Serial expertise of rhesus macaques

Here we describe the development of serial expertise in 4 experimentally naive rhesus monkeys that learned, by trial and error, the correct order in which to respond to 3-, 4-, and 7-item lists of arbitrarily selected photographs. The probabilities of guessing the correct sequence on 3-, 4-, and 7-item lists were, respectively, 1/6, 1/24, and 1/5040. Each monkey became progressively more efficient at determining the correct order in which to respond on new lists. During subsequent testing, the subjects were presented with all possible pairs of the 28 items used to construct the four 7-item lists (excluding pairs of items that occupied the same ordinal position in different lists). Subjects responded to pairs from different lists in the correct order 91% of the time on the first trials on which these pairs were presented. These features of subjects' performance, which cannot be attributed to procedural memory, satisfy two criteria of declarative memory: rapid acquisition of new knowledge and flexible application of existing knowledge to a new problem.     

Online cognitive engagement of boys with ADHD

The present study was designed to examine the role that attentional problems may play in accounting for difficulties in story comprehension experienced by children with ADHD. A secondary task methodology was used to examine whether or not online variations in cognitive engagement with a televised story were related to the continuity of central or incidental information. Twenty-two 9- to 11 -year-old boys with ADHD and 36 of their nonreferred peers watched a television program and responded to auditory probes presented at preselected points during continuous sequences of central or incidental information. The reaction times to the probes for nonreferred boys showed the expected linear increase in cognitive engagement (i.e., the RTs increased) as central, plot-relevant sequences continued. In contrast, boys with ADHD showed the expected increase in RTs relatively late in the central sequences. The results were discussed in terms of how delays in engaging with central information may contribute to the academic difficulties experienced by boys with ADHD.     

Distorted retrospective eyewitness reports as functions of feedback and delay

Participant-witnesses viewed a crime video and attempted to identify the culprit from a culprit-absent lineup. The 253 mistaken-identification eyewitnesses were randomly given confirming, disconfirming, or no feedback regarding their identifications. Feedback was immediate or delayed 48 hr, and measures were immediate or delayed 48 hr. Confirming, but not disconfirming, feedback led to distortions of eyewitnesses' recalled confidence, amount of attention paid during witnessing, goodness of view, ability to make out facial details, length of time to identification, and other measures related to the witnessing experience. Unexpectedly, neither delaying the measures nor delaying feedback for 48 hr moderated these effects. The results underscore the need for double-blind lineups and neutral assessments of eyewitnesses' certainty and other judgments prior to feedback.     

Timed picture naming: Extended norms and validation against previous studies

Factors affecting word retrieval were compared in a timed picture-naming paradigm for 520 drawings of objects. In prior timed and untimed studies by Snodgrass and Vanderwart (1980) and Snodgrass and Yuditsky (1996), concerns were raised that participants could not reliably name large numbers of items in a single session. We show that reliable results are obtained in a single session for 520 items and validate our method against previous findings by Snodgrass and colleagues for overlapping items. For these items, comparable levels of name agreement and latency are obtained, and we replicate effects of length, frequency, both objective and subjective age of acquisition, and visual complexity on reaction time (RT) and name agreement measures. Name agreement is unaffected by order of presentation, although there is a gradual increase in RTs across the session, requiring use of multiple random orders. Current extensions of our method include cross-linguistic, bilingual, developmental, and neuropsychological studies and comparisons of action naming and object naming.     

Visual perspective taking for avatars in a Simon task

In modern digital applications, users often interact with virtual representations of themselves or others, called avatars. We examined how these avatars and their perspectives influence stimulus–response compatibility in a Simon task. Participants responded to light/dark blue stimuli with left/right key presses in the presence of a task-irrelevant avatar. Changes in stimulus–response compatibility were used to quantify changes in the mental representation of the task and perspective taking toward this avatar. Experiments 1 and 2 showed that perspective taking for an avatar occurred in orthogonal stimulus–response mappings, causing a compatibility effect from the avatar’s point of view. In the following two experiments we introduced a larger variety of angular disparities between the participant and avatar. In Experiment 3, the Simon effect with lateralized stimulus positions remained largely unaffected by the avatar, pointing toward an absence of perspective taking. In Experiment 4, after avatar hand movements were added in order to strengthen the participants’ sense of agency over the avatar, a spatial compatibility effect from the avatar’s perspective was observed again, and hints of the selective use of perspective taking on a trial-by-trial basis were found. Overall, the results indicate that users can incorporate the perspective of an avatar into their mental representation of a situation, even when this perspective is unnecessary to complete a task, but that certain contextual requirements have to be met.     

Social Dominance and Social Identity in the United States and Israel: Ingroup Favoritism or Outgroup Derogation?

American and Israeli university students completed questionnaires in their native languages assessing ingroup identification, social dominance orientation (SDO), and ingroup and outgroup affect. The interrelationships among the variables were examined for high- and low-status groups in three intergroup contexts: whites and Latinos in the United States, Ashkenazim and Mizrachim in Israel, and Jews and Arabs in Israel. Theoretical predictions of social identity theory and social dominance theory were tested. Results indicated that for all high- and low-status groups, stronger ingroup identification was associated with more positive ingroup affect, and for nearly all groups, higher SDO was associated with more negative affect toward the low-status group. In addition, SDO was positively associated with ingroup identification for all high-status groups, and negatively associated with ingroup identification for almost all low-status groups. Explanations for cross-cultural differences in the factors driving group affect are suggested, and theoretical refinements are proposed that accommodate them.     

Processing of Grammatical Gender in a Three-Gender System: Experimental Evidence from Russian

Four experiments investigated the effect of grammatical gender on lexical access in Russian. Adjective–noun pairs were presented auditorily, using a cued-shadowing technique in which subjects must repeat the second word (the target noun), following adjectives that are either concordant or discordant with the noun's gender. Experiment 1 demonstrates gender priming with unambiguous adjectives and phonologically transparent masculine or feminine nouns. Experiment 2 examines priming for transparent nouns against a neutral baseline (possible only for feminines and neuters), revealing that priming is due primarily to inhibition from discordant gender. Experiment 3 demonstrates gender priming with phonologically opaque masculine and feminine nouns. Experiment 4 returns to transparent masculine and feminine nouns with a different kind of baseline, using three versions of a single word root (prost—simple, in the feminine adjectival form prostaja, masculine adjectival form prostoj, and the adverbial form prosto ), and shows that gender can also facilitate lexical access, at least for feminine nouns. We conclude that Russian listeners can exploit gender agreement cues on-line, helping them to predict the identity of an upcoming word.     

Knowledge level learning and the power law: A soar model of skill acquisition in scheduling

Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning.