Thursday night dreams: the Brazilian belief explained

The short answer

Dream interpretation is not prediction and not diagnosis. This article separates what sleep research observes from what popular interpretation associates with the theme, always saying which is which.

The idea that a dream from Thursday to Friday night comes true is a Brazilian folk belief, with no clear record of when or where it began. No study shows that dreams on that night come true more often than on any other. Sleep does not know what day it is.

What can change is your routine: the tiredness built up over the week, an after-work happy hour on Thursday, waking up differently on Friday. These changes can make a dream more vivid or easier to remember, and a dream you remember well feels more important. For the bigger question, whether dreams predict events, see I dreamed it and it happened: why it feels like premonition.

Read also: Why we forget dreams and Evening habits for better sleep.

Where this belief may have come from

There is no known document that marks the birth of this idea, and any date or author pointed to as its origin should be viewed with suspicion. What we can do is raise commonsense hypotheses, without treating them as fact.

Hypothesis 1: the weight of Friday in Christian tradition. Good Friday remembers the death of Jesus, and for a long time Friday was a day of fasting or abstaining from meat among Catholics, who are numerous in Brazil. It is possible that this symbolic weight lent the night before an air of importance. But there is no record linking the two.

Hypothesis 2: beliefs about days of the week are common. Many cultures have days considered lucky, unlucky or full of warnings, like the reputation of Friday the 13th in the West. The Thursday to Friday belief may be one more of these, passed along in family conversation.

Both hypotheses help explain why the saying sticks, but neither of them proves where it came from.

What science says about the day of the week

There is no specific study on dreams from Thursday to Friday night. What is known about sleep applies to any night: it goes through several cycles, and REM sleep, the stage most linked to vivid dreams, comes back a few times. William Dement and Edward Wolpert, in 1958, showed that people woken during this stage usually report dreams and that outside stimuli, like drops of water or sounds, can make their way into the story.

Michael Schredl and Friedrich Hofmann, in 2003, observed that dreams follow whatever fills waking life. In other words, the content of your Thursday night dream reflects your Thursday, your week, your worries. The calendar itself does not come into it.

Sources: Dement and Wolpert, Journal of Experimental Psychology, 1958; Schredl and Hofmann, Continuity between waking activities and dream activities, Consciousness and Cognition, 2003.

See also: Dream journal and Do we dream in color or in black and white?.

What really changes on Thursday night

If anything is different on that night, it is the way you live your week. Some examples:

• Built-up tiredness: after four days of work, many people sleep more heavily or later, and sleep becomes more irregular.
• Alcohol on Thursday night: alcohol tends to make sleep more restless in the second half of the night, with more awakenings and dreams that feel more intense.
• Waking up and remembering: Raphael Vallat and colleagues, in 2017, saw that people who remember more dreams have more long awakenings during the night, and they proposed that being awake for about two minutes helps store the dream in memory. A more broken night can, in this way, leave more dreams to tell.
• Paying attention: Michael Schredl, in 2002, observed that keeping a dream diary increased recall in people who remembered few or a moderate number of dreams. Those who believe the Thursday dream counts more pay more attention on Friday morning and, without realizing it, remember more.

If you wake up several times during the night, read why you wake up several times during the night.

Sources: Vallat and colleagues, Increased evoked potentials to arousing auditory stimuli during sleep, Frontiers in Human Neuroscience, 2017; Schredl, Questionnaires and diaries as research instruments in dream research, Dreaming, 2002.

Freud, Jung and faith on this night

In Freud's psychoanalysis. Freud does not talk about days of the week, but he reports that, as far back as antiquity, people separated "true" dreams, sent to warn or foretell, from vain and deceptive ones. He cites a classification attributed to Macrobius and Artemidorus that divided dreams into those that only reflect the present or the past and those that would say something about the future. The Thursday to Friday belief recalls that old wish to know which dreams "count," although there is no proven historical link between the two.

In Jung's psychology. For Jung, a dream usually compensates for what conscious life leaves aside. Read through Jung, what matters is the image and the moment of the dreamer, not the date. A striking dream on Friday may be speaking of the weight of the week that is ending.

In symbols and in faith. In the best known dream accounts in the Bible, those of Joseph in Egypt, Daniel and Joseph of Nazareth, the day of the week does not appear. Many Christians point this out to say that what matters is discernment, not the night the dream came. See dreams in the Bible.

Bringing the two readings together. Science and faith agree on one point: the calendar does not give weight to a dream. Whatever it brings deserves the same calm, whether it came on a Thursday or a Sunday.

Sources: Freud, Die Traumdeutung, 1900; Jung (ed.), Man and His Symbols; The Bible (Genesis 37, 40 and 41; Daniel 2, 4 and 7; Matthew 1 and 2).

If the Thursday night dream left you worried

• Write the dream down with the date: if it "comes true," you will be able to compare it with what you wrote, not with a memory adjusted afterward.
• Ask where it came from: think about what happened on your Thursday and what is worrying you this week.
• Do not decide anything based on the dream alone: changing plans because of one particular night tends to increase anxiety.
• Take care of your routine: less alcohol and a regular bedtime on Thursday make for calmer sleep.

If the dream was a nightmare that keeps coming back, see how to have fewer nightmares.

What the folk belief says

In Brazilian folk reading, the Thursday to Friday night dream "comes true," and that is why it is the one most often told over breakfast and in family group chats. When the dream is good, it becomes hope; when it is bad, it becomes worry. These are traditions of conversation, not predictions. See what dream meanings look like according to science and culture.