VISTO: An open-source device to measure exposure time in psychological experiments.

The study of higher cognitive processes often relies on the manipulation of bottom-up stimulus characteristics such as exposure time. While several software exist that can schedule the onset and offset time of a visual stimulus, the actual exposure time depends on several factors that are not easy to control, resulting in undesired variability within and across studies. Here we present VISTO, a simple device built on the Arduino platform that allows one to measure the exact onset and offset of a visual stimulus, and to test its synchronization with a trigger signal. The device is used to measure the profile of luminance waveforms in arbitrary analog/digital (AD) units, and the implications of these luminance profiles are discussed based on a model of information accumulation from visual exposure. Moreover, VISTO can be calibrated to match the brightness of each experimental monitor. VISTO allows for control of stimulus timing presentation, both in classical laboratory settings and in more complex settings as technology allows to use new display devices or acquisition equipment. In sum, VISTO allows one to:•measure the profile of luminance curves.•determine the exposure time of a visual stimulus.•measure the synchronization between a trigger signal and a visual stimulus.

Corrigendum to "VISTO: An open-source device to measure exposure time in psychological experiments".

[This corrects the article DOI: 10.1016/j.mex.2021.101427.].

Understanding natural scenes: Contributions of image statistics.

Visual processing of natural scenes is carried out in a hierarchical sequence of stages that involve the analysis of progressively more complex features of the visual input. Recent studies have suggested that the semantic content of natural stimuli (e.g., real world photos) can be categorized based on statistical regularities in their appearance, which can be detected early in the visual processing stream. Here we review the studies which have investigated the role of scene statistics in the perception of natural scenes, focusing on both basic visual processing and specific tasks (visual search, expert categorization, emotional picture viewing). Visual processing seems to be adapted to visual regularities in the visual input, such as the amplitude-frequency relationship. Moreover, scene statistics can aid performance in specific tasks such as distinguishing animals from artifactual scenes, possibly by modulating early visual processing stages.

Conjunction faces alter confidence-accuracy relations for old faces.

The authors used a state-trace methodology to investigate the informational dimensions used to recognize old and conjunction faces (made by combining parts of separately studied faces). Participants in 3 experiments saw faces presented for 1 s each. They then received a recognition test; faces were presented for varying brief durations and participants made 3 responses: old/new judgments, confidence judgments, and an indication of whether each response was based on memory for a feature or in general familiarity. Experiments 1 and 3 showed that, given equal confidence, familiarity-based responses were more accurate than feature-based responses; these results provide strong support for a multidimensional model in which 2 separate types of information contribute to confidence and accuracy responses. Experiment 2 showed that this feature/familiarity difference disappeared when conjunction faces were included in the test, supporting a unidimensional model in which confidence and accuracy are based on a single type of information. Inclusion of conjunction faces fundamentally alters the way that previously encountered faces are processed; participants apparently rely entirely on feature-based information to recognize them. (PsycINFO Database Record

Confidence-accuracy relations for faces and scenes: roles of features and familiarity.

Using naturalistic scenes, we recently demonstrated that confidence-accuracy relations differ depending on whether recognition responses are based on memory for a specific feature or instead on general familiarity: When confidence is controlled for, accuracy is higher for familiarity-based than for feature-based responses. In the present experiment, we show that these results generalize to face recognition. Subjects studied photographs of scenes and faces presented for varying brief durations and received a recognition test on which they (1) indicated whether each picture was old or new, (2) rated their confidence in their response, and (3) indicated whether their response was based on memory for a feature or on general familiarity. For both stimulus types, subjects were more accurate and more confident for their feature-based than for their familiarity-based responses. However, when confidence was held constant, accuracy was higher for familiarity-based than for feature-based responses. These results demonstrate an important similarity between face and scene recognition and show that for both types of stimuli, confidence and accuracy are based on different information.

Standard errors and confidence intervals in within-subjects designs: generalizing Loftus and Masson (1994) and avoiding the biases of alternative accounts.

