Ready-to-hand

Update your Facebook status: social comparison and the availability heuristic

Over at Captology Notebook, the blog of the Stanford Persuasive Technology Lab, Enrique Allen considers features of Facebook that influence users to update their status. Among other things, he highlights how Facebook lowers barriers to updating by giving users a clear sense of something they can right (”What are you doing right now?”).

I’d like to add another part of the interface for consideration: the box in the left box of the home page that shows your current status update with the most recent updates of your friends.

This visual association of my status and the most recent status updates of my friends seems to do at least a couple things:

Influencing the frequency of updates. In this example, my status was updated a few days ago. On the other hand, the status updates from my friends were each updated under an hour ago. This juxtaposes my stale status with the fresh updates of my peers. This can prompt comparison between their frequency of updates and mine, encouraging me to update.

The choice of the most recent updates by my Facebook friends amplifies this effect. Through automatic application of the availability heuristic, this can make me overestimate how recently my friends have updated their status (and thus the frequency of status updates). For example, the Facebook friend who updated their status three minutes ago might have not updated to three weeks prior. Or many of my Facebook friends may not frequently update their status messages, but I only see (and thus have most available to mind) the most recent. This is social influence through enabling and encouraging biased social comparison with — in a sense — an imagined group of peers modeled on those with the most recent performances of the target behavior (i.e., updating status).

Influencing the content of updates. In his original post, Enrique mentions how Facebook ensures that users have the ability to update their status by giving them a question that they can answer. Similarly, this box also gives users examples from their peers to draw on.

Of course, this can all run up against trouble. If I have few Facebook friends, none of them update their status much, or those who do update their status are not well liked by me, this comparison may fail to achieve increased updates.

Consider this interface in comparison to one that either

• showed recent status updates by your closest Facebook friends, or
• showed recent status updates and the associated average period for updates of your Facebook friends that most frequently update their status.

[Update: While the screenshot above is from the "new version" of Facebook, since I captured it they have apparently removed other people's updates from this box on the home page, as Sasha pointed out in the comments. I'm not sure why they would do this, but here are couple ideas:

• make lower items in this sidebar (right column) more visable on the home page -- including the ad there
• emphasize the filter buttons at the top of the news feed (left column) as the means to seeing status updates.

Given the analysis in the original post, we can consider whether this change is worth it: does this decrease status updates? I wonder if Facebook did a A-B test of this: my money would be on this significantly reducing status updates from the home page, especially from users with friends who do update their status.]

6 comments July 29th, 2008

Reprioritizing human intelligence tasks for low latency and high throughput on Mechanical Turk

Amazon Mechanical Turk is a platform and market for human intelligence tasks (HITs) that are submitted by requesters and completed by workers (or “turkers”).  Each HIT is associated with a payment, often a few cents. This post covers some basics of Mechanical Turk and shows its lack of designed-in support for dynamic reprioritization is problematic for some uses. I also mention some other factors that influence latency and throughput.

With mTurk one can create a HIT that asks someone to rate some search results for a query, evaluate the credibility of a Wikipedia article, draw a sheep facing left, enter names for a provided color, annotate a photo of a person with pose information, or create a storyboard illustrating a new product idea. So Mechanical Turk can be used in many ways for basic research, building a training set for machine learning, or actually enabling a (perhaps prototype) service in use through a kind of Wizard-of-Oz approach. Additionally, I’ve used mTurk to code images captured by participants in a lab experiment (more on this in another post or article).

When creating HITs, a requester can specify a QuestionForm (QF) (e.g., via command line tools or an SDK) that is then presented to the worker by Amazon. This can include images, free text answers, multiple choice, etc. Additionally one can embed Flash or Java objects in it. But the easiest way of creating HITs is to use a QF and not create a Java or Flash application of one’s own. This is especially true for HITs that are handled well by the basic question form. The other option is to create an ExternalQuestion (EQ), which is hosted on one’s own server and is displayed in an iFrame. This provides greater freedom but requires additional development and it is you that host the page (though you can do so through Amazon’s S3). QF HITs (without embeds) also offer a familiar interface to workers (though it is possible to create a more efficient, custom interface by e.g. making all the targets larger). So when possible, it is often preferable to use a QF rather than an EQ.

For some of the uses of mTurk for powering a service, it can be important to minimize latency for specific HITs¹, including prioritizing particular new HITs over previously created HITs. For example, after some HIT has not been completed for a specific period after creation, it may still be important to complete it, but when it is completed may become less important. This can happen easily if there the value of a HIT being completed has a sharp drop off after some time.

