Majority influence,minority influence and conversion behavior: A replication

A recent experiment by Moscovici and Personnaz (Journal of Experimental Social Psychology 1980, 16, 270–282) showed that whereas a majority produces merely compliance, or a change in the individual's verbal responses, a minority induces conversion, or a true change in one's subjective judgments. Because of the theoretical significance of these findings and because of their inconsistency with data from other experiments, an exact replication and extension of this experiment was performed. There was no evidence of compliance in any social influence condition. Instead, and in contrast to Moscovici and Personnaz, both a majority and a minority produced “conversion” behavior. Subjects' behavior is interpreted as the expression of an improved perception, resulting from a heightened level of attention to the object of judgment under social influence conditions.     

Studies in social influence III: Majority versus minority influence in a group

This experimental study was aimed at investigating the mechanisms of influence involved in the two functionally opposed phenomena of innovation and conformity. We have been concerned for several years with the former of these two phenomena because of its intrinsic importance and the limited amount of research devoted to it. In the present article we have attempted not only to analyse the position more thoroughly, but also to compare the effects of innovation with those of conformity. In particular, we have endeavoured to show that behavioural style acts as a general source of influence in the two phenomena under consideration, where manifest judgments are concerned. On the other hand, the latent effects of influence may be different in the two cases of innovation and conformity. To investigate these questions, we developed an experimental design consisting of three parts. The first part was intended to study manifest influence on a quasi-physical judgment based on a cultural truism. The second part was aimed at the study of latent modifications in the perceptual-cognitive code as a result of influence. The third, in the form of a postexperimental questionnaire, was intended to provide information about various aspects, including the perception of the agent of influence by subjects. The main function of the experimental manipulations was to vary the minority or majority relationship of the agent of influence within a group, and its behavioural style, consistent or inconsistent. Our main findings indicate that behavioural consistency is the main factor behind the influence exerted by both majority and minority. But whereas, in conformity, influence is limited to modifying manifest judgments, in innovation, it changes the perceptual-cognitive code underlying such judgments.     

Majority versus minority influence and prediction of behavioral intentions and behavior

Two experiments examined the effects of majority and minority influence on attitude-consistent behavioral intentions. In the first experiment, when attitudes were changed via minority influence there was a greater likelihood to engage in an attitude-consistent behavioral intention than when attitudes were changed via majority influence. This suggests that minority influence leads to stronger attitudes (based on systematic processing) that are more predictive of behavioral intentions, while attitude change via majority influence is due to compliance through non-systematic processing. Further support for this interpretation comes from the finding that the amount of message-congruent elaboration mediated behavioral intention. When there was no attitude change, there was no impact on behavioral intention to engage in an attitude-consistent behavior. Experiment 2 explored the role of personal relevance of the topic and also included a real behavioral measure. When the topic was of low personal relevance, the same pattern was found as Experiment 1. When the topic was of high personal relevance, thus increasing the motivation to engage in systematic processing, attitudes changed by both a majority and minority source increased behavioral intention and actual behavior. The results are consistent with the view that both majorities and minorities can lead to different processes and consequences under different situations.     

Majority and minority influence using the afterimage paradigm: A replication with an unambiguous blue slide

This study re-examines the afterimage paradigm which claims to show that a minority produces a conversion in a task involving afterimage judgements (more private influence than public influence) as opposed to mere compliance produced by a majority. Subsequent failures to replicate this finding have suggested that the changes in the afterimages could be attributed to increased attention due to an ambiguous stimulus coupled with subject suspiciousness. This study attempted to replicate the original experiment but with an unambiguous stimulus in order to remove potential biases. The results showed shifts in afterimages consistent with the increased attention hypothesis for a minority and majority and these were unaffected by the level of suspiciousness reported by the subjects. Additional data shows that no shifts were found in a no-influence control condition showing that shifts were related to exposure to a deviant source and not to response repetition.     

Interaction with a high-versus low-competence influence source in inductive reasoning

Literature on inductive reasoning shows that when testing hypotheses, people are biased toward the use of confirmatory strategies (P. C. Wason, 1960). In the present article, the authors presented 2 studies showing how people use confirmation and disconfirmation strategies during actual interaction in problem solving. Study 1 showed that participants were able to learn to use disconfirmation when confronted with a low-competence, nonthreatening partner. When the partner was high in competence (thereby threatening the participant's competence), participants used confirmation, even when the partner used disconfirmation. In Study 2, the authors aimed at generalizing the aforementioned results by exploring the hypothesis that disconfirmation stems from the possibility of diverging from norms. Participants who were confronted with the violation of a conversational norm used a high proportion of disconfirmation, whatever the source of influence. When there was no violation but there was a low-competence partner, the proportion of disconfirmation was high; when there was no violation but there was a high-competence partner, the proportion of disconfirmation was low. The authors discussed the interpersonal functions of confirmation and disconfirmation.     

