We humans are a judgemental lot. We make spontaneous personality trait inferences based on the behaviour of others almost every day. Think about that person that you saw throw rubbish out their car window – you probably immediately thought of that person as selfish or inconsiderate. These first impressions may not always be accurate, but they are thought to serve a survival purpose (ie, identifying potential aggressors, aka bad people). What is interesting is that this personality impression formation is not always overt. We often unintentionally form an impression of someone and this occurs with minimal cognitive effort. In fact, this is considered to be an implicit (vs declarative) process.
On another note, many studies have shown that a stressful situation, occurring shortly after learning, facilitates memory consolidation.[1] What is unknown, however, is how stress influences socially relevant learning. Thus the authors of the present study[2] (available here for free – check it out!) aimed to investigate whether post-learning stress influences this form of implicit impression formation.
This study was pretty full on, but here’s the main gist of things: First, participants performed an impression formation task. In this task they were given portraits of people and a description of a behavioural episode (for that person) which implied a certain personality trait. For example: “I went to the grocery store and was given too much change. I went back to the store and gave back the overpayment.” This would most likely describe a positive personality trait of honesty. So anyways, all the participants were given a bunch of portraits with a variety of negative, positive, and neutral behavioural descriptions. Participants were then randomised to either a stress condition (sticking the hand in freezing cold water + having someone watch and record facial expressions) vs a control condition (hand in nice warm water, nobody staring intently at your face – much more enjoyable I reckon).
Then the following morning participants completed a learning task – they were given portraits of people again, but this time only the trait adjective (ie, no description of behaviour, just given the trait adjective, ‘honest’). Of these portrait-trait adjective pairs some were oldies (ie, the same portraits + implied trait adjective they saw the day before) and some were newies (ie, participant had never seen them before). Then to test participant’s recall, the same portraits given earlier that morning were presented and participants were asked to recall the trait adjective associated with that portrait. The authors hypothesised that the participants who underwent stress following the impression formation task would have better recall for the oldies (ie, stress consolidating their first impressions from day 1) than the newies on the recall task.
What they found was quite intriguing. Those in the stress group had significantly higher learning performance for positive trait adjective oldies versus positive newies (no difference for the control group). However, for negative trait adjectives, it was opposite: participants in the stress group had no difference in learning performance for the negative oldies vs negative newies while the control group had a higher learning performance for the negative oldies compared to the negatives newies.
This suggests that indeed post-learning stress modulates memory consolidation for earlier brief personality impressions. What is fascinating is that stress selectively improves memory recall for positive personality trait impressions. The authors suggest that from a survival point of view it may be more cost-beneficial to remember a single helper (ie, positive personality impression) versus all the potential enemies/aggressors necessary to avoid (ie, negative personality impression). This makes sense but to me it doesn’t answer why those undergoing the control situation (ie, no stress) would selectively recall negative personality trait impressions. Perhaps when we are not at risk (ie, not stressed), we are less tentative and decide to focus on the potential aggressors. But why?? So at the end of the day, here’s hoping I meet new people when I’m stressed! Interested to hear other’s thoughts!
About Tasha
Tasha Stanton is a postdoctoral research fellow working with the Body in Mind Research Group both in Adelaide (at University of South Australia) and in Sydney (at Neuroscience Research Australia). Tash has done a bit of hopping around in her career, from studying physio in her undergrad, to spinal biomechanics in her Master’s, to clinical epidemiology in her PhD, and now to clinical neuroscience in her postdoc. Amazingly, there has been a common thread through all this hopping and that common thread is pain. What is pain? Why do we have it? And why doesn’t it go away? Tasha got herself one of the very competitive Canadian IHR post-doctoral fellowships and is establishing her own line of very interesting investigations. Her research interests lie in understanding the neuroscience behind pain and its clinical implications. She also really likes nifty experiments that may have no clinical value yet, but whose coolness factor tops the charts. Last, Tash is a bit mad about running, enjoying a good red with friends and organizing theme parties. Tasha, aka Stanton Deliver, was the all round best performer at the Inaugural BiM Table Tennis Comp.
Here is Tasha talking more about what she does and a link to her published research.
We have put BiM author’s downloadable PDFs here.
References
[1] Roozendaal B (2002). Stress and memory: opposing effects of glucocorticoids on memory consolidation and memory retrieval. Neurobiology of learning and memory, 78 (3), 578-95 PMID: 12559837
[2] Lass-Hennemann J, Kuehl LK, Schulz A, Oitzl MS, Schachinger H. Stress strengthens memory of first impressions of others’ positive personality traits. PLoS ONE 2011; 6: e16389. doi: 10.1371/journal.pone.0016389