This should be done while maintaining high throughput; that is, you don’t want to reduce the rate at which your HITs are completed. When there are more HITs of the same type, workers can check a box to immediately start the next HIT of the same type when they submit the current one (see screenshot). Workers will often complete many HITs of the same type in a row. So throughput can drop substantially if any workers run out of HITs of the same type at any point: they may switch to another HIT type, or if they do your HITs once more appear there will be a delay. As we’ll see, these two requirements don’t seem to be well met by the platform — or at least certain uses of it.

Mechanical Turk does not provide a mechanism for prioritizing HITs of the same type, so without deleting all but particular high-priority HITs of that type, there is not a way to ensure that some particular HIT gets done before the rest. And deleting the other HITs would hurt throughput and increase latency for any new high-priority HITs added int he near future (since workers won’t simply start these once they finish their previous HITs).

EQs allow one to avoid this problem. Unlike with QF HITs (without Flash and Java embeds), one does not have to specify the full content of the HIT in advance. When a worker accepts an EQ HIT, you can dynamically serve up the HIT you want to depending on changing priorities. But this means that you can’t take advantage of e.g. the simplicity of creating and managing data from QF HITs. So though there are ways of coping, adding dynamic reprioritization to Mechanical Turk would be a boon for time-sensitive uses.

There are, of course, other factors that influence latency and throughput on mTurk when (EQ) HITs are reprioritized. Here are a few:

• HIT and sub-tasks duration. How long does it take for workers to complete a HIT, which may be composed of multiple sub-tasks? A worker cannot be assigned a new HIT until they complete (or reject) the previous one. This can be somewhat avoided by creating longer HITs that are subdivided into dynamically selected sub-tasks. This can be done with an EQ HIT or an embedded Flash or Java application in a QF HIT. But the sub-task duration is always a limiting factor, unless one is willing to force abortion of the current sub-task, replacing it will still in progress (with an EQ, Flash, or Java).
• Available workers. How many workers are logged into mTurk and completing task? How many are currently switching HIT types? This can vary with the time of day.
• Appeal of your HITs. How much do workers like your HITs — are they fun? How much do you pay for how much you ask? How many of their completed assignments do you approve?
• Reliability. How accurate or precise must your results be? How many workers do you need to complete a HIT before you have reliable results? Do other workers need to complete meta-HITs before the data can be used?

1. I use the term HIT somewhat loosely in this article. There are at least three uses that each differ in their identity conditions. (1) There are HITs considered as human intelligence tasks, and thus divided as we divide tasks; this means that a HIT in another sense can be composed of multiple HITs in this sense (tasks or sub-tasks). (2) There are HITs in Amazon’s technical sense of the term: a HIT is something that has the same HIT ID and therefore has the same specification. In QF HITs without embeds, this means all instances (assignments) of a HIT are the same in content; but in EQ HIT this is not necessarily true, since the content can be determined when assigned. (3) Finally, there is what Amazon calls assignments, specific instances of a HITs that are only completed once. [↩]

2 comments July 24th, 2008

Naming this blog: Heidegger, Husserl, folk psychology, and HCI

The name of this blog, Ready-to-hand, is a translation of Heidegger’s term zuhanden, though interpreting Heidegger’s philosophy is not specifically a major interest of mine nor a focus here. Much has been made of the significance of phenomenology, most often Heidegger, for human-computer interaction (HCI) and interaction design (e.g., Winograd & Flores 1985, Dourish 2001). And I am generally pretty sympathetic to phenomenology as one inspiration for HCI research. I want to just note a bit about the term zuhanden and my choice of it in a larger context — of phenomenology, HCI, and a current research interest of mine: cues for assuming the intentional stance toward systems (more on this below).

The Lifeworld and ready-to-hand
Heidegger was a student of Edmund Husserl, and Heidegger’s Being and Time was to be dedicated to Husserl.¹ There is really no question of the huge influence of Husserl on Heidegger.

My major introduction to both Husserl and Heidegger was from Prof. Dagfinn Føllesdal. Føllesdal (1979) details the relationship between their philosophies. He argues for the value of seeing much of Heidegger’s philosophy “as a translation of Husserl’s”:

The key to this puzzle, and also, I think, the key to understanding what goes on in Heidegger’s philosophy, is that Heidegger’s philosophy is basically isomorphic to that of Husserl. Where Husserl speaks of the ego, Heidegger speaks of Dasein, where Husserl speaks of the noema, Heidegger speaks of the structure of Dasein’s Being-in-the-world and so on. Husserl also observed this. Several places in his copy of Being and Time Husserl wrote in the margin that Heidegger was just translating Husserl’s phenomenology into another terminology. Thus, for example, on page 13 Husserl wrote: “Heidegger transposes or transforms the constitutive phenomenological clarification of all realms of entities and universals, the total region World into the anthropological. The problematic is translation, to the ego corresponds Dasein etc. Thereby everything becomes deep-soundingly unclear, and philosophically it loses its value.” Similarly, on page 62, Husserl remarks: “What is said here is my own theory, but without a deeper justification.” (p. 369)

Heidegger and his terms have certainly been more popular and in wider use since then.

