Memory

During sleep the brain replays and stabilizes what it learned during the day.

George Miller's 1956 paper suggested seven, though later research put it closer to four.

He showed that people forget new information quickly unless they review it.

Henry Molaison had parts of his hippocampus removed, and his case transformed the study of memory.

Other brain regions store memories once they have been formed.

The olfactory bulb, which processes smells, is directly connected to the amygdala (emotion) and hippocampus (memory) parts of the brain. This bypasses the thalamus, explaining why smells trigger vivid memories.

They tend to remember feelings and emotional atmospheres of past events with striking clarity, rather than just factual details. This deep emotional recall makes them incredibly empathetic but also prone to holding onto past hurts.

Memory is not a perfect recording; it's a reconstructive process. Each time you recall an event, your brain actively rebuilds it, often incorporating new information or biases, leading to vivid but inaccurate "false memories."

Olfactory memory is remarkably powerful and long-lasting, often linked to vivid emotional recall. This vast capacity allows us to distinguish a wide array of smells, from subtle perfumes to complex food aromas, influencing our perceptions daily.

Studies have shown that crows can remember specific human faces for years and even teach other crows about 'dangerous' individuals. If you treat a crow badly, it might remember you and share that information with its flock, leading to collective scolding.