Repeated measures designs are common in experimental psychology. Because of the correlational structure in these designs, the calculation and interpretation of confidence intervals is nontrivial. One solution was provided by Loftus and Masson (Psychonomic Bulletin & Review 1:476-490, 1994). This solution, although widely adopted, has the limitation of implying same-size confidence intervals for all factor levels, and therefore does not allow for the assessment of variance homogeneity assumptions (i.e., the circularity assumption, which is crucial for the repeated measures ANOVA). This limitation and the method's perceived complexity have sometimes led scientists to use a simplified variant, based on a per-subject normalization of the data (Bakeman & McArthur, Behavior Research Methods, Instruments, & Computers 28:584-589, 1996; Cousineau, Tutorials in Quantitative Methods for Psychology 1:42-45, 2005; Morey, Tutorials in Quantitative Methods for Psychology 4:61-64, 2008; Morrison & Weaver, Behavior Research Methods, Instruments, & Computers 27:52-56, 1995). We show that this normalization method leads to biased results and is uninformative with regard to circularity. Instead, we provide a simple, intuitive generalization of the Loftus and Masson method that allows for assessment of the circularity assumption.

Global and local vision in natural scene identification.

The results of previous studies have suggested that to optimize the decoding of visual information, global contents of a scene are analyzed before local features (global precedence hypothesis). Evidence supporting this hypothesis has been provided for identification of characters, faces, hybrid stimuli, and simple objects. In the present study, we examined identification of high- and low-pass filtered natural pictures. Despite the radical differences in the type of information conveyed by global and local features, confident and accurate identification was achieved on the basis of either kind of information when an intermediate range of spatial frequencies was preserved. The present data are consistent with the notion of global precedence in scene identification.

Hindsight bias from 3 to 95 years of age.

Upon learning the outcome to a problem, people tend to believe that they knew it all along (hindsight bias). Here, we report the first study to trace the development of hindsight bias across the life span. One hundred ninety-four participants aged 3 to 95 years completed 3 tasks designed to measure visual and verbal hindsight bias. All age groups demonstrated hindsight bias on all 3 tasks; however, preschoolers and older adults exhibited more bias than older children and younger adults. Multinomial processing tree analyses of these data revealed that preschoolers' enhanced hindsight bias resulted from them substituting the correct answer for their original answer in their recall (a qualitative error). Conversely, older adults' enhanced hindsight bias resulted from them forgetting their original answer and recalling an answer closer to, but not equal to, the correct answer (a quantitative error). We discuss these findings in relation to mechanisms of memory, perspective taking, theory of mind, and executive function.

Different confidence-accuracy relationships for feature-based and familiarity-based memories.

Participants studied naturalistic pictures presented for varying brief durations and then received a recognition test on which they indicated whether each picture was old or new and rated their confidence. In 1 experiment they indicated whether each "old"/"new" response was based on memory for a specific feature in the picture or instead on the picture's general familiarity; in another experiment, we defined pictures that tended to elicit feature versus familiarity responses. Thus, feature/familiarity was a dependent variable in 1 experiment and an independent variable in the other. In both experiments feature-based responses were more accurate than those that were familiarity based, and confidence and accuracy increased with duration for both response types. However, when confidence was controlled for, mean accuracy was higher for familiarity-based than for feature-based responses. The theoretical implication is that confidence and accuracy arise from different underlying information. The applied implication is that confidence differences should not be taken as implying accuracy differences when the phenomenal basis of the memory reports differ.

What can a perception-memory expert tell a jury?

Witnesses to crimes and other forensically relevant events sometimes describe memories in which they express confidence that, on the basis of research in perception and memory, may be inappropriately high, given the circumstances of the case. The most effective way of conveying this observation and the reasons for it to a jury is via an expert in perception and memory. In any given case, a mosaic of factors having to do with perception and memory are relevant. I briefly sketch the most common of these factors and categorize them as to the degree to which they may be unambiguously and/or quantitatively applied to a specific case. I discuss one such factor, witness-object distance, in some detail, showing how an expert might describe distance effects on perception and providing examples from actual cases.

Hindsight bias and developing theories of mind.

Although hindsight bias (the "I knew it all along" phenomenon) has been documented in adults, its development has not been investigated. This is despite the fact that hindsight bias errors closely resemble the errors children make on theory of mind (ToM) tasks. Two main goals of the present work were to (a) create a battery of hindsight tasks for preschoolers, and (b) assess the relation between children's performance on these and ToM tasks. In two experiments involving 144 preschoolers, 3-, 4-, and 5-year olds exhibited strong hindsight bias. Performance on hindsight and ToM tasks was significantly correlated independent of age, language ability, and inhibitory control. These findings contribute to a more comprehensive account of perspective taking across the lifespan.

