all trials of the three experiments, humans received two briefly presented coloured bars, separated by adelay ranging from 1 to 10 s, and the bars could differ in length, duration of presentation, or both. In Experiment 1 two groups of subjects made either length or duration judgements, and subjective shortening-type forgetting functions were observed only for duration. Experiments 2 and 3 used the same general procedure, but the stimuli judged could differ both in length and duration within a trial, and different subject groups (Experiment 2) or the same subjects in two conditions (Experiment 3) made either length or duration judgements of stimuli, which were on average physically identical. Subjective shortening was only found with duration, and never with length, supporting the view that subjective shortening may be unique to time judgements.     

Memory retrieval and discrimination learning

A better reinforcement schedule may be associated with one exteroceptive stimulus (S+) than with another exteroceptive stimulus (S−). While all theories agree that performance in such discrimination tasks is affected by the reinforcement schedules associated with the exteroceptive S+ and S− cues, some theories suggest that performance is also affected by the reinforcement schedule associated with interoceptive reward produced cues. The two experiments reported here were concerned with identifying the conditions under which the interoceptive cues produced by nonreward come to affect performance. According to one hypothesis, such cues will acquire control over approach responding if animals make an approach response in their presence, but not otherwise. According to the memory hypothesis, the memory of nonreinforcement will become a signal for reinforcement, thus invigorating performance, if it is retrieved on a rewarded trial. In two experiments, two groups made strong approach responses to the nonreinforced cues on S− trials, but the memory of nonreward was better retrieved on a subsequent rewarded trial in one group than in the other. Subsequently, both groups were extinguished. The extinction findings support the memory view.