Robert B. Zajonc’s research while affiliated with Stanford University and other places

The confluence model explains birth-order differences in intellectual performance by quantifying the changing dynamics within the family. Wichman, Rodgers, and MacCallum (2006) claimed that these differences are a between-family phenomenon--and hence are not directly related to birth order itself. The study design and analyses presented by Wichman et al. nevertheless suffer from crucial shortcomings, including their use of unfocused tests, which cause statistically significant trends to be overlooked. In addition, Wichman et al. treated birth-order effects as a linear phenomenon thereby ignoring the confluence model's prediction that these two samples may manifest opposing results based on age. This article cites between- and within-family data that demonstrate systematic birth-order effects as predicted by the confluence model. The corpus of evidence invoked here offers strong support for the assumption of the confluence model that birth-order differences in intellectual performance are primarily a within-family phenomenon.

: The theories of balance and dissonance which assume that balance, congruity, and consonance are the normal, expected, and desired state, and that it is easier to learn a balanced structure than an unbalanced one were tested on twelve volunteer college students. Six structures, three balanced and three unbalanced, were employed. Each structure involved an issue and two hypothetical men and an issue. The issues were Integration and Newsweek. These structures were arranged graphically and connected by arrows each of which constituted an item in the paired associates list. The six structures generated eighteen items. Of these items, nine required a positive response and nine a negative response. One group of subjects learned the six structures with Integration as the issue and the other group with Newsweek as the issue. An unbalanced structure was found more difficult to learn than a balanced one, but only when the issue was an important one. Negative relationships were found to be more difficult to learn than positive ones.

Beliefs about birth rank reflect what the society regards as social reality, and they may also influence that reality. Three studies found that people believe those with different birth ranks differ in their personalities, that higher birth ranks are likely to attain higher occupational prestige, and that the personality characteristics attributed to the various birth ranks favor the actual attainment of higher occupational prestige. In one example of such beliefs, firstborns were rated as most intelligent but least creative whereas the opposite was true of last-borns. The 4th study found that those with higher birth ranks in fact attain more prestigious occupations and actually do complete more years of schooling.

In the mere-repeated-exposure paradigm, an individual is repeatedly exposed to a particular stimulus object, and the researcher records the individual's emerging preference for that object. Vast literature on the mere-repeated-exposure effect shows it to be a robust phenomenon that cannot be explained by an appeal to recognition memory or perceptual fluency. The effect has been demonstrated across cultures, species, and diverse stimulus domains. It has been obtained even when the stimuli exposed are not accessible to the participants’ awareness, and even prenatally. The repeated-exposure paradigm can be regarded as a form of classical conditioning if we assume that the absence of aversive events constitutes the unconditioned stimulus. Empirical research shows that a benign experience of repetition can in and of itself enhance positive affect, and that such affect can become attached not only to stimuli that have been exposed but also to similar stimuli that have not been previously exposed, and to totally distinct stimuli as well. Implications for affect as a fundamental and independent process are discussed in the light of neuroanatomical evidence.

The mere repeated exposure paradigm involves repeated exposures of a particular stimulus object and observes the emerging preference for that object. It is claimed here that the resulting preferences are direct and unmediated. Vast literature on the mere repeated exposure effects shows it to be a robust phenomenon that cannot be explained by an appeal to recognition memory or perceptual fluency. These effects are valid across cultures, species, and diverse stimulus domains. They have been obtained even when the stimuli exposed were not accessible to the participants' awareness, even prenatally. The mere repeated exposure paradigm can be regarded as a form of classical conditioning if we assume that the absence of aversive events constitutes the unconditioned stimulus. Empirical research shows that a benign repetition experience can in and of itself enhance positive affect, and that such affect can become attached not only to stimuli exposed but to similar but previously not exposed sti...

Birth order effects on intellectual performance show both positive and negative results. The confluence model reconciles these conflicting data by proving that these effects interact with the age of participants at testing, such that young children should show negative or no effects, whereas older individuals (past age 11 +/- 2 years) should show positive effects. Birth order studies strongly support this prediction. Some writers have claimed the apparent relation between birth order and intelligence is an artifact created by applying a cross-sectional analysis to data that should have been analyzed by comparing siblings within families. However, if siblings within the same family are compared all at the same time, their ages are necessarily different. As a result, birth order effects are confounded with age effects. Moreover, within-family data conceal patterns of aggregate effects that cross-sectional data reveal.