It’s easy to remember when it’s Monday or Friday: one is depressing, the other exciting! These two days of the week are clearly identified, and we rarely confuse them with other days. But what about the middle of the week? It’s a bit hazy. We’re often lost. Especially when we’re on vacation! How many times have you said to yourself: “What day is it anyway?" Researchers have recently examined the question.

Mixing up the days of the week is a common phenomenon of daily life that occurs more frequently on Tuesday, Wednesday, and Thursday. During these three days, it isn't unusual to have the feeling we’re experiencing a particular day of the week when in reality it's actually not that day at all. Is this phenomenon real? How are our emotions involved?

Psychologists at the universities of Lincoln, Hertfordshire, and York recently published a study on the subject. Three experiments were conducted in order to identify the mechanisms behind these confusions.

The first experiment lasted 2 weeks during which 1115 participants replied to a questionnaire asking them what day of the week they felt they were experiencing. The first was a “normal” workweek, the second week contained a bank holiday. During the “normal” workweek, confusions tended to occur toward the middle of the week (37.5%), while during the week with a holiday, rates of confusion were much higher (52.2%) and included Monday and Friday.

The second experiment also tested participants’ (none of whom had participated in the first experiment) reaction time in identifying the current day of the week. The results were conclusive: 612 milliseconds for Monday and 593 for Friday, compared to 1422 for Wednesday. More than twice as long! Monday and Friday (non-holidays) were thus much easier to recognize than Wednesday. This led researchers to look more closely at the emotions felt during these specific days to see if a parallel could be drawn between the perception of time and the associated mental representations.

“The main aim of this study was to characterize mental representations of weekdays by analyzing their semantic associations. Participants were asked to list associations for each weekday name in the context of a free association task,” the authors explain.

The participants had to match a series of words to different days of the week. The results showed a clear difference: certain days were associated with many words, either positive or negative, while others had far fewer associations. The negative words and expressions were mostly associated with Monday, while Friday and the weekend were seen in a much more positive light. Tuesdays, Wednesdays, and Thursdays had far fewer associations which could explain why we have trouble keeping track of these days.

The authors conclude their study by saying that “midweek days are confusable because their mental representations are sparse and similar. Mondays and Fridays are less confusable, because their mental representations are rich and distinctive. Previous studies have shown that natural temporal cycles (days, months, years) have psychological consequences. The present findings demonstrate that socially constructed temporal cycles can also shape our thinking.”