It was a humid, sticky 90 degrees when I made a quick trip to the grocery store in shorts and a tank top earlier this week. Despite the heat, however, the store clearly wanted me to think fall.

Weaving in and out of each aisle, I was inundated with row upon row of pumpkin spice M&Ms, pumpkin spice yogurt, pumpkin spice Oreos, pumpkin spice cereal, pumpkin spice beer, pumpkin spice cookies, pumpkin spice bagels, pumpkin spice Pop-Tarts, pumpkin spice popcorn, pumpkin spice hummus, pumpkin spice creamer for my pumpkin spice coffee...

At the risk of sounding any more like Forrest Gump's shrimp-obsessed friend Bubba, let's just say that we've all gone a little mad. And with the official release of everyone's favorite - the Starbucks Pumpkin Spice Latte - this past Tuesday, it's time we ask: why are we so obsessed with pumpkin spice everything?

It's only around for a limited time

Debuting only after Labor Day - and soon replaced with gingerbread and mint-chocolatey goodness by wintertime - the anticipation for pumpkin spice's annual return can be explained by a psychological theory called "reactance."

In short, reactance theory explains why we become motivated to respond to offers when we feel that our choices and alternatives are limited. The more important the choice is to us, the stronger we'll react when we know it'll soon be gone.

Marketers have known this for years. We've all seen commercials for products being offered for a "limited time only!" or felt more motivated to go shopping for new clothes when a snazzy "30% off, only good through Sunday" coupon shows up in the newspaper. We might prefer to eat regular Oreos, but knowing that pumpkin spice Oreos are only around for a few weeks makes the latter choice more appealing to us. "Get it before it's gone!"

Everyone else is doing it

When it comes to the pumpkin spice craze, there's certainly a bit of social influence at play. Sure, pumpkin spice is good, but so are chocolate, vanilla, strawberry, apple cinnamon, and caramel. But when your Instagram feed is filled with friends wielding their first Pumpkin Spice Lattes of the season, or when everyone in your 2pm coffee break group decides to go for a PSL, you're probably more likely to get one, too.

Social conformity is when we match our attitudes and behaviors to unspoken "norms" of small groups or society as a whole. The phenomenon often stems from a desire to feel secure within a group. Imagine approaching a mall food court with five restaurants. Although all five are open and willing to serve, everyone is lined up and eating at just one restaurant. Based on your perception, which place are you most likely to pick for the best food?

Of course, you aren't going to be ostracized by society if you choose peanut M&Ms over pumpkin spice at the grocery store. But when it comes to any craze - slap bracelets, Beanie Babies, the Macarena, and pumpkin spice - it makes us happy and secure to feel included with the rest of society.

It makes us feel warm and fuzzy inside

Dead leaves falling to the ground, early sunsets, and the gray chill of the impending winter months don't exactly inspire positive feelings toward autumn. But when we attach meaning to fall - the start of school, new leather boots, big cozy scarves, and holidays like Halloween and Thanksgiving - it's significantly more enjoyable.

Injecting meaning into something - in this case, a season - stimulates feelings of nostalgia when we look back in the winter, spring, and summer months. Feeling nostalgic toward something has been shown to improve our mood, make us feel more socially connected, comfort us, and make us more willing to view ourselves in a positive light.

Like hot cocoa, fuzzy sweaters, and apple picking, the pumpkin spice flavor has become synonymous with autumn. Our desire to return to the crisp fall air during a blizzard or heat wave is also accompanied, for many of us, by our nostalgic feelings toward pumpkin spice everything.

The sugar makes our brains happy

It helps that most pumpkin spice products are superbly sweet. As I've previously written, our brains are strongly wired to respond to the taste of sugar and other carbohydrates. Of course, not all products do justice to the pumpkin spice brand - like comedian John Oliver says, some truly taste like a candle might taste. (I won't mention any names.)

Now, if you'll excuse me, I'm going to go reward myself for writing this article with a Pumpkin Spice Latte. And, yes, I'll admit that I was first in line on Tuesday - despite the thermometer reading 95 degrees at the time of my purchase.

Image credit: ParentingPatch, Wikimedia Commons (sign); Joel Kramer, Flickr (Pringles); Tabercil, Wikimedia Commons (food line); idogcow, Flickr (Starbucks latte)

Post by guest blogger Lina Jamis

Chances are you've been through it before: the agony of falling in love and suffering a break-up.

Your heart bursts at the mention of their name. Every song on the radio seems to speak to you. Every mundane happening of your day serves as a sadistic reminder of things that once were.

We often speak about break-ups in terms of physical pain, but it is still not clear to what extent emotional pain reflects the biological happenings in the brain.

Is it painful? Yes. Permanent? Not so much.

So how does such a sudden loss affect the neural circuits that underlie behavior? And what does it take to get over the ‘brain-break' of a break-up?

The interruption of social ties and attachment elicit a body-wide distress response. In fact, brain regions that control responses to distress and physical pain, such as the dorsomedial thalamus and parts of the brainstem, have been shown to be particularly active in the brains of those suffering loss. These parts of the brain that control the pain response act up as if something awful is happening; from a psychological and physiological perspective, something awful often is happening.

Humans are wired for social interactions; our very health depends on making and maintaining healthy relationships. When we are close to a partner, our reward system activates, secreting powerfully rewarding neurotransmitters that make being close to our partners an immensely rewarding human experience. Furthermore, there is evidence that healthy social relationships even contribute to longer life expectancy. Given our dependence on relationships for good health, it makes sense that the pathways linked to social attachment are also responsible for physical pain. Loss is undeniably painful, and now there is physiological evidence to support this.

Several lines of evidence also suggest that the amygdala (see image, in red) is involved in feelings of separation distress, sadness, and, more generally, emotional memory. The amygdala may contribute to separation distress during acute bereavement. Other regions that may control the amygdala or modulate grief symptomatology are the dorsolateral prefrontal cortex, the rostral anterior cingulate cortex, and the dorsal anterior cingulate cortex. Differences in attention and grief-related emotion may correlate with the strength of the connections between these regulatory regions and the amygdala.

Many imaging studies suggest that activity between the amygdala and prefrontal regions of the brain regulate attention and sadness during pangs of grief. This might explain why it's so difficult to concentrate on anything during the mourning period that follows a break-up. Variations in this circuitry may even be used to distinguish between differences in grief style and indicate the individual's gender, since men seem more likely to distract, while women may be more likely to ruminate.

Going through a break up can also elicit feelings more closely related to that of addicts going through withdrawal.

When you experience feelings of love, the brain's reward system triggers the release of dopamine in the caudate nucleus and ventral tegmental areas. Furthermore, not only does this system provide pleasure at first, but over time, provides relief from distress, and can also resemble withdrawal when denied this kind of behavior or outcome.

There seems to be no advantage to the hell that a break-up. But could this post-break-up sadness be good for us in the right doses?

It well may be. When we have lost something or when a relationship ends, the individual responds with sadness, a signal that we should give up a possibly senseless goal and try to obtain a new, more manageable one.

The good news, at least, is that according to studies on neural pathways and emotion, healing from a break-up comes down to re-wiring the brain. In fact, imaging studies suggest that heart-broken brains also show high activity in the areas of frontal cortex that inhibit our impulses and redirect behavior.

So the next time you find yourself thinking about that ex-someone, don't be so hard on yourself. Your brain is doing everything it can be doing to get over it.

As it turns out, time (and neural plasticity) heal all psychological wounds.