Agonistic rank,aggression, social context,and testosterone in male pigtail monkeys

Two groups of pigtail monkeys were merged, a third was formed, and individual males were introduced into a group in a series of experiments examining the effects of social context upon agonistic rank, aggressive expression, and testosterone levels. In the first experiment, two heterosexual groups, containing adult males unfamiliar to the other group, were merged. The two groups fought, and the smaller group was defeated. The alpha and beta males of the defeated group were singled out for repeated attack and both showed significant drops in circulating levels of testosterone. Both males were removed from the group during the first day, but testosterone levels did not recover to baseline levels for several days. The alpha male of the victorious group, on the other hand, showed a significant rise in testosterone, which was apparent only on the day following the merger. In order to study the influence of previous social familiarity on male reception into a group, another group was formed by removing males from the victorious group and placing them in a separate enclosure. The males in the new group established a dominance hierarchy unrelated to their previous social ranks with one another. Three months later, each of the six adult males remaining in the parent group was individually introduced into the new group for one day or less. Each of the males introduced into the new group accepted a social position at the lower end of the dominance hierarchy without regard to his previous rank relationships with the host males when they were all in the parent group. Even the alpha and beta males of the parent group were relegated to low rank positions in the new group, despite having ranked over each of the host males since birth. In contrast to the aggression directed at the unfamiliar males in the first experiment, a minimum of aggression was directed to the familiar males introduced into the new group in the second experiment. Although the males introduced accepted low social ranks, it appeared that each was readily integrated into the group with a minimum of aggressive interaction during the time he was scheduled to remain in the group. There were no significant changes in circulating levels of testosterone in any of the males during the introductions of familiar males to one another.     

A test of the interactive effects of anxiety sensitivity and mindfulness in the prediction of anxious arousal, agoraphobic cognitions, and body vigilance

The present investigation sought to examine the interactive effects of anxiety sensitivity [AS; Reiss, S., & McNally, R. J. (1985). Expectancy model of fear. In S. Reiss, & R. R. Bootzin (Eds.), Theoretical issues in behavior therapy (pp. 107-121). San Diego: Academic Press] and mindfulness [Brown, K. W., & Ryan, R. M. (2003). The benefit of being present: Mindfulness and its role in psychological well-being. Journal of Personality and Social Psychology, 84, 822-848] in predicting panic-relevant processes. A community sample of 248 individuals participated in the study by completing a battery of self-report instruments. Consistent with prediction, the interaction between AS and mindfulness significantly predicted anxious arousal symptoms and agoraphobic cognitions, above and beyond the individual main effects, and did not significantly predict anhedonic depression symptoms. Contrary to prediction, the AS by mindfulness interaction did not significantly predict body vigilance. Theoretical implications are discussed and future directions are delineated.     

Hindsight bias from 3 to 95 years of age

Upon learning the outcome to a problem, people tend to believe that they knew it all along (hindsight bias). Here, we report the first study to trace the development of hindsight bias across the life span. One hundred ninety-four participants aged 3 to 95 years completed 3 tasks designed to measure visual and verbal hindsight bias. All age groups demonstrated hindsight bias on all 3 tasks; however, preschoolers and older adults exhibited more bias than older children and younger adults. Multinomial processing tree analyses of these data revealed that preschoolers' enhanced hindsight bias resulted from them substituting the correct answer for their original answer in their recall (a qualitative error). Conversely, older adults' enhanced hindsight bias resulted from them forgetting their original answer and recalling an answer closer to, but not equal to, the correct answer (a quantitative error). We discuss these findings in relation to mechanisms of memory, perspective taking, theory of mind, and executive function.     

Photographs cause false memories for the news

What is the effect on memory when seemingly innocuous photos accompany false reports of the news? We asked people to read news headlines of world events, some of which were false. Half the headlines appeared with photographs that were tangentially related to the event; others were presented without photographs. People saw each headline only once, and indicated whether they remembered the event, knew about it, or neither. Photos led people to immediately and confidently remember false news events. Drawing on the Source Monitoring Framework (Johnson, Hashtroudi, & Lindsay, 1993), we suggest that people often relied on familiarity and other heuristic processes when making their judgments and thus experienced effects of the photos as evidence of memory for the headlines.     

