A comparison of classical eyelid conditioning in adults and infants

In a classical conditioning procedure an eyeblink-eliciting tap to the glabella (the flat region of skin between the eyebrows) was presented 500 ms after the onset of a mild l-kHz tone. As tone-tap presentations proceeded, the probability of an eyeblink during the latter part of the tone increased in both infants (median age 8 months) and adults, but the infants were slower to condition than the adults and were more variable. Overall, the latency of the conditioned response to tone was significantly longer for infants than for adults, but the latency of the unconditioned response to tap was significantly shorter for infants than for adults.     

Cross-cultural differences in temperament: Comparing paternal ratings of US and Dutch infants

This study conducted longitudinal comparisons of US and Dutch paternal ratings of temperament, measured via the Infant Behaviour Questionnaire-Revised, at 4 months (US n = 99; Dutch n = 127) and 12 months (US n = 66; Dutch n = 112) of age. US fathers rated their infant higher in the broad temperament trait Surgency, and its subscales vocal reactivity, high-intensity pleasure, and activity level. US fathers also rated their infants higher in negative emotionality, and its subscales of sadness, distress to limitations, and fear. Dutch infants received higher ratings in falling reactivity. Though the cultures did not differ in ratings of Orienting/regulatory capacity, US infants were higher on the subscale duration of orienting, and lower in soothability. Significant culture-by-age and culture-by-gender interactions were also noted. Overall, results are largely consistent with those reported for Dutch mothers and speak to considerable differences in early temperament development between cultures viewed as largely similar because of their Western/individualistic orientations.     

Irrational choice behavior in human and nonhuman primates

Choice behavior in humans has motivated a large body of research with a focus on whether decisions can be considered to be rational. In general, humans prefer having choice, as do a number of other species that have been tested, even though having increased choice does not necessarily yield a positive outcome. Humans have been found to choose an option more often only because the opportunity to select it was diminishing, an example of a deviation from economic rationality. Here we extend this paradigm to nonhuman primates in an effort to understand the mechanisms underlying this finding. In this study, we presented two groups of laboratory monkeys, capuchins (Cebus apella) and rhesus macaques (Macaca mulatta), as well as human subjects, with a computerized task in which subjects were presented with two differently colored icons. When the subject selected an icon, differing numbers of food pellets were dispensed (or points were assigned), making each icon correspond to a certain level of risk (one icon yielded 1 or 4 pellets/points and the other yielded 2 or 3). Initially, both options remained constantly available and we established choice preference scores for each subject. Then, we assessed preference patterns once the options were not continuously available. Specifically, choosing one icon would cause the other to shrink in size on the screen and eventually disappear if never selected. Selecting it would restore it to its full size. As predicted, humans shifted their risk preferences in the diminishing options phase, choosing to click on both icons more equally in order to keep both options available. At the group level, capuchin monkeys showed this pattern as well, but there was a great deal of individual variability in both capuchins and macaques. The present work suggests that there is some degree of continuity between human and nonhuman primates in the desire to have choice simply for the sake of having choice.     

Newborn temperament and Sudden Infant Death Syndrome: A comparison of victims and their cotwins

Temperament assessed in the newborn period was compared for four twin infants who subsequently died of Sudden Infant Death Syndrome (SIDS) and their surviving cotwins. The assessment focused on irritability, resistance to soothing, reactivity, reinforcement value, activity while awake, and activity during sleep. No differences were observed between cotwins on a combined irritability rating. SIDS victims, however, were less irritable than their siblings in response to aversive stimuli. When irritable, the SIDS infants were more difficult to soothe than their cotwins. While awake, SIDS infants were less active than their cotwins, but during sleep, no activity differences were observed. The SIDS infants were more reactive to orienting stimuli, and neither group was found to be more or less rewarding to the examiner. It was concluded that this study has helped to define behavioral variables that might be characteristic of infants whose subsequent deaths are attributed to SIDS.     

The BDNFval66met polymorphism and individual differences in temperament in 4-month-old infants: A pilot study

Individual differences in infants’ temperament are under genetic control. We investigated the association between brain-derived-neurotrophic-factor (BDNF_val66met) polymorphism and temperament in 63 full-term infants. Met-carriers (N = 25) had lower Regulatory capacities compared to val-homozygotes (N = 38). These findings suggest that the BDNF polymorphism affects early temperament individual differences.     

