Effect of typicality on online category verification of animate category exemplars in aphasia

Normal young, elderly, Broca's aphasic, and Wernicke's aphasic individuals participated in an online category verification task where primes were superordinate category labels while targets were either typical or atypical examples of animate categories or nonmembers belonging to inanimate categories. The reaction time to judge whether the target belonged to the preceding category label was measured. Results indicated that all four groups made significantly greater errors on atypical examples compared to typical examples. Young and elderly individuals, and Broca's aphasic patients performed similarly on the verification task; these groups demonstrated faster reaction times on typical examples than atypical examples. Wernicke's aphasic patients made the most errors on the task and were slowest to respond than any other participant group. Also, these participants were not significantly faster at accepting correct typical examples compared to correct atypical examples. The results from the four groups are discussed with relevance to prototype/family resemblance models of typicality.     

What is typical about the typicality effect in category-based induction?

Research on category-based induction has documented a consistent typicality effect: Typical exemplars promote stronger inferences about their broader category than atypical exemplars. This work has been largely confined to categories whose central tendencies are also the most typical members of the category. Does the typicality effect apply to the broad set of categories for which the ideal category member is considered most typical? In experiments with natural and artificial categories, typicality and induction-strength ratings were obtained for ideal and central-tendency exemplars. Induction strength was greatest for the central-tendency exemplars, regardless of whether the central tendency or the ideal was rated more typical. These results suggest that the so-called “typicality” effect is a special case of a more universal central-tendency effect in category-based induction.     

The prediction of group motor performance from individual member abilities

Two experiments were conducted to investigate the prediction of group performance on the motor-maze task from individual member abilities. In both experiments subjects performed 20 individual trials on the maze task in an initial session prior to the actual experiment. On the basis of these individual performance scores, two-person groups were formed so that the groups represented a range of average ability levels and a range of discrepancies in abilities between partners. In Experiment 1, all groups performed a cooperative and a noncooperative group task in separate sessions both involving competition with another group. Only the cooperative group task was used in Experiment 2, but all groups performed under both competitive and noncompetitive conditions. Multiple regression analyses yielded a moderate, positive relationship between member abilities and group performance in both experiments; group performance on the highly cooperative task was dominated by the lower-ability partner.     

You detect while I search: examining visual search efficiency in a joint search task

Numerous factors impact attentional allocation, with behaviour being strongly influenced by the interaction between individual intent and our visual environment. Traditionally, visual search efficiency has been studied under solo search conditions. Here, we propose a novel joint search paradigm where one individual controls the visual input available to another individual via a gaze contingent window (e.g., Participant 1 controls the window with their eye movements and Participant 2 – in an adjoining room – sees only stimuli that Participant 1 is fixating and responds to the target accordingly). Pairs of participants completed three blocks of a detection task that required them to: (1) search and detect the target individually, (2) search the display while their partner performed the detection task, or (3) detect while their partner searched. Search was most accurate when the person detecting was doing so for the second time while the person controlling the visual input was doing so for the first time, even when compared to participants with advanced solo or joint task experience (Experiments 2 and 3). Through surrendering control of one’s search strategy, we posit that there is a benefit of a reduced working memory load for the detector resulting in more accurate search. This paradigm creates a counterintuitive speed/accuracy trade-off which combines the heightened ability that comes from task experience (discrimination task) with the slower performance times associated with a novel task (the initial search) to create a potentially more efficient method of visual search.     

