You can objectively measure many behaviours, e.g. how many seconds it took someone to walk down a hallway after viewing images of younger versus older adults, how many times a person presses a lever to receive a reward and how behaviours change under different reinforcement of punishment schedules, whether an intervention reduces rates of suicide, whether behaviours associated with a depressive episode change in relation to an intervention. You can measure a whole bunch of physiological reactions also, like blood pressure, skin conductivity, eye blinks, sleep cycles - all which are used as dependent variables by psychologists. And medical researchers have a whole bunch of objective physiological measures also (accepting that all measures have a sensitivity, specificity, positive and negative predictive values that are not 100).
Don’t sell us short man, psychology or medicine. We’re studying the natural world and it’s fucking hard to do. Now in terms of this study, the dependent measure is self-report which is always a bullshit measure. But, I think it shows that theory about people being more positive about groups they identify with, and what scientist doesn’t want to be seen as rational and objective. There are plenty of shitty psychology studies around, which I believe comes down to poor education about statistics and experimental design.
