Friendship similarity during early adolescence: gender and racial patterns.

We studied the relationship of reciprocity, gender, and racial composition (Caucasian, African American, cross-race) of adolescent friendship dyads to similarity and proximity in 136 young adolescents. We found that adolescents selected friends who were of the same gender and race and that female dyads were more similar than male dyads on verbal achievement and several personality dimensions. Caucasian dyads were more similar than African American dyads on verbal achievement, mental alertness, and dominance. African American adolescents had more contact with their best friends outside school, whereas Caucasian adolescent friends had more in-school contact. African American students had fewer reciprocal relationships than the Caucasian students. Cross-race friendships were less reciprocal than same-race friendships. Race and gender were important in determining friendship patterns. Similarity and proximity were more important than reciprocity in understanding early adolescent friendships.     

Holding a mirror up to the self: egocentric similarity beliefs underlie social projection in cooperation

Similarity between partners entails positive consequences for cooperative interactions. But do people rely on this assumption to construe egocentric judgments about others? Five experiments examined the possibility that people project onto their partners because they believe that similarity to the self leads to success in cooperation. Studies 1a and 1b show that people hold an egocentric similarity belief in cooperation. Studies 2a and 2b test the existence of this belief in more indirect ways. The next three studies manipulate the applicability of the similarity belief and investigate its impact on projection. Study 3 finds that cooperation no longer leads to projection when participants expect a low probability of success. Study 4 replicates this effect in a real cooperative setting. Finally, Study 5 shows that projection occurs only when participants expect their characteristics to be responsible for the success of cooperation. The negative consequences of overestimating similarities in cooperation are discussed.     

Recognition of temporal patterns: from engineering to psychology and back again.

An overview is presented on research conducted in our lab to quantify the underlying principles behind the recognition of temporal patterns. We have been developing a theory based upon pattern matching and time-series analysis, which allows us to model and understand how humans recognize familiar patterns evolving over time and how performance degrades with noise. While our studies are primarily scientific in nature, the work has application beyond the elucidation of psychological and physiological mechanisms. We illustrate an application of these ideas to computer-based human identification through gait analysis. This study also illustrates a novel approach to interdisciplinary research by integrating experimental psychology with that of engineering design.     

Applying an exemplar model to the artificial-grammar task: Inferring grammaticality from similarity

We present three artificial-grammar experiments. The first used position constraints, and the second used sequential constraints. The third varied both the amount of training and the degree of sequential constraint. Increasing both the amount of training and the redundancy of the grammar benefited participants' ability to infer grammatical status; nevertheless, they were unable to describe the grammar. We applied a multitrace model of memory to the task. The model used a global measure of similarity to assess the grammatical status of the probe and captured performance both in our experiments and in three classic studies from the literature. The model shows that retrieval is sensitive to structure in memory, even when individual exemplars are encoded sparsely. The work ties an understanding of performance in the artificial-grammar task to the principles used to understand performance in episodic-memory tasks.     

Applying an exemplar model to the artificial-grammar task: inferring grammaticality from similarity

We present three artificial-grammar experiments. The first used position constraints, and the second used sequential constraints. The third varied both the amount of training and the degree of sequential constraint. Increasing both the amount of training and the redundancy of the grammar benefited participants' ability to infer grammatical status; nevertheless, they were unable to describe the grammar. We applied a multitrace model of memory to the task. The model used a global measure of similarity to assess the grammatical status of the probe and captured performance both in our experiments and in three classic studies from the literature. The model shows that retrieval is sensitive to structure in memory, even when individual exemplars are encoded sparsely. The work ties an understanding of performance in the artificial-grammar task to the principles used to understand performance in episodic-memory tasks.     

Grammaticality is inferred from global similarity: A reply to Kinder (2010)

Jamieson and Mewhort (2009b) proposed an account of performance in the artificial-grammar judgement-of-grammaticality task based on Hintzman's (1986) model of retrieval, Minerva 2. In the account, each letter is represented by a unique vector of random elements, and each exemplar is represented by concatenating its constituent letter vectors. Although successful in simulating several experiments, Kinder (2010) showed that the model fails for three selected experiments. We track the model's failure to a constraint introduced by concatenating letter vectors to construct the exemplar representation. To fix the problem, we use a holographic representation. Holographic representation not only provides the flexibility missing with the concatenation scheme but also acknowledges variability in what subjects notice when they inspect training exemplars. Armed with holographic representations, we show that the model successfully captures the three problematic data sets. We argue for retrospective accounts, like the present one, that acknowledge subjects' skill in drawing unexpected inferences based on memory of studied items against prospective accounts that require subjects to learn statistical regularities in the training set in anticipation of an undefined classification test.     