Category typicality effects in children's memory performance: Qualitative and quantitative differences in the processing of category information

Kindergarten, third, and sixth graders (6, 9, and 12 years of age, respectively) received a cue-at-input/cue-at-output recall task, using category typical and atypical items that were based on either (1) children's conceptions of item typicality, or (2) adults' conceptions of item typicality. At each grade level, recall was greater with the child-defined lists than with the adult-defined lists, and typical items were recalled to a greater extent than atypical items. Further analyses items were recalled to a greater extent than atypical items. Further analyses revealed that the recall of typical items varied as a function of children's typicality ratings of items, and that the “typicality effect” in the adult-norm condition was due primarily to the childrennot realizing that many of the atypical items were appropriate category exemplars. In contrast, typicality effects in the child-norm condition were attributed to qualitative differences in the judged “goodness of example” of the typical and atypical items. The results were discussed in terms of the appropriateness of typicality as a dimension of children's natural language concepts, the role of age differences in knowledge base in affecting performance on a cognitive task, and of the importance of using child-generated norms in studies of children's processing of category information.     

A particular resiliency to threatening environments

Being in the numerical minority can impair intellectual performance. We suggest, however, that these negative effects need not extend to everyone because some people—specifically high self-monitors—can overcome the effects of situationally activated stereotypes. In two studies, we manipulated the race/sex composition of small groups and assessed intellectual performance. Results revealed that: (a) self-monitoring moderated the effects of group-composition on performance, such that it was positively related to performance in stressful minority settings, (b) the number of out-group members in a group caused a linear effect on performance that differed for high and low self-monitors, and (c) stereotype activation mediated self-monitoring’s moderating effect on performance. Thus, high self-monitors may be resilient to threatening environments because they react to negative stereotypes with increased (and not decreased) performance. We discuss these results in relation to theories of inter-group contact, stereotype threat, and stress and coping.     

Sex Composition of Groups and Member Motivation II: Effects of Relative Task Ability

This study examined the effects of group members' relative task ability on the relationship between group sex composition and member task motivation. Male and female subjects performed a simple motor task with an opposite-sex partner, a same-sex partner, or no partner. Partners had higher, equal, or lower task ability than subjects. When the partner was more able than the subject, both sexes did more work with an opposite-sex partner than when working individually, whereas subjects with a same-sex partner did no more work than individual controls. Group sex composition did not affect member motivation when the partner was equally or less able. These findings disconfirmed several models of the sex composition-motivation relationship. They supported an esteem maintenance model which holds that both sexes place greater value on demonstrating competence to opposite-sex partners than to same-sex partners.     

Effects of attentional demand,cue typicality,and priming on an event‐based prospective memory task

The main purpose of this experiment was to examine the independent and interactive effects of three variables—attentional demand, cue typicality, and priming—on an event‐based prospective memory task. High attentional demand was expected to lower performance, but cue typicality and priming were expected to improve performance. The prospective memory task entailed writing an ‘X’ after hearing items from four semantic categories (e.g. birds), while performing a free‐association task. Results showed the predicted effects of attentional demand and typicality. Priming did not affect overall prospective memory performance but, as predicted, improved performance under conditions of high attentional demand with a typical cue. Overall, these results show the importance of cue and capacity variables, but they also support the value of examining how different variables in the prospective memory task can interact in affecting performance. Copyright © 2005 John Wiley & Sons, Ltd.     

Emergent Power Hierarchies and Group Performance

In newly formed groups, informal hierarchies emerge automatically and readily. In this study, we argue that emergent group hierarchies enhance group performance (Hypothesis 1) and we assume that the more the power hierarchy within a group corresponds to the task‐competence differences of the individual group members, the better the group performs (Hypothesis 2). Twelve three‐person groups and 28 four‐person groups were investigated while solving the Winter Survival Task. Results show that emerging power hierarchies positively impact group performance but the alignment between task‐competence and power hierarchy did not affect group performance. Thus, emergent power hierarchies are beneficial for group performance and although they were on average created around individual group members' competence, this correspondence was not a prerequisite for better group performance.     

