The role of stimulus type in list length effects in recognition memory

While many studies have investigated the list length effect in recognition memory, few have done so with stimuli other than words. This article presents the results of four list length experiments that involved word pairs, faces, fractals, and photographs of scenes as the stimuli. A significant list length effect was identified when faces and fractals were the stimuli, but the effect was nonsignificant when the stimuli were word pairs or photographs of scenes. These findings suggest that the intrastimulus similarity is what dictates whether list length has a significant effect on recognition performance. As is the case with words, word pairs and photographs of scenes are not sufficiently similar to generate detectable item interference.     

Metamemory for faces, names, and common nouns

This study examined the metacognitive aspects of face–name learning with the goal of providing a comprehensive profile of monitoring performance during this task. Four types of monitoring judgments were solicited during encoding and retrieval of novel face–name associations. Across all of the monitoring judgments, relative accuracy was significantly above chance for face and name targets. Furthermore, metamemory performance was similar between both target conditions, even though names were more difficult to recognize than faces. As a preliminary test of the stability of monitoring accuracy across different categories of stimuli, we also compared metamemory performance between face–name pairs and noun–noun pairs. Prospective monitoring accuracy was similar across the categories of stimuli, but retrospective monitoring accuracy was superior for noun targets compared with face or name targets. Altogether, our results indicate that participants can monitor their memory for face–name associations at a level above chance, and retrospective monitoring is more accurate with nouns compared with faces and names.     

Matching familiar and unfamiliar faces on internal and external features

Two experiments are reported in which subjects were asked to match a photograph of a complete face and a simultaneously presented photograph of internal or external features of a face, deciding whether or not the two photographs were pictures of the same person. In experiment 1 'same' pairs were derived from different pictures of the same face, so that subjects had to match the faces and not the particular photographs used. Matches based on internal features were found to be faster for familiar than for unfamiliar faces, whereas there was no difference in reaction time between matches based on the external features of familiar and unfamiliar faces. Faster matching of internal features of familiar faces was found to hold equally for pairs of photographs that differed in orientation of the face or in facial expression. In experiment 2 'same' pairs were derived from the same photographs, which gave subjects the choice of matching on the basis of the features of the depicted faces or matching the photographs. Reaction times were faster than in experiment 1, and there were no differences between familiar and unfamiliar faces. The study confirms reports of differential saliency of the internal features of familiar faces, and shows that this only holds when stimuli are treated as faces. The finding thus reflects properties of structural rather than pictorial codes.     

Pythagorean distance and the judged similarity of schematic stimuli

Independent groups of Ss rated the similarity of pairs of patterns belonging to the same class, either bef ore or af ter a discrimination task of schematic concept formation (SCF). Mean similarity increased as a function of SCF pretraining. A linear relationship was found between a Pythagorean distance measure on the patterns and subjective similarity of pairs of stimuli (r=.88). No such relationship was obtained from an analysis of judgments from a group that viewed random, nonschematic stimuli. A secondary analysis of the discrimination judgments in the SCF task showed that the Pythagorean distance measure was predictive of judgments on pairs of stimuli from the same schema family, but the relationship did not hold for pairs representing two different schemata. Multidimensional scaling analyses indicated that mildly deviant schematic stimuli were perceived to be instances of a single family. The dimensions describing a schema cluster appeared to be specific to the sample of stimuli. A tendency for the Kruskal procedures to collapse certain types of stimulus clusters was observed and discussed.     

Relative attention in judgments of heterogeneous similarity

Shepard’s (1964) study on similarity of stimuli with clearly discernible dimensions was repeated with some modifications, the most important being that the Os had to make numerical similarity estimates of the stimulus pairs. The overall outcome did not deviate much from Shepard’s findings. By using quantitative estimates and choosing stimulus series so that the two dimensions were negatively correlated, data for each 0 could be analyzed separately with a partial correlation technique. It was found that the more an 0 attended to one dimension the less he attended to the other. The shifts in attention seemed to be random rather than regular. Consequently, the meaningfulness of a contention like Shepard’s as to the nonexistence of a metric is questioned.     