International comparison of Cloninger’s temperament dimensions

Cloninger’s Tridimensional Personality Questionnaire (TPQ) and Temperament and Character Inventory (TCI) have been developed to measure the following temperament dimensions: novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (P). We used our previous Finnish normative study of the TPQ and TCI (Miettunen et al., 2004) to estimate correction coefficients to convert TPQ scales to comparable TCI scales. Our aim was to compare these corrected temperament dimension scores across 20 countries adjusting for study sample differences in age and gender. In all, some variations were found in these temperament scores between countries. Differences were especially apparent between the Asian and the Western countries. By far the lowest mean score of the RD was in Japan (11.2 vs. 15.4 for other countries; effect size Cohen’s d = −5.74; z-test p < 0.001) and the highest mean score in P was in USA (5.5 vs. 4.4; d = 4.24, p = 0.001). Some of the findings could be explained by sample differences (e.g. age and education); while some may reflect real differences in the ways which personality is related to cultural factors, such as individualism/collectivism. These differences should be considered when interpreting studies with data on TPQ/TCI from different countries.     

Younger apes and human children plan their moves in a maze task

Planning defined as the predetermination of a sequence of actions towards some goal is crucial for complex problem solving. To shed light on the evolution of executive functions, we investigated the ontogenetic and phylogenetic origins of planning. Therefore, we presented all four great apes species (N = 12) as well as 4- and 5-year-old human preschoolers (N = 24) with a vertical maze task. To gain a reward placed on the uppermost level of the maze, subjects had to move the reward to the bottom through open gaps situated at each level of the maze. In total, there were ten gaps located over three of the maze’s levels, and free passage through these gaps could be flexibly blocked using multiple traps. Due to the decision tree design of the maze, the subjects had to plan their actions depending on the trap configuration up to two steps ahead to successfully retrieve the reward. We found that (1) our measure of planning was negatively correlated with age in nonhuman apes, (2) younger apes as well as 5-year-old children planned their moves up to two steps ahead whereas 4-year-olds were limited to plan one step ahead, and (3) similar performance but different underlying limitations between apes and children. Namely, while all species of nonhuman apes were limited by a lack of motor control, human children exhibited a shortage in shifting their attention across a sequence of subgoals.     

A factorial study of temperament

The theory is advanced that personality factors obtained in the first order may often represent combinations of temperament traits that occur in the experimental population. Under these circumstances an investigation of the second order represents a purification process and yields factors which represent the more basic or pervasive characteristics of the original behavior items included in the factorial study. These second-order factors can be obtained directly in the first order by a careful selection of the variables which enter into the analysis. A second-order analysis was undertaken of the nine factors inherent in three of J. P. Guilford's inventories, and four clearly interpretable second-order factors were obtained. Three of these factors were obtained directly in the first order in a new factorial study of twenty-two behavior items. Attention is drawn to the similarities between these factors and traits of temperament postulated by an independent investigator.This paper abstracts portions of the writer's Ph.D. dissertation.     

Inferential reasoning by exclusion in great apes, lesser apes, and spider monkeys

Using the cups task, in which subjects are presented with limited visual or auditory information that can be used to deduce the location of a hidden reward, Call (2004) found prima facie evidence of inferential reasoning by exclusion in several great ape species. One bonobo (Pan paniscus) and two gorillas (Gorilla gorilla) appeared to make such inferences in both the visual and auditory domains. However, common chimpanzees (Pan troglodytes) were successful only in the visual domain, and Bornean orangutans (Pongo pygmaeus) in neither. The present research built on this paradigm, and Experiment 1 yielded prima facie evidence of inference by exclusion in both domains for two common chimpanzees, and in the visual domain for two Sumatran orangutans (Pongo abelii). Experiments 2 and 3 demonstrated that two specific associative learning explanations could not readily account for these results. Because an important focus of the program of research was to assess the cognitive capacities of lesser apes (family Hylobatidae), we modified Call's original procedures to better suit their attentional and dispositional characteristics. In Experiment 1, testing was also attempted with three gibbon genera (Symphalangus, Nomascus, Hylobates), but none of the subjects completed the standard task. Further testing of three siamangs (Symphalangus syndactylus) and a spider monkey (Ateles geoffroyi) using a faster method yielded prima facie evidence of inferential reasoning by exclusion in the visual domain among the siamangs (Experiment 4).     

Spatial cognition in apes and humans

The debate on whether language influences cognition is sometimes seen as a simple dichotomy: cognitive development is governed either by innate predispositions or by influences of language and culture. In two recent papers on spatial cognition, Haun and colleagues break new ground in bringing together a comparative cognition approach with a cross-linguistic framework to arrive at a third position: that humans begin with the same spatial reference frames as our near relatives, the great apes, and diverge later owing to the influence of language and culture.     