Demonstrator skill modulates observational aversive learning

Learning to avoid danger by observing others can be relatively safe, because it does not incur the potential costs of individual trial and error. However, information gained through social observation might be less reliable than information gained through individual experiences, underscoring the need to apply observational learning critically. In order for observational learning to be adaptive it should be modulated by the skill of the observed person, the demonstrator. To address this issue, we used a probabilistic two-choice task where participants learned to minimize the number of electric shocks through individual learning and by observing a demonstrator performing the same task. By manipulating the demonstrator’s skill we varied how useful the observable information was; the demonstrator either learned the task quickly or did not learn it at all (random choices). To investigate the modulatory effect in detail, the task was performed under three conditions of available observable information; no observable information, observation of choices only, and observation of both the choices and their consequences. As predicted, our results showed that observable information can improve performance compared to individual learning, both when the demonstrator is skilled and unskilled; observation of consequences improved performance for both groups while observation of choices only improved performance for the group observing the skilled demonstrator. Reinforcement learning modeling showed that demonstrator skill modulated observational learning from the demonstrator’s choices, but not their consequences, by increasing the degree of imitation over time for the group that observed a fast learner. Our results show that humans can adaptively modulate observational learning in response to the usefulness of observable information.     

The role of cognitive abilities in children's inferences about social atypicality and peer exclusion and inclusion in intergroup contexts

Children aged 6–7 years judged a loyal and a partially disloyal member of a school in terms of how typical they are within the school group and their likely acceptance by peers from the same school and a different school. Second‐order mental‐state understanding (SOMSU) predicted whether children thought atypical members would be included differently in the two groups. Counterfactual reasoning ability, multiple classification ability, and working memory ability did not predict children's judgements of group members. Moreover, as predicted by the developmental subjective group dynamics model, only children with higher levels of SOMSU and who discerned differences in the typicality of normative and deviant ingroup members inferred that peers would differently include atypical individuals from the same and different groups.     

The dissemination of critical,unshared information in decision‐making groups: the effects of pre‐discussion dissent

Previous research in group decision making has found that in situations of a hidden profile (i.e. the best choice alternative is hidden from individual members as they consider their pre‐discussion information), unshared information is disproportionately neglected and sub‐optimal group choices are highly likely. In an experimental study, three‐person groups decided which of three candidates to select for a professorial appointment. We hypothesised that minority dissent in pre‐discussion preferences improves the consideration of unshared information in groups and increases the discovery rate of hidden profiles. As predicted, consideration of unshared information increased with minority dissent. The expectation of an improvement of group decision quality was partially supported. In diversity groups (i.e. each member prefers a different alternative) consideration of unshared information and group decision quality was significantly higher than in simple minority groups. Results are discussed in the light of theories of minority influence. The benefits of using the hidden profile paradigm with minority and diversity groups for theory development in the area of group decision making are highlighted. Copyright © 2002 John Wiley & Sons, Ltd.     

Modeling collective choice: decision‐making on complex intellective tasks

Three studies examined group problem‐solving on complex intellective tasks. In Study 1, a decision model proposed by Laughlin and Hollingshead ( 1995 ) provided the best fit to actual group choices. This study also compared three‐person group versus individual performance with time constrained and number of problems unconstrained, with individuals solving non‐significantly more problems and groups obtaining significantly superior trials‐to‐solution scores. In Study 2, one member of each group was given additional information on how to perform the task and member extroversion was measured. Neither factor significantly impacted the decision‐making process. In Study 3, task expertise was assessed prior to the group interaction. Results indicate that group members were twice as likely to adopt an option proposed by an expert compared to other group members. Together these studies demonstrate that group problem solving is governed jointly by qualities of the task and qualities of the group members. Copyright © 2006 John Wiley & Sons, Ltd.     

Solo status revisited: Examining racial group differences in the self-regulatory consequences of self-presenting as a racial solo

The present study examined the impact of racial group membership on the self-regulatory consequences of self-presenting with racial solo status. Based on the strength model of self-regulation, we proposed that individuals who acquire more practice with solo status by virtue of their racial group membership, may find it less depleting relative to individuals with less practice. To examine this, White and racial minority (Black, Hispanic) students at a predominantly White university were asked to engage in a self-presentation task in which they were assigned either racial solo or nonsolo status. Persistence on a subsequent hidden objects task served as the measure of depletion. Results revealed an interaction between racial group membership and solo status. In particular, consistent with previous research, White participants were more depleted (i.e., persisted less) after self-presenting with solo (vs. nonsolo) status. Racial minority participants, however, were not similarly impaired by solo status. These results suggest that our social group memberships, by virtue of the experiences they typically confer, may play an important role in determining which social demands will be depleting for whom.     