Majority and minority influence in group negotiation: the moderating effects of social motivation and decision rules

In organizational groups, often a majority has aligned preferences that oppose those of a minority. Although such situations may give rise to majority coalitions that exclude the minority or to minorities blocking unfavorable agreements, structural and motivational factors may stimulate groups to engage in integrative negotiation, leading to collectively beneficial agreements. An experiment with 97 3-person groups was designed to test hypotheses about the interactions among decision rule, the majority's social motivation, and the minority's social motivation. Results showed that under unanimity rule, minority members block decisions, thus harming the group, but only when the minority has proself motivation. Under majority rule, majority members coalesce at the minority's expense, but only when the majority has a proself motivation. Implications for negotiation research and group decision making are discussed.     

Recruitment of the pre-motor area in human inductive reasoning: An fMRI study

Recent studies indicated that the pre-motor area may be recruited in human higher level cognitive functions, including inductive reasoning. In the present study, a typical task of inductive reasoning, function-finding, was explored using functional MRI. fMRI results showed the significant activation of bilateral pre-motor cortex (BA 6), and its left lateralization. Taking together the previous studies and the present experimental design, we concluded that the left pre-motor cortex in the present study may associate with implicit relation synthesis, while the right pre-motor cortex may reflect spatial information processing involved in arithmetic rules.     

Broadening the study of inductive reasoning: Confirmation judgments with uncertain evidence

Although evidence in real life is often uncertain, the psychology of inductive reasoning has, so far, been confined to certain evidence. The present study extends previous research by investigating whether people properly estimate the impact of uncertain evidence on a given hypothesis. Two experiments are reported, in which the uncertainty of evidence is explicitly (by means of numerical values) versus implicitly (by means of ambiguous pictures) manipulated. The results show that people’s judgments are highly correlated with those predicted by normatively sound Bayesian measures of impact. This sensitivity to the degree of evidential uncertainty supports the centrality of inductive reasoning in cognition and opens the path to the study of this issue in more naturalistic settings.     

Indirect majority and minority influence: An exploratory study

In a 2 × 2 design, 85 subjects were asked to estimate the size of angles (direct influence) that were either 90 or 85°, after being confronted with incorrect judgements of a majority (88 per cent) or a minority (12 per cent) of people estimating the angles at 50°. Additionally, pre- and post-test measures were used to establish indirect influence on subjects' judgements pertaining to acute angles (i.e. on the estimation of the length of lines constituting the angles, and on the imaginary weight of figures represented by these angles). Overall, little direct influence is observed. This may partly be due to the introduction of a denial of the credibility of the source in all conditions. In fact, some evidence of direct influence is only found in the majority–85° angles condition. An instance of indirect influence (on the estimation of length of lines) appeared as the result of a majority stance when the angles in the experimental phase were 90°. When these angles were 85°, indirect minority influence (on the estimation of weight of figures) was observed. These effects had been predicted on the basis of the hypothesis stating that indirect majority influence would be possible when subjects expected consensus on the correct response (in the 90° angles condition), without being able to reach consensus at the manifest level (because of the denial and the restriction imposed by the clear shape of 90° angles). Indirect minority influence was hypothesized to be stronger in a situation that allows for diverse responses (i.e. for 85° angles).     

Causal relations and feature similarity in children's inductive reasoning

Four experiments examined the development of property induction on the basis of causal relations. In the first 2 studies, 5-year-olds, 8-year-olds, and adults were presented with triads in which a target instance was equally similar to 2 inductive bases but shared a causal antecedent feature with 1 of them. All 3 age groups used causal relations as a basis for property induction, although the proportion of causal inferences increased with age. Subsequent experiments pitted causal relations against featural similarity in induction. It was found that adults and 8-year-olds, but not 5-year-olds, preferred shared causal relations over strong featural similarity as a basis for induction. The implications for models of inductive reasoning and development are discussed.     

Theory-based Bayesian models of inductive learning and reasoning

Inductive inference allows humans to make powerful generalizations from sparse data when learning about word meanings, unobserved properties, causal relationships, and many other aspects of the world. Traditional accounts of induction emphasize either the power of statistical learning, or the importance of strong constraints from structured domain knowledge, intuitive theories or schemas. We argue that both components are necessary to explain the nature, use and acquisition of human knowledge, and we introduce a theory-based Bayesian framework for modeling inductive learning and reasoning as statistical inferences over structured knowledge representations.     

Sample diversity and premise typicality in inductive reasoning: evidence for developmental change

Evaluating whether a limited sample of evidence provides a good basis for induction is a critical cognitive task. We hypothesized that whereas adults evaluate the inductive strength of samples containing multiple pieces of evidence by attending to the relations among the exemplars (e.g., sample diversity), six-year-olds would attend to the degree to which each individual exemplar in a sample independently appears informative (e.g., premise typicality). To test these hypotheses, participants were asked to select between diverse and non-diverse samples to help them learn about basic-level animal categories. Across various between-subject conditions (N=133), we varied the typicality present in the diverse and non-diverse samples. We found that adults reliably selected to examine diverse over non-diverse samples, regardless of exemplar typicality, six-year-olds preferred to examine samples containing typical exemplars, regardless of sample diversity, and nine-year-olds were somewhat in the midst of this developmental transition.     