The effects of accountability on bias in physician decision making: Going from bad to worse

Members of the Iowa Academy of Family Physicians participated in a survey study in which they were asked to make hypothetical decisions in either high- or low-conflict treatment conditions. In the low-conflict treatment condition the options were a common medication with a referral or a referral only. In the high-conflict treatment condition the same two options were given plus another attractive medication. In addition, we manipulated accountability by asking half of the participants to provide a written defense of their treatment options, which they would then agree to discuss at a later time. The results showed that physicians in the high-conflict condition chose the referral-only option significantly more than the physicians in the low-conflict condition, thus violating the normative rule of regularity. Moreover, that pattern was significantly amplified for physicians who were held accountable for their treatment decisions. These findings replicate and extend previous research and are discussed within the framework of reason-based choice.     

Autonomy in Action: Linking the Act of Looking to Memory Formation in Infancy via Dynamic Neural Fields

Looking is a fundamental exploratory behavior by which infants acquire knowledge about the world. In theories of infant habituation, however, looking as an exploratory behavior has been deemphasized relative to the reliable nature with which looking indexes active cognitive processing. We present a new theory that connects looking to the dynamics of memory formation and formally implement this theory in a Dynamic Neural Field model that learns autonomously as it actively looks and looks away from a stimulus. We situate this model in a habituation task and illustrate the mechanisms by which looking, encoding, working memory formation, and long‐term memory formation give rise to habituation across multiple stimulus and task contexts. We also illustrate how the act of looking and the temporal dynamics of learning affect each other. Finally, we test a new hypothesis about the sources of developmental differences in looking.     

Disentangling similarity judgments from pragmatic judgments: Response to Sloutsky and Fisher (2012)

Sloutsky and Fisher (2012) attempt to reframe the results presented in Noles and Gelman (2012) as a pure replication of their original work validating the similarity, induction, naming, and categorization (SINC) model. However, their critique fails to engage with the central findings reported in Noles and Gelman, and their reanalysis fails to examine the key comparison of theoretical interest. In addition to responding to the points raised in Sloutsky and Fisher's (2012) critique, we elaborate on the pragmatic factors and methodological flaws present in Sloutsky and Fisher (2004) that biased children's similarity judgments. Our careful replication of that study suggests that, rather than measuring the influence of labels on judgments of perceptual similarity, the original design measured sensitivity to the pragmatics of task demands. Together, the results reported in Noles and Gelman and the methodological problems highlighted here represent a serious challenge to the validity of the SINC model specifically and the words-as-features view more generally. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Sensorimotor synchronization: motor responses to regular auditory patterns.

Subjects (N = 32) were asked to synchronize a motor response with tones in auditory patterns. These patterns were created from six tones and six intertone intervals of equal duration. The pitch of the first tone differed from the others. It was found that subjects used three types of timing in their motor response: (1) the first intertone interval was prolonged and the second interval was shortened, (2) the second intertone interval was prolonged and the first interval was shortened, and/or (3) the first interval and the second interval were of approximately the same length. The prolongation of the fifth interval was observed during all three types of timing. The results are explained using the concept of suprasegmental control of timing, which explains a prolongation of intervals at critical control point of the patterns. The occurrence of three different strategies of timing is discussed in connection with similar principles in musical performance.     

The whole is equal to the sum of its parts: a probabilistic model of grouping by proximity and similarity in regular patterns

The authors investigated whether the gestalt grouping principles can be quantified and whether the conjoint effects of two grouping principles operating at the same time on the same stimuli differ from the sum of their individual effects. After reviewing earlier attempts to discover how grouping principles interact, they developed a probabilistic model of grouping by proximity, which allows measurement of strength on a ratio scale. Then, in 3 experiments using dot lattices, they showed that the strength of the conjoint effect of 2 grouping principles--grouping by proximity and grouping by similarity--is equal to the sum of their separate effects. They propose a physiologically plausible model of this law.     

Memory deficits in early infantile autism: some similarities to the amnesic syndrome.

