When quantity trumps number: discrimination experiments in cotton-top tamarins (<Emphasis Type="Italic">Saguinus oedipus</Emphasis>) and common marmosets (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>)

The capacity for non-linguistic, numerical discrimination has been well characterized in non-human animals, with recent studies providing careful controls for non-numerical confounds such as continuous extent, density, and quantity. More poorly understood are the conditions under which animals use numerical versus non-numerical quantification, and the nature of the relation between these two systems. Here we test whether cotton-top tamarins and common marmosets can discriminate between two quantities on the basis of the amount of food rather than on number. In three experiments, we show that when choosing between arrays containing different numbers and sizes of food objects, both species based their decisions on the amount of food with only minor influences of numerical information. Further, we find that subjects successfully discriminated between two quantities differing by a 2:3 or greater ratio, which is consistent with the ratio limits found for numerical discrimination with this species. These studies demonstrate that non-human primates possess mechanisms that enable quantification of total amount, in addition to the numerical representations demonstrated in previous studies, with both types of quantification subject to similar processing limits.     

Trait expectancies and stereotype expectancies have the same effect on person memory

Two studies examined whether trait expectancies and stereotype expectancies similarly affected memory for expectancy-relevant behaviors. The results of both studies showed that, when activated in identical ways, trait expectancies and stereotype expectancies had similar effects on recall. Better recall was obtained for expectancy-incongruent items when expectancies were activated in relatively overt ways, while better recall for expectancy-congruent items was obtained when expectancies were activated in less overt ways. Additional analyses examining the order of events that emerged in the recall protocols provided little evidence that participants attempted to reconcile the items, as would be predicted by some earlier models of person memory (e.g., Srull, 1981). The implications of these findings for how social expectancies guide social information processing are discussed.     

Subjective impact, meaning making, and current and recalled emotions for self-defining memories

Two studies examined the impact of self-defining events on individuals (i.e., subjective impact), meaning making with regard to these events, and how subjective impact may account for the pattern of current and recalled emotions for these self-defining memories (Singer & Moffitt, 1991-1992). In Study 1, participants recalled self-defining memories, indicating how much impact the recalled events have had on them and described meaning making for these events. Subjective impact was shown to be a good marker for meaning making. Participants in Study 2 each recalled five self-defining memories, reporting their current emotions about the events, the emotions they recalled feeling at the time, and the impact the events have had on them. As expected, for negative memories, people reported less negative emotion (e.g., sadness) and more positive emotion (e.g., pride) compared to how they recalled feeling at the time. For positive memories, people reported equally intense positive emotion (e.g., love) and less negative emotion (e.g., fear) compared to how they recalled feeling at the time. These patterns of current and recalled emotions were accounted for by impact ratings.     

Chronometric studies of numerical cognition in five-month-old infants

Developmental research suggests that some of the mechanisms that underlie numerical cognition are present and functional in human infancy. To investigate these mechanisms and their developmental course, psychologists have turned to behavioral and electrophysiological methods using briefly presented displays. These methods, however, depend on the assumption that young infants can extract numerical information rapidly. Here we test this assumption and begin to investigate the speed of numerical processing in five-month-old infants. Infants successfully discriminated between arrays of 4 vs. 8 dots on the basis of number when a new array appeared every 2 s, but not when a new array appeared every 1.0 or 1.5 s. These results suggest alternative interpretations of past findings, provide constraints on the design of future experiments, and introduce a new method for probing infants' enumeration process. Further experiments using this method provide initial evidence that infants' enumeration mechanism operates in parallel and yields increasingly accurate numerical representations over time, as does the enumeration mechanism used by adults in symbolic and non-symbolic tasks.     

Cognitive dissonance in groups: the consequences of disagreement

As L. Festinger (1957) argued, the social group is a source of cognitive dissonance as well as a vehicle for reducing it. That is, disagreement from others in a group generates dissonance, and subsequent movement toward group consensus reduces this negative tension. The authors conducted 3 studies to demonstrate group-induced dissonance. In the first, students in a group with others who ostensibly disagreed with them experienced greater dissonance discomfort than those in a group with others who agreed. Study 2 demonstrated that standard moderators of dissonance in past research--lack of choice and opportunity to self-affirm, similarly reduced dissonance discomfort generated by group disagreement. In Study 3, the dissonance induced by group disagreement was reduced through a variety of interpersonal strategies to achieve consensus, including persuading others, changing one's own position, and joining an attitudinally congenial group.     

Changing circumstances, disrupting habits

The present research investigated the mechanisms guiding habitual behavior, specifically, the stimulus cues that trigger habit performance. When usual contexts for performance change, habits cannot be cued by recurring stimuli, and performance should be disrupted. Thus, the exercising, newspaper reading, and TV watching habits of students transferring to a new university were found to survive the transfer only when aspects of the performance context did not change (e.g., participants continued to read the paper with others). In some cases, the disruption in habits also placed behavior under intentional control so that participants acted on their current intentions. Changes in circumstances also affected the favorability of intentions, but changes in intentions alone could not explain the disruption of habits. Furthermore, regardless of whether contexts changed, nonhabitual behavior was guided by intentions.     

A cross-cultural analysis of the behavior of women and men: implications for the origins of sex differences

This article evaluates theories of the origins of sex differences in human behavior. It reviews the cross-cultural evidence on the behavior of women and men in nonindustrial societies, especially the activities that contribute to the sex-typed division of labor and patriarchy. To explain the cross-cultural findings, the authors consider social constructionism, evolutionary psychology, and their own biosocial theory. Supporting the biosocial analysis, sex differences derive from the interaction between the physical specialization of the sexes, especially female reproductive capacity, and the economic and social structural aspects of societies. This biosocial approach treats the psychological attributes of women and men as emergent given the evolved characteristics of the sexes, their developmental experiences, and their situated activity in society.     

Assessing future possible selves by gender and socioeconomic status using the anticipated life history measure

This is a report from the first phase of a longitudinal study of the ways young adults imagine their future lives. The future possible selves of 223 18- and 19-year-old adults were examined using the Anticipated Life History measure (ALH), a psychological instrument prompting participants to describe their future life course from their 21st birthday until their death. When the ALH narratives were coded for presence/absence of life events, female participants were more likely to predict career choice, marriage, children, divorce, and death of spouse than their male counterparts; when coded for psychological qualities, female participants demonstrated greater psychological complexity and awareness of future life role choices and conflicts. Participants with lower SES wrote ALH narratives with fewer altruistic acts, less awareness of life role complexity, and fewer anticipated conflicts and their resolutions than those with higher SES.