How human a robot should look like

The design of a robot is not important in every scope of application. Contrary to social robots, which could be used in our home in the next few years, robots used “by example given the military, rescue teams or the law enforcement are designed with functionality as a higher priority, and thus, they do not appear very human-like and have limited means to support natural human-robot interaction.“

Importance of design for different scope of application

The same observation is made in the industrial field, where robots aren’t designed like humans. In the automotive industry, robots have long found their role and they are used for many years as a helping hand for the line workers. This is because the main goal in this field of application is to increase functionality rather than the interaction with human co-workers. This opens a discussion about the „form-versus-function issue“. At first Robots were designed to complete tasks, which go beyond the human constraints. But as time goes by they are completing a variety of chores for us, which we don’t like or get bored of like cleaning the house or cooking. For these tasks robots need to assist and interact socially. This requires a design, which is not aversing people to get in touch with robots. The study of strait is showing how humanlike a robot should look like.

Various Experiments were conducted to understand how people react to different robot designs. All of them are focussed on two different design patterns. On the one hand they can be designed machine-like oder humanoid. The Paper of Strait deals with how human a robot should look like without being described as unnerving. By focussing on humanoid aspects, they differentiate robots with low, moderate and high human similarity and humans. Hereby it can be approximated how human a robot should be and which features a robot needs to have, example given mouth, eyes, body. The goal is to increase human trust in robots so they can support humans in their every day life.

Artist Tony Matelli’s Sleepwalker installation on the Wellesley College campus in Wellesley, MA. Photo credit: Megan Strait
Artist Tony Matelli’s Sleepwalker installation on the Wellesley College campus in Wellesley, MA. Photo credit: Megan Strait

Humaness in robot design

Nowadays robots continue to become an integral part in our daily lives by being accepted not only as a tool, but rather as a interdependent teammate. The Human Robot Interaction not only depends on their possible functions, but much more on their design. Many robotics Researchers believe that robots need to get more human-like features such as facial expressions, human shape and speech capabilities. People anthropomorphize robots and treat them like they are actually human. This Trend was described by Masahiro Mori’s „uncanny Valley“ in a manner that robots or things could be disliked by their user, if they are too humanlike. One example is the sleepwalker statue of Tony Matelli. The robot, which looked like a man, “appeared to be hopelessly lost and vulnerable”. Many people got annoyed and stressed and they couldn’t stand it. The conclusion was that dressing the statue, could make it less intimidating.

The research of Megan Strait

The paper of strait had the goal to investigate, if the „Uncanny valley“ presents a realistic consideration for human-agent interactions. In the study subjects could press a button, in case they got bored or annoyed by the images they saw. The researchers also tracked the movement of their eyes and their face expressions while the subjects saw different images of robots. Therefore the analysis had three hypothesis. The first hypothesis checked, how fast people got annoyed in response to highly humanlike robots than the less humanlike (low, moderate) and humans. Contrary to the expectations, for the people there is no direct difference between the different types of designs. The second hypothesis expected that a greater human likeness might increase the interest in robots and if they look too human like, subjects get more unnerved about them. Although subjects did not react differently on the encounter with the different types of human-likeness, they reacted unnerved on the highly human-like robots and bored with the others. The last hypothesis tested, what people do if they couldn’t discard the pictures. They started to avert their gaze, but showed more attention on Robots with a face. They mostly reacted when the robot had eyes and a mouth. By adding these features, robots could show more facial expressions and more Humanlikeness. Humanoid robots are seen as the best variant for social robots and their head will be the primary place, where human-robot interaction will take place.

Design of humanoid robot heads

We have learned, that the face of a robot attracts the attention of their user and make them less eerie. Many researchers support this by focussing on the design of the head. The body doesn’t matter much by forming our opinion about robots. Robots will assist people in their lives with their daily tasks. A robots head should have three features increasing the attention and trust in robots. These are the nose, eyelids and mouth. It is important that the robot still has little of its robotness, because users don’t get to much expectations of the emotional capabilities of their agents. The face should be humanlike enough to make the user feel comfortable with their robotic interactions. The Study of Disalvo contribute several design suggestions, which create a good balance between what „we expect from a human, a machine and a product for an effective design“. The Head needs to look less humanlike and the eyes should have a wider gap between their eyelids The eyes are particularly important, because the gaze of the user concentrates on the eyes and their mouth, when they are speaking. They should have some complexity like eyeballs, iris and pupils and the mouth could have lips. Also very important is a skin covering the mechanical structure.

Robot head design with the design suggestions
Robot head design with the design suggestions


People couldn’t get close with robots on an emotional level, if they didn’t look highly human like, but too many human features lead to unnerving the people. It is a fine line between a trustable and a unnerving/eriee design. They need humanlikefeatures like a human shape or facial expressions. In different fields of application people need to team up with their not human counterparts. In the evaluation of the paper of strait, facial expression with mouth, ears and eyes got more trust in robots. Focussing on the Design of a robots head, there are several suggestions on how to design them to make robots more trustable. The film „I Robot“ shows how Robots could automatically evolve their design after generations. It shows a generation, where people trust robots in their daily lives and let them complete their household tasks. The message was that the robot is the human’s best friend and there is a robot for everybody. Taking a look on their design, there is this too humanlike face, which makes them a bit eriee, but on the other hand they look trustable.

different People – different robots

People have different kind of perception and people like different kind of designs. That depends also on their culture and how often they get in touch with technology. Eventually, the robot shouldn’t look too much like a human, because people are afraid of robots that look like humans and simultaneously perform the respective work better than them. By taking a look on the different scopes of Application, it is noticeable that the industrial sector designs robots for their functionality and that social robots, which are primarily designed to help us in our daily lives, are designed to get peoples trust. These robots have more humanlike features and make them feel like a helping teammate/friend by increasing human trust towards a robot. If we are giving robots access to our home, we need to look on one important problem. Robots, who look too human, could not get only our trust, people also could develop feelings like love. People have the habit to anthropomorphize pets, why they shouldn’t do the same thing with robots. That shows the design of a robot is important, but much more important is the empathy that a robot shows to its user. The robot must respond to the wishes of the users and they should process them.