Autistic children were compared with control children on tasks in which retention was tested by different methods. In three tests of recall, using named pictures, written words and spoken words as test stimuli, autistic children were impaired in comparison with age-matched normal children and with controls matched for verbal ability. In one test of forced-choice recognition of pictures, autistic children were impaired in comparison with ability-matched controls. In three tests of cued recall, using named pictures, written words and spoken words as test stimuli, and acoustic, graphemic and semantic cues, autistic children were not impaired in comparison with normal age-matched controls. In one test of paired-associate learning using non-related word pairs as test stimuli autistic children were not impaired in comparison with normal age-matched controls. These experimental paradigms were similar to some that have been used to investigate the amnesic syndrome in man. Thus findings on paired-associate learning differ in autistic and amnesic subjects, but findings on recall, recognition and cued recall are comparable. A possible parallel between autism and amnesia is discussed.     

Social responding to mirrors in rhesus monkeys (Macaca mulatta): effects of temporary mirror removal.

As a result of a long-term, longitudinal project initiated in 1978, a pair of rhesus macaques (Macaca mulatta) housed together in front of a mirror all their lives now exhibit relatively little interest in their reflection. Previous work has shown, however, that simply moving the mirror to a new location produces a short-term reinstatement of social responding to their images. As an extension of these findings, in this study the mirror was left in the same position but turned away from the cage. On turning the mirror back to face the cage 5 days later, both animals reacted as if confronted with another pair of monkeys and directed a burst of social responses at the mirror.     

When theory and practice diverge: gender-related patterns of referral to psychoanalysts.

This study tests the hypothesis that female analysts, relative to male analysts, receive a disproportionately small percentage of male referrals. Referral patterns for 170 analysts from four institutes accredited by the American Psychoanalytic Association were examined. One thousand, five hundred and ten patients referrals were studied. The findings were extremely robust and offered dramatic confirmation of our hypothesis. The major implications of the study are as follows: (1) Women analysts receive relatively few adult male referrals, making it difficult for them to gain requisite clinical experience with men. (2) Analysts and nonanalysts alike demonstrate a reluctance to refer male patients to female analysts. (3) Adult referrals, including those made by analysts, are significantly influenced by the issue of gender match between patient and analyst. (4) Analysts' behavior with regard to making referrals does not correspond to explicit clinical theory regarding how analysts make referrals--specifically, the extent to which gender influences the referral process is not adequately described by theory. We believe that these findings are of some concern from the standpoint of analytic education and that they also raise questions regarding unacknowledged aspects of how gender match between patient and analyst enters into clinical decision making.(ABSTRACT TRUNCATED AT 250 WORDS)     

Memory and the hippocampus: a synthesis from findings with rats, monkeys, and humans.

This article considers the role of the hippocampus in memory function. A central thesis is that work with rats, monkeys, and humans--which has sometimes seemed to proceed independently in 3 separate literatures--is now largely in agreement about the function of the hippocampus and related structures. A biological perspective is presented, which proposes multiple memory systems with different functions and distinct anatomical organizations. The hippocampus (together with anatomically related structures) is essential for a specific kind of memory, here termed declarative memory (similar terms include explicit and relational). Declarative memory is contrasted with a heterogeneous collection of nondeclarative (implicit) memory abilities that do not require the hippocampus (skills and habits, simple conditioning, and the phenomenon of priming). The hippocampus is needed temporarily to bind together distributed sites in neocortex that together represent a whole memory.     

Going for distance and going for speed: Effort and optical variables shape information for distance perception from observation to response

Visually guided distance perception reflects a relationship of geometrical optical variables with the effort required when traversing the distance. We probed how the representations encoding optical variables might define this relationship. Participants visually judged distances on sloped surfaces and reproduced these distances over flat terrain by walking while blindfolded. We examined the responses for the effects of optical variables (i.e., angular declinations from eye height) and tested whether four measures of trial-by-trial effort moderated the use of the represented optical variables. We predicted that observation time and response speed relative to the observed distance would accentuate the effects of encoded optical variables, and that response time and response speed relative to the traversed distance would reduce the effects of those variables. The results confirmed all of the effects except those of observation time. Given the benefits of longer study for strengthening a memory trace, the failure of observation time to predict the use of optical variables raises questions about the representational encoding of visual traces for distance perception. Relationships among optical variables and other effort measures implicate the interaction of processes across multiple time scales, as in cascade dynamics. Cascade dynamics may provide new directions for accounts of visually guided distance perception.