Similar as well as dissimilar contextual stimuli increase rated similarity

Contextual stimuli from one category increase the rated similarity of stimuli from a second category. In Experiment 1, associates of one of the members of pairs of target words increased the rated similarity of the members slightly more than did much less similar contextual stimuli. In Experiment 2, contextual category names and good exemplars increased the rated similarity of pairs of poor to medium target exemplars and were also rated as more similar to these targets than the targets were to each other. In both cases, the category names resulted in the stronger effect. This ability of contextually similar stimuli to increase rated similarity opposes the distance-density and averaging-judgmental theories of the effect of context on similarity. However, the theory that a positive association exists between the perceived similarity of stimuli and the strength of the category to which they belong explains how both contextually dissimilar and contextually similar stimuli can increase rated similarity.     

On facial expertise: processing strategies of twins' parents

Parents of monozygotic twins typically learn to recognise their own children and also to tell them apart on photographs. However, it is unknown whether such exemplar expertise can be generalised to unfamiliar faces of equal similarity (ie other twins). In the present study, parents of monozygotic twins were compared to 'control' parents whose children were non-twin siblings. In a same/different task with familiar and unfamiliar twin faces as stimuli, twins' parents were faster than control parents in distinguishing their own children, but slower when distinguishing unfamiliar twin faces. These unexpected findings can be interpreted as a generalisation of a habitual perceptual strategy that is efficient only with familiar face exemplars. When pictures of the twins' faces were inverted by 180degrees, the typical inversion costs for familiar faces were observed, but the twins' parents recognised unfamiliar twins' faces better when these were inverted than when upright. This inverted inversion effect could be caused by the high similarity of the face pairs as well as by experience with familiar faces of equally high similarity. We conclude that the facial expertise of twins' parents is idiosyncratic to their own children and not based on an enhanced general facial expertise.     

Multidimensional similarity: an experimental and theoretical comparison of vector,distance, and set theoretical models : I. Models and internal consistency of data

In an experiment (conducted by the senior author) subjects were instructed to give three kinds of quantitative judgment on pairs of simple geometrical stimuli: similarity, commonality ratio and magnitude ratio. It was assumed that the different kinds of judgments could be interpreted in terms of one cognitive structure, and that formal models for each of these judgments should be validated by predicting one kind of judgment from knowledge of another kind of judgment. The present report proposes two different, though related, systems of formal models for similarity, commonality and magnitude ratio judgments. One, called E-model, interprets the judgments in terms of set- and vector-representations, and connections between them; the other, called R-model, interprets the judgments in terms of set- and distance-representations and their connections. The results are slightly in favor of the E-model. In a subsequent paper, the authors will report the results of multidimensional analyses for the same data, which slightly favor the R-model.     

The Role of Face Familiarity in Judgments of Personality and Intelligence

Personality judgments based on facial features are a common occurrence. The face familiarity overgeneralization hypothesis states that people make judgments of unknown faces based on their similarity to known faces. However, there is a dearth of research regarding how face familiarity relates to perceptions of personality and intelligence in strangers. The current article used two studies to provide evidence for the relationship between face familiarity and judgments of personality and intelligence. Study 1 showed that photographs perceived as familiar by one set of participants were rated more positively regarding personality and intelligence by a second group of participants. Study 2 found that high perceived familiarity resulted in positive judgments of personality and intelligence, whereas familiarity based on exposure did not. These findings indicate both that perceived familiarity significantly impacts positive judgments of personality and intelligence and that the face familiarity overgeneralization hypothesis is a useful framework for this area of research.     

Levels of coding in picture-picture comparison tasks

Two experiments are reported in which subjects had to match pairs of pictures of objects. "Same" pairs could be either identical (Ps), pictures of different views of the same object (Pv), or pictures of different objects having the same name (Pd). With line drawings as stimuli, RTs for Condition Ps were shorter than for Condition Pv, which in turn were shorter than for Condition Pd. Visual similarity had no effect on Pd RTs. However, in Experiment II, where photographs of objects with high-frequency (HF) and low-frequency (LF) names were used, no difference was found between Conditions Ps(HF), Ps(LF) and Condition Pv(HF); and no difference occurred between Conditions Pd(HF), Pd(LF) and Condition Pv(LF), the latter set of conditions being associated with longer RTs than the former. This pattern of results was found with both a .25-sec and a 2-sec ISI. The results are discussed in terms of the levels of coding involved in processing information from picture stimuli. It is concluded that at least two levels are involved in matching photographs of real objects (an object-code level and a nonvisual semantic code level), while a third level may be used in matching tasks involving stylized line drawings (a picture-code level).     

