Epstein (1983) studied college students with the aim of showing the importance of the time frame in which the behaviour is assessed in the trait theory, thus supporting the trait theory in the condition that an appropriate time frame is adopted. For the method a correlational study was used. A correlational study is used to look for relationships between variables; it is a non-experimental method, as the independent variables are not manipulated. Epstein’s study was a naturalistic observation, involving observing and recording the variables of interest in the natural environment without interference or manipulation by the experimenter. The sample consisted of college students recruited using convenience sampling: a group of participants were not randomly selected from the target population, but used in the study because they were easily contactable. A possible relationship between the variables of behavioural variability and the time period in which the behaviour occurred was measured. The procedure included recording the behaviour of college students during a time period of almost a month. After, the consistency of behaviour whilst comparing 1-day intervals and 2-week intervals, was analysed. The results of this study showed that how the participants behaved in a particular situation on one day could not predict their behaviour in similar circumstances on another day. However, when the participants’ behaviour was aggregated over a two-week interval it was highly predictive of their behaviour in similar circumstances over another two-week period. The implications of this study support the existence of traits provided the appropriate time perspective is adopted. The advantage of a naturalistic observation is that it gives the experimenter the opportunity to view the variable of interest in a natural setting, disadvantages include that this type of a study does not allow for scientific control of variables and the experimenters cannot control extraneous variables. The major drawback of the opportunity (convenience) sampling method is that there may be differences between the group that is easy to contact and the other members of the target population. The results of Epstein’s (1983) study have been replicated (e.g. Moskowitz, 1986) increasing their dependability. As it is impossible to remove all ambiguity from this type of research process, it is important to instead consider the breath and depth of information gathered and how well the research appears to have analysed it. The credibility of the researcher’s conclusions can be judged if the researcher has given very detailed description of context and methods and has acknowledged potential sources of bias. The sources of bias in Epstein’s study could have been the situational factors (e.g. participant’s health and mood).
Another theory, which aims to explain behaviour in terms of dispositions is the five-factor model of personality (FFM, McCrae and Costa, 1999). An impressive number of studies have supported that personality can be captured by someone’s position on the scales of five measureable personality factors or traits represented in the table below.
The FFM offers the basis of valid predictions both in research settings and in everyday life settings. Ozer and Benet-Martinez (2006) have reported that personality, as captured by the FFM, relates to several real-life outcomes, thus being high in ecological validity. Therefore, dispositions in the form of personality factors emerge as significant determinants of behaviour and should be taken into account when trying to explain behaviour.
The claim is not that personality is in general the most important determinant of behaviour, much less that we can predict with great accuracy how a particular individual will behave in a specific situation. On the contrary, the associations are almost always modest enough to allow for significant situational influences.
Two most famous social psychology experiments dealing with the importance of situational factors in explaining behaviour are Milgram’s studies of obedience to authority (Milgram, 1974) and Asch’s studies of conformity (Asch, 1951, 1956).
The aim of Milgram’s experiment was to find out whether the participants would obey an authority figure (the experimenter) to administer a series of increasingly severe, and eventually potentially lethal, electric shocks to an innocent learner, thus demonstrating the importance of situational factors in explaining behaviour. This study was a laboratory experiment meaning that it was conducted in a controlled setting and the variables were strictly controlled by the experimenter. As the participants were volunteers, responding to a newspaper advertisement, a self-selecting sampling technique was used. The sample was also purposive, as only men were used in the experiment. Purposive sample means that participants, who are considered to offer the most appropriate information for the study, are invited to participate. This study used the within-subjects design because there was only one experimental condition and all participants received the same level of the independent variable. The independent variable was the instruction given by the experimenter. The dependent variable was the level of the participants’ obedience to punish the learners with electric shocks if they made a mistake. The procedure included the participants being acquainted with the other participant who was actually a confederate of the experimenter. They were then told that they have to carry out a memory task where the actual participant was to teach the confederate a list of word pairs and administer him electric shocks increasing in voltage if they made a mistake. The confederate was led to another room and the actual participant was let to observe how he was being attached to some wires that were explained to give electric shocks to the confederate if the real participant would punish them for making a mistake. The confederate did not actually receive any genuine shocks, but behaved as if he did in order to deceive the real participant. The participant and the confederate then carried out the memory task. Each time the real participant doubted about continuing the task of administering electric shocks, the experimenter commanded them to carry on. The results showed that during the first of Milgram’s studies a disturbing 65% of the participants obeyed throughout the experiment and administered the maximum punishment of 450 volts. This implicates that situational factors play an extensively influential role in explaining behaviour. The criticism of the study is the following: Laboratory experiments increase internal validity. If the internal validity is high, the conclusions made are a correct interpretation, and the variables defined are accurately and appropriately manipulated and measured in a representative sample. The sample was not representative of the whole population as it consisted of men only. Nevertheless, it should be noted that Milgram later carried out the same experiment with women only and he obtained very similar results. Reliability refers to the consistency of a measure. An experimental design is considered reliable if we get the same results repeatedly. Milgram carried out a series of 21 experiments to investigate the extent to which participants, in the role of the teacher, would obey an authority figure to administer potentially lethal electric shocks to an innocent learner, thus increasing the reliability of his experiments. It is still very unethical as during the experiment the participants were told that they could not discontinue, even though the subjects have the right to withdraw from any experiment at any moment.
Milgram never denied the importance of dispositional determinants on obedience, he claimed that he had not managed to identify them in his research. It has been shown that individuals high on authoritarianism, for example, are more likely to obey in Milgram’s experiment than those low on this personality dimension. It has even been argued that all the situational explanations used to account for Milgram’s findings can easily be turned into dispositional explanations. Unless somebody has the disposition to obey, no obedience will occur. What happened in Milgram’s experiment, from this point of view, was that the disposition to obey, cooperate with, or be liked by the experimenter, proved stronger than rival dispositions to be compassionate towards the victim or act according to one’s conscience. The results can also be viewed in terms of what Mischel identified as a strong situation. According to him strong situations are powerful enough to suppress individual differences. Weak situations allow for more personality influences on behaviour.
In Asch’s (1951, 1956) study, the participants had to estimate the lengths of lines in comparison to three options in a room with other participants who were actually the confederates of the experimenter and gave wrong answers to see if the real participant would conform. Asch’s results showed that many of the participants conformed and explained it with trying “to avoid criticism and social disapproval.” These experiments portray that situational factors play at least as important of a role in determining behaviour as dispositional factors do.
Bandura’s social-cognitive perspective on personality emphasizes the interaction of traits and situations. Bandura (1986, 2006) views the person-environment relationship in terms of reciprocal determinism, which suggests that personality and environment interact in several ways that often determine each other. In this sense, we are both influenced by and design the environments we inhabit.
Most psychologists nowadays espouse some form or other of interactionism and accept that dispositions and situations co-determine behavior. Our task is not to ignore one and focus on the other, but to appreciate and understand the interplay between the two.