Føllesdal also highlights where the two philosophers diverge.² In particular, Heidegger gives a central role to the role of the body and action in constituting the world. While in his publications Husserl stuck to a focus on how perception constitutes the Lifeworld, Heidegger uses many examples from action.³ Our action in the world, including our skillfulness in action constitutes those objects we interact with for us.

Heidegger contrasts two modes of being (in addition to our own mode — being-in-the-world): present-at-hand and ready-to-hand (or alternatively, the occurant and the available (Dreyfus 1990)). The former is the mode of being consideration of an object as a physical thing present to us — or occurant, and Heidegger argues it constitutes the narrow focus of previous philosophical explorations of being. The latter is the stuff of every skilled action — available for action: the object becomes equipment, which can often be transparent in action, such that it becomes an extension of our body.

J.J. Gibson expresses this view in his proposal of an ecological psychology (in which perception and action are closely linked):

When in use, a tool is a sort of extension of the hand, almost an attachment to it or a part of the user’s own body, and thus is no longer a part of the environment of the user. [...] This capacity to attach something to the body suggests that the boundary between the animal and the environment is not fixed at the surface of the skin but can shift. More generally it suggests that the absolute duality of “objective” and “subjective” is false. When we consider the affordances of things, we escape this philosophical dichotomy. (1979, p. 41)

While there may be troubles ahead for this view, I think the passage captures well something we all can understand: when we use scissors, we feel the paper cutting; and when a blind person uses a cane to feel in front of them, they can directly perceive the layout of the surface in front of them.

Transparency, abstraction, opacity, intentionality
Research and design in HCI has sought at times to achieve this transparency, sometimes by drawing on our rich knowledge of and skill with the ordinary physical and social world. Metaphor in HCI (e.g., the desktop metaphor) can be seen as one widespread attempt at this (cf. Blackwell 2006). This kind of transparency does not throw abstraction out of the picture. Rather the two go hand-in-hand: the specific physical properties of the present-at-hand are abstracted away, with quickly perceived affordances for action in their place.

But other kinds of abstraction are in play in HCI as well. Interactive technologies can function as social actors and agents– with particular cues eliciting social responses that are normally applied to other people (Nass and Moon 2000, Fogg 2002). One kind of social response, not yet as widely considered in the HCI literature, is assuming the intentional stance — explanation in terms of beliefs, desires, hopes, fears, etc. — towards the system. This is a powerful, flexible, and easy predictive and explanatory strategy often also called folk psychology (Dennett 1987), which may be a tacit theory or a means of simulating other minds. We can explain other people based on what they believe and desire.

But we can also do the same for other things. To use one of Dennett’s classic examples, we can do the same for a thermostat: why did it turn the heat on? It wanted to keep the house at some level of warmth, it believed that it was becoming colder than desired, and it believed that it could make it warmer by turning on the heat. While in the case of the thermostat, this strategy doesn’t hide much complexity (we could explain it with other strategies without much trouble), it can be hugely useful when the system in question is complex or otherwise opaque to other kinds of description (e.g., it is a black box).

We might think then that perceived complexity and opacity should both be cues for adopting the intentional stance. But if the previous research on social responses to computers (not to mention the broader literature on heuristics and mindlessness) has taught us anything, it is that made objects such as computers can evoke unexpected responses through other simplier cues. Some big remaining questions that I hope to take up in future posts and research:

• What are these cues, both features of the system and situational factors?
• How can designers influence people to interpret and explain systems using folk psychology?
• What are the advantages and disadvantages of evoking the intentional stance in users?
• How should we measure the use of the intentional stance?
• How is assuming the intentional stance towards a thing different (or the same) as it having being-in-the-world as its mode of being?

1. But Husserl was Jewish, and Heidegger was himself a member of the Nazi party, so this did not happen in the first printing. [↩]
2. Dreyfus (1990) is an alternative view that takes the divergence as quite radical; he sees Føllesdal as hugely underestimating the originality of Heidegger’s thought. Instead Dreyfus characterizes Husserl as formulating so clearly the Cartesian worldview that Heidegger recognized its failings and was thus able to radically and successfully critique it. [↩]
3. It is worth noting that Husserl actually wrote about this as well, but in manuscripts, which Heidegger read years before writing Being and Time. [↩]

2 comments July 23rd, 2008