Variables influencing memory over long periods of time for recently learned face-name pairs

The ability to match faces with corresponding names was studied under various conditions involving encoding and retrieval. Twenty photographs of undergraduates were randomly paired with 20 common names. Experiment 1 presented the photographs for 10 s each, followed by either presentation of the names alone with the instruction to write face characteristics from memory or presentation of the photographs again with instructions to write from memory the names and anything unusual about the names themselves. Later retrieval was best for the former condition and was interpreted as showing that names could prime image representations of faces. Experiment 2 was a partial replication of Experiment 1 with retrieval measured over 7 weeks. These results showed that memories for face-name matches lasted several weeks. Also, consistent with Experiment 1, the number of reported initial face characteristics was highly predictive of matches between faces and names. These studies show the importance for later retrieval of forming and maintaining vivid images of faces even when the faces have no outstanding characteristics.     

Perception of relative and absolute age in facial photographs

Longitudinal series of photographs of faces of secondary school students were used to evaluate observers’ ability to perceive age. Information in individual stimuli was manipulated by masking out parts of the photographs, while information provided by the relations among stimuli was manipulated by task conditions. The ability to perceive relative age was assessed in two tasks requiring subjects to order photographs by age. Absolute age perception was studied in a third task requiring age estimates in years to photographs presented one at a time. While judgments were beyond chance accuracy in all combinations of masking and task conditions, a decrease in either type of information generally produced a decrease in accuracy.

     

Perceptual separability and spatial models

Highly analyzable two-dimensional color stimuli were generated using stimulus cards such that one part of each card varied only on the first dimension and the other part varied only on the second. Subjects were required to make judgments of similarity between pairs of these analyzable stimuli, between pairs of relatively unanalyzable color stimuli, and between pairs of geometric stimuli. The results support previous findings that the Euclidean combining rule is appropriate for judgments of single color patches but indicate that the city block combining rule may be appropriate for simple stimuli that vary on perceptually distinct dimensions.     

Recognition memory for faces: When familiarity supports associative recognition judgments

Recognition memory for single items can be dissociated from recognition memory for the associations between items. For example, recognition tests for single words produce curvilinear receiver operating characteristics (ROCs), but associative recognition tests for word pairs produce linear ROCs. These dissociations are consistent with dual-process theories of recognition and suggest that associative recognition relies on recollection but that item recognition relies on a combination of recollection and assessments of familiarity. In the present study, we examined associative recognition ROCs for facial stimuli by manipulating the central and external features, in order to determine whether linear ROCs would be observed for stimuli other than arbitrary word pairs. When the faces were presented upright, familiarity estimates were significantly above zero, and the associative ROCs were curvilinear, suggesting that familiarity contributed to associative judgments. However, presenting the faces upside down effectively eliminated the contribution of familiarity to associative recognition, and the ROCs were linear. The results suggest that familiarity can support associative recognition judgments, if the associated components are encoded as a coherent gestalt, as in upright faces.     

Computer graphic studies of the role of facial similarity in judgements of attractiveness

Anecdotally, spouses are often said to resemble one another. This study investigates the effects of similarity between participants and stimuli on judgements of facial attractiveness: does “like prefer like”? Using computer graphic techniques, opposite sex facial stimuli were generated from subjects' photographs. Experiment 1 showed a correlation between attractiveness and similarity but the effect can be explained by the attractiveness of average faces. Beyond this, there was a trend for individual subjects to rate opposite sex images with a similar face shape to their own face as more attractive than other subjects. Experiment 2 allowed subjects to interactively manipulate an opposite sex facial image along a continuum from a self-similar shape, through an average face shape, to a face with opposite characteristics. No significant preferences for self-similar or opposite characteristics were found. Preferences for average faces are stronger than preferences for self-similar faces.     

Computer graphic studies of the role of facial similarity in judgements of attractiveness

Anecdotally, spouses are often said to resemble one another. This study investigates the effects of similarity between participants and stimuli on judgements of facial attractiveness: does “like prefer like”? Using computer graphic techniques, opposite sex facial stimuli were generated from subjects' photographs. Experiment 1 showed a correlation between attractiveness and similarity but the effect can be explained by the attractiveness of average faces. Beyond this, there was a trend for individual subjects to rate opposite sex images with a similar face shape to their own face as more attractive than other subjects. Experiment 2 allowed subjects to interactively manipulate an opposite sex facial image along a continuum from a self-similar shape, through an average face shape, to a face with opposite characteristics. No significant preferences for self-similar or opposite characteristics were found. Preferences for average faces are stronger than preferences for self-similar faces.     