Pronouncing novel graphemes: The role of consonantal context

In three experiments, we examined how readers learn and generalize new pronunciations for vowel graphemes. Children ages 6 1/2 to 9 (n = 97) and college students (n = 21) were taught a nonword that included a novel vowel pronunciation in the middle position (e.g., zuop is pronounced /zup/). They were then asked to pronounce other nonwords that contained the same vowel grapheme. Participants were more likely to use the taught pronunciation when the target item and the training item shared a consonant as well as a vowel than when they shared only the vowel. The new pronunciation was not significantly more likely to appear when the target shared the vowel and final consonant (rime) of the training stimulus than when it shared the initial consonant and vowel. We discuss implications for views of reading and its development.     

We saw it all along: visual hindsight bias in children and adults

Abstract— We traced the developmental origins and trajectory of the hindsight bias. Three-, 4-, and 5-year-old children and adults identified gradually clarifying images of degraded common objects on a computer. Half the time, observers did not know in advance what the object would become. The rest of the time, observers knew the object's identity in advance and estimated when a naive same-age peer would identify the clarifying object. In two experiments, children and adults demonstrated hindsight bias by using advance knowledge to overestimate their same-age peers' ability to identify the objects. The magnitude of this bias declined across age in one experiment, but remained relatively stable over age in the other experiment. These findings link developmental psychology and adult cognitive science.     

Susceptibility to memory distortion: how do we decide it has occurred?

When given suggestive information, some people can be led to believe that they had experiences that they did not actually have. For example, they may come to believe falsely that they got sick eating particular foods as children, and as a result of that belief they may avoid the foods. But how do we know that someone has developed a false belief or memory in this research? The criteria we choose when classifying whether someone has fallen for the suggestion are somewhat arbitrary. We reanalyze our prior data, using different criteria for deciding that a person fell for the suggestion (called a "believer") or did not (called a "non-believer"). Changing criteria obviously affects the percentage of people who are called susceptible and could conceivably affect the conclusions reached about that group. Comparisons between false memories and true memories could differ, too, depending on how memories are defined.     

Anxiety sensitivity interacts with marijuana use in the prediction of anxiety symptoms and panic-related catastrophic thinking among daily tobacco users

The present investigation evaluated whether anxiety sensitivity interacted with marijuana use in relation to the prediction of panic-relevant variables among young adult tobacco smokers (n=265). Approximately 73% of the sample was composed of current marijuana smokers, with 78.5% of this sub-sample using marijuana more than once per week. As expected, after covarying cigarettes per day, alcohol use, and negative affectivity, the interaction between marijuana use and anxiety sensitivity predicted anxiety symptoms and agoraphobic cognitions. Partially consistent with prediction, the interaction between frequency of marijuana use and anxiety sensitivity predicted only anxiety symptoms. These results are discussed in relation to better understanding the potential role of regular marijuana use and anxiety sensitivity for panic-relevant emotional vulnerability among regular tobacco smokers.     

Bootstrapping the lexicon: a computational model of infant speech segmentation

Prelinguistic infants must find a way to isolate meaningful chunks from the continuous streams of speech that they hear. BootLex, a new model which uses distributional cues to build a lexicon, demonstrates how much can be accomplished using this single source of information. This conceptually simple probabilistic algorithm achieves significant segmentation results on various kinds of language corpora - English, Japanese, and Spanish; child- and adult-directed speech, and written texts; and several variations in coding structure - and reveals which statistical characteristics of the input have an influence on segmentation performance. BootLex is then compared, quantitatively and qualitatively, with three other groups of computational models of the same infant segmentation process, paying particular attention to functional characteristics of the models and their similarity to human cognition. Commonalities and contrasts among the models are discussed, as well as their implications both for theories of the cognitive problem of segmentation itself, and for the general enterprise of computational cognitive modeling.