Cognitive science and the law.

Numerous innocent people have been sent to jail based directly or indirectly on normal, but flawed, human perception, memory and decision making. Current cognitive-science research addresses the issues that are directly relevant to the connection between normal cognitive functioning and such judicial errors, and suggests means by which the false-conviction rate could be reduced. Here, we illustrate how this can be achieved by reviewing recent work in two related areas: eyewitness testimony and fingerprint analysis. We articulate problems in these areas with reference to specific legal cases and demonstrate how recent findings can be used to address them. We also discuss how researchers can translate their conclusions into language and ideas that can influence and improve the legal system.

Why is it easier to identify someone close than far away?

It is a matter of common sense that a person is easier to recognize when close than when far away. A possible explanation for why this happens begins with two observations. First, the human visual system, like many image-processing devices, can be viewed as a spatial filter that passes higher spatial frequencies, expressed in terms of cycles/degree, progressively more poorly. Second, as a face is moved farther from the observer, the face's image spatial frequency spectrum, expressed in terms of cycles/face, scales downward in a manner inversely proportional to distance. An implication of these two observations is that as a face moves away, progressively lower spatial frequencies, expressed in cycles/face--and therefore, progressively coarser facial details--are lost to the observer at a rate that is likewise inversely proportional to distance. We propose what we call the distance-as-filtering hypothesis, which is that these two observations are sufficient to explain the effect of distance on face processing. If the distance-as-filtering hypothesis is correct, one should be able to simulate the effect of seeing a face at some distance, D, by filtering the face so as to mimic its spatial frequency composition, expressed in terms of cycles/face, at that distance. In four experiments, we measured face perception at varying distances that were simulated either by filtering the face as just described or by shrinking the face so that it subtended the visual angle corresponding to the desired distance. The distance-as-filtering hypothesis was confirmed perfectly in two face perception tasks: assessing the informational content of the face and identifying celebrities. Data from the two tasks could be accounted for by assuming that they were mediated by different low-pass spatial filters within the human visual system that have the same general mathematical description but that differ in scale by a factor of approximately 0.75. We discuss our results in terms of (1) how they can be used to explain the effect of distance on visual processing, (2) what they tell us about face processing, (3) how they are related to "flexible spatial scale usage," as discussed by Schyns and colleagues, and (4) how they may be used in practical (e.g., legal) settings to demonstrate the loss of face information that occurs when a person is seen at a particular distance.

Object identification in preschool children and adults.

We introduce computer-based methodologies for investigating object identification in 3- to 5-year-old children. In two experiments, preschool children and adults indicated when they could identify degraded pictures of common objects as those pictures either gradually improved or degraded in clarity. Clarity transformations were implemented in four ways: blurring, decreasing the picture's physical size, decreasing the pixel signal-to-noise ratio, and cropping. In Experiment 1, all age groups correctly identified objects at a more degraded state when those objects began moderately, as opposed to very, degraded and then clarified. This finding supports the notion that previous perceptual hypotheses interfere with object identification (i.e. the perceptual interference effect). In Experiment 2, children, but not adults, overestimated their ability to recognize objects in a degraded state when the object's identity was given to them beforehand. This suggests that for young children knowledge of the object's true identity cannot be ignored when evaluating their current perceptions. This is the first demonstration of the perceptual interference effect in children. We discuss both methodological and theoretical implications of the findings for research on object perception and theory of mind.

Linear theory, dimensional theory, and the face-inversion effect.

We contrast 2 theories within whose context problems are conceptualized and data interpreted. By traditional linear theory, a dependent variable is the sum of main-effect and interaction terms. By dimensional theory, independent variables yield values on internal dimensions that in turn determine performance. We frame our arguments within an investigation of the face-inversion effect--the greater processing disadvantage of inverting faces compared with non-faces. We report data from 3 simulations and 3 experiments wherein faces or non-faces are studied upright or inverted in a recognition procedure. The simulations demonstrate that (a) critical conclusions depend on which theory is used to interpret data and (b) dimensional theory is the more flexible and consistent in identifying underlying psychological structures, because dimensional theory subsumes linear theory as a special case. The experiments demonstrate that by dimensional theory, there is no face-inversion effect for unfamiliar faces but a clear face-inversion effect for celebrity faces.