The Role of the Face and Body in Unfamiliar Person Identification

Information useful for identifying a person can be found both in the face and body. Previous studies indicate that when an entire person is visible, we rely strongly on the face for identification, even if the body can be useful. We measured the utility of the face versus body for identification, by using images of unfamiliar people that varied in the quality of identity information in the face. Face quality was varied using similarity scores generated by state‐of‐the‐art face recognition algorithms from an international competition. These algorithms estimated the similarity of faces in a large set (>1 000 000) of image pairs that showed ‘people’, including the face and the top half of the body. By using these similarity scores, image pairs were stratified into three groups representing good, moderate, and poor performance for the face recognition algorithm. Participants matched identity in image pairs sampled from the three groups, by using versions of the stimuli edited digitally to show only the face or body. Consistent with the algorithm stratifications, performance with the face declined across the three conditions. The face supported more accurate identification than the body in the good and moderate conditions. In the poor condition, performance from the face and body was comparable. Using data from a previous study, we compared the face‐only and body‐only identity judgments with judgments based on the original image. The original unedited image supported the best overall performance in the good and moderate conditions. Notably, performance in the poor condition was equivalent for the face, body, and original images. The results indicate that in poor viewing conditions, identification decisions from the body may be as accurate as those made from the face or the entire person. Copyright © 2013 John Wiley & Sons, Ltd.     

Integration of faces and voices, but not faces and names, in person recognition

Recent studies on cross-modal recognition suggest that face and voice information are linked for the purpose of person identification. We tested whether congruent associations between familiarized faces and voices facilitated subsequent person recognition relative to incongruent associations. Furthermore, we investigated whether congruent face and name associations would similarly benefit person identification relative to incongruent face and name associations. Participants were familiarized with a set of talking video-images of actors, their names, and their voices. They were then tested on their recognition of either the face, voice, or name of each actor from bimodal stimuli which were either congruent or novel (incongruent) associations between the familiarized face and voice or face and name. We found that response times to familiarity decisions based on congruent face and voice stimuli were facilitated relative to incongruent associations. In contrast, we failed to find a benefit for congruent face and name pairs. Our findings suggest that faces and voices, but not faces and names, are integrated in memory for the purpose of person recognition. These findings have important implications for current models of face perception and support growing evidence for multisensory effects in face perception areas of the brain for the purpose of person recognition.     

Subjective ratios and differences in perceived heaviness

In previous studies, judgments of ratios and differences in subjective magnitude have yielded similar orders, consistent with a hypothesis that a single perceived relation underlies both judgment tasks. In the present research, 15 subjects estimated heaviness differences between 28 pairs of eight weights and each of 8 groups of 10 subjects evaluated heaviness ratios of eight variable stimuli with respect to a different standard stimulus. Presenting stimuli that were equally spaced on a cube-root scale of weight enhanced expected ordinal discrepancies between ratio and difference estimates, and employing independent groups for each standard stimulus in ratio estimation eliminated a possible bias due to varying standards within the presentation sequence. Differences in orders of ratio and difference estimates together with differences in scales obtained from non-metric analyses in terms of a difference model indicated that the judgments were based on two perceived relations that are ordinally consistent with arithmetic operations of ratios and differences. A ratio scale of heaviness was derived from the combined orders of subjective ratios and differences.     

Very short term recognition memory for odors

An investigation of very short term olfactory recognition memory was made with odors of low familiarity to subjects. The experimental procedure was that currently used to make qualitative similarity judgments on odors delivered in paired succession. Subjects made similarity judgments in a yes/no recognition paradigm on odors that were either identical or different. The dependence of recognition performance upon the degree of qualitative similarity was assessed by using two sets of dissimilar odor pairs: slightly dissimilar pairs (S1) and very dissimilar pairs (S2). Performance in terms of correct judgments (hits, correct rejections) was rather good for identical pairs in both sets and was nearly perfect for very dissimilar pairs with a delay of 2–300 sec, suggesting no effect of time or similarity on performance. However, for slightly dissimilar pairs, false alarms increased in number, thereby indicating a dependence of the recognition score on the qualitative distance between odors. In addition, false alarms tended to increase with the lengthening of the retention interval. It was suggested that the subjects based their responses on their capability to detect differences between odors rather than recognizing their similarities. Correct identifications were thus preserved at the cost of increasing false alarms when the discrimination task was made more difficult by closer similarity between odors (S1) or by the fading of memory traces with time. Studying the congruence between the similarity judgments and the kind of evocations associated with paired odors gives some support to the view that recognition performances had some cognitive/semantic basis.