Categorical target templates: Typical category members are found and identified quickly during word-cued search

What information do people use to guide search when they lack precise details about the appearance of their target? In this study, we employed categorical (word-cued) search and eye tracking, to examine how category typicality influences search performance. We found that typical category members were fixated and identified more quickly than atypical categories. This finding held when the participant was cued at the superordinate level (finding “clothing” among non-clothing items) or the basic level (finding a “shirt” among other clothing items). This suggests that categorical target templates may be constructed by piecing together features from the most typical category member(s).     

"Princess Alice is watching you": children's belief in an invisible person inhibits cheating

Two child groups (5-6 and 8-9 years of age) participated in a challenging rule-following task while they were (a) told that they were in the presence of a watchful invisible person (“Princess Alice”), (b) observed by a real adult, or (c) unsupervised. Children were covertly videotaped performing the task in the experimenter’s absence. Older children had an easier time at following the rules but engaged in equal levels of purposeful cheating as the younger children. Importantly, children’s expressed belief in the invisible person significantly determined their cheating latency, and this was true even after controlling for individual differences in temperament. When “skeptical” children were omitted from the analysis, the inhibitory effects of being told about Princess Alice were equivalent to having a real adult present. Furthermore, skeptical children cheated only after having first behaviorally disconfirmed the “presence” of Princess Alice. The findings suggest that children’s belief in a watchful invisible person tends to deter cheating.     

Categorization by groups and individuals

Categorization is a core psychological process that is central to decision making. While a substantial amount of research has been conducted to examine individual categorization behavior, little is known about how the outputs of individual and group categorization may differ. Four experiments demonstrate that group categorization differs systematically from individual categorization in the structural dimension of category breadth: categorizing the same set of items, groups tend to create a larger number of smaller categories than individuals. This effect of social context is a function of both taskwork and teamwork. In terms of taskwork, groups’ greater available knowledge mediates differences in category breadth between individuals and groups by increasing utilized knowledge (study 2). In terms of teamwork, task conflict moderates the effect of social context on category breadth (study 3). Moreover, the experience of categorizing individually or in a group influences individuals’ subsequent judgments (study 4).     

Category knowledge in Alzheimer's disease: normal organization and a general retrieval deficit.

Three hypotheses that could account for deficits in the retrieval of category information in Alzheimer's disease (AD) were evaluated: abnormal organization, class- or category-specific vulnerability, and limitation by general factors, such as decreased processing speed. Relative to 18 elderly control subjects, 18 patients with AD produced fewer items in a category fluency task and had longer reaction times in a category decision task. The pattern of performance across categories on both tasks was normal in the AD group: The same categories elicited the most (or fastest) responses in both the control group and the AD group. AD patients showed normal performance in ranking of category exemplars by typicality. There was no evidence for differential accessibility by category or by class of information (animate vs. inanimate). The authors conclude that a general factor or factors limit(s) retrievability equally across all categories.     

The effects of member expertise on group decision-making and performance

This study assesses the effects of member expertise on group decision-making and group performance. Three-person cooperative groups and three independent individuals solved either an easy or moderately difficult version of the deductive logic game Mastermind. Experimental groups were given veridical performance information, i.e., the members' rankings on prior individual administrations of the task. Control groups were not provided with this information. Results supported the predictions of this study: (1) groups gave more weight to the input of their highest performing members with the group decision-making process being best approximated by post hoc “expert weighted” social decision schemes and (2) groups performed at the level of the best of an equivalent number of individuals.