The "saw-it-all-along" effect: demonstrations of visual hindsight bias.

The authors address whether a hindsight bias exists for visual perception tasks. In 3 experiments, participants identified degraded celebrity faces as they resolved to full clarity (Phase 1). Following Phase 1, participants either recalled the level of blur present at the time of Phase 1 identification or predicted the level of blur at which a peer would make an accurate identification. In all experiments, participants overestimated identification performance of naive observers. Visual hindsight bias was greater for more familiar faces--those shown in both phases of the experiment--and was not reduced following instructions to participants to avoid the bias. The authors propose a fluency-misattribution theory to account for the bias and discuss implications for medical malpractice litigation and eyewitness testimony.

Why is it difficult to see in the fog? How stimulus contrast affects visual perception and visual memory.

Processing visually degraded stimuli is a common experience. We struggle to find house keys on dim front porches, to decipher slides projected in overly bright seminar rooms, and to read 10th-generation photocopies. In this research, we focus specifically on stimuli that are degraded via reduction of stimulus contrast and address two questions. First, why is it difficult to process low-contrast, as compared with high-contrast, stimuli? Second, is the effect of contrast fundamental in that its effect is independent of the stimulus being processed and the reason for processing the stimulus? We formally address and answer these questions within the context of a series of nested theories, each providing a successively stronger definition of what it means for contrast to affect perception and memory. To evaluate the theories, we carried out six experiments. Experiments 1 and 2 involved simple stimuli (randomly generated forms and digit strings), whereas Experiments 3-6 involved naturalistic pictures (faces, houses, and cityscapes). The stimuli were presented at two contrast levels and at varying exposure durations. The data from all the experiments allow the conclusion that some function of stimulus contrast combines multiplicatively with stimulus duration at a stage prior to that at which the nature of the stimulus and the reason for processing it are determined, and it is the result of this multiplicative combination that determines eventual memory performance. We describe a stronger version of this theory--the sensory response, information acquisition theory--which has at its core, the strong Bloch's-law-like assumption of a fundamental visual system response that is proportional to the product of stimulus contrast and stimulus duration. This theory was, as it has been in the past, highly successful in accounting for memory for simple stimuli shown at short (i.e., shorter than an eye fixation) durations. However, it was less successful in accounting for data from short-duration naturalistic pictures and was entirely unsuccessful in accounting for data from naturalistic pictures shown at longer durations. We discuss (1) processing differences between short- and long-duration stimuli, (2) processing differences between simple stimuli, such as digits, and complex stimuli, such as pictures, (3) processing differences between biluminant stimuli (such as line drawings with only two luminance levels) and multiluminant stimuli (such as grayscale pictures with multiple luminance levels), and (4) Bloch's law and a proposed generalization of the concept of metamers.

We saw it all along: visual hindsight bias in children and adults.

We traced the developmental origins and trajectory of the hindsight bias. Three-, 4-, and 5-year-old children and adults identified gradually clarifying images of degraded common objects on a computer. Half the time, observers did not know in advance what the object would become. The rest of the time, observers knew the object's identity in advance and estimated when a naive same-age peer would identify the clarifying object. In two experiments, children and adults demonstrated hindsight bias by using advance knowledge to overestimate their same-age peers' ability to identify the objects. The magnitude of this bias declined across age in one experiment, but remained relatively stable over age in the other experiment. These findings link developmental psychology and adult cognitive science.

How different spatial-frequency components contribute to visual information acquisition.

We test 3 theories of global and local scene information acquisition, defining global and local in terms of spatial frequencies. By independence theories, high- and low-spatial-frequency information are acquired over the same time course and combine additively. By global-precedence theories, global information acquisition precedes local information acquisition, but they combine additively. By interactive theories, global information also affects local-information acquisition rate. We report 2 digit-recall experiments. In the 1st, we confirmed independence theories. In the 2nd, we disconfirmed both independence theories and interactive theories, leaving global-precedence theories as the remaining alternative. We show that a specific global-precedence theory quantitatively accounted for Experiments 1-2 data as well as for past data. We discuss how their spatial-frequency definition of spatial scale comports with definitions used by others, and we consider the suggestion by P. G. Schyns and colleagues (e.g., D. J. Morrison & Schyns, 2001) that the visual system may act flexibly rather than rigidly in its use of spatial scales.