Differential involvement of left prefrontal cortex in inductive and deductive reasoning

While inductive and deductive reasoning are considered distinct logical and psychological processes, little is known about their respective neural basis. To address this issue we scanned 16 subjects with fMRI, using an event-related design, while they engaged in inductive and deductive reasoning tasks. Both types of reasoning were characterized by activation of left lateral prefrontal and bilateral dorsal frontal, parietal, and occipital cortices. Neural responses unique to each type of reasoning determined from the Reasoning Type (deduction and induction) by Task (reasoning and baseline) interaction indicated greater involvement of left inferior frontal gyrus (BA 44) in deduction than induction, while left dorsolateral (BA 8/9) prefrontal gyrus showed greater activity during induction than deduction. This pattern suggests a dissociation within prefrontal cortex for deductive and inductive reasoning.     

ERP characteristics of sentential inductive reasoning in time and frequency domains

Earlier studies have examined the issues of brain spatial localization in human sentential inductive reasoning using PET/fMRI. However, the temporal characteristics of such reasoning remain unclear. In our present study, we have used ERP (Event-related Potential) to further study human inductive reasoning involving sentential tasks. For congruent induction tasks, in which premises and conclusions are related, participants need to synthesize semantic information from the premises, conclusions, as well as background knowledge, while for incongruent induction tasks (baseline), in which premises and conclusions are unrelated, participants can respond “no” immediately. Behavioral data have been obtained that is consistent with expectations. ERPs imply that participants may integrate semantic information within the time window of 350–650 ms. Statistical analysis in the frequency domain has revealed a significant increase in the power of the gamma band (30–50 Hz) for congruent induction tasks in contrast to incongruent induction tasks.     

Majority — minority status and perceived ingroup variability revisited

Social identity theory predicts that ingroup members should see their group as more homogeneous when confronted by a large and presumably dominant outgroup. This prediction has been supported in a series of recent studies, all of which purport to show that the usual ingroup—outgroup difference in perceived variability, i.e. outgroup homogeneity, is reversed when the ingroup is in a minority position. In all of these studies, however, the ingroup—outgroup distinction has been confounded with the size of the target group judged. The present study was conducted to overcome this confound. Subjects judged both the ingroup and outgroup, under one of two different orders, and the first group judged varied in size across subjects while the size of the second group was held constant. This permitted comparisons of the perceived variability of the second judged group (be it the ingroup or outgroup) when it followed the judgment of either a larger or equal size first group. Consistent with social identity theory, ingroups were judged as less variable when judged after a large outgroup than after a small one. This was true, however, only on measures of perceived dispersion and not on measures of perceived stereotypicality. On both sorts of measures, however, overall outgroup homogeneity was found, over and above the difference due to the comparison of the ingroup with a large or small outgroup.     

Knowledge, expectations, and inductive reasoning within conceptual hierarchies

Previous research (e.g. Cognition 64 (1997) 73) suggests that the privileged level for inductive inference in a folk biological conceptual hierarchy does not correspond to the “basic” level (i.e. the level at which concepts are both informative and distinct). To further explore inductive inference within conceptual hierarchies, we examine relations between knowledge of concepts at different hierarchical levels, expectations about conceptual coherence, and inductive inference. In Experiments 1 and 2, 5- and 8-year-olds and adults listed features of living kind (Experiments 1 and 2) and artifact (Experiment 2) concepts at different hierarchical levels (e.g. plant, tree, oak, desert oak), and also rated the strength of generalizations to the same concepts. For living kinds, the level that showed a relative advantage on these two tasks differed; the greatest increase in features listed tended to occur at the life-form level (e.g. tree), whereas the greatest increase in inductive strength tended to occur at the folk-generic level (e.g. oak). Knowledge and induction also showed different developmental trajectories. For artifact concepts, the levels at which the greatest gains in knowledge and induction occurred were more varied, and corresponded more closely across tasks. In Experiment 3, adults reported beliefs about within-category similarity for concepts at different levels of animal, plant and artifact hierarchies, and rated inductive strength as before. For living kind concepts, expectations about category coherence predicted patterns of inductions; knowledge did not. For artifact concepts, both knowledge and expectations predicted patterns of induction. Results suggest that beliefs about conceptual coherence play an important role in guiding inductive inference, that this role may be largely independent of specific knowledge of concepts, and that such beliefs are especially important in reasoning about living kinds.     

Training research in aging on the fluid ability of inductive reasoning

The modifiability of older adults' performance on Induction tasks was examined through cognitive training. The posttraining performance of 52 older adults ($\text{X}\text{age = 70.3}\text{years}$) was assessed with regard to a transfer-of-training paradigm and maintenance of training effects at three posttests (one week, one month, six months). A pattern of differential training transfer across the posttest battery of fluid and crystallized intelligence measures was predicted, with the largest training effects expected for near transfer (Induction) measures. The predicted pattern of training transfer was obtained at one-week and one-month posttests, with significant training effects to the nearest Induction measure. Large retest (practice) effects across posttests also occurred for training and control groups. This research contributes to the position that modifiability of intellectual performance through cognitive intervention extends across the adult life span.