A study of temperament and personality in anorexia and bulimia nervosa

Although temperament and personality traits could influence the development and course of eating disorders, only a few studies examined the similarities and differences in personality between anorexia and bulimia nervosa. We compared 72 patients with DSM-IV eating disorders and 30 healthy controls. Dimensions of personality and personality disorders were evaluated with the Eysenck's EPQ, Cloninger's TCI, and the SCID-II questionnaires. The rates of impulsivity and clinical features were evaluated using specific rating scales. A comorbid personality disorder was found in 61.8% of patients with eating disorder. Avoidant personality disorder appeared was relatively common in anorexia nervosa restricting type; borderline personality disorder was most frequent in bulimia nervosa and the binge eating-purging type of anorexia nervosa. From a dimensional perspective, anorexic patients presented high scores in the dimension of persistence. Higher harm avoidance and impulsivity was found in bulimic patients. The overall eating disorders group presented high scores in neuroticism and low scores in self-directedness. Eating disorder patients have heterogeneous features of temperament and personality traits. Cluster C personality disorders seem more common in anorexia nervosa restricting type and impulsive personality features are associated with bulimic symptoms. Impulsivity seems to be a key aspect of temperament of bulimic patients, whereas anorexic symptoms are linked to persistent temperament traits.     

A comparison of monocular and binocular depth perception in 5- and 7-month-old infants

Monocular depth perception was compared with binocular depth perception in 5- and 7-month-old infants. Reaching was used as the dependent measure. Two objects, identical except in size, were presented simultaneously to each infant. The smaller object was within reach for the infants while the larger object was just beyond reach. The two objects subtended equal visual angles from the infants' observation point. With binocular presentation, 96% of the 7-month-olds' reaches and 89% of the 5-month-olds' reaches were for the nearer object. With monocular presentation, 58% of the 7-month-olds' reaches and 65% of the 5-month-olds' reaches were for the nearer object. The reaching preferences observed in the monocular condition indicated sensitivity to monocular depth information (motion parallax, accommodation, and relative size information were available). Binocular viewing, however, resulted in a far more consistent tendency to reach for the nearer object. This result suggests that the infants' perception of the objects' distances was more veridical in the binocular condition than in the monocular condition.     

A test of color constancy in 4-month-old human infants

Forty-five 4-month-old infants were tested for color constancy using a familiarization, paired-comparison paradigm. Infants were familiarized and tested with colored stimuli under two conditions: (1) no change in the illuminant between familiarization and test and (2) a change in the illuminant between familiarization and test. Infants correctly recognized the familiarization color when tested with no change in the illuminant. Infants tested with a change in the illuminant correctly recognized the familiar color under some conditions yet failed to do so under others. Several explanations are considered for these results and it is concluded that color constancy operates immaturely at 4 months of age.     

The influence of attachment and temperament on venipuncture distress in 14-month-old infants: the Generation R Study

Objective

This study examined the effects of attachment and temperament on infant distress during venipuncture.

Method

The study was embedded in the Generation R Study, a prospective population-based study. Two different research procedures (i.e., blood sampling and the Ainsworth Strange Situation Procedure) yielded measures of venipuncture distress and attachment security and disorganization in 246 infants aged 14 months. Four temperament traits (distress to limitations, fear, recovery from distress, and sadness) were assessed using the maternally reported Infant Behavior Questionnaire - Revised, at the age of 6 months.

Results

There were no differences between mean levels of distress during venipuncture in infants classified as having insecure attachment, but there was a trend for disorganized attachment. The temperament traits were not related to distress. However, children with a disorganized attachment and higher temperamental fear had more venipuncture distress.

Conclusion

When different risk factors are present simultaneously, infant distress is heightened.     

Some factors of temperament: A re-examination

By application of the technique presented earlier, the factors found by the Guilfords in two studies of personality factors are reanalyzed. The rotation technique for the isolation of meaningful factors relates the factors of the two studies to each other through three common items, and to other factors and traits appearing in the literature of personality measurement. For each of four of the factors resulting from the analysis of the first battery there is close agreement with its counterpart from the analysis of the second battery with respect to loadings of the three common items. These factors are interpreted as perseverance, surgency, flexibility, and tension. Other factors appearing in only one or the other of the batteries are tentatively identified.     

A comparison of depressed and nondepressed disturbed children on measures of attributional style,hopelessness, life stress,and temperament

Upon admission to a hospital treatment program, clinically depressed and nondepressed children (aged 9–17 years) were assessed on measures of attributional style, hopelessness, depression, life stress, and child temperament. The depressed group tended to attribute positive events to specific and unstable factors when compared with the nondepressed sample. Group differences also were found on child temperament measures. However, no differences were reported between the diagnostic groups on self-reported depression, hopelessness, or life stress. The findings suggested that there may not be a unique constellation of cognitive characteristics in depressed children when compared with a nondepressed clinical sample. For both depressed and nondepressed groups, treatment did appear to affect self-reported depression and overall ratings of depressogenic attributional style.